Multi-Pixel Photon Counter Module For Mri Compatible Application

A new detector for PET using multi-pixel photon counters (MPPCs) was developed for MRI compatible applications. This module has an 8 x 8 MPPC array, each segment has a 3 mm x 3 mm active area, and the pitch of the array is 4.1 mm in both directions. A temperature sensor is attached to the back of the array for temperature compensation. The MPPC array is connected to the front-end circuit with a detachable flexible printed circuit cable (FPC), which provides flexibility for detector arrangement. The front-end circuit consists of preamplifiers, a register network, buffer amplifiers, a built-in high voltage (HV) unit, and an embedded microprocessor unit. The HV unit is a down-regulator and requires an external HV supply. The preamplifier also has a sum output, which can be used for timing pick-off and energy discrimination. With LYSOs, the timing performance was evaluated using flexible printed cables of two different lengths. Set in a copper shield box, energy spectra and flood images were evaluated with a 3T-MRI. Very little interference was observed during simultaneous MRI measurements.