Sub-millimetre DOI detector based on monolithic LYSO and digital SiPM for a dedicated small-animal PET system
Sub-millimetre DOI detector based on monolithic LYSO and digital SiPM for a dedicated small-animal PET system
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DOI：
10.1088/0031-9155/61/5/2196
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发表时间：
2016-03-07
影响因子：
3.5
通讯作者：
Vandenberghe, Stefaan
中科院分区：
文献类型：
--
作者：
Marcinkowski, Radoslaw;Mollet, Pieter;Vandenberghe, Stefaan
小鼠模型广泛用于各种生物医学和临床前研究。由于能够在体内分子水平上检测和量化生物过程，PET已成为这些研究中的一种成熟工具。然而，需要可视化和量化的放射性药物在解剖结构的毫米或更少需要良好的空间分辨率和灵敏度从小动物PET imaging systems.In以前的工作中，我们已经提出了一个概念验证的专用高分辨率小动物PET扫描仪的基础上薄单片闪烁晶体和数字光子计数器光电传感器。薄单片晶体和MLE定位算法的组合导致在整个视场（FOV）中均匀的0.7 mm的优异空间分辨率。然而，扫描仪的局限性是它的低灵敏度，由于小厚度的氧化硅酸镥钇（LYSO）晶体（2毫米）。在这里，我们提出了一种改进的探测器设计的小动物PET系统，同时实现更高的灵敏度和维持亚毫米的空间分辨率。建议的检测器由5 mm厚的单片LYSO晶体光学耦合到数字光子计数器。平均最近邻（MNN）定位结合相互作用深度（DOI）解码，以实现亚毫米级的空间分辨率。为了评价探测器的性能，测量了固有空间分辨率、能量分辨率和符合分辨时间（CRT）。探测器的平均固有空间分辨率为0.60 mm半高全宽（FWHM）。DOI分辨率达到1.66 mm。在511 keV能量下，能量分辨率为23%FWHM，CRT为529 ps。改进的探测器设计通过增加探测器块的标称灵敏度克服了先前设计的灵敏度限制，并且保留了优异的固有空间分辨率。
The mouse model is widely used in a vast range of biomedical and preclinical studies. Thanks to the ability to detect and quantify biological processes at the molecular level in vivo, PET has become a well-established tool in these investigations. However, the need to visualize and quantify radiopharmaceuticals in anatomic structures of millimetre or less requires good spatial resolution and sensitivity from small-animal PET imaging systems.In previous work we have presented a proof-of-concept of a dedicated high-resolution small-animal PET scanner based on thin monolithic scintillator crystals and Digital Photon Counter photosensor. The combination of thin monolithic crystals and MLE positioning algorithm resulted in an excellent spatial resolution of 0.7 mm uniform in the entire field of view (FOV). However, the limitation of the scanner was its low sensitivity due to small thickness of the lutetium-yttrium oxyorthosilicate (LYSO) crystals (2 mm).Here we present an improved detector design for a small-animal PET system that simultaneously achieves higher sensitivity and sustains a sub-millimetre spatial resolution. The proposed detector consists of a 5 mm thick monolithic LYSO crystal optically coupled to a Digital Photon Counter. Mean nearest neighbour (MNN) positioning combined with depth of interaction (DOI) decoding was employed to achieve sub-millimetre spatial resolution. To evaluate detector performance the intrinsic spatial resolution, energy resolution and coincidence resolving time (CRT) were measured. The average intrinsic spatial resolution of the detector was 0.60 mm full-width-at-half-maximum (FWHM). A DOI resolution of 1.66 mm was achieved. The energy resolution was 23% FWHM at 511 keV and CRT of 529 ps were measured. The improved detector design overcomes the sensitivity limitation of the previous design by increasing the nominal sensitivity of the detector block and retains an excellent intrinsic spatial resolution.