Scrotal Nuclear Medicine Scan Health Article

Definition

Scrotal nuclear medicine scan is a study of the tissues in the scrotum, using a radioactive contrast agent to identify masses, blood flow, and areas of infection.

Purpose

The scrotal nuclear medicine scan is used to assess blood flow within the testicles and damage caused by injury. It is also used to ascertain the cause of swollen testes (testicles) which may be due to infection or the twisting of the entire tissues of the testicle. This is done in an emergency setting if the testicle swells suddenly and painfully.

This scan can be used to diagnose tumors and cysts (pockets of fluid), but testicular ultrasound has become the diagnostic tool of choice for these growths in 2001.

Precautions

There are no precautions with a scrotal nuclear medicine scan, except that the patient must remain still during the procedure.

Description

A radioisotope, technetium-99, combined with a chemical (pertechnate) is injected intravenously while the patient is under a gamma camera that detects radiation. This special camera scans the scrotum at one minute intervals for about five minutes, then less often for another 10 or 15 minutes. It then creates pictures (either x ray or Polaroid) that reveal where the isotope is in the scrotum. Since both sides of the scrotum are scanned, even greater accuracy is obtained by comparison.

Some areas accumulate the tracer in greater than normal amounts. These are called "hot" spots and may indicate tumors or other masses. Areas that have less than normal amounts of the tracer or none at all are called "cold" spots and may indicated cysts or infection.

It is important to differentiate infection from twisting torsion and infection. A common infection called epididymitis involves a collection of tubules on top of the testicle called the epididymis that carry sperm. Twisting of the spermatic cord inside the scrotum, outside the testicle often shuts off the testes' blood supply and is called testicular torsion. Both conditions cause a very painful, swollen testicle on one side of the scrotum. Epididymitis and testicular torsion occur most often in young men, although infection usually occurs at a slightly older age. Infection increases the blood supply, showing up as a "hot" spot on the scan, whereas testicular torsion cuts off the blood supply, appearing as a "cold" spot. The distinction is critically important, because testicular torsion must be untwisted immediately by surgery or the testicle will die. On the other hand, epididymitis responds to antibiotics, and surgery might further injure it.

After the patient has changed into gown, he will lie on a scanning table. The penis will be taped to the abdomen to prevent it from shadowing the scan. A towel may be used to support the testicles during the test. The tracer will be injected into a vein on the inside of the elbow, and the camera will begin taking pictures of the testicles. It is important that the patient remain still during the scans.

Two complete passes are made about 15 minutes apart. The total scrotal scan takes about 45 minutes.