Bieniosek M F, Cates J W, Grant A M, Levin C S
Department of Radiology, Stanford University, Stanford, CA 94305, USA. Molecular Imaging Program at Stanford (MIPS), Stanford, CA 94305, USA. Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA.
Phys Med Biol. 2016 Aug 21;61(16):N427-40. doi: 10.1088/0031-9155/61/16/N427. Epub 2016 Aug 3.
Multiplexing many SiPMs to a single readout channel is an attractive option to reduce the readout complexity of high performance time of flight (TOF) PET systems. However, the additional dark counts and shaping from each SiPM cause significant baseline fluctuations in the output waveform, degrading timing measurements using a leading edge threshold. This work proposes the use of a simple analog filtering network to reduce the baseline fluctuations in highly multiplexed SiPM readouts. With 16 SiPMs multiplexed, the FWHM coincident timing resolution for single [Formula: see text] mm LYSO crystals was improved from 401 ± 4 ps without filtering to 248 ± 5 ps with filtering. With 4 SiPMs multiplexed, using an array of [Formula: see text] mm LFS crystals the mean time resolution was improved from 436 ± 6 ps to 249 ± 2 ps. Position information was acquired with a novel binary positioning network. All experiments were performed at room temperature with no active temperature regulation. These results show a promising technique for the construction of high performance multiplexed TOF PET readout systems using analog leading edge timing pickoff.
将多个硅光电倍增管（SiPM）复用至单个读出通道是一种颇具吸引力的选择，可降低高性能飞行时间（TOF）PET系统的读出复杂性。然而，每个SiPM额外产生的暗计数和整形会导致输出波形出现显著的基线波动，从而降低使用前沿阈值的定时测量精度。这项工作提出使用一个简单的模拟滤波网络来减少高度复用的SiPM读出中的基线波动。在16个SiPM复用的情况下，对于单个[公式：见原文]毫米LYSO晶体，半高宽符合定时分辨率从无滤波时的401 ± 4皮秒提高到有滤波时的248 ± 5皮秒。在4个SiPM复用的情况下，使用[公式：见原文]毫米LFS晶体阵列，平均时间分辨率从436 ± 6皮秒提高到249 ± 2皮秒。通过一种新颖的二进制定位网络获取位置信息。所有实验均在室温下进行，未进行主动温度调节。这些结果表明，使用模拟前沿定时提取技术构建高性能复用TOF PET读出系统是一项很有前景的技术。
