基于非标准扫描轨道HRT的小动物SPECT活体成像方法

In vivo animal SPECT imaging based on nonstandard HRT scan schemes

在分子影像学中,正电子发射断层成像(PET)和单光子发射断层成像(SPECT)因其功能成像特性及高检测灵敏性倍受瞩目。为了在PET固定探测器上,利用槽缝(slitslat)式准直器的嵌入实现SPECT的动物活体成像,实现小动物PET/SPECT双功能成像系统,研究了一类结合混合旋转-平移(hybrid rotation-translation,HRT)的非标准扫描轨道。通过定义采样完整度和采样均匀度指标,评价了不同平移和旋转运动组合的10种非标准扫描轨道在物体不同位置的表现,并进行了10种HRT轨道的Monte Carlo模拟成像实验,理论分析和Monte Carlo模拟结果都表明该方案在相同采集时间下可获得不差于传统圆轨道的成像质量。

Positron emission tomography （PET） and single photon emission computed tomography （SPECT） are key components in molecular imaging due to their functional imaging and high detection sensitivity. A small animal SPECT system was developed based on a fixed commercial animal PET scanner and a slit-slat collimator insert. In vivo animal imaging is possible with a class of non-conventional scanning schemes using a hybrid of limited-angle rotational and translational movements of the imaging object （HRT scheme）. The sampling completeness and sampling uniformity were used to characterize the performance for varied positions of the imaging object using ten different HRT schemes which were combinations of 2 translational modes and 5 rotational modes. SPECT imaging studies were performed with simulated Monte Carlo data to evaluate these 10 schemes. Theoretical results and the Monte Carlo imaging results show no image quality loss when compared to a conventional rotation scan scheme.