THE USE OF A CLINICAL WHOLE-BODY COUNTER IN LONG-TERM EXCHANGEABLE SODIUM STUDIES FOR THE COMPARISON OF THE EFFECT OF DIFFERENT DIURETICS

¹ Division of Radioisotopes, "Alexandra" Hospital, and Department of Clinical Therapeutics, School of Medicine, University of Athens, Athens, Greece

By employing a clinical body counter and the long-lived gamma-ray emitter Na²², a method for studying sodium metabolism in human subjects has been developed which appears to be superior to the conventional balance techniques. The clinical body counter is composed of a 4-by 8-inch sodium iodide crystal which is connected to a 400-channel analyzer. Miller’s chair and geometry were used for the measurements. At the start of the study a tracer dose of 15 µc of Na²² was administered orally. The exchangeable body sodium was determined from Na²² body retention (as percentage of dose) and serum sodium specific activity (percentage of dose/mEq). The effect of polythiazide and quinethazone upon the body exchangeable sodium was compared in normal subjects and patients with cardiac and renal edema. No significant difference was observed in the diuretic effect of polythiazide and quinethazone in normal subjects. In the groups of cardiac and renal patients the diuretics used produced changes of the body exchangeable sodium.