A PET detector interface board and slow control system based on the Raspberry Pi®

Construction of a full PET system requires scaling up from a few detectors on the bench top to dozens or even hundreds of detectors all operating simultaneously and connected to high channel count electronics. Our collaboration is building a MRI compatible PET insert system that will contain 16 detector modules in the prototype phase and 64 detector modules in the final phase. This number of detectors makes it difficult, if not impossible, to manually configure and monitor each detector in the system. In order to make possible the scaling of the system for up to 64 detectors, we require a scalable slow control system to manage the low level functions of the PET system, such as controlling detector bias and monitoring temperature and power consumption, that can be interfaced to and controlled by a host computer. We have implemented this slow control system in conjunction with a detector interface board (DIB) that is an intermediary between the detectors and the OpenPET digitizer system. Each DIB is connected to four detector modules and is controlled by a Raspberry Pi^® computer directly attached to it. The Raspberry Pi^® computers report to a host PC software program developed in National Instruments LabWindows™/CVI to provide the capability of central monitoring and control.