Improving the Time Resolution of TOF-PET Detectors by Double-Sided Readout
Improving the Time Resolution of TOF-PET Detectors by Double-Sided Readout
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DOI：
10.1109/tns.2014.2368932
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发表时间：
2015-02-01
影响因子：
1.8
通讯作者：
Schaart, Dennis R.
中科院分区：
文献类型：
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作者：
Seifert, Stefan;Schaart, Dennis R.
用于离光时间正电子发射断层扫描（TOF-PET）的现有技术的闪烁探测器通常采用具有高纵横比（例如，G. mm）在其中一个小晶体表面上读出。这种单侧读出（SSR）几何结构在可以实现的符合分辨时间（CRT）方面可能是不利的，因为其对光收集效率的影响;闪烁光子传播时间的扩展;以及与相互作用深度（DOI）相关的可变检测延迟。在这项工作中，它是调查在何种程度上可以减轻这些影响，通过应用快速的光电传感器上的每个小晶体表面。这种双面读出（DSR）先前已经被引入以对抗DOI相关视差误差的问题。为了本目的，我们使用滨松MPPC-S10362-33-050 C硅光电倍增管（SiPM）光耦合到LSO：Ce，Ca晶体管。对于抛光后的毫米级晶体，分别测定了正面和侧面辐照的ps半高宽和ps半高宽CRT值。在这种情况下，DSR改善CRT下测得的侧面照射到ps的FWHM。对于具有蚀刻侧表面的同等尺寸的晶体，观察到更大的改善。对于这些晶体，CRT从SSR的ps FWHM（正面照射）和FWHM（侧面照射）变为DSR的ps FWHM（侧面照射）。这些值与采用LSO：Ce，Ca晶体的探测器的时间分辨率进行了比较，其尺寸为mm（ps FWHM）和mm（ps FWHM和ps分别用于抛光和蚀刻晶体）。
State-of-the-art scintillation detectors for time-offlight positron emission tomography (TOF-PET) typically employ scintillation crystals with a high aspect ratio (e. g. mm) read out on one of the small crystal surfaces. This single-sided readout (SSR) geometry may be unfavorable in terms of the coincidence resolving time (CRT) that can be achieved because of its effect on the light collection efficiency; the spread in the scintillation photon propagation times; and depth-of-interaction (DOI) related, variable detection delays. In this work it is investigated to which extent these effects can be mitigated by applying a fast photosensor on each of the small crystal surfaces. Such double-sided readout (DSR) has been introduced previously to counter the issue of DOI-related parallax errors. For the present purpose, we used Hamamatsu MPPC-S10362-33-050 C silicon photomultipliers (SiPMs) optically coupled to LSO: Ce, Ca scintillators. For polished mm crystals with SSR, CRT values of ps FWHM and ps FWHM were determined for irradiation head-on and from the side, respectively. In this case, DSR improved the CRT measured under side irradiation to ps FWHM. A much more substantial improvement was observed for equally sized crystals having etched side surfaces. For these crystals the CRT changed from ps FWHM (head-on irradiation) and FWHM (side irradiation) with SSR to ps FWHM with DSR (side irradiation). These values are compared with the time resolution of detectors employing LSO: Ce, Ca crystals with a size of mm (ps FWHM) and mm (ps FWHM and ps for polished and etched crystals, respectively).