Radioactive uptake
Key points
- Nuclear Radiology is a sub-specialty of Radiology in which radioisotopes (compounds containing radioactive forms of atoms) are introduced into the body for the purpose of imaging, evaluating organ function, or localizing disease or tumors.
- A radioactive isotope needs to be introduced into the body.
- 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.
- The preparation you can provide for this test depends on your child's age and experience.
Alternative names
Scintillation; Radionuclide organ imaging; Radioisotope; Isotope study; PET scan; Nuclear Radiography; Nuclear medicine scan
Definition
Nuclear Radiology is a sub-specialty of Radiology in which radioisotopes (compounds containing radioactive forms of atoms) are introduced into the body for the purpose of imaging, evaluating organ function, or localizing disease or tumors.
Unlike conventional or computed radiography (such as plain X-rays and CT scans) in which X-ray beams are generated within a machine and projected through the patient, in isotope studies the radiation (gamma rays) originates from within a radiopharmaceutical (material tagged with a radioisotope) in the body.
Special detector cameras are placed close against the area of interest for a period of time, and once enough gamma rays are "seen," a computer creates an image representing where the isotope localized within the organ or body.
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.
See bone scan, nuclear ventriculography (MUGA or RNV), pulmonary ventilation/perfusion scan, thyroid scan, lung scan, and 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.
Written and revised by
Gerald Hurowitz, M.D.
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