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2009-01-21T01:12:00.001-08:00

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Interesting Article from MDLinx

2008-11-30T06:02:00.000-08:00

srktouched@yahoo.co.in has forwarded you an article from gilinx, part of the MDLinx network

Article Summary

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Capecitabine and radiotherapy as neoadjuvant treatment for rectal cancer
American Journal of Clinical Oncology, 01/14/08

Edgar B-J - Emerging data from Phase II trials of neoadjuvant regimens in which capecitabine has been substituted for 5-Fluorouracil (5-FU) are encouraging.

Methods

A review article to describe that Capecitabine may be as effective as 5-FU in colorectal cancer

Results

5-Fluorouracil (5-FU)-based neoadjuvant chemoradiotherapy is used in rectal cancer to prolong survival, downsize tumors prior to surgery, and allow for sphincter-sparing surgery
Capecitabine is an oral fluoropyrimidine that generates 5-FU preferentially within the tumor
It has been shown to be as effective as 5-FU and well tolerated in the metastatic and adjuvant settings in colorectal cancer
Capecitabine is more convenient for patients than 5-FU, and it avoids the risks of infection and thromboembolism associated with intravenous administration
It was also shown to reduce the use of medical resources, healthcare professionals' time, and cost of therapy

Body-mass index and incidence of cancer

2008-11-30T05:58:00.000-08:00

Body-mass index and incidence of cancer

Renehan AG et al. - In a trial to assess the strength of associations between body-mass index (BMI) and different sites of cancer and to investigate differences in these associations between sex and ethnic groups, it was found that increased BMI is associated with increased risk of common and less common malignancies

Methods

Electronic searches on Medline and Embase were done and reports were searched to identify prospective studies of incident cases of 20 cancer types
Random-effects meta-analyses and meta-regressions were done of study-specific incremental estimates to determine the risk of cancer associated with a 5 kg/m2 increase in BMI

Results

221 datasets, including 282,137 incident cases were analyzed
In men, a 5 kg/m2 increase in BMI was strongly associated with oesophageal adenocarcinoma and with thyroid, colon, and renal cancers
In women, strong associations were recorded between a 5 kg/m2 increase in BMI and endometrial, gallbladder, oesophageal adenocarcinoma, and renal cancers
Weaker positive associations were noted between increased BMI and rectal cancer and malignant melanoma in men; postmenopausal breast, pancreatic, thyroid, and colon cancers in women; and leukaemia, multiple myeloma, and non-Hodgkin lymphoma in both sexes
Associations were stronger in men than in women for colon cancer
Associations were generally similar in studies from North America, Europe and Australia, and the AsiaPacific region
Stronger associations were found in AsiaPacific populations between increased BMI and premenopausal and postmenopausal breast cancers

Proton pump inhibitors and the risk of colorectal cancer

2008-11-30T05:57:00.000-08:00

Proton pump inhibitors and the risk of colorectal cancer

van Soest EM et al. - In a study to investigate the association between the use of proton pump inhibitors (PPI) and the risk of colorectal cancer (CRC), it seems that no association was found between PPI use and the risk of CRC

Methods
Cases with CRC were matched with up to 20 controls on age, gender, calendar time, and duration of follow-up prior to diagnosis
Cumulative exposure to PPIs was assessed in the 5 yr prior to diagnosis with a 1-yr lag time analysis
Adjusted odds ratios (OR) were calculated with 95% confidence intervals using multivariate, conditional logistic regression analysis
Results
Within the source population of 457,024 persons, 595 CRC cases were identified
The odds of CRC were not increased among pts ever using PPIs compared with pts who never used PPIs
Use of PPIs for >365 days was not associated with a greater risk of CRC compared with nonusers
The odds of CRC in neither the right nor the left hemicolon were significantly increased in pts using PPIs

A randomised phase III study on capecitabine, oxaliplatin and bevacizumab with or without cetuximab in first-line advanced colorectal cancer, the CAIRO2 study of the Dutch Colorectal Cancer Group (DCCG). An interim analysis of toxicity

2008-11-30T05:55:00.000-08:00

Tol J et al. For first-line treatment of advanced colorectal cancer (ACC), cetuximab addition to capecitabine, oxaliplatin and bevacizumab is safe and feasible with no observed excessive or unexpected toxicity in the cetuximab treatment arm

Methods

Study to evaluate the effect of adding cetuximab to capecitabine, oxaliplatin and bevacizumab in first-line treatment of ACC (CAIRO2 study)
Randomization of 755 pts to treatment with capecitabine, oxaliplatin and bevacizumab with or without cetuximab
Primary end point: progression-free survival
Toxicity results for first 400 pts reported

Results
Incidence of overall grade 34 toxicity was significantly higher in arm B (81%) vs arm A (72%)
Toxicity difference is fully attributed to cetuximab-related skin toxicity
Addition of cetuximab did not increase gastrointestinal toxicity or treatment-related mortality

64-Slice CT High Definition Coronary Artery Scans

2008-11-27T18:00:00.002-08:00

64-Slice CT High Definition Coronary Artery Scans

Coronary artery disease is the leading cause of death in the United States. Every 60 seconds, someone in this country suffers a fatal heart attack. In half of those cases, there is NO warning or previous symptoms.

When detected early, chances are good that the progression of the disease can be halted or even reversed and heart attacks or strokes can be prevented.

Studies have shown that the "usual" risk factors, such as cholesterol levels, are no better at predicting who will have a heart attack than a coin-toss. Seventy-percent of all heart attacks occur in people with normal cholesterol levels.

Stress tests don't show any abnormalities until an artery is at least 60% narrowed. Most heart attacks occur in arteries that are less than 50% narrowed and are therefore NOT detectable by any form of stress testing.

A coronary artery scan can determine if you are at risk for a heart attack years before the first symptoms.

By detecting calcium deposits in the artery walls, the Seimens Sensation 64-Slice High Definition Heart Scan can detect the presence of blockages in your coronary arteries that may not yet be severe enough to show up on other tests.

The Coronary Artery Scan is the most sensitive non-invasive method currently available to accurately identify the presence of early coronary artery disease.

Siemens Sensation 64-Slice CT Scanner

2008-11-27T18:00:00.001-08:00

Siemens Sensation 64-Slice CT Scanner

"This is vastly more accurate than any other available way of identifying apparently healthy people who are at risk for the development of CAD"
Alan Guerci, MD, Executive VP, St. Francis Hospital, Roslyn, NY

The new "Gold Standard" technology for Preventive Medicine

Princeton Longevity is proud to be the region's first preventive medical center to offer the Siemens Sensation 64-Slice CT Scanner, the newest and one of the most important technologies in preventive medicine.

The Siemens Sensation 64-Slice CT Scanner takes Electron Beam Technology (EBT) to the next generation with dramatic image detail and resolution that allows us even greater accuracy in detecting who is at risk for heart disease, early cancers or many other diseases. That translates into earlier and more effective treatment that empowers you to take a more preventive approach to your health.

Until now, preventive medicine often relied almost entirely upon indirect measurements, such as blood pressure and cholesterol levels, to try to predict which patients were at risk for disease. Even in those patients who were considered to be "high risk" and were told to change their lifestyle, there was no accurate way to assess whether they had lowered their risk. The patient had to "wait and see" if they had a heart attack or other serious illness.

The Sensation 64-Slice CT provides High Definition scans with the ability to see details as small as 0.4 mm (about 1/50^th of an inch), create stunningly detailed images of organs and blood vessels for a more accurate diagnosis.

With High Definition Vascular Scans and CT Angiography, the Siemens Sensation 64-Slice CT is a state-of-the-art scanner for detailed visualization of the coronary arteries with extremely high precision and clarity. This means that more invasive procedures, such as Cardiac Catheterization, can often be avoided.

High Definition 64-Slice CT scans are safe, reliable and accurate. Your scan takes only a few minutes and, for most scans, you are able to stay fully clothed. The scanner is very open and, unlike an MRI, is not at all claustrophobic. You lie comfortably on your back and hold your breath for just a few seconds. All our screening scans are done with special Low Dose Protocols to minimize any radiation exposure so you get much less radiation than a typical CT Scan.

The Sensation 64-Slice CT Scanner's unparalleled image detail and clarity allows Princeton Longevity Center to offer the most advanced and effective imaging for diagnostic and preventive medicine.

Treating brain disease with Gamma Knife Perfexion

2008-11-27T17:59:00.001-08:00

Treating brain disease with Gamma Knife Perfexion

Imagine undergoing brain surgery as an outpatient with reduced pain, a brief recovery period and no incision. Hoag Gamma Knife Center is the only facility in Orange County providing this effective treatment option for patients with brain disease.

And Hoag Neurosciences Center is the now the first center in Southern California to employ the revolutionary Leksell Gamma Knife® Perfexionthe newest, most efficient and precise radiosurgical device available. With an expanded treatment area and enhanced accuracy, this Gamma Knife technology benefits significantly more patients who can now be treated with Gamma Knife radiosurgery instead of a more invasive procedure.

Gamma Knife is the gold standard in minimally invasive neurosurgery

Backed by over two decades of clinical application in the U.S. with unsurpassed outcomes, Gamma Knife is recognized as the gold standard in minimally invasive neurosurgery. Hoag Hospital's new Gamma Knife Perfexion takes the gold standard platinum.

The Gamma Knife administers a single dose of radiation to stop and/or reduce the growth of abnormal tissue by destroying the DNA mapping of the cells, which renders them unable to divide. 192 precise gamma ray beams are focused on the abnormal tissue area with the area of intersection conforming to the size and shape of the tumor.

"With Gamma Knife Perfexion, we're able to prevent injury to surrounding healthy tissue while delivering a powerful dose to the targeted tumor," explains accomplished Gamma Knife surgeon, Chris Duma, MD, medical director of Hoag's Brain Tumor Program. "We utilize the Gamma Knife most frequently in treating brain metastases, where we'll often incorporate it in conjunction with surgery, radiation therapy or chemotherapy. And, for high-risk patients that may not be able to tolerate an open-skull surgery, Gamma Knife offers an effective treatment alternative."

The team of specialists at Hoag Gamma Knife Center, a program of Hoag Neurosciences Center, treats more than 200 patients annually, adding months and even years to the lives of those treated with this state-of-the-art technology. And with Hoag's upgraded Gamma Knife system, Hoag specialists are now able to offer this minimally invasive approach to even more patientstreating areas of the brain, skull base and cervical spine that could not previously be reached without surgical incision.

With Gamma Knife Perfexion Hoag specialists can now treat tumors that were unreachable using previous technology

Perfexion's anatomical reach has been expanded to treat the brain, skull base and cervical spine, which allows Hoag specialists to address difficult to reach tumors that were not previously treatable when compared to earlier generations of Gamma Knife and current competing technologies. Additionally, while other radiosurgical tools require more than one session to treat multiple brain lesions, Gamma Knife Perfexion can safely and effectively irradiate multiple lesions in a single treatment session.

"The enhanced design of Gamma Knife Perfexion provides us with almost unlimited ability for sculpting the treatment plan with incomparable accuracy," confirms Dr. Duma. "This more precise system can now be used to treat patients whose tumors are very near vital parts of the body, such as the optic nerve."

Radiosurgery with the new Gamma Knife Perfexion remains an outpatient procedure, free of the risks of invasive brain surgery. Following Gamma Knife treatment, patients can immediately return to preoperative lifestyle without any need for intensive care or extended hospitalization.

FDG Automation Arrives in the United States

2008-11-26T21:18:00.005-08:00

With the PET business booming these days, Medrad Inc, based in Warrendale, Pa, has introduced to the market a product addressing the workflow issues that arise from the influx of patients.
Medrad's Intego PET infusion system is the first in the United States to automate and control the FDG delivery process.

Enabling health care providers to administer fluorodeoxyglucose at any time throughout the day, the Intego PET infusion system is the first in the United States to automate and control the FDG delivery process.

"FDG PET scanning is one of the most efficient and accurate methods to stage cancer patients," said Alfred Buck, professor of nuclear medicine at the University Hospital in Zurich. With colleague Bruno Weber, Buck co-invented the machine, built the first prototype, and has been using the device at the PET center at his hospital for the last 4 years. The principle was patented and licensed to Medrad.

"The number of patients receiving PET scans is steeply increasing," he continued. "With this increased throughput, it is very helpful to have an automatic injection device."

The system was developed to enhance the clinician's ability to deliver FDG with accuracy and precision, as well as with safety. It works by automatically extracting a patient dose from a multidose vial and then delivering it directly to the patient. As a result, manual dose preparation and handling is eliminated, as well as radiation exposure for the technologist.

"With respect to single-syringe deliveries, the injector is more economical," Buck added. "It allows clinicians to deliver a predetermined amount of FDG to each patient with high accuracy. In this way, one can easily adjust the injected dose to the individual patient according to weight."

Specifically, with its dose-on-demand capability, the prescribed dose is delivered when the patient and technologist are ready. This affords technologists an efficient way to respond to schedule changes, patient delays, and add-on patients. More features include real-time dose availability information, an integrated ionization chamber, and an optional weight-based dose calculation. Among the safety features offered are a tungsten multidose vial shield, a fully lead-lined mobile cart, and an automated saline flush to remove residual FDG from the line after each infusion.

