NONINVASIVE ARTERIAL MONITOR FOR QUANTITATIVE OXYGEN-15-WATER BLOOD-FLOW STUDIES

A noninvasive monitor has been developed for monitoring arterial radio activity in quantitative PET studies of blood flow. The significance o f this probe is that quantitative blood flow studies can be performed without the use of arterial catheterization. The method employed is ba sed on the flux of photons emanating from the superior lobe of the rig ht lung following an intravenous bolus of (H2O)-O-15. Calibration of t he monitor is obtained by measuring the relationship between lung moni tor counts and arterial radioactivity after arterial and venous radioa ctivity levels have equilibrated following inhalation of (CO)-O-15. To determine the accuracy of the lung probe as a measure of arterial rad ioactivity, 44 brain blood flow determinations were made in 11 volunte ers using arterial radioactivity measures based both on the lung probe and continuous sampling from a radial artery. Repeated measures analy sis of variance found no differences between invasive and noninvasive estimates of blood flow. These results suggest that the lung monitor e nables quantitation of cerebral blood flow yet avoids the trauma of an arterial puncture.