Kidney Scan

Renal Scan

How It Is Done

A kidney scan is usually done by a nuclear medicine technologist. The scan pictures are usually interpreted by a radiologist or nuclear medicine specialist.

You will need to remove any jewelry that might interfere with the scan. You may need to take off all or most of your clothes, depending on which area is being examined (you may be allowed to keep on your underwear if it does not interfere with the test). You will be given a cloth or paper covering to use during the test.

The technologist cleans the site on your arm where the radioactive tracer will be injected. A small amount of the radioactive tracer is then injected. Medication to increase your urine output (a diuretic) may also be injected. You may lie on your back on a table, stand, or sit upright. A large scanning camera will be positioned closely above your abdomen. After the radioactive tracer is injected, the camera will scan for radiation released by the tracer and produce pictures as the tracer moves through your kidneys.

You need to lie very still during each scan to avoid blurring the pictures. The camera does not produce any radiation, so you are not exposed to any additional radiation while the scan is being done.

For the kidney function study, a different tracer may be injected and a series of pictures will be taken every few minutes for 30 minutes. These images monitor flow of the tracer through the kidneys, into the ureters and, finally, into the bladder. As each picture is being taken, you must lie completely still. Occasionally, scans may be done while you are sitting upright or standing. In some studies, other medications such as captopril or a diuretic, may be given to help assess specific functions of the kidneys.

A chart called a renogram may be made using the information from the perfusion study scans by plotting the movement of the tracer through the kidneys and recording it on a graph. A series of chart recordings is then made based on the amount of tracer uptake in the kidneys over a period of time. These recordings provide information about different phases of blood flow and kidney function. Another type of scan, called a static scan, also may be done several hours after a tracer is injected.

The kidney scan usually takes about 1 to 2 hours but can last up to 4 to 5 hours depending on what functions are being studied.

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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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