"With our new Intego system that fully automates FDG delivery, we can once again improve how molecular imaging is done," said Cliff Kress, senior vice president, CT Business Unit.

In related news, Medrad is working with FDG suppliers to provide FDG in multidose vials and vial shields that are compatible with the Intego System. The company recently announced a distribution and co-marketing agreement with radiopharmacy network PETNET Solutions, a fully owned subsidiary of Siemens Medical solutions USA Inc.

Research Alert: MITA Spotlights Value of PET

2008-11-26T21:18:00.004-08:00

The Medical Imaging and Technology Alliance (MITA), a division of the National Electrical Manufacturers Association, recently expressed its take on the results of a nationwide study that examined the impact of positron emission tomography (PET) scans.

Published in the May 1 issue of the Journal of Clinical Oncology, the study discusses PET technology and its benefits for patients with ovarian, prostate, pancreatic, and other cancers.

Andrew Whitman, MITA vice president, called on the Centers for Medicare and Medicaid Services to strongly consider the study as it makes future national coverage decisions.

"MITA applauds the work of Dr Bruce Hillner and his team, which we hope will result in improved treatment and health outcomes for cancer patients with tumor types not currently on the 'approved' Medicare list," Whitman said, adding that PET scans are just one of the many medical technologies that have revolutionized cancer diagnosis and treatment. "These research findings remind us that it's critical that patients have access to innovative medical imaging technology to help fight cancer and other serious illnesses."

In the study, Hillner and his group of researchers demonstrated that using PET scans for cancer diagnosis, staging, restaging, and recurrence monitoring was associated with a significant reduction in unnecessary additional procedures. Also, in the aggregate of cases that had an initial treatment plan, referring physicians indicated that PET scanning enabled them to avoid additional tests or procedures 77% of the time. For approximately three-quarters of cases in which a biopsy was the original pre-PET recommendation, PET scanning enabled the procedure to be ultimately avoided.

MITA pointed out that the latest coverage with evidence development study is one of a number of studies that demonstrate the value of PET scanning in cancer diagnosis and treatment. For example, MITA described research efforts led by Paul Verboom, of the Institute for Medical Technology Assessment, Erasmus University Rotterdam, who exhibited the cost-effectiveness of PET scanning. The 2003 study, called "Cost-Effectiveness of FDG-PET in Staging Non-Small Cell Lung Cancer: The PLUS Study," showed PET scans produced an average savings of 13% through avoiding unnecessary surgery, hospital stays, and intensive care.

"Now more than ever, it's crucial that patients and policymakers alike look to studies like these as a reminder of why and how medical imaging improves patient health outcomes and reduces overall health care costs," Whitman said.

Intensity-Modulated Radiation Therapy (IMRT)

2008-11-26T21:18:00.003-08:00

What is Intensity-Modulated Radiation Therapy and how is it used?

Intensity-modulated radiation therapy (IMRT) is an advanced mode of high-precision radiotherapy that utilizes computer-controlled x-ray accelerators to deliver precise radiation doses to a malignant tumor or specific areas within the tumor. IMRT allows for the radiation dose to conform more precisely to the three-dimensional (3-D) shape of the tumor by modulatingor controllingthe intensity of the radiation beam. IMRT also allows higher radiation doses to be focused to regions within the tumor while minimizing the dose to surrounding normal critical structures. Treatment is carefully planned by using 3-D computed tomography (CT) images of the patient in conjunction with computerized dose calculations to determine the dose intensity pattern that will best conform to the tumor shape. Typically, combinations of several intensity-modulated fields coming from different beam directions produce a custom tailored radiation dose that maximizes tumor dose while also protecting adjacent normal tissues.

Because the ratio of normal tissue dose to tumor dose is reduced to a minimum with the IMRT approach, higher and more effective radiation doses can safely be delivered to tumors with fewer side effects compared with conventional radiotherapy techniques. IMRT also has the potential to reduce treatment toxicity, even when doses are not increased. IMRT does require longer daily treatment times and delivers a low dose to larger volumes of normal tissue than conventional radiotherapy.

Currently, IMRT is being used most extensively to treat cancers of the prostate, head and neck, and central nervous system. IMRT has also been used in limited situations to treat breast, thyroid, lung, as well as in gynecologic malignancies and certain types of sarcomas. IMRT may also be beneficial for treating certain types of pediatric malignancies.

Radiation therapy, including IMRT, stops cancer cells from dividing and growing, thus slowing tumor growth. In many cases, radiation therapy is capable of killing all of the cancer cells, thus shrinking or eliminating tumors.
Who will be involved in this procedure?

Most facilities rely on a specially trained team for IMRT delivery. This team includes the radiation oncologist, medical radiation physicist, dosimetrist, radiation therapist and radiation therapy nurse.

The radiation oncologist, a specially trained physician who heads the treatment team, sets an individualized course of treatment with the help of the radiation physicist, who ensures the linear accelerator delivers the precise radiation dose and that computerized dose calculations are accurate. A dosimetrist, under the supervision of the medical radiation physicist, calculates the IMRT exposures and beam configurations necessary to deliver the dose prescribed by the radiation oncologist. A highly trained radiation therapist positions the patient on the treatment table and operates the machine. The radiation therapy nurse provides the patient with information about the treatment and possible adverse reactions as well as help in managing any reaction.
What equipment is used?

A medical linear accelerator generates the photons, or x-rays, used in IMRT. The machine is the size of a small carapproximately 10 feet high and 15 feet long. The patient lies on the treatment table, while the linear accelerator delivers multiple beams of radiation to the tumor from various directions. The intensity of each beam's radiation dose is dynamically varied according to treatment plan.

See the Linear Accelerator page for more information.
Who operates the equipment?

The radiation therapist operates the equipment from a radiation-protected area nearby. The therapist is able to communicate with the patient throughout the procedure. The therapist observes the patient on closed circuit television.
Is there any special preparation needed for the procedure?

Before planning treatment, a physical examination and medical history review will be conducted. Next, there is a treatment simulation session, which includes CT scanning, from which the radiation oncologist specifies the three-dimensional shape of the tumor and normal tissues. In some cases, a treatment preparation session may be necessary to mold a special device that will help the patient maintain an exact treatment position. The dosimetrist and medical radiation physicist use the CT information to design the IMRT beams used for treatment. Several additional scanning procedures, including positron emission tomography (PET) and magnetic resonance imaging (MRI), might also be required for IMRT planning. These diagnostic images can be merged with the planning CT and help the radiation oncologist determine the precise location of the tumor target. In some cases it is necessary to insert radio dense markers into the target for more accurate positioning. Typically, IMRT sessions begin about a week after simulation. Prior to treatment, the patient's skin may be marked or tattooed with colored ink to help align and target the equipment.
How is the procedure performed?

IMRT often requires multiple or fractionated treatment sessions. Several factors come into play when determining the total number of IMRT sessions and radiation dose. The oncologist considers the type, location and size of the malignant tumor, doses to critical normal structures, as well as the patient's health. Typically, patients are scheduled for IMRT sessions five days a week for six to ten weeks.

At the beginning of the treatment session, the therapist positions the patient on the treatment table, guided by the marks on the skin defining the treatment area. If molded devices were made, they will be used to help the patient maintain the proper position. The patient may be repositioned during the procedure. Imaging systems on the treatment machine may be used to check positioning and marker location. Treatment sessions usually take between 15 and 30 minutes.
What will I feel during and after this procedure?

IMRT is painless. You will not feel or sense anything out of the ordinary during treatment. However, the machine can be stopped if you become uncomfortable. As treatment progresses, some patients may experience treatment-related side effects. The nature of the side effects depend on the normal tissue structures being irradiated. The radiation oncologist and the nurse will discuss and try to help you with any side effects.

CT - Head

2008-11-26T21:18:00.002-08:00

What is CT Scanning of the Head?

CT scanningsometimes called CAT scanningis a noninvasive medical test that helps physicians diagnose and treat medical conditions.

CT imaging combines special x-ray equipment with sophisticated computers to produce multiple images or pictures of the inside of the body. These cross-sectional images of the area being studied can then be examined on a computer monitor or printed.

CT scans of internal organs, bone, soft tissue and blood vessels provide greater clarity and reveal more details than regular x-ray exams.

CT scanning provides more detailed information on head injuries, stroke, brain tumors and other brain diseases than regular radiographs (x-rays).
What are some common uses of the procedure?

CT scanning of the head is typically used to detect:
bleeding, brain injury and skull fractures in patients with head injuries
bleeding caused by a ruptured or leaking aneurysm in a patient with a sudden severe headache
a blood clot or bleeding within the brain shortly after a patient exhibits symptoms of a stroke
a stroke, especially with a new technique called Perfusion CT
brain tumors
enlarged brain cavities (ventricles) in patients with hydrocephalus
diseases or malformations of the skull

CT scanning is also performed to:
evaluate the extent of bone and soft tissue damage in patients with facial trauma, and planning surgical reconstruction
diagnose diseases of the temporal bone on the side of the skull, which may be causing hearing problems
determine whether inflammation or other changes are present in the paranasal sinuses
plan radiation therapy for cancer of the brain or other tissues
guide the passage of a needle used to obtain a tissue sample (biopsy) from the brain
assess aneurysms or arteriovenous malformations through a technique called CT angiography. For more information, see the CT Angiography page.
How should I prepare?

You should wear comfortable, loose-fitting clothing to your exam. You may be given a gown to wear during the procedure.

Metal objects including jewelry, eyeglasses, dentures and hairpins may affect the CT images and should be left at home or removed prior to your exam. You may also be asked to remove hearing aids and removable dental work.

You may be asked not to eat or drink anything for several hours beforehand, especially if a contrast material will be used in your exam. You should inform your physician of any medications you are taking and if you have any allergies. If you have a known allergy to contrast material, or "dye," your doctor may prescribe medications to reduce the risk of an allergic reaction.

Also inform your doctor of any recent illnesses or other medical conditions, and if you have a history of heart disease, asthma, diabetes, kidney disease or thyroid problems. Any of these conditions may increase the risk of an unusual adverse effect.

The radiologist also should know if you have asthma, multiple myeloma or any disorder of the heart, kidneys or thyroid gland, or if you have diabetesparticularly if you are taking Glucophage.

Women should always inform their physician and the CT technologist if there is any possibility that they are pregnant. See the Safety page for more information about pregnancy and x-rays.
What does the equipment look like?

The CT scanner is typically a large, box like machine with a hole, or short tunnel, in the center. You will lie on a narrow examination table that slides into and out of this tunnel. Rotating around you, the x-ray tube and electronic x-ray detectors are located opposite each other in a ring, called a gantry. The computer workstation that processes the imaging information is located in a separate room, where the technologist operates the scanner and monitors your examination.
How does the procedure work?

In many ways CT scanning works very much like other x-ray examinations. X-rays are a form of radiationlike light or radio wavesthat can be directed at the body. Different body parts absorb the x-rays in varying degrees.

In a conventional x-ray exam, a small burst of radiation is aimed at and passes through the body, recording an image on photographic film or a special image recording plate. Bones appear white on the x-ray; soft tissue shows up in shades of gray and air appears black.

With CT scanning, numerous x-ray beams and a set of electronic x-ray detectors rotate around you, measuring the amount of radiation being absorbed throughout your body. At the same time, the examination table is moving through the scanner, so that the x-ray beam follows a spiral path. A special computer program processes this large volume of data to create two-dimensional cross-sectional images of your body, which are then displayed on a monitor. This technique is called helical or spiral CT.

CT imaging is sometimes compared to looking into a loaf of bread by cutting the loaf into thin slices. When the image slices are reassembled by computer software, the result is a very detailed multidimensional view of the body's interior.

Refinements in detector technology allow new CT scanners to obtain multiple slices in a single rotation. These scanners, called "multislice CT" or "multidetector CT," allow thinner slices to be obtained in a shorter period of time, resulting in more detail and additional view capabilities.

Modern CT scanners are so fast that they can scan through large sections of the body in just a few seconds. Such speed is beneficial for all patients but especially children, the elderly and critically ill.

For some CT exams, a contrast material is used to enhance visibility in the area of the body being studied.
How is the procedure performed?

The technologist begins by positioning you on the CT examination table, usually lying flat on your back or possibly on your side or on your stomach. Straps and pillows may be used to help you maintain the correct position and to hold still during the exam.

If contrast material is used, it will be swallowed, injected through an intravenous line (IV) or administered by enema, depending on the type of examination.

Next, the table will move quickly through the scanner to determine the correct starting position for the scans. Then, the table will move slowly through the machine as the actual CT scanning is performed.

You may be asked to hold your breath during the scanning.

When the examination is completed, you will be asked to wait until the technologist verifies that the images are of high enough quality for accurate interpretation.

A CT scan of the head is usually completed within 10 minutes.
What will I experience during and after the procedure?

Most CT exams are painless, fast and easy. With helical CT, the amount of time that the patient needs to lie still is reduced.

