[Computer simulation of DOI-PET detector (1) -analysis of DOI discrimination accuracy in a detector block-]

A detector proposed by Murayama et al. for detection of depth-of-interaction (DOI) in PET consists of three-dimensionally arranged crystal elements with proper optical reflectors and is coupled to an array of photomultiplier tubes. This detector has a great advantage in easiness and cost in fabrication. We implemented a simulator of this detector that allows us to find appropriate values of parameters such as optical properties of crystal or detector unit geometry before making detectors. The simulator is based on the Monte Carlo method that traces the migration of optical photons generated by interaction of a gamma ray with crystal. First, the simulator performance was validated by comparing with the experimental data obtained with some prototype detectors. Then, on some parameters including refractive index of inter-crystal material, reflectance of optical reflector and detector geometry, appropriate values were investigated for accurate discrimination of crystal element of interaction.