Electrical delay line multiplexing for pulsed mode radiation detectors

Abstract

Medical imaging systems are composed of a large number of position sensitive radiation detectors to provide high resolution imaging. For example, whole-body Positron Emission Tomography (PET) systems are typically composed of thousands of scintillation crystal elements, which are coupled to photosensors. Thus, PET systems greatly benefit from methods to reduce the number of data acquisition channels, in order to reduce the system development cost and complexity. In this paper we present an electrical delay line multiplexing scheme that can significantly reduce the number of readout channels, while preserving the signal integrity required for good time resolution performance. We experimented with two 4 × 4 LYSO crystal arrays, with crystal elements having 3 mm × 3 mm × 5 mm and 3 mm × 3 mm × 20 mm dimensions, coupled to 16 Hamamatsu MPPC S10931-050P SiPM elements. Results show that each crystal could be accurately identified, even in the presence of scintillation light sharing and inter-crystal Compton scatter among neighboring crystal elements. The multiplexing configuration degraded the coincidence timing resolution from ~ 243 ps FWHM to ~272 ps FWHM when 16 SiPM signals were combined into a single channel for the 4 × 4 LYSO crystal array with 3 mm × 3 mm × 20 mm crystal element dimensions, in coincidence with a 3 mm × 3 mm × 5 mm LYSO crystal pixel. The method is exible to allow multiplexing configurations across different block detectors, and is scalable to an entire ring of detectors.

Silicon photomultiplier signal readout and multiplexing techniques for positron emission tomography: a review

“…The fired SiPM element can be identified by measuring the time difference of signal propagation from the SiPM element to each readout channel at the corners. Similar to the stripline multiplexing method mentioned above, PCB design parameters, including the PCB materials, the dielectric Vinke et al [149] proposed an electrical delay line multiplexing method (Fig. 11).…”

Feasibility Study of a Time-of-Flight Brain Positron Emission Tomography Employing Individual Channel Readout Electronics

“…However, due to readout electronics, the CTR deteriorates as the output signal of a silicon photomultiplier (SiPM) corresponding to the detected gamma ray is distorted or the amplitude of noise increases. The improved CTR can be achieved using individual channel readout electronics that minimize distortion of the output signal in comparison to a multiplexing circuit based on the method such as charge division or signal delay [ 11 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. Therefore, the fast TOF PET could be achieved using low-noise individual channel readout electronics that allow for fast TOF measurements as well as a PET detector with excellent CTR.…”

A multiplexed TOF and DOI capable PET detector using a binary position sensitive network

“…Multiplexing allows the acquisition of PET data from many photodetectors using fewer readout channels. Previously published multiplexing methods include light sharing (Kim, McDaniel, Malaney, McBroom, Peterson, Tran, Guo, Ivan, Dolinsky, Wagadarikar et al 2012) or charge sharing (Vinke, Yeom & Levin 2015) (Kwon & Lee 2014) (Downie, Yang & Peng 2013) (H.-J. 2014) (Kim, Chen, Eclov, Ronzhin, Murat, Ramberg, Los, Wyrwicz, Li & Kao 2015).…”

“…Multiplexing allows the acquisition of PET data from many photodetectors using fewer readout channels. Previously published multiplexing methods include light sharing (Kim et al 2012) or charge sharing (Downie et al 2013, Choe et al 2014, Kwon and Lee 2014, Vinke et al 2015. Multiplexed detectors using SiPM photodetectors can also maintain excellent timing properties while significantly reducing the number of readout channels (Bieniosek et al 2016a(Bieniosek et al , 2016b.…”