Generally, nuclear medicine scans do not provide the level of anatomic detail seen on X-ray, ultrasound, CT, or MR images. However, correlation with other imaging, clinical information, and laboratory results helps identify and confirm disease processes.

See bone scan, nuclear ventriculography (MUGA or RNV), pulmonary ventilation/perfusion scan, thyroid scan, lung scan, renal scan.

How the Test is Performed

A radioactive isotope needs to be introduced into the body. This may be done in several ways:

• Through a needle into a vein (usually the inside of the elbow).
• Through a catheter, that is inserted into a vein or artery and is then guided to the organ being tested.
• Ingestion (for example, to test the thyroid, the patient drinks radioactive iodine).
• Subcutaneous injection (under the skin)
• Collecting a patient's own blood from a vein, adding the radioisotope compound in a laboratory, and then injecting back into the patient.

After a certain period of time has passed (ranging from a few hours to a day or more for different exams), you will be placed on a table (called a gantry) under the scanner, which may rotate around the body. Is it imperative that you remain still to produce accurate and useful sets of images.  For some tests, a counter is placed over the organ, and the amount of radioactivity or intensity of radioactivity is recorded.

A technician interprets the information as it is transmitted to the computer and can guide the camera to specific locations to improve the imaging.

How to Prepare for the Test

Inform the technician or physician of all medications you are currently and have recently been taking, since they may interfere with the isotopes given for the exam. Also be sure to mention any recent imaging studies involving injected contrast media (dye) and oral or rectal contrast (such as from gastrointestinal studies) since they may also limit the study. You must sign a consent form before the radioactive compound is given. You may need to fast overnight before the test. Depending on the region being scanned, you may need to wear a hospital gown. Remove jewelry, dentures, and other metal that may affect the scan by blocking the gamma rays from the detectors.

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child’s age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child’s age:

• infant test or procedure preparation (birth to 1 year)
• toddler test or procedure preparation (1 to 3 years)
• preschooler test or procedure preparation (3 to 6 years)
• schoolage test or procedure preparation (6 to 12 years)
• adolescent test or procedure preparation (12 to 18 years)

How the Test will Feel

If the isotope is injected, there will be a sharp prick when the needle is inserted. If a catheter is inserted, the site of insertion is usually numbed with an anesthetic. You will first feel a prick when the needle is inserted but will feel little more than slight pressure or tugging during the injection of the isotope. If the isotope is ingested, the flavor of the liquid may be unpleasant, but no pain is involved.

For patients who are extremely sensitive to the isotope, there may be nausea, headache, or vomiting. Discuss allergies with the health care provider or technician before the test.

Why the Test is Performed

Nuclear radiography shows the size, shape, position, and some function of the target organs specific for a particular radioisotope molecule. If another test has indicated cancer or abscess, this test can help support that diagnosis and indicate the location. Repeat examinations can be used to gauge response to therapies.

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