Though the scanning itself causes no pain, there may be some discomfort from having to remain still for several minutes. If you have a hard time staying still, are claustrophobic or have chronic pain, you may find a CT exam to be stressful. The technologist or nurse, under the direction of a physician, may offer you a mild sedative to help you tolerate the CT scanning procedure.

If an intravenous contrast material is used, you will feel a slight pin prick when the needle is inserted into your vein. You may have a warm, flushed sensation during the injection of the contrast materials and a metallic taste in your mouth that lasts for a few minutes. Occasionally, a patient will develop itching and hives, which can be relieved with medication. If you become light-headed or experience difficulty breathing, you should notify the technologist or nurse, as it may indicate a more severe allergic reaction. A radiologist or other physician will be available for immediate assistance.

If the contrast material is swallowed, you may find the taste mildly unpleasant; however, most patients can easily tolerate it. You can expect to experience a sense of abdominal fullness and an increasing need to expel the liquid if your contrast material is given by enema. In this case, be patient, as the mild discomfort will not last long.

When you enter the CT scanner, special lights may be used to ensure that you are properly positioned. With modern CT scanners, you will hear only slight buzzing, clicking and whirring sounds as the CT scanner revolves around you during the imaging process.

You will be alone in the exam room during the CT scan, however, the technologist will be able to see, hear and speak with you at all times.

With pediatric patients, a parent may be allowed in the room but will be required to wear a lead apron to prevent radiation exposure.

After a CT exam, you can return to your normal activities. If you received contrast material, you may be given special instructions.
Who interprets the results and how do I get them?

A physician, usually a radiologist with expertise in supervising and interpreting radiology examinations, will analyze the images and send a signed report to your primary care or referring physician, who will discuss the results with you.
What are the benefits vs. risks?
Benefits
CT scanning is painless, noninvasive and accurate.
A major advantage of CT is that it is able to image bone, soft tissue and blood vessels all at the same time.
Unlike conventional x-rays, CT scanning provides very detailed images of many types of tissue as well as the lungs, bones, and blood vessels.
CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives.
CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems.
CT is less sensitive to patient movement than MRI.
CT can be performed if you have an implanted medical device of any kind, unlike MRI.
CT imaging provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as needle biopsies and needle aspirations of many areas of the body, particularly the lungs, abdomen, pelvis and bones.
A diagnosis determined by CT scanning may eliminate the need for exploratory surgery and surgical biopsy.
No radiation remains in a patient's body after a CT examination.
X-rays used in CT scans usually have no side effects.
Risks
There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
The effective radiation dose from this procedure is about 1 to 2 mSv, which is about the same as the average person receives from background radiation in four to eight months. See the Safety page for more information about radiation dose.
Women should always inform their physician and x-ray or CT technologist if there is any possibility that they are pregnant. See the Safety page for more information about pregnancy and x-rays.
CT scanning is, in general, not recommended for pregnant women unless medically necessary because of potential risk to the baby.
Nursing mothers should wait for 24 hours after contrast material injection before resuming breast-feeding.
The risk of serious allergic reaction to contrast materials that contain iodine is extremely rare, and radiology departments are well-equipped to deal with them.
Children should have a CT study only if it is essential for making a diagnosis and should not have repeated CT studies unless absolutely necessary.
What are the limitations of CT Scanning of the Head?

A person who is very large may not fit into the opening of a conventional CT scanner or may be over the weight limit for the moving table.

Compared to MR imaging, the precise details of soft tissue (particularly the brain, including the disease processes) are less visible on CT scans. CT is not sensitive in detecting inflammation of the meningesthe membranes covering the brain.

CT Colonography

2008-11-26T21:18:00.001-08:00

What is CT Colonography?

CT scanningsometimes called CAT scanningis a noninvasive medical test that helps physicians diagnose and treat medical conditions.

CT scans of internal organs, bone, soft tissue and blood vessels provide greater clarity and reveal more details than regular x-ray exams.

CT colonography uses CT scanning to obtain an interior view of the colon (the large intestine) that is otherwise only seen with a more invasive procedure where an endoscope is inserted into the rectum.
What are some common uses of the procedure?

The major reason for performing CT colonography is to screen for polyps and other lesions in the large intestine. Polyps are growths that arise from the inner lining of the intestine. Some polyps may grow and turn into cancers.

The goal of screening with colonography is to find these growths in their early stages, so that they can be removed before cancer has had a chance to develop. Most physicians agree that everyone older than 50 years should be screened for polyps every seven to 10 years. Individuals at increased risk should be screened every five years and may start screening at age 40 or younger. Risk factors for the disease include a history of polyps, a family history of colon cancer, or the presence of blood in the stool.
How should I prepare?

You should wear comfortable, loose-fitting clothing to your exam. You may be given a gown to wear during the procedure.

Women should always inform their physician and the CT technologist if there is any possibility that they are pregnant. See the Safety page for more information about pregnancy and x-rays.

It is very important to clean out your bowel the night before your CT colonography examination so that the radiologist can clearly see any polyps that might be present. You will be asked to take either a set of pills or a cathartic liquid. Some common preparations are the Fleet Prep Kit 1 (phospho-soda and Bisacodyl) and NuLytely® or Go-Lytely® (Polyethylene glycol electrolyte solutions).

Be sure to inform your physician if you have heart, liver or kidney disease to be certain that the bowel prep will be safe. On the day before your exam, you should limit your food intake to clear liquids such as broth, tea or juice. You will be able to resume your usual diet immediately after the exam.
What does the equipment look like?

During CT colonography, you will be asked to lie on your back and then on your stomach or side.
How does the procedure work?

For CT colonography, the computer generates a detailed three-dimensional model of the abdomen and pelvis, which the radiologist uses to view the bowel in a way that simulates traveling down the colon. This is why it is often called a virtual colonoscopy.
How is the procedure performed?

A very small, flexible tube will be passed two inches into your rectum to allow air to be gently pumped into the colon using a hand-held squeeze bulb. Sometimes an electronic pump is used to deliver carbon dioxide gas into the colon. The purpose of the gas is to distend the colon as much as possible to eliminate any folds or wrinkles that might obscure polyps from the physician's view.

Next, the table will move through the scanner. Patients are asked to hold their breath for about 15 seconds before turning over and lying on their back or side for a second pass is made through the scanner. In some centers the sequence of positions may be the opposite: facing upward first and then facing down. Once the scan is done, the tube is removed.

The entire examination is usually completed within 15 minutes.
What will I experience during and after the procedure?

The vast majority of patients who have CT colonography report a feeling of fullness when the colon is inflated during the exam, as if they need to pass gas. Significant pain is uncommon, occurring in fewer than 5 percent of patients. A muscle-relaxing drug may be injected intravenously or subcutaneously to lessen discomfort, but this is seldom necessary. After the tube is inserted, your privacy will be respected. The scanning procedure itself causes no pain or other symptoms.

You will be alone in the exam room during the CT scan, however, the technologist will be able to see, hear and speak with you at all times.

After a CT exam, you can return to your normal activities.
Who interprets the results and how do I get them?

A physician, usually a radiologist with expertise in supervising and interpreting radiology examinations, will analyze the images and send a signed report to your primary care or referring physician, who will discuss the results with you.
What are the benefits vs. risks?
Benefits
This new minimally invasive test provides three-dimensional images that can depict many polyps and other lesions as clearly as when they are directly seen by optical colonoscopy.
CT colonography has a markedly lower risk of perforating the colon than conventional colonoscopy. Most of those examined do not have polyps, and can be spared having to undergo a full colonoscopy.
CT colonography is an excellent alternative for patients who have clinical factors that increase the risk of complications from colonoscopy, such as treatment with a blood thinner or a severe breathing problem.
Elderly patients, especially those who are frail or ill, will tolerate CT colonography better than conventional colonoscopy.
CT colonography can be helpful when colonoscopy cannot be completed because the bowel is narrowed or obstructed for any reason, such as by a large tumor.
If conventional colonoscopy cannot reach the full length of the colonwhich occurs up to 10 percent of the timeCT colonography can be performed on the same day because the colon has already been cleansed.
CT colonography provides clearer and more detailed images than does a conventional barium enema x-ray examination.
CT colonography is tolerated well. Sedation and pain-relievers are not needed, so there is no recovery period.
CT colonography is less costly than colonoscopy.
No radiation remains in a patient's body after a CT examination.
X-rays used in CT scans usually have no side effects.
Risks
There is a very small risk that inflating the colon with air could injure or perforate the bowel. This has been estimated to happen in fewer than one in 2,000 patients.
There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
The effective radiation dose from this procedure is about 5 mSv, which is about the same as the average person receives from background radiation in 20 months. See the Safety page for more information about radiation dose.
Women should always inform their physician and x-ray or CT technologist if there is any possibility that they are pregnant. See the Safety page for more information about pregnancy and x-rays.
CT scanning is, in general, not recommended for pregnant women unless medically necessary because of potential risk to the baby.
What are the limitations of CT Colonography?

A person who is very large may not fit into the opening of a conventional CT scanner or may be over the weight limit for the moving table.

CT colonography is strictly a diagnostic procedure. If any significant polyps are found, they will have to be removed by conventional colonoscopy.

Many insurance companies do not cover CT colonography as a screening test for colonic polyps, but they may cover the cost if a patient has symptoms related to the colon.

Children's (Pediatric) CT (Computed Tomography)

2008-11-26T21:18:00.000-08:00

What is Children's CT?

CT scanningsometimes called CAT scanningis a noninvasive medical test that helps physicians diagnose and treat medical conditions.

CT scans of internal organs, bone, soft tissue and blood vessels provide greater clarity and reveal more details than regular x-ray exams.

Newborns, infants and older children may undergo CT scanning.
What are some common uses of the procedure?

Physicians use the CT examination to help detect a wide range of abnormalities and disease, including cancer, in any part of a child's body.

Children's (pediatric) CT is typically used to help diagnose and monitor treatment for infectious or inflammatory disorders, abdominal pain, headaches and injury-related changes.

CT is also performed to evaluate:
blood vessels serving the brain, face or neck
the spinal cord and bones making up the spinal column

In the case of head injury, the exam can display or rule out serious complications such as bleeding within the brain or other forms of brain damage.

Except for the chest x-ray, CT is the most commonly used imaging procedure for evaluating the chest. CT of the chest is used to evaluate:
complications from infections such as pneumonia
a tumor that arises in the lung or has spread there from a distant site
airway disease such as inflammation of the bronchi (breathing passages)
birth defects
injured blood vessels or lung damage

Using multidetector CT, it is possible to obtain very detailed pictures of the heart and large blood vessels of the chest in children, even newborn infants.

CT is well-suited for visualizing diseases or injury of important organs in the abdomen including the liver, kidney and spleen. CT is sometimes used to:
diagnose appendicitis
evaluate adolescents who have inflammatory disorders of the bowel, such as colitis
detect abdominal tumors or birth defects

In the pelvic region, CT scans can help detect:
cysts or tumors of the ovary
abnormalities of the bladder
stones in the urinary tract
disease of the pelvic bones
How should we prepare?

Your child should wear comfortable, loose-fitting clothing to the exam. He or she may be given a gown to wear during the procedure.

Metal objects including jewelry, eyeglasses, removable dental work, hearing aids and hairpins may affect the CT images and should be left at home or removed prior to your child's exam.

Your child may be asked not to eat or drink anything for several hours beforehand, especially if a contrast material, sedative or anesthesia will be used in the exam. With sedation or anesthesia, your child probably will not be allowed to eat for three to six hours prior to the exam. In general, children who have recently been ill are not sedated or anesthetized. If this is the case or if you suspect that your child may be getting sick, you should talk with your physician about rescheduling the CT exam.

You should also inform your physician of any medications your child is taking and if he/she has any allergies, especially to contrast materials, iodine, or seafood.

Also inform your doctor of any recent illnesses or other medical conditions your child may have, and if there is a history of heart disease, asthma, diabetes, kidney disease or thyroid problems. Any of these conditions may increase the risk of an allergic reaction.
What does the equipment look like?

The CT scanner is typically a large machine with a hole, or tunnel, in the center. A moveable examination table slides into and out of this tunnel. In the center of the machine, the x-ray tube and electronic x-ray detectors are located opposite each other on a ring, called a gantry, which rotates around the patient. The computer that processes the imaging information and monitor are located in a separate room.
How does the procedure work?

With CT scanning, numerous x-ray beams and a set of electronic x-ray detectors rotate around the patient, measuring the amount of radiation being absorbed throughout the body. At the same time, the examination table is moving through the scanner, so that the x-ray beam follows a spiral path. A special computer program processes this series of pictures, or slices of the body, to create two-dimensional cross-sectional images, which are then displayed on a monitor.

For some CT exams, a contrast material is used to enhance visibility in the area of the body being studied.
How is the procedure performed?

The technologist begins by positioning the patient on the CT examination table, usually lying flat on his/her back or possibly on their side or on their stomach. Straps and pillows may be used to help the patient maintain the correct position and to hold still during the exam.

You should encourage your child to report any discomfort during positioning because it is important to keep very still during the exam. Once the child is correctly positioned, the CT technologist will leave the room to begin the scan.

