用于脑专用 TOF-DOI PET 探测器的高多重 SiPM 信号读出。

Highly multiplexed SiPM signal readout for brain-dedicated TOF-DOI PET detectors.

机构信息

Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, South Korea; Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul 03080, South Korea; Institute of Radiation Medicine, Medical Research Center, Seoul National University College of Medicine, Seoul 03080, South Korea; Brightonix Imaging Inc., Seoul 04782, South Korea.

出版信息

Phys Med. 2019 Dec;68:117-123. doi: 10.1016/j.ejmp.2019.11.016. Epub 2019 Nov 27.

DOI:10.1016/j.ejmp.2019.11.016

PMID:31783221

Abstract

PURPOSE

We investigated the highly multiplexed readout of SiPM signals that are useful in developing brain-dedicated PET detectors with DOI-capable crystal blocks and large-area SiPM arrays.

METHODS

The PET detector module used in this study was equipped with a two-layer relative-offset DOI crystal block and a 2 × 2 array of 16-channel SiPMs. The lower crystal-layer consisted of a 14 × 14 array of 1.78 × 1.78 × 8 mm LSO crystals and the upper crystal-layer consisted of a 13 × 13 array of 1.78 × 1.78 × 12 mm LSO crystals. The energy and position information was obtained via signals from the 8 × 8 resistive charge division multiplexing circuit. The timing performance was evaluated with varying multiplexing ratios (i.e. 16:1, 32:1, and 64:1) via first-order analog high-pass filtering.

RESULTS

For three different multiplexing schemes, all LSO crystals with two-layer DOI information were clearly resolved and yielded good energy resolutions of 10.5 ± 1.0% (upper) and 12.1 ± 1.7% (lower). The 16:1 multiplexing yielded an optimal timing performance with average CRT values of 325 ps FWHM (upper) and 342 ps FWHM (lower); however, the timing performances were maintained almost constant even for 64:1 multiplexing with average CRT values of 336 ps FWHM (upper) and 347 ps FWHM (lower).

CONCLUSIONS

The highly multiplexed SiPM signal readout via the first-order analog high-pass filtering could be an attractive solution to develop brain-dedicated PET scanners, effectively decreasing the burden of DAQ systems with moderate compromise in terms of TOF and DOI performances.

摘要

目的

我们研究了硅光电倍增管（SiPM）信号的高度多路复用读出，这在开发具有 DOI 能力的晶体块和大面积 SiPM 阵列的专用脑部 PET 探测器方面很有用。

方法

本研究使用的 PET 探测器模块配备了双层相对偏移 DOI 晶体块和 2×2 16 通道 SiPM 阵列。下晶体层由 14×14 1.78×1.78×8mm 的 LSO 晶体阵列组成，上晶体层由 13×13 1.78×1.78×12mm 的 LSO 晶体阵列组成。能量和位置信息是通过 8×8 电阻电荷分复用电路的信号获得的。通过一阶模拟高通滤波，评估了不同多路复用比（即 16:1、32:1 和 64:1）下的定时性能。

结果

对于三种不同的多路复用方案，所有具有双层 DOI 信息的 LSO 晶体都能清晰分辨，得到了较好的能量分辨率，分别为 10.5±1.0%（上层）和 12.1±1.7%（下层）。16:1 多路复用获得了最佳的定时性能，上、下层面的 CRT 值平均值分别为 325 ps FWHM 和 342 ps FWHM；然而，即使在 64:1 多路复用下，定时性能也能保持几乎不变，上、下层面的 CRT 值平均值分别为 336 ps FWHM 和 347 ps FWHM。