Abstract: In a blood flow measuring apparatus, a data processor in a computer determines three parameters from a (?CT value of CT image data corresponding to) time-course change, consisting of a test region rate constant K, an arterial blood rate constant Ka, and a xenon partition coefficient ?. A blood flow f is determined using the determined rate constant K, and the xenon partition coefficient ?.

Abstract: In a blood flow measuring apparatus, a data processor in a computer determines three parameters from a (?CT value of CT image data corresponding to) time-course change, consisting of a test region rate constant K, an arterial blood rate constant Ka, and a xenon partition coefficient ?. A blood flow f is determined using the determined rate constant K, and the xenon partition coefficient ?.

Abstract: It is intended to correctly determine the cerebral blood flow in a successful manner. When a constant &ggr; is determined in a relational expression of {Ka=&ggr;×(1−exp(−Ke/&ggr;))} provided that Ke represents an end-tidal air velocity constant and Ka represents an arterial blood velocity constant concerning a xenon CT examination, a K-S-calculating means determines a temporary calculated value &lgr;&agr; of a brain/blood distribution coefficient &lgr; from temporary calculated values Kai&agr;, Kao&agr; obtained by a Ke/Ka conversion means on the basis of an assumed value &ggr;&agr; of the Ke/Ka conversion constant &ggr; set by an assumed value-setting means. In this case, the assumed value-setting means varies the assumed value &ggr;&agr; within a desired range.

Abstract: In order to easily measure the hepatic arterial blood flow amount and the portal blood flow amount flowing through the liver, a mixed gas supply apparatus is used to supply a mixed gas of xenon gas and oxygen gas to the lung of a specimen for a certain period of time so that the change in xenon concentration in the tissue of the liver of the specimen is measured (detected) while making decomposition into picture elements by using an X-ray CT system. The hepatic arterial blood flow amount and the portal blood flow amount concerning the respective picture elements obtained by the decomposition are determined by using a computer on the basis of the fact that the xenon concentration in the liver tissue is determined by the xenon concentration in the hepatic arterial blood flow and the xenon concentration in the portal blood flow.