Tc-99m DTPA or MAG3 renal scan
What is a DTPA Renal Scan?
This Nuclear Medicine scan can determine overall renal (kidney) function and also relative left and right kidney function. The test is performed using the radiotracer called Tc-99m diethylene-triamine-penta-acetic acid (DTPA). The test is often used in combination with a diuretic drug such as frusemide to determine if a kidney is obstructed. This scan is also used to look for narrowing of the renal arteries as a cause of high blood pressure (hypertension). It is often combined with a type of anti-hypertensive drug known as an angiotension-converting enzyme inhibitor (ACEI) for this purpose. The scan can also be very useful in assessing the function of renal transplant grafts.
How is the scan performed?
The patient needs to be well hydrated before the scan. This usually means that an extra glass or two of water taken an hour before the scan is adequate. Before the scan a small intravenous cannula will be placed in an arm vein. The patient is then positioned on a comfortable scanning bed and a small dose of Tc-99m DPTA is given intravenously through the cannula. Imaging of the urinary tract (abdomen) is then performed over the next 20-30 minutes using a gamma camera.
What does the referring doctor need to know?
If the referring doctor is looking for a cause of hypertension and wishes to use an ACEI for this purpose, some of the patient’s regular antihypertensive drugs may need to be temporarily stopped. This is best discussed with the attending Nuclear Medicine physician.
PLEASE BRING ANY OTHER X-RAYS, ULTRASOUNDS, CT SCANS, MRI SCANS, MEDICATION LIST OR RELEVANT MEDICAL HISTORY ON THE DAY OF NUCLEAR MEDICINE SCAN