[Parametric images of central-type benzodiazepine receptor binding and ligand transport by two SPECT scans of 123I-iomazenil: relative quantification without blood data].

Parametric images of intrasubject distribution of the central-type benzodiazepine receptor binding and ligand transport were determined from two SPECT images after an intravenous bolus injection of 123I-iomazenil in six healthy volunteers and five patients by using a table look-up procedure based on a 3-compartment, 2-parameter kinetic model. Individual arterial input functions were estimated by calibrating a standardized input function with the injected dose to avoid blood sampling. The parametric images without blood data provided the same information as those determined by using measured arterial input function. A simulation study suggested that this method gave relatively small error as long as true receptor binding and ligand transport did not differ from each other in a large extent. The present method may be practical in clinical settings.