核素成象的散射校正研究

The low-energy gamma photons employed in radionuclide imaging, gamma camera and SPECT, are largely scattered by body tissues. Scattering will decrease image contrast and spatial resolution, increase noise, and destroy the quantificational relationship between image and activity. The project investigates into the spatial and energy distribution of scattered photons emitted by the radiopharmaceutical in vivo, and the scattering effect to radionuclide imaging. We developed a spectrum-imaging acquisition system, estimated the scatter contribution according to the energy spectrum of each pixel, and correct it. And then examined above method by means of phantom and clinical study, evaluated the correction results and its accuracy. Basing on physical laws of interaction between photons and matter, an accurately scatter modeling (ASM) method was introduced to analytically calculate the spatial and energy distribution of scattered photons. A numerical integration method based on number theory improved scatter modeling calculation speed by one order of magnitude. Scatter model was incorporated into the system transfer matrix of OS-EM iterative reconstruction for scatter correction. The accuracy and racticability of ASM method was validated by Monte-Carlo simulated experiment. Results of physical experiments show that ASM method has obvious advantage in comparison with energy window subtracted scatter correction method, and can effectively improve the quality of radionuclide imaging and diagnostic level of nuclear medicine.During the research, we took the know-how about radionuclide imaging and analysis, developed the advanced nuclear medicine imaging system with picture archiving and communication system (PACS), which is adopted by manufactories.

核素显象（包括γ相机和SPECT）所使用的低能γ光子会被人体组织强烈地散射。散射本底贾峦枷蠖员榷群头直媛氏陆担蛊涫ザ恳庖濉１究翁饽庋芯咳颂迥诜派湫砸┪锼⑸涞摩霉庾颖簧⑸浜蟮目占浞植己湍芰糠植迹约吧⑸涠院怂爻上竦难兄颇芷资酵枷蟛杉低常萃枷笾懈鞲鱿笏氐哪芷追植脊兰破渲械纳⑸涑煞郑云浣行Ｕ煌üＰ秃土俅彩笛檠芯亢脱橹ど鲜龇椒ǎ⒍孕ＵЧ熬沸宰鞒銎兰邸４讼钛芯拷刮颐歉钊肓私猞霉庾釉诓∪颂迥诘纳⑸涔媛桑纳坪怂爻上裰柿浚岣吆艘窖У恼锒纤剑徽莆咋孟嗷蚐PECT的关键技术。.