Prolonged half-life following diuretic radionuclide urography as evidence of ureteral obstruction.

Diuretic radionuclide urography is an accurate technique for detecting obstruction as a possible cause of nephroureteral dilatation. This technique was used to evaluate radioisotope retention in the renal pelvis noted on the bone scan of a patient with prostate carcinoma. There was some washout of the pelvic radioactivity following intravenous furosemide, but the half-life was markedly prolonged, allowing the correct diagnosis of partial obstruction to be made.