Applications to Development of PET/SPECT System by Use of Geant4

In this chapter, two applications of Monte Carlo method in medicine are described. The first application is development of a Single Photon Emission Computed Tomography (SPECT), in which the intrinsic spatial and energy resolutions were estimated by simulating scintillation lights. The adequacy of the simulation was verified by comparisons of experimental results from a high-resolution SPECT. In addition, we proposed a method related to improving the spatial resolution relative to the conventional method, (the Anger method). The usefulness of the method and the performance were estimated by the simulation. The second application is an evaluation of a quantification technique for Positron Emission Tomography (PET). In cardiac PET using the isotope O-15, scatter events originating from outside the field of view (FOV), especially from the liver, influence the quantification of myocardial blood flow. We evaluated this influence by simulating trajectories of gamma rays. In section 1, we briefly describe Monte Carlo simulation tools in medicine and principle of PET/SPECT imaging. In sections 2 and 3, respectively, we describe applications to SPECT and PET.