[A functional diagnostic method by measuring of distribution volume of 123I-IMP with SPECT].

To measure distribution volume of 123I-IMP with one-point sampling of arterial blood and 2 times SPECT scans using the Magic square method (Rate constant square method), we introduced a program on a SPECT computer system. In this program four functional images; distribution volume, CBF (K1), k2 and delayed/early ratio, and absolute values with S.D. are obtained on the computer. We have been using the program on daily SPECT studies. In this study we discussed the usefulness of the method. Redistribution phenomenon of 123I-IMP, which is not exactly enough investigated, can be transformed into a functional parameter, distribution volume. Since distribution volume represents an extent of retention of 123I-IMP in brain tissue, it can play an important role to evaluate functional activity in the brain and to diagnose cerebral diseases.