[Determination of cerebral blood flow using an 81Rb/81mKr generator system]

A method is being developed which not only measures cerebral blood flow as a static quantity but also its changes with time. For that purpose a semiconductor device ascertains the proportion of intracerebral 81 Rb and 81mKr activities. By opening the hemato-encephalic barrier in animal experiments a sufficient concentration of intracerebral 81 Rb could be attained and the modified blood circulation after step-wise ligature of all brain arteries brought into relation to the corresponding Rb/Kr quotient. Over the range from undisturbed to completely interrupted cerebral blood flow this quotient varied up to 25% of its initial value.