What is Nuclear Medicine?
Nuclear medicine involves the use of small amounts of radioactive materials (or tracers) to help diagnose and treat a variety of diseases. Nuclear medicine determines the cause of the medical problem based on the function of the organ, tissue or bone. This is how nuclear medicine differs from an x-ray, ultrasound or any other diagnostic test that determines the presence of disease based on structural appearance. Read more, Stanford Hospital & Cliniccs »
VIDEO: What is Nuclear Medicine?
What is positron emission tomography (PET)?
PET is a powerful diagnostic test that is having a major impact on the diagnosis and treatment of disease. Because disease is a biological process and PET is a biological imaging examination, PET can detect and stage most cancers, often before they are evident through other tests. PET can also give physicians important early information about heart disease and many neurological disorders, like Alzheimer's.
A PET scan examines your body's chemistry. Most common medical tests, like CT and MR scans, only show details about the structure of your body. PET is different. It also provides information about function. With a single PET procedure, physicians can collect images of function throughout the entire body, uncovering abnormalities that might otherwise go undetected.
For example, a PET scan is the most accurate, non-invasive way to tell whether or not a tumor is benign or malignant, sparing patients expensive, often painful diagnostic surgeries and suggesting treatment options earlier in the course of the disease. And although cancer spreads silently in the body, PET can inspect all organs of the body for cancer in a single examination!
PET is able to detect extremely small cancerous tumors and very subtle changes of function in the brain and heart. This allows physicians to treat these diseases earlier and more accurately. A PET scan puts time on your side! The earlier the diagnosis, the better the chance for treatment.
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Is nuclear medicine safe?
Nuclear medicine procedures are among the safest diagnostic imaging exams available. A patient only receives an extremely small amount of a radiopharmaceutical, just enough to provide sufficient diagnostic information. In fact, the amount of radiation from a nuclear medicine procedure is comparable to, or often times less than, that of a diagnostic x-ray.
Although we don't think much about it, everyone is continually exposed to radiation from natural and manmade sources. For most people, natural background radiation from space, rocks, soil, and even carbon and potassium atoms in his or her own body, accounts for 85 percent of their annual exposure. Additional exposure is received from consumer products such as household smoke detectors, color television sets, and luminous dial clocks. The remainder is from x-rays and radioactive materials used for medical diagnosis and therapy. With most nuclear medicine procedures, the patient receives about the same amount of radiation as that acquired in a few months of normal living.
Because of their special training, the nuclear medicine physician is able to select the most appropriate examination for the patient's particular medical problem, thereby avoiding any unnecessary radiation exposure.
What are the benefits of nuclear medicine?
Nuclear medicine is a safe, painless, and cost-effective way of gathering information that may otherwise be unavailable or require a more expensive and risky diagnostic test. One unique aspect of a nuclear medicine test is its extreme sensitivity to abnormalities in an organ's structure or function. As an integral part of patient care, nuclear medicine is used in the diagnosis, management, treatment and prevention of serious disease. Nuclear medicine imaging procedures often identify abnormalities very early in the progression of a disease long before some medical problems are apparent with other diagnostic tests. This early detection allows a disease to be treated early in its course when there may be a better prognosis.
Although nuclear medicine is commonly used for diagnostic purposes, it also has valuable therapeutic applications such as treatment of hyperthyroidism, thyroid cancer, blood imbalances, and any bony pain from certain types of cancer.
How do I schedule a PET/CT scan?
Contact your physician's office and have their office contact the nuclear medicine schedulers in order to get the proper paperwork for the exam.
How should I prepare for the procedure?
No special preparation is required for scans involving the bones, inflammatory, lymphatic, brain, renal and pulmonary systems. Certain drug allergies should be noted for brain scans using Diamox.
Scans involving the gastrointestinal system require fasting at least 4 hours. Some scans require pre-medicating as a preparation.
Cardiac exams involve fasting for at least 4 hours before the exam and stress/persantine tests require no caffeine for 24 hours prior to the scan.
Thyroid scans may require cessation of certain medications prior to the scan.
How is the procedure performed?
You are given a small dose of radioactive material, usually intravenously but sometimes orally, that localizes in specific body organ systems. This compound, called a radiopharmaceutical or tracer, eventually collects in the organ and gives off energy as gamma rays. The gamma camera detects these rays and works with a computer to produce images and measurements of organs and tissues.
After the radiopharmaceutical is administered, depending on which type of scan is being performed, the imaging will be done either immediately, a few hours later, or even several days after it's administration. Imaging time varies, generally ranging from 20 to 45 minutes.
The radiopharmaceutical that is used is determined by what part of the body is under study since some compounds collect in specific organs better than others. Depending on the type of scan, it may take several seconds to several days for the substance to travel through the body and accumulate in the organ under study, thus the wide range in scanning times.
While the images are being obtained, you must remain as still as possible. This is especially true when a series of images are obtained to show how an organ functions over time.
After the procedure, a physician with specialized training in nuclear medicine checks the quality of the images to ensure that an optimal diagnostic study has been performed.
Patient Advocacy Sites
- Go to the Resources page to learn about nuclear medicine and its many different studies.