부산대학교 도서관

PET imaging of rodents is increasingly used in preclinical research, but its utility is limited by the spatial resolution and statistical quality of the images. In a new approach, a specially designed pinhole collimator enables high-resolution, simultaneous imaging of PET and SPECT tracers. Such a physical collimation technique strongly departs from traditional electronic collimation achieved via coincidence detection in PET. This work compares two small animal PET scanners, one with electronic collimation (Focus120) and one with physical collimation using clustered pinholes (VECTor). Data were compared from Jaszczak (hot-rod) and uniform phantoms and point source measurements. Mouse brain images from [18F]FDG PET were acquired on both systems, and compared with quantitative ex-vivo autoradiography as a gold standard. Using typical reconstruction settings, the pinhole system resolved the smallest rods (0.85 mm diameter) in the Jaszczak phantom while the coincidence system resolved 1.3 mm diameter rods. This was in agreement with the recovered contrast. The contrast-to-noise ratio was better for the pinhole system when imaging small rods (