Optimization of PET instrumentation for brain activation studies

By performing cerebral blood flow studies with positron emission tomography (PET) and comparing blood flow images of different states of activation, functional mapping of the brain is possible. The ability of current commercial instruments to perform such studies is investigated, based on a comparison of noise equivalent count (NEC) rates. Differences in the NEC performance of different scanners, in conjunction with scanner design parameters, provide insight into the importance of block design (size, dead time, crystal thickness) and overall scanner design (sensitivity and scatter fraction) for optimizing data from activation studies. The newer scanners with removable septa, operating with 3-D acquisition, have much higher sensitivity, but require new methodology for optimized operation. Only by administering multiple low doses (fractionation) of the flow tracer can the high sensitivity be utilized