A new modular and scalable detector for a Time-of-Flight PET scanner

We describe a detector design for a new low-cost Time-of-Flight PET scanner. Each independent detector module is two-side buttable in the transaxial direction. To maximize the optical collection efficiency, the design uses two different-sized circular PMT types with concave photocathodes and each type is placed at a different distance from the scintillator array. The detector consists of multiple axial segments. Each axial segment is read-out by four PMTs arranged in a rectangular pattern, and neighboring segments share two PMTs in order to reduce channel count and improve optical collection efficiency. To reduce deadtime and pile-up effects, each axial segment is essentially optically isolated from its neighbors. The detector length is scalable in the axial direction by changing the number of segments. In addition to the detector design, we present timing resolution measurements as a function of singles rate.