If contrast material is used, it will be swallowed, injected through an intravenous line (IV) or administered by enema, depending on the type of examination.

Patients are periodically asked to hold their breath during the scanning.

Most children older than six years are able to hold their breath long enough to complete the scan although they may need coaching and practice. Younger children may not be able to hold their breath long enough to complete the scan. Irregular breathing can affect the quality of a CT scan, especially one done to evaluate the chest or upper abdomen. It is often better to have young children breathe quietly and regularly during the scan. Modern systems known as multidetector or multislice CT are able to image large regions of the body in a very short time.

When the examination is completed, the patient will be asked to wait until the technologist determines that the images are of high enough quality for the radiologist to read.
What will my child experience during and after the procedure?

Most CT exams are painless, fast and easy. With helical CT, the amount of time that the patient needs to lie still is reduced.

Though the scanning itself causes no pain, your child may experience some discomfort from having to remain still for several minutes.

If an intravenous contrast material is used, your child will feel a slight pin prick when the needle is inserted into a vein in the hand or arm. The child may have a warm, flushed sensation during the injection of the contrast materials and a metallic taste in his/her mouth that lasts for a few minutes. Occasionally, a patient will develop itching and hives, which can be relieved with medication. If your child becomes light-headed or experiences difficulty breathing, you should notify the technologist or nurse, as it may indicate a more severe allergic reaction.

If the contrast material is swallowed, your child may find the taste mildly unpleasant; however, most patients can easily tolerate it. Your child can expect to experience a sense of abdominal fullness and an increasing need to expel the liquid if the contrast material is given by enema. In this case, encourage your child to be patient, as the mild discomfort will not last long.

When your child enters the scanner, special lights may be used to ensure that he/she is properly positioned. With modern CT scanners, your child will hear only slight buzzing, clicking and whirring sounds as the CT scanner revolves around him/her during the imaging process.

Your child will be alone in the exam room during the CT scan, however, the technologist will be able to see, hear and speak with him/her at all times. A parent may be allowed in the room but will be required to wear a lead apron to prevent radiation exposure. If you suspect you may be pregnant it would be better for someone else to be with your child.

Some imaging facilities may use general anesthesia in young children who are unable to hold still. In this case you will be permitted to stay in the exam room until your child has fallen asleep. There may be a somewhat longer wait after the exam to be sure that your child is fully alert.

When the exam is completed and your childif sedatedis fully awake, you will be free to return home. After a CT exam, your child can return to his/her normal activities. If a contrast material was used during the exam, you will be given special instructions.
Who interprets the results and how do we get them?

A physician, usually a radiologist with expertise in supervising and interpreting radiology examinations, will analyze the images and send a signed report to your primary care or referring physician, who will discuss the results with you.
What are the benefits vs. risks?
Benefits
Using a spiral (helical) CT unit to examine children is faster than the older CT scanners, reducing the need for sedation and general anesthesia.
New technologies that will make even faster scanning possible are becoming increasingly available. For children this means shorter imaging times and less time required to hold still in order to produce clear images. Also, shorter scan times will make it easier for children to hold their breath during critical parts of the exam.
CT scanning is painless, noninvasive and accurate.
A major advantage of CT is that it is able to image bone, soft tissue and blood vessels all at the same time.
Unlike conventional x-rays, CT scanning provides very detailed images of many types of tissue as well as the lungs, bones, and blood vessels.
CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives.
CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems.
CT is less sensitive to patient movement than MRI.
CT can be performed if you have an implanted medical device of any kind, unlike MRI.
CT imaging provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as needle biopsies and needle aspirations of many areas of the body, particularly the lungs, abdomen, pelvis and bones.
A diagnosis determined by CT scanning may eliminate the need for exploratory surgery and surgical biopsy.
No radiation remains in a patient's body after a CT examination.
X-rays used in CT scans usually have no side effects.
Risks
There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
The risk of serious allergic reaction to contrast materials that contain iodine is rare, and radiology departments are well-equipped to deal with them.
Radiation is necessary to obtain CT images. It is known that high levels of radiation may cause cancer. However, CT scans result in a low-level exposure. Whether such levels cause cancer is debatable but because it is possible, every effort is made to limit the amount of radiation children may receive from a CT scan. The thyroid gland, bone marrow and gonads of a child are especially sensitive to radiation. In addition, children have a longer time to accumulate radiation throughout their lives. Each exposure, including that from a CT exam, adds to this total lifetime exposure.

One of the best ways of limiting radiation exposure is to avoid CT scans that are not clearly needed. Other measures are to restrict the area scanned as much as possible and to "fine tune" the CT settings based on the reason for the exam, the body area being examined, and the child's size. Radiologists generally attempt to use the lowest radiation dose that will provide the needed diagnostic information. See the Safety page for more information about radiation dose.
There always is a risk of complications from general anesthesia or sedation. Every measure will be taken to protect the welfare of your child, including close monitoring.
Children should have a CT study only if it is essential for making a diagnosis and should not have repeated CT studies unless absolutely necessary.
What are the limitations of Children's CT?

A person who is very large may not fit into the opening of a conventional CT scanner or may be over the weight limit for the moving table.

Other imaging methods such as ultrasound or magnetic resonance (MR) imaging can provide pictures of certain areas of the body that sometimes are as good as or better than those obtained by CT scanning. Working together, your primary care physician or pediatrician and the radiologist will decide which type of examination is best for your child.

Motion can affect the quality of a CT scan even when every effort is made to see that your child holds still.
Additional Information and Resources:
The Alliance for Radiation Safety in Pediatric Imaging's "Image Gently" Campaign:

www.pedrad.org/associations/5364/ig/index.cfm?page=388

CT - Chest

2008-11-26T21:16:00.004-08:00

What is CT Scanning of the Chest?

CT scanningsometimes called CAT scanningis a noninvasive medical test that helps physicians diagnose and treat medical conditions.

CT scans of internal organs, bone, soft tissue and blood vessels provide greater clarity and reveal more details than regular x-ray exams.
What are some common uses of the procedure?

CT of the chest is used to:
further examine abnormalities found on conventional chest x-rays
help diagnose the cause of clinical signs or symptoms of disease of the chest
detect and evaluate the extent of tumors that arise in the chest, or tumors that have spread there from other parts of the body
assess whether tumors are responding to treatment
help plan radiation therapy
evaluate injury to the chest, including the blood vessels, lungs, ribs and spine

Chest CT can demonstrate various lung disorders, such as:
lung cancer
old or new pneumonia
tuberculosis
emphysema
bronchiectasis
inflammation or other diseases of the pleura, the membrane covering the lungs
diffuse interstitial lung disease

A CT angiogram (CTA) may be performed to evaluate the blood vessels (arteries and veins) in the chest. This involves the rapid injection of an iodine-containing fluid (contrast material) into a vein while obtaining numerous, thinner CT images. See the CT Angiography (CTA) page for more information.
How should I prepare?

You should wear comfortable, loose-fitting clothing to your exam. You may be given a gown to wear during the procedure.

If a contrast material is used, it will be injected into a vein shortly before scanning begins.

You may be asked to hold your breath during the scanning.

When the examination is completed, you will be asked to wait until the technologist verifies that the images are of high enough quality for accurate interpretation.

The actual CT scanning takes less than 30 seconds and the entire process is usually completed within 30 minutes.
What will I experience during and after the procedure?

Most CT exams are painless, fast and easy. With helical CT, the amount of time that the patient needs to lie still is reduced.

You will be alone in the exam room during the CT scan, however, the technologist will be able to see, hear and speak with you at all times.

With pediatric patients, a parent may be allowed in the room but will be required to wear a lead apron to prevent radiation exposure.

After a CT exam, you can return to your normal activities. If you received contrast material, you may be given special instructions.
Who interprets the results and how do I get them?

A physician, usually a radiologist with expertise in supervising and interpreting radiology examinations, will analyze the images and send a signed report to your primary care or referring physician, who will discuss the results with you.
What are the benefits vs. risks?
Benefits
CT is fast. This is especially important for patients with chest injury, because internal damage or bleeding can be diagnosed in time to give life-saving treatment.
CT scanning is painless, noninvasive and accurate.
A major advantage of CT is that it is able to image bone, soft tissue and blood vessels all at the same time.
Unlike conventional x-rays, CT scanning provides very detailed images of many types of tissue as well as the lungs, bones, and blood vessels.
CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives.
CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems.
CT is less sensitive to patient movement than MRI.
CT can be performed if you have an implanted medical device of any kind, unlike MRI.
CT imaging provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as needle biopsies and needle aspirations of many areas of the body, particularly the lungs, abdomen, pelvis and bones.
A diagnosis determined by CT scanning may eliminate the need for exploratory surgery and surgical biopsy.
No radiation remains in a patient's body after a CT examination.
X-rays used in CT scans usually have no side effects.
Risks
There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
The effective radiation dose from this procedure is about 8 mSv, which is about the same as the average person receives from background radiation in three years. See the Safety page for more information about radiation dose.
Women should always inform their physician and x-ray or CT technologist if there is any possibility that they are pregnant. See the Safety page for more information about pregnancy and x-rays.
CT scanning is, in general, not recommended for pregnant women unless medically necessary because of potential risk to the baby.
Nursing mothers should wait for 24 hours after contrast material injection before resuming breast-feeding.
The risk of serious allergic reaction to contrast materials that contain iodine is extremely rare, and radiology departments are well-equipped to deal with them.
Children should have a CT study only if it is essential for making a diagnosis and should not have repeated CT studies unless absolutely necessary.
What are the limitations of CT Scanning of the Chest?

A person who is very large may not fit into the opening of a conventional CT scanner or may be over the weight limit for the moving table.

Magnetic resonance imaging (MRI) may be better than CT for showing some types of soft-tissue.
Additional Information and Resources:
RadiologyInfo:

Radiation Therapy for Lung Cancer

Needle Biopsy of Lung (Chest) Nodules

Cardiac CT for Calcium Scoring

2008-11-26T21:16:00.003-08:00

What is Cardiac CT for Calcium Scoring?

CT scanningsometimes called CAT scanningis a noninvasive medical test that helps physicians diagnose and treat medical conditions.

CT scans of internal organs, bone, soft tissue and blood vessels provide greater clarity and reveal more details than regular x-ray exams.

A cardiac CT scan for coronary calcium is a non-invasive way of obtaining information about the presence, location and extent of calcified plaque in the coronary arteriesthe vessels that supply oxygen-containing blood to the heart wall. Calcified plaque is a build-up of fat and other substances, including calcium, and is a sign of atherosclerosis a disease of the vessel wall, which is called coronary artery disease (CAD). People with this disease have an increased risk for heart attacks. In addition, over time, progression of plaque build up (CAD) can narrow the arteries or even close off blood flow to the heart. The result may be painful angina in the chest or a heart attack.

Because calcium is a marker of CAD, the amount of calcium detected on a cardiac CT scan is a helpful prognostic tool. The findings on cardiac CT are expressed as a calcium score. Another name for this test is coronary artery calcium scoring.
What are some common uses of the procedure?

The goal of cardiac CT for calcium scoring is to determine if CAD is present and to what extent, even if there are no symptoms. It is a screening study that may be recommended by a physician for patients with risk factors for CAD but no clinical symptoms.

The major risk factors for CAD are:
abnormally high blood cholesterol levels
a family history of heart disease
diabetes
high blood pressure
cigarette smoking
being overweight or obese
being physically inactive
How should I prepare?

No special preparation is necessary in advance of a cardiac CT examination. You may continue to take your usual medications, but should avoid caffeine and smoking for four hours before the exam.

You should wear comfortable, loose-fitting clothing to your exam. You may be given a gown to wear during the procedure.

Electrodes (small metal discs) will be attached to your chest and to an electrocardiograph (ECG) machine that records the electrical activity of the heart. This makes it possible to record CT scans when the heart is not actively contracting.

Patients are asked to hold their breath for a period of 20 to 30 seconds while images are recorded.

When the examination is completed, you will be asked to wait until the technologist verifies that the images are of high enough quality for accurate interpretation.

The entire procedure including the actual CT scanning is usually completed within 10 minutes.
What will I experience during and after the procedure?

Most CT exams are painless, fast and easy. With helical CT, the amount of time that the patient needs to lie still is reduced.

You will be alone in the exam room during the CT scan, however, the technologist will be able to see, hear and speak with you at all times.

After a CT exam, you can return to your normal activities.
Who interprets the results and how do I get them?

A negative cardiac CT scan shows no calcification within the coronary arteries. This suggests that CAD is minimal and that the chance of having a heart attack over the next two to five years is very low.

A positive test means that CAD is present, regardless of whether or not the patient is experiencing any symptoms. The amount of calcificationexpressed as the calcium scoremay help to predict the likelihood of a myocardial infarction (heart attack) in the coming years.

