A renal scan is a diagnostic imaging test that allows healthcare providers to assess the structure and function of the kidneys. This nuclear medicine procedure involves introducing a small amount of radioactive material, called a radiotracer, into the body. The radiotracer travels through the bloodstream to the kidneys, and a special camera then detects the emissions to create images. Patients often inquire about the expected duration of this procedure.
Understanding the Renal Scan Duration
Imaging for a renal scan is brief, lasting between 20 to 45 minutes. However, the overall appointment often extends from 45 minutes to three hours, depending on the specific type of scan. The process begins with the intravenous injection of a radiotracer into a vein.
Following the injection, there is a waiting period, from 15 minutes to several hours, for the radiotracer to distribute in the kidneys. Some scans require a 2 to 3 hour waiting period before imaging. Once the tracer has distributed, the patient lies on an examination table while a gamma camera captures images of the kidneys. During this imaging phase, remaining still is important for clear, accurate pictures.
Variables Affecting Scan Time
The total duration of a renal scan varies due to the specific type of scan ordered. A standard renogram, or dynamic renal scintigraphy, assesses blood flow and urine drainage from the kidneys. The scan lasts 20 to 40 minutes, with the overall procedure taking 1 to 1.5 hours. If additional imaging with a diuretic like Lasix is required to assess for obstruction, the total time extends to 2 to 3 hours.
A DMSA scan evaluates the renal cortical tissue. For this scan, there’s a waiting period of 90 minutes to 4 hours after tracer injection before imaging begins, and the scan takes 30 to 45 minutes. A Captopril renal scan, used to investigate high blood pressure related to kidney arteries, involves two distinct scanning phases: one before and one after administering Captopril, a blood pressure medication. This specialized scan takes 2.5 to 3 hours, including a one-hour waiting period for the Captopril to take effect between the two 30-minute imaging sessions. Patient cooperation, especially for children or individuals who find it difficult to remain still, influences the need for repeated images, extending the overall time.