Investigation of the Power Consumption of the PETsys TOFPET2 ASIC

In state-of-the-art positron emission tomography (PET) systems, application-specific integrated circuits (ASICs) are commonly used to precisely digitize the signals of analog silicon photomultipliers (SiPMs). However, when operating PET electronics in a magnetic resonance (MR) system, one faces the challenge of mutual interference of these imaging techniques. To prevent signal deterioration along long analog signal lines, PET electronics with a low-power consumption digitizing the signals close to the SiPMs are preferred. In this article, we evaluate the power consumption of the TOFPET2 ASIC. Its power consumption ranges from 3.6 mW/channel to 7.2 mW/channel as a function of the input stage impedance and discriminator noise settings. We present an analytical model allowing to compute the power consumption of a given ASIC configuration. The input stage impedance and discriminator noise have an impact on the coincidence resolution time (CRT), energy resolution, and photon trigger level. Since the TOFPET2 ASIC delivers state-of-the-art performance with a power consumption similar or even lower than other ASICs typically used for PET applications, it is a favorable candidate to digitize the signals of SiPMs in future simultaneous PET/MR systems.