The extent of CAD is graded according to your calcium score: Calcium Score Presence of CAD
0 No evidence of CAD
1-10 Minimal evidence of CAD
11-100 Mild evidence of CAD
101-400 Moderate evidence of CAD
Over 400 Extensive evidence of CAD

What are the benefits vs. risks?
Benefits
Cardiac CT for calcium scoring is a convenient and noninvasive way of evaluating whether you may be at increased risk for a heart attack.
The exam takes little time, causes no pain, and does not require injection of contrast material.
No radiation remains in a patient's body after a CT examination.
X-rays used in CT scans usually have no side effects.
Risks
There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
The effective radiation dose from this procedure is about 2 mSv, which is about the same as the average person receives from background radiation in eight months. See the Safety page for more information about radiation dose.
Women should always inform their physician and x-ray or CT technologist if there is any possibility that they are pregnant. See the Safety page for more information about pregnancy and x-rays.
CT scanning is, in general, not recommended for pregnant women unless medically necessary because of potential risk to the baby.
A high calcium score may sometimes be followed by other diagnostic tests for heart disease, which may not be necessary and might cause side effects.
What are the limitations of Cardiac CT for Calcium Scoring?

A person who is very large may not fit into the opening of a conventional CT scanner or may be over the weight limit for the moving table.

CAD, especially in people below 50 years of age can be present without calcium and may not be detected by this exam.

Not all health insurance plans cover cardiac CT for calcium scoring.

A high heart rate may interfere with the test. If a patient's heart rate is 90 or more beats per minute, the exam may need to be rescheduled.

Exactly how your treatment or prevention for heart attacks should be modified according to your calcium score remains uncertain.

MR Angiography (MRA)

2008-11-26T21:16:00.002-08:00

What is MR Angiography?

Angiography is a minimally invasive medical test that helps physicians diagnose and treat medical conditions. Angiography uses one of three imaging technologies and, in some cases, a contrast material to produce pictures of major blood vessels throughout the body.

Angiography is performed using:
x-rays with catheters
computed tomography (CT)
magnetic resonance imaging (MRI)

In magnetic resonance angiography (MRA), a powerful magnetic field, radio waves and a computer produce the detailed images. MR angiography does not use ionizing radiation (x-rays).

MR angiography may be performed with or without contrast material. If needed, the contrast material is usually injected using a vein in the arm.
What are some common uses of the procedure?

MR angiography is used to examine blood vessels in key areas of the body, including the:
brain
kidneys
pelvis
legs
lungs
heart
neck
abdomen

Physicians use the procedure to:
identify disease and aneurysms in the aorta, both in the chest and abdomen, or in other major blood vessels
detect atherosclerosis disease in the carotid artery of the neck, which may limit blood flow to the brain and cause a stroke
identify a small aneurysm or arteriovenous malformation inside the brain
detect atherosclerotic disease that has narrowed the arteries to the legs and help prepare for endovascular intervention or surgery
indicate disease in the renal artery or visualize blood flow to help prepare for a kidney transplant
guide surgeons making repairs to diseased blood vessels, such as implanting or evaluating a stent
detect injury to one of more arteries in the neck, chest, abdomen, pelvis or extremities in trauma patients
evaluate the details of arteries feeding a tumor prior to surgery or other procedures such as chemoembolization or selective internal radiation therapy
identify dissection or splitting in the aorta in the chest or abdomen or its major branches
show the extent and severity of atherosclerosis in the coronary arteries
plan for a surgical operation, such as coronary bypass
sample blood from specific veins in the body to detect any endocrine disease
examine pulmonary arteries in the lungs to detect pulmonary embolism (blood clots from leg veins)
screen individuals for arterial disease, especially patients with a family history of arterial disease or disorders
How should I prepare?

You may be asked to wear a gown during the exam or you may be allowed to wear your own clothing if it is loose-fitting and has no metal fasteners.

Guidelines about eating and drinking before an MRI exam vary at different facilities. Unless you are told otherwise, you may follow your regular daily routine and take medications as usual.

The MR angiogram may require the patient to receive an injection of contrast into the bloodstream. The radiologist or technologist may ask if you have allergies of any kind such as allergy to iodine or x-ray contrast material, drugs, food, the environment, or asthma. However, the contrast material used for an MRI exam, called gadolinium, does not contain iodine and is less likely to cause an allergic reaction than iodine used for CT scan.

The radiologist should also know if you have any serious health problems and what surgeries you have undergone. Some conditions, such as severe kidney or liver disease may prevent you from having an MRI with contrast material.

Women should always inform their physician or technologist if there is any possibility that they are pregnant. MRI has been used for scanning patients since the 1980's with no reports of any ill effects on pregnant women or their babies. However, because the baby will be in a strong magnetic field, pregnant women should not have this exam unless the potential benefit from the MRI is assumed to outweigh the potential risks. See the Safety page for more information about pregnancy and MR imaging.

If you are breastfeeding at the time of the exam, you should ask your radiologist how to proceed. It may help to pump breast milk ahead of time and keep it on hand for use after contrast material has cleared from your body, about 24 hours after the test.

If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want to ask your physician for a prescription for a mild sedative.

Young children should not eat or drink for about four hours if they will receive a sedative.

Jewelry and other accessories should be left at home if possible, or removed prior to the MRI scan. Because they can interfere with the magnetic field of the MRI unit, metal and electronic objects are not allowed in the exam room. These items include:
jewelry, watches, credit cards and hearing aids, all of which can be damaged.
pins, hairpins, metal zippers and similar metallic items, which can distort MRI images.
removable dental work.
pens, pocketknives and eyeglasses.
body piercings.

In most cases, an MRI exam is safe for patients with metal implants, except for a few types. People with the following implants cannot be scanned and should not enter the MRI scanning area unless explicitly instructed to do so by a radiologist or technologist who is aware of the presence of any of the following:
internal (implanted) defibrillator or pacemaker
cochlear (ear) implant
some types of clips used on brain aneurysms

You should tell the technologist if you have medical or electronic devices in your body, because they may interfere with the exam or potentially pose a risk. Examples include but are not limited to:
artificial heart valves
implanted drug infusion ports
implanted electronic device, including a cardiac pacemaker
artificial limbs or metallic joint prostheses
implanted nerve stimulators
metal pins, screws, plates or surgical staples.

In general, metal objects used in orthopedic surgery pose no risk during MRI. However, a recently placed artificial joint may require the use of another imaging procedure. If there is any question of their presence, an x-ray may be taken to detect the presence of any metal objects.

Patients who might have metal objects in certain parts of their bodies may also require an x-ray prior to an MRI. Dyes used in tattoos may contain iron and could heat up during MRI, but this is rarely a problem. Tooth fillings and braces usually are not affected by the magnetic field but they may distort images of the facial area or brain, so the radiologist should be aware of them.
What does the equipment look like?

The traditional MRI unit is a large cylinder-shaped tube surrounded by a circular magnet. You will lie on a moveable examination table that slides into the center of the magnet.

Some MRI units, called short-bore systems, are designed so that the magnet does not completely surround you; others are open on all sides (open MRI). These units are especially helpful for examining patients who are fearful of being in a closed space and for those who are very obese. Newer open MRI units provide very high quality images for many types of exams; however, open MRI units with older magnets may not provide this same quality. Certain types of exams cannot be performed using open MRI. For more information, consult your doctor.

The computer workstation that processes the imaging information is located in a separate room than the scanner.
How does the procedure work?

Unlike conventional x-ray examinations and computed tomography (CT) scans, MRI does not depend on radiation. Instead, while in the magnet, radio waves redirect the axes of spinning protons, which are the nuclei of hydrogen atoms, in a strong magnetic field.

The magnetic field is produced by passing an electric current through wire coils in most MRI units. Other coils, located in the machine and in some cases, placed around the part of the body being imaged, send and receive radio waves, producing signals that are detected by the coils.

A computer then processes the signals and generates a series of images each of which shows a thin slice of the body. The images can then be studied from different angles by the interpreting physician.

Overall, the differentiation of abnormal (diseased) tissue from normal tissues is often easier with MRI than with other imaging modalities such as x-ray, CT and ultrasound.

When a contrast material is introduced to the bloodstream during the procedure, it clearly defines the blood vessels being examined by making them appear bright white.
How is it performed?

This examination is usually done on an outpatient basis.

You will be positioned on the moveable examination table. Straps and bolsters may be used to help you stay still and maintain the correct position during imaging.

Small devices that contain coils capable of sending and receiving radio waves may be placed around or adjacent to the area of the body being studied.

If a contrast material will be used in the MRI exam, a nurse or technologist will insert an intravenous (IV) line into a vein in your hand or arm. A saline solution will drip through the IV to prevent blockage of the IV line until the contrast material is injected.

You will be moved into the magnet of the MRI unit and the radiologist and technologist will leave the room while the MRI examination is performed.

If a contrast material is used during the examination, it will be injected into the intravenous line (IV) after an initial series of scans. Additional series of images will be taken following the injection.

When the examination is completed, you may be asked to wait until the technologist checks the images in case additional images are needed.

Your intravenous line will be removed.

MRI exams generally include multiple runs (sequences), some of which may last several minutes.

The entire examination is usually completed within 30 to 60 minutes.
What will I experience during and after the procedure?

Most MRI exams are painless.

Some patients, however, find it uncomfortable to remain still during MR imaging. Others experience a sense of being closed-in (claustrophobia). Therefore, sedation can be arranged for those patients who anticipate anxiety, but fewer than one in 20 require it.

It is normal for the area of your body being imaged to feel slightly warm, but if it bothers you, notify the radiologist or technologist. It is important that you remain perfectly still while the images are being recorded, which is typically only a few seconds to a few minutes at a time. For some types of exams, you may be asked to hold your breath. You will know when images are being recorded because you will hear tapping or thumping sounds when the coils that generate the radiofrequency pulses are activated. You will be able to relax between imaging sequences, but will be asked to maintain your position as much as possible.

You will be alone in the exam room during the MR imaging, however, the technologist will be able to see, hear and speak with you at all times using a two-way intercom. Many MRI centers allow a friend or parent to stay in the room.

You may be offered or you may request earplugs to reduce the noise of the MRI scanner, which produces loud thumping and humming noises during imaging. MRI scanners are air-conditioned and well-lit. Some scanners have music to help you pass the time.

When the contrast material is injected, it is normal to feel coolness and a flushing for a minute or two. The intravenous needle may cause you some discomfort when it is inserted and once it is removed, you may experience some bruising. There is also a very small chance of irritation of your skin at the site of the IV tube insertion.

If you have not been sedated, no recovery period is necessary. You may resume your usual activities and normal diet immediately after the exam. A few patients experience side effects from the contrast material, including nausea and local pain. Very rarely, patients are allergic to the contrast material and experience hives, itchy eyes or other reactions.

It is recommended that nursing mothers not breastfeed for 36 to 48 hours after an MRI with a contrast material.
Who interprets the results and how do I get them?

Unlike CT angiography, MR angiography is not able to capture images of calcium deposits.

The clarity of MR angiography images does not yet match those obtained with conventional angiography. MRI of small vessels, in particular, may not be adequate for diagnosis and treatment planning. Sometimes it may be difficult to separate images of arteries from veins with MR angiography.

Individuals who cannot lie still or who cannot lay on their back may have MR angiography images that are of poor quality. Some tests require patients to hold their breath for 15 to 25 seconds at a time in order to get good MR angiography pictures.

High-quality images are assured only if you are able to remain perfectly still while the images are being recorded. If you are anxious, confused or in severe pain, you may find it difficult to lie still during imaging.

A person who is very large may not fit into the opening of a conventional MRI machine.

The presence of an implant or other metallic object often makes it difficult to obtain clear images and patient movement can have the same effect.

Although there is no reason to believe that magnetic resonance imaging harms the fetus, pregnant women usually are advised not to have an MRI exam unless medically necessary.

Contrast injections, especially early in the pregnancy, are usually avoided except when absolutely necessary for medical treatment.

CT Angiography (CTA)

2008-11-26T21:16:00.001-08:00

What is CT angiography?

Angiography is performed using:
x-rays with catheters
computed tomography (CT)
magnetic resonance imaging (MRI)

In CT angiography (CTA), computed tomography using a contrast material produces the detailed pictures. CT imaging uses special x-ray equipment to produce multiple images and a computer to join them together in multidimensional views.
What are some common uses of the procedure?

CT angiography is used to examine blood vessels in key areas of the body, including the:
brain
kidneys
pelvis
legs
lungs
heart
neck
abdomen

You should wear comfortable, loose-fitting clothing to your exam. You may be given a gown to wear during the procedure.

Women should always inform their physician and the CT technologist if there is any possibility that they are pregnant. See the Safety page for more information about pregnancy and x-rays.

When a contrast material is introduced to the bloodstream during the procedure, it clearly defines the blood vessels being examined by making them appear bright white.
How is the procedure performed?

This examination is usually done on an outpatient basis.

A nurse or technologist will insert an intravenous (IV) line into a small vein in your arm or hand.

A small dose of contrast material may be injected through the IV to determine how long it takes to reach the area under study. During scanning, the table will then move to the start point and then move relatively rapidly through the gantry opening in the machine as the actual CT scanning is performed. An automatic injection machine connected to the IV will inject contrast material at a controlled rate both prior to and during scanning.

