Systematic difference of extrarenal background in left and right kidney regions at renography.

The problem of whether the extrarenal sodium [131I]iodohippurate background activity at renography is higher in the right kidney region than in the left was studied by analyzing data from 711 consecutive renographies. The 3 conical collimators had an aperture diameter of 78 mm, an internal diameter at crystal surface of 50 mm, and a skin-to-crystal surface distance of 115 mm, thus allowing the radioactivity of almost the entire kidney to be registered with equal efficiency.