Integration and Testing of the Hybrid Gamma Cameras for AdaptiSPECT-C

Recent advances in scintillation light sensors are enabling new designs for single-photon-emission computed tomography (SPECT) cameras for use in nuclear medicine, achieving higher sensitivity and spatial resolution than previously possible. One such camera is AdaptiSPECT-C: a new stationary and adaptive SPECT system designed for clinical whole-brain imaging. It employs a 24-stationary-camera configuration in conjunction with multi-pinhole apertures, significantly increasing its overall sensitivity to gamma radiation. Each of the five pinholes assigned to a camera can actively select among several different aperture diameters and a shuttered state; the latter function enabling the acquisition of both non-multiplexed and multiplexed image data in a single session.Each 18-cm-square camera in AdaptiSPECT-C houses 25 photomultiplier tubes (PMTs) and 24 multi-pixel photon counters (MPPCs). This combination results in a camera that achieves uniformly high spatial resolution across the entire crystal area. In this work we present the combined MPPC/PMT hybrid camera design, prioritizing modularity and space efficiency. We also cover schematics for the front-end electronics and their hardware integration, specifically highlighting initial test pulses from the two sensor types. The results of said testing show promise for the eventual merging of hybrid signal information into a comprehensive dataset during real world image acquisitions. Finally, we present preliminary calibration results and compare to predictions based on light-transport simulations.