You may be asked to hold your breath during the scanning.

When the examination is completed, you will be asked to wait until the technologist verifies that the images are of high enough quality for accurate interpretation.

Your intravenous line will be removed.

With modern equipment, the CT scanning only takes between 5 and 20 seconds to acquire the appropriate images. Your actual time in the scanner room will be longer as the technologist will have to position you on the table, check or place an IV line, do preliminary imaging to verify the beginning and end points of the study, and enter the injection and acquisition sequence into a computer.
What will I experience during and after the procedure?

Most CT exams are painless, fast and easy. With helical CT, the amount of time that the patient needs to lie still is reduced.

You will be alone in the exam room during the CT scan, however, the technologist will be able to see, hear and speak with you at all times.

With pediatric patients, a parent may be allowed in the room but will be required to wear a lead apron to prevent radiation exposure.

After a CT exam, you can return to your normal activities. If you received contrast material, you may be given special instructions.
Who interprets the results and how do I get them?

A physician, usually a radiologist with expertise in supervising and interpreting radiology examinations, will analyze the images and send a signed report to your primary care or referring physician, who will discuss the results with you.
What are the benefits vs. risks?
Benefits
Angiography may eliminate the need for surgery. If surgery remains necessary, it can be performed more accurately.
CT angiography is able to detect narrowing of blood vessels in time for corrective therapy to be done.
CT angiography gives more precise anatomical detail of blood vessels than magnetic resonance imaging (MRI).
Many patients can undergo CT angiography instead of a conventional catheter angiogram.
Compared to catheter angiography, which involves placing a catheter (plastic tube) and injecting contrast material into a large artery or vein, CT angiography is a much less invasive and more patient-friendly procedure.
This procedure is a useful way of screening for arterial disease because it is safer and much less time-consuming than catheter angiography and is a cost-effective procedure. There is also less discomfort because contrast material is injected into an arm vein rather than into a large artery in the groin.
No radiation remains in a patient's body after a CT examination.
X-rays used in CT scans usually have no side effects.
Risks
There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
If you have a history of allergy to x-ray contrast material, your radiologist may advise that you take special medication for 24 hours before CT angiography to lessen the risk of allergic reaction. Another option is to undergo a different exam that does not call for contrast material injection.
If a large amount of x-ray contrast material leaks out from the vessel being injected and spreads under the skin where the IV is placed, skin damage or damage to blood vessels and nerves, though unlikely, can result. If you feel any pain in this area during contrast material injection, you should immediately inform the technologist.
Women should always inform their physician and x-ray or CT technologist if there is any possibility that they are pregnant. See the Safety page for more information about pregnancy and x-rays.
Nursing mothers should wait for 24 hours after contrast material injection before resuming breast-feeding.
The risk of serious allergic reaction to contrast materials that contain iodine is extremely rare, and radiology departments are well-equipped to deal with them.
What are the limitations of CT Angiography?

A person who is very large may not fit into the opening of a conventional CT scanner or may be over the weight limit for the moving table.

CT angiography should be avoided in patients with advanced kidney disease or severe diabetes, because x-ray contrast material can further harm kidney function.

If a patient's heart is not functioning normally, or if there are multiple blocked blood vessels, CT angiograms may be hard to interpret. CT angiograms are not yet as reliable as selective catheter injections (performed after puncture of the artery in the groin) in imaging small tortuous arteries, particularly coronary arteries in the rapidly moving heart.

Catheter Angiography

2008-11-26T21:16:00.000-08:00

What is Catheter Angiography?

Angiography is performed using:
x-rays with catheters
computed tomography (CT)
magnetic resonance imaging (MRI)

In catheter angiography, a thin plastic tube, called a catheter, is inserted into an artery through a small incision in the skin. Once the catheter is guided to the area being examined, a contrast material is injected through the tube and images are captured using a small dose of ionizing radiation (x-rays).
What are some common uses of the procedure?

Catheter angiography is used to examine blood vessels in key areas of the body, including the:
brain
kidneys
pelvis
legs
lungs
heart
neck
abdomen

You should inform your physician of any medications you are taking and if you have any allergies, especially to iodinated contrast materials. Also inform your doctor about recent illnesses or other medical conditions.

You may be asked to remove some or all of your clothes and to wear a gown during the exam. You may also be asked to remove jewelry, eye glasses and any metal objects or clothing that might interfere with the x-ray images.

Women should always inform their physician or x-ray technologist if there is any possibility that they are pregnant. Many imaging tests are not performed during pregnancy so as not to expose the fetus to radiation. If an x-ray is necessary, precautions will be taken to minimize radiation exposure to the baby. See the Safety page for more information about pregnancy and x-rays.

If you are going to be given a sedative during the procedure, you may be asked not to eat or drink anything for four to eight hours before your exam. Be sure that you have clear instructions from your health care facility.

If you are sedated, you should not drive for 24 hours after for your exam and you should arrange for someone to drive you home. Because an observation period is necessary following the exam, you may be admitted to the hospital for an overnight stay if you live more than an hour away.
What does the equipment look like?

The equipment typically used for this examination consists of a radiographic table, an x-ray tube and a television-like monitor that is located in the examining room or in a nearby room. When used for viewing images in real time (called fluoroscopy), the image intensifier (which converts x-rays into a video image) is suspended over a table on which the patient lies. When used for taking still pictures, the image is captured either electronically or on film.

The catheter used in angiography is a long plastic tube about as thick as a strand of spaghetti.
How does the procedure work?

Catheter angiography works much the same as a regular x-ray exam.

X-rays are a form of radiation like light or radio waves. X-rays pass through most objects, including the body. Once it is carefully aimed at the part of the body being examined, an x-ray machine produces a small burst of radiation that passes through the body, recording an image on photographic film or a special digital image recording plate.

Different parts of the body absorb the x-rays in varying degrees. Dense bone absorbs much of the radiation while soft tissue, such as muscle, fat and organs, allow more of the x-rays to pass through them. As a result, bones appear white on the x-ray, soft tissue shows up in shades of gray and air appears black.

When a contrast material is introduced to the bloodstream during the procedure, it clearly defines the blood vessels being examined by making them appear bright white.
How is the procedure performed?

This examination is usually done on an outpatient basis.

A nurse or technologist will insert an intravenous (IV) line into a small vein in your hand or arm.

A small amount of blood will be drawn before starting the procedure to make sure that your kidneys are working and that your blood will clot normally. A small dose of sedative may be given through the IV line to lessen your anxiety during the procedure.

The area of the groin or arm where the catheter will be inserted is shaved, cleaned, and numbed with local anesthetic. The radiologist will make a small incision (usually a few millimeters) in the skin where the catheter can be inserted into an artery. The catheter is then guided through the arteries to the area to be examined. After the contrast material is injected through the catheter and reaches the blood vessels being studied, several sets of x-rays are taken. Then the catheter is removed and the incision site is closed by placing pressure on the area for approximately 10 minutes (or by using a special closure device).

When the examination is complete, you will be asked to wait until the radiologist determines that all the necessary images have been obtained.

Your intravenous line will be removed.

A catheter angiogram may be performed in less than an hour; however, it may last several hours.
What will I experience during and after the procedure?

Prior to beginning the procedure, you will be asked to empty your bladder.

You will feel a slight pin prick when the needle is inserted into your vein for the intravenous line (IV).

Injecting a local anesthetic at the site where the catheter is inserted may sting briefly, but it will make the rest of the procedure pain-free.

You will not feel the catheter in your artery, but when the contrast material is injected, you may have a feeling of warmth or a slight burning sensation. The most difficult part of the procedure may be lying flat for several hours. During this time, you should inform the nurse if you notice any bleeding, swelling or pain at the site where the catheter entered the skin.

You may resume your normal diet immediately after the exam. You will be able to resume all other normal activities 8 to 12 hours after the exam.
Who interprets the results and how will I get them?

A radiologist, a physician specifically trained to supervise and interpret radiology examinations, will analyze the images and send a signed report to your primary care or referring physician, who will discuss the results with you.
What are the benefits vs. risks?
Benefits
Angiography may eliminate the need for surgery. If surgery remains necessary, it can be performed more accurately.
Catheter angiography presents a very detailed, clear and accurate picture of the blood vessels. This is especially helpful when a surgical procedure or some percutaneous intervention is being considered.
By selecting the arteries through which the catheter passes, it is possible to assess vessels in several specific body sites. In fact, a smaller catheter may be passed through the larger one into a branch artery supplying a small area of tissue or a tumor; this is called superselective angiography.
Unlike computed tomography (CT) or magnetic resonance (MR) angiography, use of a catheter makes it possible to combine diagnosis and treatment in a single procedure. An example is finding an area of severe arterial narrowing, followed by angioplasty and placement of a stent.
The degree of detail displayed by catheter angiography may not be available with any other noninvasive procedures.
No radiation remains in a patient's body after an x-ray examination.
X-rays usually have no side effects in the diagnostic range.
Risks
There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
If you have a history of allergy to x-ray contrast material, your radiologist may advise that you take special medication for 24 hours before catheter angiography to lessen the risk of allergic reaction. Another option is to undergo a different exam that does not call for contrast material injection.
If a large amount of x-ray contrast material leaks out under the skin where the IV is placed, skin damage can result. If you feel any pain in this area during contrast material injection, you should immediately inform the technologist.
Women should always inform their physician or x-ray technologist if there is any possibility that they are pregnant. See the Safety page for more information about pregnancy and x-rays.
Nursing mothers should wait for 24 hours after contrast material injection before resuming breast-feeding.
The risk of serious allergic reaction to contrast materials that contain iodine is extremely rare, and radiology departments are well-equipped to deal with them.
There is a small risk that blood will form a clot around the tip of the catheter, blocking the artery and making it necessary to operate to reopen the vessel.
If you have diabetes or kidney disease, the kidneys may be injured when contrast material is eliminated through the urine.
Rarely, the catheter punctures the artery, causing internal bleeding. It also is possible that the catheter tip will separate material from the inner lining of the artery, causing a block downstream in the blood vessel.
What are the limitations of Catheter Angiography?

Patients with impaired kidney function, especially those who also have diabetes, are not good candidates for this procedure.

Patients who have previously had allergic reactions to x-ray contrast materials are at risk of having a reaction to contrast materials that contain iodine. If angiography is essential, a variety of methods is used to decrease risk of allergy:
You may be given one or more doses of a steroid medication ahead of time.
Contrast material without iodine may be used instead of standard x-ray contrast.

Catheter angiography should be done very cautiouslyif at allin patients who have a tendency to bleed.

External Beam Therapy (EBT)

2008-11-26T21:15:00.001-08:00

What is external beam therapy and how is it used?

External beam therapy (EBT) is a method for delivering a beam of high-energy x-rays to a patient's tumor. The beam is generated outside the patient (usually by a linear accelerator, see below) and is targeted at the tumor site. These high energy x-rays can deposit their dose deep within the body to destroy the cancer cells and, with careful treatment planning, spare the surrounding normal tissues. No radioactive sources are placed inside the patient's body.

External beam therapy can be used to treat the following diseases as well as many others:
Breast Cancer - see breast cancer page
Colorectal Cancer (Bowel Cancer) - see colorectal cancer page
Head and Neck Cancer - see head and neck cancer page
Lung Cancer - see lung cancer page
Prostate Cancer - see prostate cancer page

Who will be involved in this procedure?

Delivery of external beam therapy requires a treatment team, including a radiation oncologist, radiation physicist, dosimetrist and radiation therapist. The radiation oncologist is a physician who evaluates the patient and determines the appropriate therapy or combination of therapies. He or she determines what area to treat and what dose to deliver. Together with the radiation physicist and the dosimetrist, the radiation oncologist determines what techniques to use to deliver the prescribed dose. The physicist and the dosimetrist then make detailed treatment calculations. The radiation therapists are specially trained technologists who deliver the daily treatments
What equipment is used?

Radiation oncologists use linear accelerators or cobalt machines to deliver external beam therapy. Your radiation oncologist will determine the equipment most suited to your treatment. The linear accelerator is the most commonly used device for external beam therapy.

Linear Accelerator - see linear accelerator page
Who operates the equipment?

The equipment is operated by a radiation therapist, a highly trained technologist. The overall treatment plan is created by the radiation oncologist, a highly trained physician specializing in treating cancer with radiotherapy.
Is there any special preparation needed for the procedure?

The process of external beam therapy can be divided into three parts:
Simulation
Treatment Planning
Treatment Delivery

During simulation, the radiation therapist places the patient in the treatment position on a special x-ray machine or CT scanner and takes simulation x-rays. Masks, pads or other devices may be used to help the patient to hold still and in a specific position during the simulation. The radiation oncologist then locates the tumor volume and the region to be treated on these images. The dosimetrist and the radiation oncologist determine the best arrangement of radiation beams needed to treat the patient and the radiation therapist places small marks on the patients to help guide the daily treatments.

