Kidney Scan

Renal Scan

Test Overview

A kidney scan is a nuclear scanning test that is done to evaluate kidney function.

During a kidney scan, a radioactive tracer substance is injected into a vein in the arm and then travels through the bloodstream to the kidneys. The tracer flows through the blood vessels in the kidneys. A special camera (gamma) takes pictures of the tracer in the kidneys. This helps show cell activity and function in the kidneys. Areas of the kidneys where the tracer shows up in higher-than-normal amounts, such as in some types of cancer, result in bright or “hot” spots in the pictures. Areas where the tracer does not show up appear as dark or “cold” spots. Cold spots can indicate narrowing or blockage of the blood vessels, pockets of fluid (cysts), some cancers, or pockets of infection (abscesses).

Two types of kidney scans can be done:

• A perfusion study can be done to evaluate the blood flow through the kidneys.
• A function study can be done to measure the amount of time it takes for the tracer to move through the kidney, collect in the urine, and drain into the bladder. See an illustration of the tracer in the kidneys and bladder.

These two types of kidney scans are often done at the same time.

A kidney scan may be done for people who are allergic to the special dye (contrast material) used for the kidney X-ray test called an intravenous pyelogram (IVP).

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Author:	Jan Nissl, RN, BS	Last Updated: November 1, 2006
Medical Review:	Patrice Burgess, MD - Family Medicine Kenneth B. Sutherland, CD, BSc, MD, FRCPC - Diagnostic Radiology
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