GAMOS: A Geant4-based easy and flexible framework for nuclear medicine applications

The use of Monte Carlo has proved to be an essential tool in nuclear medicine, to assist in the design of new medical devices, in the development of new image reconstruction algorithms and correction techniques in PET and SPECT, for the precise determination of the dose in radiotherapy, etc. Among the several general-purpose codes, Geant4 is widely used for its modern technology, its flexibility and its wide range of applications. Nevertheless the use of Geant4 in nuclear medicine requires often a long learning-curve that implies a good knowledge of C++ and the Geant4 codes itself to write the code needed to obtain the required results. GAMOS, the Geant4-based Architecture for Medicine-Oriented Simulations, facilitates the use of Geant4 by providing a simple script language that covers almost all the needs of a nuclear medicine simulation. Its modular and flexible design, based on the use of the plug-in technology, as well as a clear documentation and detailed examples, makes easy to extend the framework to cover any extra need an expert user may have. We describe in this paper the basic components of GAMOS as well as provide a few examples of its use in PET and Radiotherapy simulations.