Absorbed radiation dose in adults from iodine-131 and iodine-123 orthoiodohippurate and technetium-99m DTPA renography.

A mathematic model for evaluation of absorbed dose in radionuclide renography has been developed and programmed for automatic calculation in the computer. Input data to the model are readily available from the results of the renography and, hence, the method described is suitable for individual dose determinations in adults. Apart from the situation with very considerable outflow obstructions [131I]OIH single probe renography involves a 15-20 times smaller dose to radiation sensitive organs than [123I]OIH gamma camera renography. Further, the latter examination results in a 2-10 times smaller dose than [99mTc]DTPA gamma camera renography under normal outflow conditions. Absorbed renal dose is large, approximately 70 mGy, in the three renographies in the borderline case with total outflow obstructions. For comparison, i.v. pyelography, which is the x-ray examination often used instead of radionuclide renography, involves an absorbed dose to ovaries 10-1000 times larger than in radionuclide renography.