Simplified simulation of four-layer depth of interaction detector for PET.

A four-layer depth-of-interaction (DOI) detector was proposed from and developed at the research project at the National Institute of Radiological Sciences in Japan, with the aim of achieving high resolution and high spatial sensitivity. Previously, we had developed a Monte Carlo simulation for a DOI detector with 2 x 2 x 4 crystal elements. In this study, in order to simulate the final version of the DOI detector of the project, which uses a larger number of crystal elements, we have developed a much faster and simpler simulator. In this paper the algorithm of the simplified simulator as well as the previously proposed Monte Carlo method is presented and the validation of the simplified simulator through comparisons with the full Monte Carlo simulation and with some experimental results is described.