RIVL: a radiation imager virtual laboratory

A software suite for the modeling of medical imaging detectors has been constructed that uses GEANT4 for particle tracking and DETECT2000 for the optical modeling of scintillation photons. The Radiation Imager Virtual Laboratory (RIVL) is a collection of modular, stand-alone programs that are interfaced to each other via format conversion utilities and is intended to model the energy deposition, scintillation conversion, optical photon transport, signal sensing, electronics and pulse processing. RIVL makes use of a GEANT4 application developed at General Electric Global Research called the Virtual Radiation Imager (VRAI). VRAI is based on GEANT4, a sophisticated and mature collection of C++ libraries that are commonly used in nuclear and particle physics and is seeing an increased use in the medical imaging community. With GEANT4, the physical interactions of particles are well modeled in the energy regime relevant for medical imaging. Modeling of the optical transport of scintillation photons is performed with the program DETECT2000, which enables detailed control over optical properties and is better suited than GEANT4 for modeling the transport of optical scintillation photons. Interfacing GEANT with DETECT2000 harnesses the strengths of each of these programs to create a complete model for various medical imaging applications. The simulation of the response of the photosensor to scintillation photons, as well as the logic applied to the photosensor signals to reconstruct the hit position and energy are accomplished with custom software modules written at the GE Global Research Center.