[Clinical evaluation of renoscintigraphy using 123I-orthoiodohippurate--comparison with 131I-OIH and measurement of the effective renal blood flow].

Renoscintigraphy using 123I-orthoiodohipprate (123I-OIH) was conducted, and the dynamic imaging study results and the renograms were analyzed. The results using 123I-OIH were compared with those using 131I-OIH in 22 of 33 patients. Measurement of the effective renal blood flow (ERBF) was also performed using 123I-OIH by the single blood-sample method. 123I is a more suitable nuclide for gamma-camera scintigraphy than 131I in terms of physical characteristics, and a larger dose of 123I-OIH is possible than 131I-OIH because of its lesser radiation. These are the reasons why clearer dynamic images of the blood flow phase, functional phase and excretion phase can be obtained. These make possible diagnoses associated with the organic changes and functions. No essential differences could be found in the functional study results of renogram between the two drugs because on the nuclide of 131I is replaced by 123I, but a renogram with less statistical noise could be obtained using 123I-OIH than 131I-OIH. The radiation dose of 123I-OIH is less than that of 131I-OHI, and clearer dynamic images and functional indexes can be easily obtained in scintigraphy using 123I-OIH. It is concluded that 123I-OIH is a useful radiopharmaceutical for renal examination, and it should replace 131I-OIH.