Nuclear medicine is a specialized area of radiology that utilizes very small amounts of radioactive materials, or radiopharmaceuticals, to examine organ function and structure or to treat a specific disease or organ.
A small amount of a radioactive substance, called a radionuclide (radiopharmaceutical or radioactive tracer), is administered to the patient. The substance is absorbed by body tissue. Several different types of radionuclides are available. The radionuclide used will depend on the type of study or therapy and the body part being studied.
After the radionuclide has been administered and has collected in the body tissue under study, radiation will be given off. This radiation is detected by a radiation detector. The most common type of detector is the gamma camera. Digital signals are produced and stored by a computer when the gamma camera detects the radiation.
By assessing the pattern of uptake of the tracer in the body during a nuclear scan, the healthcare provider can assess and diagnose various conditions, such as tumors, infections, hematomas, organ enlargement, and cysts. A nuclear scan may also be used to assess organ function and blood circulation.
Scans are used to diagnose many medical conditions and diseases. Some of the more common tests include the following:
- Renal scans
- Thyroid scans
- Bone scans
- Infection imaging
- Brain/neurological imaging
- Tumor imaging/localization
- Hepatobiliary scans
- Gastrointestinal studies
- Cardiac ejection fraction
- Radionuclide therapy (thyroid problems, cancer, and pain management)
- I-131 therapy
- Y90 Sir Spheres
Patients may be asked to wear a gown during the exam, or they may be allowed to wear their own clothing.
Women should always inform their physician or technologist if there is any possibility that they are pregnant or if they are breastfeeding.
The patient will receive specific instructions based on the type of scan they are undergoing.
What to expect
Depending on the type of nuclear medicine exam the patient is undergoing, the dose of radiotracer is injected intravenously, swallowed, or inhaled as a gas.
It can take anywhere from several seconds to several days for the radiotracer to travel through the body and accumulate in the organ or area being studied. As a result, imaging may be done immediately, a few hours later, or even several days after the patient has received the radioactive material.
When it is time for the imaging to begin, the camera or scanner will take a series of images. The camera may rotate around the patient, or it may stay in one position. The patient may be asked to change positions in between images. While the camera is taking pictures, the patient will need to remain still for brief periods of time. This is necessary to obtain the best quality images.
The length of time for nuclear medicine procedures varies greatly, depending on the type of exam. Actual scanning time for nuclear imaging exams can take from 20 minutes to several hours and may be conducted over several days.
Except for intravenous injections, most nuclear medicine procedures are painless and are rarely associated with significant discomfort or side effects.