A nuclear medicine procedure is sometimes described as an “inside-out” x-ray because it records radiation emitting from the patient’s body rather than radiation that is directed through the patient’s body. Nuclear medicine is unique because it shows how organs and tissues are working. It allows physicians to see how a kidney is functioning, not just what it looks like. Most other diagnostic imaging tests, such as x-ray exams, reveal only anatomical structure. There are more than 100 different nuclear medicine examinations to assess organ function. A thyroid uptake study shows how well the thyroid gland is working. A cardiac stress-rest test shows blood flow to the heart and helps your physician detect coronary artery disease. Bone scans can detect fractures, tumors and infections.
For most nuclear medicine examinations, you are positioned on a scanning table underneath a gamma camera. A radiopharmaceutical is administered by injecting it into a vein, taking it by mouth or inhaling it in aerosol form. It travels through your bloodstream to a specific area of the body where it accumulates in the organs or tissues to be imaged. The camera then detects and records the radioactive emissions from your body. Images are taken three to four hours after administration of the radiopharmaceutical. Most nuclear medicine procedures require several different images from different angles, and the technologist may ask you to change positions during the examination. You will need to lie still during each scan.
After the examination, your scans will be reviewed by a radiologist or nuclear medicine physician, specialists in interpreting diagnostic medical images. Your personal physician will receive a report of the findings. Your physician then will advise you of the results and discuss what further procedures, if any, are needed. In most cases, the radiation that you are exposed to during a nuclear medicine procedure is equal to or less than a standard x-ray of the same body area.
In general, the radiopharmaceutical administered during the examination will be eliminated naturally from your body in one or two days. Drinking fluids will help clear some kinds of radiopharmaceuticals from your system more quickly. You usually do not need to avoid contact with other people during this time, although your physician may recommend simple acts, such as flushing the toilet twice after using it, to reduce the small chance of radiation exposure to others in your household.