For treatment planning the dosimetrist, radiation physicist and radiation oncologist use a special computer to calculate the radiation dose that will be delivered to the patient's tumor and the surrounding normal tissue. The radiation oncologist will determine the volume of the tumor and other areas that needed to be treated and outline those on the treatment planning films. He or she will also outline normal structures that should be avoided or considered in devising the treatment plan. Together, the oncologist, dosimetrist and physicist will generate a treatment plan that delivers the appropriate dose to the tumor while minimizing dose to surrounding normal tissues. In certain cases, this process may employ such techniques as three-dimensional conformal therapy or intensity-modulated radiation therapy.

After the simulation and treatment planning have been completed, the treatment itself can begin.
How is the procedure performed?

The radiation therapist brings the patient into the treatment room and places him/her on the treatment couch of the linear accelerator in exactly the same position that was used for simulation using the same immobilization devices. The therapist carefully positions the patient using the alignment lasers and the marks that had been placed on the patient during simulation. Some form of imaging is often used prior to the treatment delivery to verify the accuracy of the patient setup. Some of the types of imaging that can be used include x-rays, ultrasound, and cone beam CT. The therapist goes outside the room and turns on the linear accelerator from outside. Beams from one or more directions may be used and the beam may be on for as long as several minutes for each field.

The treatment process can take 10 to 30 minutes each day and most of the time is often spent positioning the patient. The duration of a patient's treatment depends on the method of treatment delivery such as IMRT and the dose given. The length of each treatment will usually be the same from day to day.

Patients usually receive radiation treatments once a day, five days a week for a total of two to nine weeks. The patient's diagnosis determines the total duration of treatment. Occasionally, treatments are given twice a day.
What will I feel during this procedure?

External beam therapy is painless but you will hear a buzzing noise during treatment. You feel nothing out of the ordinary. Patients may sometimes smell an odd smell during treatment that is caused by the ozone produced by the linear accelerator. Some patients may also see a colored light when they receive their treatment; this event is especially true for patients having their brain treated.

Radiation Therapy for Lymphoma

2008-11-26T21:15:00.000-08:00

Facts About Lymphoma

The lymphatic system is a network of tiny vessels extending throughout the body. They are often next to the veins and arteries but are even smaller than them. Scattered along these vessels are lymph nodes. The lymphatic vessels carry a clear fluid called lymph from the extremities and organs back to the blood circulation. The job of the lymphatic system is to fight infection and disease. Cancer of the lymphatic system is called lymphoma. The two main types are Hodgkin's and non-Hodgkin's lymphomas.
Hodgkin's Lymphoma
Hodgkin's lymphoma (or Hodgkin's disease) most often begins in the larger, more central lymph nodes of the body 0 those along the largest blood vessels of the neck, central chest, abdomen along the spine, and armpit and groin areas where the vessels return from the arms and legs.
It is names for the British doctor Thomas Hodgkin, who first described the disease in 1832.
According to the American Cancer Society, more than 8,000 people will be diagnosed with Hodgkin's in the United States each year.
Hodgkin's is very treatable and often curable. More than 75 percent of patients with Hodgkin's live longer than 10 years after diagnosis.
Hodgkin's is usually treated with radiation therapy and/or chemotherapy, either alone or together.
Non-Hodgkin's Lymphoma (NHL)
NHL is a cancerous growth of cells that make up the lymph nodes.
NHL is eight times more common than Hodgkin's lymphoma. The American Cancer Society expects that 63,000 people will be diagnosed with the disease annually.
Since the 1970s, the number of people with NHL has increased significantly. Researchers are studying to see whether a gene makes people more likely to develop NHL.
There are about 30 types of NHL, and the best treatment depends on the exact type. All types of NHL are treatable, and many are curable.
NHL is usually treated with chemotherapy, radiation therapy, biologic therapy and/or a stem cell transplant. Depending on your cancer and overall health, you might receive only one of these treatments or several in combination.

Staging of Lymphoma

The stage of lymphoma is a term used to describe the extent of the disease.
Stage I: Single lymph node or non-lymph node region is affected.
Stage II: Two or more lymph nodes or non-lymph node regions are affected on the same side os the diaphragm (the muscle under the lungs).
Stage III: Lymph nodes or non-lymph node regions above and below the diaphragm are affected.
Stage IV: The cancer has spread outside the lymph nodes to organs such as the liver, bones or lungs. Stage IV can also refer to a tumor in another organ and/or tumors in the distant lymph nodes.

Talk to your physician to find out exactly which stage you have. Determining the stage and exact type of lymphoma (by microscopic examination of tissue from a biopsy) are essential steps toward planning the best treatment to cure your disease.

Treatment Options for Lymphoma

Treatment options depend on the type of lymphoma, its stage and your overall health. Treatment may include chemotherapy or radiation therapy, either alone or in combination. It may help to talk to several specialists before deciding on the best course of treatment for you, your disease and your lifestyle.
A radiation oncologist is a doctor who specializes in destroying diseased cells with high-energy X-rays or other types of radiation.
A medical oncologist is a doctor who is an expert at prescribing special drugs (chemotherapy) to treat disease. Some medical oncologists are also hematologists, meaning they have experience treating drug disorders.

Understanding Radiation Therapy

Radiation therapy, also called radiotherapy, is the careful use of radiation to kill diseased cells safely and effectively while avoiding nearby healthy tissue.
Radiation oncologists use radiation therapy to cure disease, to control disease growth or to relieve symptoms, such as pain.
Radiation therapy works within diseased cells by damaging their ability to grow. When these cells are destroyed by the radiation, the body naturally eliminates them.
Healthy tissue can also be affected by radiation, but they are usually able to repair themselves in a way that cancer cells cannot.

External Beam Radiation Therapy

External beam radiation therapy is a series of outpatient treatments to deliver radiation to the diseased cells accurately. Radiation therapy has been proven to be very successful at treating and curing lymphoma.
Radiation oncologists deliver external beam radiation therapy to the lymphoma from a machine called a linear accelerator.
Each treatment is painless and is similar to getting an X-ray. Treatments last less than 30 minutes each, every day but Saturday and Sunday, for several weeks.
Involved field radiation is when your doctor delivers radiation only to the parts of your body known to have the disease. It is often combined with chemotherapy. Radiation above the diaphragm to the neck, chest and/or underarms is called mantle field radiation. Treatment below the diaphragm to the abdomen, spleen and/or pelvis is called inverted-Y field radiation.
Your radiation oncologist may deliver radiation to all the lymph nodes in the body to destroy cells that may have spread to other lymph nodes. This is called total nodal irradiation.
Your radiation oncologist may also deliver radiation to the entire body. This is called total body irradiation. It is often done before chemotherapy and a stem cell or bone marrow transplant to eliminate any diseased cells.

Radiation therapy may be used alone or in combination with chemotherapy or biologic therapy. You will work with your radiation oncologist to agree on a treatment plan that is best for you.

Biologic Therapy

Also called immunotherapy, biologic therapy works with your immune system to fight disease. Biologic therapy is like chemotherapy. The difference is that chemotherapy attacks the diseased cells directly, and biologic therapy helps your immune system fight the disease.
Monoclonal antibodies work by targeting certain molecules in the body and attaching themselves to those molecules.This causes some cells to die and makes others more likely to be destroyed by radiation and chemotherapy.
Radiolabeled antibodies are monoclonal antibodies with radioactive particles attached. These antibodies are designed to attach themselves directly to the diseased cells and damage them with small amounts of radiation without injuring nearby healthy tissue.

Possible Side Effects

The side effects you might experience will depend on the part of the body being treated, the dose of radiation given and whether you also receive chemotherapy. Before treatment begins, ask you doctor about possible side effects and how best to manage them.
You may experience mild skin irritation like a sunburn, sore throat or upset stomach, loose bowels movement and/or fatigue. Most side effects will go away when treatment ends.
Radiation to your head or mouth may cause mouth dryness that can lead to tooth decay. Fluoride treatments may help, so your radiation oncologist will ask you to see a dentist before treatment begins.
You might loose you hair in areas treated. Your hair will grow back, but it might not have the same texture or thickness.
Tell your doctor or nurse if you experience any discomfort. They may be able to prescribe medication or change your diet to help.

These side effects are temporary and should go away after treatment ends. Your doctor will discuss any possible long-term side effects with you before treatment begins.

Brachytherapy

2008-11-26T21:14:00.005-08:00

What is brachytherapy and how is it used?

Brachytherapy is one type of radiation therapy used to treat cancer. Radiation therapy is the use of a type of energy, called ionizing radiation, to kill cancer cells and shrink tumors.

Unlike external beam therapy (EBT), in which high-energy x-ray beams generated by a machine are directed at the tumor from outside the body, brachytherapy involves placing a radioactive material directly inside the body.

Brachytherapy, also called internal radiation therapy, allows a physician to use a higher total dose of radiation to treat a smaller area and in a shorter time than is possible with external radiation treatment.

Brachytherapy is used to treat cancers throughout the body, including the:
Prostate - see the "Prostate Cancer" page
Cervix
Head and neck - see the "Head and Neck Cancer" page
Ovary
Breast - see the "Breast Cancer" page
Gallbladder
Uterus
Vagina

Brachytherapy may be either temporary or permanent:

In temporary brachytherapy, the radioactive material is placed inside or near a tumor for a specific amount of time and then withdrawn. Temporary brachytherapy can be administered at a low-dose rate (LDR) or high-dose rate (HDR).

Permanent brachytherapy, also called seed implantation, involves placing radioactive seeds or pellets (about the size of a grain of rice) in or near the tumor and leaving them there permanently. After several weeks or months, the radioactivity level of the implants eventually diminishes to nothing. The seeds then remain in the body, with no lasting effect on the patient.
Who will be involved in this procedure?

The delivery of brachytherapy requires a treatment team, including a radiation oncologist, radiation physicist, dosimetrist, and radiation therapist. The radiation oncologist is a physician who evaluates the patient and determines the appropriate therapy. He or she determines what area of the body to treat and how much radiation to deliver. Together with the radiation physicist and the dosimetrist, the radiation oncologist determines what techniques to use to deliver the prescribed dose. The physicist and the dosimetrist then make detailed treatment calculations. The radiation therapists are specially trained technologists who may assist in delivery of the treatments.
What equipment is used?

For permanent implants, radioactive material (which is enclosed within small seeds or pellets) is placed directly in the site of the tumor using a specialized delivery device. For temporary implants, needles, plastic catheters or specialized applicators are placed in the treatment site. Different types of radioactive material may be used according to the type of brachytherapy; some types of radiation sources used in brachytherapy are: iodine, palladium, cesium and iridium. In all cases of brachytherapy, the source of radiation is encapsulated which means that the radioactive material is enclosed within a non-radioactive metallic capsule.

After accurate positioning of the device(s) has been confirmed, the radiation sources are then inserted (afterloaded). The radiation oncologist may insert and remove the radioactive material manually after placing the delivery device, or the source(s) of radiation may be inserted using a computer-controlled machine. X-rays, ultrasound or CT scans may be used to help position the radioactive material to most effectively treat the tumor. For treatment planning, a computer is used to help calculate the amount of time needed to deliver the correct dose of radiation to the tumor.
Who operates the equipment?

The equipment is operated by a radiation physicist, a licensed dosimetrist who is supervised by a physicist, or a radiation oncologist. The overall treatment plan is created by the radiation oncologist, who is a highly trained physician specializing in treating cancer with radiotherapy.
Is there any special preparation needed for the procedure?

Your physician will determine which tests need to be done prior to your brachytherapy procedure. These may include:
Blood tests
Electrocardiogram (EKG)
Chest X-rays

Your physician may also schedule special imaging studies (such as MRI, CT or ultrasound) and use computer programs to plan the brachytherapy before the actual treatment procedure.

A few days before your procedure, you will be given specific instructions on how to prepare for your brachytherapy procedure.
How is the procedure performed?

Permanent brachytherapy:

In permanent brachytherapy, also called seed implantation, needles that are pre-filled with the radioactive seeds are inserted into the tumor. The needle or device is then removed, leaving the radioactive seeds behind. Seeds may also be implanted using a device that inserts them individually at regular intervals. X-rays, ultrasound or CT scans may be used to assist the physician in positioning the seeds. Additional imaging tests may be done after the implantation to verify seed placement.

Temporary brachytherapy:

In temporary brachytherapy, a delivery device, such as a catheter, needle, or applicator, is placed into the tumor using fluoroscopy, ultrasound or CT to help position the radiation sources. The delivery device may be inserted into a body cavity such as the vagina or uterus (intracavitary brachytherapy) or applicators (usually needles or catheters) may be inserted into body tissues (interstitial brachytherapy).

Treatments may be delivered at a high dose-rate (HDR) or a low dose-rate (LDR). Treatment may also be delivered in periodic pulses (pulsed dose-rate or PDR).

High-dose rate (HDR) brachytherapy is usually an outpatient procedure although patients are sometimes admitted to the hospital to have several HDR treatments using the same applicator. With HDR brachytherapy, a specified dose of radiation is delivered to the tumor in a short burst using a remote-afterloading unit. The treatment lasts only a few minutes although the entire procedure (including placement of the delivery device) may take up to several hours. This may be repeated several times in a day before the delivery device is removed and the patient returns home. Patients may receive up to 12 separate HDR brachytherapy treatments over one or more weeks.

