부산대학교 도서관

The purpose of this study was to investigate an optimal readout for a high-resolution compact gamma camera with maximum performance in crystal element identifications. The compact camera is based on a pixellated NaI(Tl) crystal with 1.2mm pixel size coupled to a 5” Hamamatsu R3292 PSPMT. A conventional resistive-chain readout was initially developed for the camera. Then a novel subtractive resistive readout developed was utilized to optimize the performance of the camera. The performance of the camera was evaluated by raw flood images of a 137 Cs source. The results show that the conventional resistive readout results in a significant shrinkage of the useful field-ofview (UFOV) of the detector with a maximum of resolvable crystal elements of 64×64, which is about 89% of the active-area of the PSPMT’s (∼10cm). The subtractive resistive readout can maximize the crystal element identifications up to 71×71 while improve the UFOV of the detector up to almost the full activearea of the PSPMT’s. In the central region of the camera, the subtractive resistive readout also improve the peak-valley ratio of the crystal elements from 1.5:1 to 2:1 as compared the conventional resistive readout. The phantom and in vivo mouse imaging studies demonstrate that the compact camera with subtractive resistive readout can provide very good performance for high-resolution SPECT. We concluded that the subtractive resistive readout is an effective approach for an optimal readout for the development of high-resolution compact gamma cameras.