Radionuclides in the evaluation of urinary obstruction.

Radionuclide renography and renal scanning techniques are ideally suited to the initial and follow-up evaluation of patients with obstructive uropathy. While other modalities are superior in their ability to provide anatomic information, the radionuclide study yields functional information for each kidney without the necessity to resort to invasive studies. In addition, the Nuclear Medicine study is well suited to the evaluation of obstruction where serial studies often are required because of a lower radiation burden compared to urography. This lower radiation dose is especially important in obstruction because of the recurrent nature of several kinds of obstructive uropathy and because of the high incidence in the pediatric age group. The ability to control urine flow rate during the procedure through dehydration or administration of diuretics is an additional benefit. Increasing availability of computerization of nuclear medicine procedures as well as interest in studies employing physiologic intervention (including the diuresis renogram) have assured an important place for radionuclide studies in the evaluation of patients with urinary obstruction.