What is Nuclear Medicine?
Nuclear medicine is used to determine how an organ is functioning. For example, nuclear medicine can be used to study how a damaged heart is functioning or how blood flow is restricted in parts of the brain. Other organs that can be imaged using nuclear medicine include the liver, kidneys, thyroid, bones, and many others.
During a nuclear medicine study, chemicals "tagged" with radionuclides that emit gamma rays are injected into the body. The chemicals collect in the area of the body that is to be studied. Images, which may be taken immediately or days after the injection, are obtained by using a gamma camera that detects the gamma rays and produces an image map called a scintigram.
Nuclear medicine studies provide information that can help your doctor diagnose and treat diseases in their early stages. Nuclear medicine, using radioactive substances, can also be used to treat certain diseases and conditions, such as overactive thyroid glands or thyroid tumors.
Preparing for a Nuclear Medicine Study
Generally, there are no special preparations that need to be made prior to having a nuclear medicine study. However, certain types of studies may require some preparation. For example, prior to having a thyroid uptake and scan, your doctor may ask that you avoid foods and medications with iodine for one week prior to the test. Your doctor or radiologist can advise you about any special instructions you may need to follow.
What to Expect During a Nuclear Medicine Study
The most widely used tests include the thyroid uptakes and scans, and lung, liver, and bone scans.
- Thyroid Uptakes and Scans
During the thyroid uptake procedure, you will be asked to swallow a small amount of radioactive material. A counter measures how fast the material is "taken up" by the thyroid. This determines how well the thyroid is functioning. During a thyroid scan, you will either be asked to drink a radioactive material or receive the material through an injection. A gamma camera or scanner produces an image that shows your physician which parts of the thyroid are working properly.
- Lung Scans
The lung scan measures how air and blood move in and out of your lungs. Clots in the lungs can also be found and some heart and lung conditions can be monitored using lung scans.
During the lung scan, you will receive an injection of radioactive material, which is carried to the lungs. The gamma camera or scanner records images that determine how the lungs are functioning. X-rays of the lungs are also usually taken at this time.
- Liver Scans
A liver scan is used to diagnose disorders of the liver and problems in the digestive system. During a liver structure scan, you will receive an injection of radioactive material, and the scanner will measure how the liver, spleen, and bone marrow are functioning. The liver function scan (Hepatobiliary or "HIDA" scan) visualizes the function of the liver, gall bladder and intestines. You may also have various x-rays and blood tests taken to detect other problems that may result from a liver disorder.
- Bone Scans
Bone scans are used to detect abnormalities in the bones, such as fractures, tumors, inflammation and bone growth. During a bone scan, radioactive material is administered intravenously and is then carried by the blood to the skeletal system. The scans are usually done 2-3 hours later with the gamma camera. The images may visualize your whole body as well as other images of specific areas of your body.