Introduction: Acute scrotal pain is an important clinical presentation that necessitates rapid and precise imaging
techniques to differentiate between urgent surgical cases and non-surgical cases. Radioisotope tyesticular
scintigraphy is a very helpful imaging modality to assess testicular blood flow. However, until now, all scrotal
scintigrphy studies have no standard values to compare with the other testicle and increase its diagnostic accuracy.
In this study we are going to find a standard, fixed-comparison region of interest.
Methods: Scrotal scintigraphy was done for 40 patients with acute scrotal pain after intravenous technetium
pertechnetate injection. Time-activity curve data was created and analyzed to create standard numeric data to
calculate the ratio between the testicular radioactivity count rate/background radioactivity count rate.
Results: Forty male patients between the ages of 7 to 21 years (mean 13.5 ± 5.3) were included. Their main complaint
was acute testicular pain. Twenty-four cases (60%) had left side pain and 16 cases (40%) had right side pain. Twentytwo
cases (45%) had a past history of similar attacks. A history of trauma was encountered in 9 cases (22.5%), 9
cases (22.5%) had a past history of recurrent inflammatory processes proved by previous ultrasonography, 6 cases
(18%) were known to have varicoceles, and 13 cases (32.5%) had testicular torsion after surgical exploration. The
numeric data showed that there was a correlation and a significant critical cut-off ratio between the testicular
radioactivity count. A background radioactivity count was determined by drawing symmetrical regions of interest
at both the testis and the medial aspect of the ipsilateral thigh, with a cut-off figure of 1.45 for normal testicular
radiotracer uptake and with a mean ratio of