A kidney nuclear medicine scan is a simple outpatient test that involves administering a small amounts of radioactive substances, called tracers, into the body and then imaging the kidneys and bladder with a gamma camera. A kidney (renal) nuclear medicine scan is used to diagnose certain kidney diseases such as renal failure, obstruction in their urine collection systems, renal artery stenosis, a kidney transplant etc.
While many tests, such as X rays, ultrasound exams, or computed tomography scans (CT scans), can reveal the structure of the kidneys (its anatomy), the kidney nuclear medicine scan is unique in that it reveals not only the anatomy of the kidneys, but how the kidneys are functioning. This additional "functional information" allows radionuclide imaging to diagnose certain diseases and various medical conditions much sooner than other imaging examinations.
For nuclear renal scan test a radioisotope "tracer" (Technetium DTPA) to molecule of which a radioactive atom or "tag" has been attached so that it can be followed through the kidney system with special detectors, is injected into a vein. Immediately after the tracer is injected, imaging begins. A gamma camera detects the radioactivity and the images may be projected on a computer screen and then stored on film. This test can take 45 minutes to three hours, depending on the goals of the test.
Radionuclide imaging is considered safe since it does not carry the risk of toxicity or allergic reaction found with intravenous dyes. Also the radioisotope tracer exposes the patient to less radiation than an X-ray.