The importance of Monte Carlo simulations in modeling detectors for Nuclear Medicine

Nowadays, Monte Carlo techniques are very common for the development of Nuclear Medicine systems. Simulations can be very helpful for the optimization of SPECT and PET cameras, and for investigating the importance of several physical effects involved in image formation. In this paper, a simulation study for evaluating various aspects influencing image formation in detectors for Nuclear Medicine is presented. To this end, the EGSnrc Monte Carlo code has been used, which transports photons and electrons in any material and handling various physical phenomena. Here, some detector systems are simulated, consisting of a parallel-hole collimator and a pixellated scintillator. Various effects are investigated, such as electron transport, fluorescence photons, collimator septa penetration. Results are evaluated by means of energy spectra, photon fluxes, uniformity of response, SNR and spatial resolution.