Optimization of H2(15)O-CBF method for higher signal-to-noise ratio

We described theoretical principle and data analysis for PET study using intravenous H2(15)O for measurement of cerebral blood flow (CBF) with emphasis on stimulation study for psychophysiological test. In order to improve signal-to-noise (S/N) ratio in CBF images, we optimized the scan procedures and data analysis. We determined optimal scantime of autoradiographic image to provide minimum S/N ratio as to 90 through 120 sec. Increase of full-width at half-maximum (FWHM) of smoothing filter did reduce the image noise (standard deviation, SD) more rapidly than the partial volume effect. Phantom experiment showed a tendency that a larger FWHM provided a higher statistical t-value.