With low-dose rate (LDR) brachytherapy, the patient is treated with radiation delivered at a continuous rate over several hours or days. A patient receiving LDR brachytherapy stays overnight at the hospital so the delivery device can remain in place throughout the treatment period. Pulsed dose-rate (PDR) brachytherapy is delivered in a similar way but the treatment occurs in periodic pulses (usually one per hour) rather than continuously.
The physician may insert the radioactive material manually through the delivery device and later remove the material and delivery device when the treatment is done.

Alternatively, the patient may be moved to a hospital room that contains a remote afterloading unit, which inserts the radioactive material to the delivery device within the tumor site. The radioactive material is automatically withdrawn when someone enters the patient's room and when the treatment is completed.

When the treatment is completed, the delivery device is removed from the patient.
What will I feel during this procedure?

Before the brachytherapy procedure begins, an intravenous line may be inserted into your arm or hand to deliver anesthetic medications. Depending on the site of the tumor and your physician's recommendations, you may receive general anesthesia and/or a sedative to make you feel drowsy. If anesthesia or heavy sedation is used, you may be transferred to a recovery room after the procedure. Depending on the type of brachytherapy, you may return home the same day or moved to a hospital room.

Patients who have an afterloaded implant for temporary brachytherapy may hear a clicking or humming noise from the treatment machine as the radioactive material is being pushed to the tumor site. Although you will be alone during the procedure, you will be able to speak via a speaker with members of your treatment team, who will be located nearby, where they can see and hear you. If you are treated with pulsed dose-rate brachytherapy, you may have visitors between the treatment pulses. With low dose-rate brachytherapy, visitors are usually limited to about 30 minutes per visitor per day.

With LDR, PDR, and some HDR brachytherapy treatments that require one or more days in the hospital, you may experience discomfort related to having to stay relatively still for a prolonged period of time. Your physician will prescribe medications to help relieve this.

Following permanent brachytherapy, in which radioactive seeds are implanted permanently in the body, the radioactivity of the seeds decays very quickly with time. However, you should discuss with your physician any recommendations for limiting close contact with others, such as pregnant women or children. For patients who have temporary implants, all radiation is removed before the patient returns home; there is no risk of radiation after the delivery device and radiation sources have been removed.

Your physician and/or treatment team will give you specific home-care instructions. You may experience tenderness and swelling in the treatment area or other symptoms depending on your specific procedure. Most patients are able to resume normal activities within days of brachytherapy. However, there may also be possible long-term side effects of radiation treatment. Members of your treatment team can advise you on managing the anticipated side effects of your brachytherapy treatment.

CT - Body

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What is CT Scanning of the Body?

CT scanningsometimes called CAT scanningis a noninvasive medical test that helps physicians diagnose and treat medical conditions.

CT scans of internal organs, bone, soft tissue and blood vessels provide greater clarity and reveal more details than regular x-ray exams.

Using specialized equipment and expertise to create and interpret CT scans of the body, radiologists can more easily diagnose problems such as cancers, cardiovascular disease, infectious disease, trauma and musculoskeletal disorders.
What are some common uses of the procedure?

CT imaging is:
one of the best and fastest tools for studying the chest, abdomen and pelvis because it provides detailed, cross-sectional views of all types of tissue.
often the preferred method for diagnosing many different cancers, including lung, liver and pancreatic cancer, since the image allows a physician to confirm the presence of a tumor and measure its size, precise location and the extent of the tumor's involvement with other nearby tissue.
an examination that plays a significant role in the detection, diagnosis and treatment of vascular diseases that can lead to stroke, kidney failure or even death. CT is commonly used to assess for pulmonary embolism (a blood clot in the lung vessels) as well as for abdominal aortic aneurysms (AAA).
invaluable in diagnosing and treating spinal problems and injuries to the hands, feet and other skeletal structures because it can clearly show even very small bones as well as surrounding tissues such as muscle and blood vessels.

Physicians often use the CT examination to:
quickly identify injuries to the lungs, heart and vessels, liver, spleen, kidneys or other internal organs in cases of trauma
guide biopsies and other procedures such as abscess drainages and minimally invasive tumor treatments
plan for and assess the results of surgery
plan and properly administer radiation treatments for tumors
measure bone mineral density for the detection of osteoporosis
How should I prepare?

You should wear comfortable, loose-fitting clothing to your exam. You may be given a gown to wear during the procedure.

For some CT exams, a contrast material is used to enhance visibility in the area of the body being studied.
How is the CAT scan performed?

If contrast material is used, it will be swallowed, injected through an intravenous line (IV) or administered by enema, depending on the type of examination.

You may be asked to hold your breath during the scanning.

When the examination is completed, you will be asked to wait until the technologist verifies that the images are of high enough quality for accurate interpretation.

CT scanning of the body usually lasts between five and 30 minutes.
What will I experience during and after the procedure?

Most CT exams are painless, fast and easy. With helical CT, the amount of time that the patient needs to lie still is reduced.

You will be alone in the exam room during the CT scan, however, the technologist will be able to see, hear and speak with you at all times.

With pediatric patients, a parent may be allowed in the room but will be required to wear a lead apron to prevent radiation exposure.

After a CT exam, you can return to your normal activities. If you received contrast material, you may be given special instructions.
Who interprets the results and how do I get them?

A physician, usually a radiologist with expertise in supervising and interpreting radiology examinations, will analyze the images and send a signed report to your primary care or referring physician, who will discuss the results with you.
What are the benefits vs. risks?
Benefits
CT scanning is painless, noninvasive and accurate.
A major advantage of CT is that it is able to image bone, soft tissue and blood vessels all at the same time.
Unlike conventional x-rays, CT scanning provides very detailed images of many types of tissue as well as the lungs, bones, and blood vessels.
CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives.
CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems.
CT is less sensitive to patient movement than MRI.
CT can be performed if you have an implanted medical device of any kind, unlike MRI.
CT imaging provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as needle biopsies and needle aspirations of many areas of the body, particularly the lungs, abdomen, pelvis and bones.
A diagnosis determined by CT scanning may eliminate the need for exploratory surgery and surgical biopsy.
No radiation remains in a patient's body after a CT examination.
X-rays used in CT scans usually have no side effects.
Risks
There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
The effective radiation dose from this procedure ranges from approximately two to 10 mSv, which is about the same as the average person receives from background radiation in three to five years. See the Safety page for more information about radiation dose.
Women should always inform their physician and x-ray or CT technologist if there is any possibility that they are pregnant. See the Safety page for more information about pregnancy and x-rays.
CT scanning is, in general, not recommended for pregnant women unless medically necessary because of potential risk to the baby.
Nursing mothers should wait for 24 hours after contrast material injection before resuming breast-feeding.
The risk of serious allergic reaction to contrast materials that contain iodine is extremely rare, and radiology departments are well-equipped to deal with them.
Children should have a CT study only if it is essential for making a diagnosis and should not have repeated CT studies unless absolutely necessary.
What are the limitations of CT Scanning of the Body?

Soft-tissue details in areas such as the brain, internal pelvic organs, knee or shoulder can be more readily and clearly seen with magnetic resonance imaging (MRI). The exam is not generally indicated for pregnant women.

A person who is very large may not fit into the opening of a conventional CT scanner or may be over the weight limit for the moving table.

Linear Accelerator

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What is this equipment used for?

A linear accelerator (LINAC) is the device most commonly used for external beam radiation treatments for patients with cancer. The linear accelerator can also be used in stereotactic radiosurgery similar to that achieved using the gamma knife on targets within the brain. The linear accelerator can also be used to treat areas outside of the brain. It delivers a uniform dose of high-energy x-ray to the region of the patient's tumor. These x-rays can destroy the cancer cells while sparing the surrounding normal tissue.

A linear accelerator is also used for Intensity-Modulated Radiation Therapy (IMRT).
How does the equipment work?

The linear accelerator uses microwave technology (similar to that used for radar) to accelerate electrons in a part of the accelerator called the "wave guide", then allows these electrons to collide with a heavy metal target. As a result of the collisions, high-energy x-rays are scattered from the target. A portion of these x-rays is collected and then shaped to form a beam that matches the patient's tumor. The beam comes out of a part of the accelerator called a gantry, which rotates around the patient. The patient lies on a moveable treatment couch and lasers are used to make sure the patient is in the proper position. Radiation can be delivered to the tumor from any angle by rotating the gantry and moving the treatment couch.
Who operates this equipment?

The patient's radiation oncologist prescribes the appropriate treatment volume and dosage. The medical radiation physicist and the dosimetrist determine how to deliver the prescribed dose and calculate the amount of time it will take the accelerator to deliver that dose. Radiation therapists operate the linear accelerator and give patients their daily radiation treatments.
How is safety ensured?

Patient safety is very important. During treatment the radiation therapist continuously watches the patient through a closed-circuit television monitor. There is also a microphone in the treatment room so that the patient can speak to the therapist if needed. Port films (x-rays taken with the treatment beam) are checked regularly to make sure that the beam position doesn't vary from the original plan.

The linear accelerator sits in a room with lead and concrete walls so that the high-energy x-rays do not escape. The radiation therapist must turn on the accelerator from outside the treatment room. Because the accelerator only gives off radiation when it is actually turned on, the risk of accidental exposure is extremely low. Indeed, pregnant women are allowed to operate linear accelerators.

Modern radiation machines have internal checking systems to provide further safety so that the machine will not turn on until all the treatment requirements prescribed by your physician are perfect. When all the checks match and are perfect, the machine will turn on to give your treatment.

Quality control of the linear accelerator is also very important. There are several systems built into the accelerator so that it won't deliver a higher dose than the radiation oncologist prescribed. Each morning before any patients are treated, the radiation therapist uses a piece of equipment called a "tracker" to make sure that the radiation intensity is uniform across the beam. In addition, the radiation physicist makes more detailed weekly and monthly checks of the accelerator beam.

Gamma Knife

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What is this equipment used for?

The gamma knife and its associated computerized treatment planning software enable physicians to locate and irradiate relatively small targets in the head (mostly inside the brain) with extremely high precision. Intense doses of radiation can be given to the targeted area(s) while largely sparing the surrounding tissues. The gamma knife can be used for a wide variety of problems. For example, it can be used to treat selected malignant tumors that arise in or spread to the brain (primary brain tumors or metastatic tumors), benign brain tumors (meningiomas, pituitary adenomas, acoustic neuromas), blood vessel defects (arteriovenous malformations) and functional problems (trigeminal neuralgia). Possible future uses are being evaluated for epilepsy and Parkinson's disease.

The gamma knife is usually unsuitable for targets larger than three or four centimeters in size.
How does the equipment work?

The gamma knife utilizes a technique called stereotactic radiosurgery, which uses multiple beams of radiation converging in three dimensions to focus precisely on a small volume, such as a tumor, permitting intense doses of radiation to be delivered to that volume safely. Gamma knife treatments are given in a single session.

Under local anesthesia, a special rigid head frame incorporating a three-dimensional coordinate system is attached to the patient's skull with four screws. Imaging studies, such as magnetic resonance imaging (MRI), computed tomography (CT), or angiography are then obtained and the results are sent to the gamma knife's planning computer system. Together, physicians (radiation oncologists and neurosurgeons) and medical radiation physicists delineate targets and normal anatomical structures and use the planning computer to determine the exact relationship between them and the headframe and calculate gamma knife treatment parameters. Targets often are best treated during the treatment session with combinations of several successive aimings, commonly known as "shots." The physicians and physicists routinely consider numerous fine-tuning adjustments of treatment parameters until an optimal plan and dose are determined.

Using the three-dimensional coordinates determined in the planning process, the frame is then precisely attached to the gamma knife unit to guarantee that when the unit is activated, the target is placed exactly in the center of approximately 200 precision-aimed, converging beams of (Cobalt-60 generated) gamma radiation. Treatment takes anywhere from several minutes to a few hours to complete depending on the shape and size of the target and the dose required. Patients do not feel the radiation. Following treatment the headframe is removed and the patient may return to normal activity.

See the Stereotactic Radiosurgery page for additional information.
Who operates this equipment?

A multidisciplinary team approach provides patients with the greatest safety. The team is most commonly comprised of a radiation oncologist, a medical radiation physicist and a neurosurgeonall specially trained in the use of the gamma knifewith support from nursing staff, anesthesiologists (for patients who are unable to cooperate, such as children) and radiation therapists, who work together to provide patients with the high-quality care they deserve.
How is safety ensured?

Because placement accuracy of the shots is critical to localization of the radiation (to a fraction of a millimeter) anything that would degrade this precision is unacceptable. Rigid attachment of the headframe, geographic targeting accuracy of the imaging studies, shaping of the volume of tissue to be treated (selection of the number, size and relative intensity of the shots) and accuracy of attachment of the frame to the gamma knife unit are all critical. As is true of all radiation therapy, correct selection and calculation of the amount of radiation to deliver are essential. A qualified medical physicist assures that the imaging and treatment planning computers and software are correct and acceptable. The mechanical functions of the machine are tested on a regular basis to ensure the safety of patients and medical staff.