[Determination of 131-J-hippuran clearance in renal camera functional scintigraphy using simplified Oberhausen's...

The determination of 131-I-Hippuran clearance in connection with renography or renal camera sequential scintigraphy will give a quantitative evaluation of total and individual renal function. The "single shot" method of Oberhausen yields clearance values corresponding very well to the PAH standard clearance. To simplify this method for routine use in connection with camera sequential scintigraphy, we studied some modifications of the method, using regional activity curves instead of the activity curve of the partially shielded whole body. Simultaneously with the camera sequential scintigraphy we measured activity curves of the partially shielded whole body (lead-shielding of kidneys and bladder, two probes), the shoulder (one probe), the head (one probe) and a background region of the camera (ROI) above the kidneys for 30 min. All four curves were analyzed, using computer analysis (bi-exponential curve fitting) as well as tables of Oberhausen, and his formula was used for clearance calculation. Under two conditions a) taking blood samples between 15 and 25 min. p.i. b) using the tables of Oberhausen for curve analysis, the clearance out of the regional activity curves correlates well with the clearance out of the partially shielded whole body activity curve (r greater than 0,97). Therefore, it is possible determine 131-I-Hippuran clearance in a simple manner without lead-shielding of kidneys and bladder, either with one additional probe measurement at shoulder or head or without any probe measurement, using the camera and measuring a background curve (ROI) above the kidneys. This simple clearance method can easily be performed simultaneously with 131-I-Hippuran renography or renal camera sequential scintigraphy in routine.