【摘要】 为使小动物成像专用的MicroSPECT(micro single photon emission computed tomography)达到预期的分辨率和灵敏度指标,基于Monte Carlo方法对针孔准直器和成像系统参数进行设计并确定了两套设计方案。方案A保证灵敏度不低于9.19×10-6s-1.Bq-1,且视野中心位置的分辨率不差于1.0 mm;方案B在保证分辨率好于1.2 mm的前提下,可达到5.86×10-5s-1.Bq-1的灵敏度。进一步采用Monte Carlo方法估计了γ光子的准直器孔壁穿透效应和Compton散射效应对投影数据的影响。结果表明:穿透效应在方案A和B中对投影数据的贡献分别为28.6%和40.4%,而散射光子的贡献分别为12.4%和12.9%。更多还原

【Abstract】 Monte Carlo simulations were used to improve the spatial resolution and sensitivity of the MicroSPECT(micro single photon emission computed tomography) system by analyzing the system for various pinhole collimator and imaging system parameters.Design A offered a resolution better than 1.0 mm with over 9.19×10-6 s-1·Bq-1 sensitivity,while design B provided a sensitivity of 5.86×10-5 s-1·Bq-1 with a resolution of at least than 1.2 mm.The effects of collimator edge penetration and Compton scattering on the projection data were estimated by Monte Carlo simulations. The results show that the contributions of edge penetration are 28.6% for design A and 40.4% for design B and that of scattering are 12.4% for design A and 12.9% for design B.更多还原