RADIONUCLIDE IMAGING OF THE URINARY-TRACT

Nuclear medicine procedures for urology have evolved during the past three decades. This article reviews the utility of the procedures, placing special emphasis on new developments and indications. The new radiopharmaceutical technetium Tc99m mercaptoacetyltriglycine ([Tc-99m]-MAG3), which is excreted via tubular secretion, is likely to replace technetium Tc99m diethylenetriaminepentacetic acid ([Tc-99m]-DTPA) and iodine I131 orthoiodohippurate ([I-131]-OIH) as the most desirable agent for renal radionuclide examinations. The most common uses of renal radionuclide examinations are to evaluate equivocal urinary obstruction and to evaluate renal transplants. Renewed interest in renography for hypertension has resulted from the use of Captopril as an adjunct to renography. Bone scintigraphy is more sensitive than radiography in detecting metastatic bone lesions, but other bone abnormalities can produce false-positive findings. Scrotal scintigraphy is very accurate as an aid in differentiating testicular torsion from other acute scrotal abnormalities. The major advantage of nuclear cystograms is decreased exposure of the patient to radiation.