A utility to read automatically DICOM format data for GAMOS/Geant4 simulation

Introduction The simulation of a real clinical radiotherapy treatment requires using the detailed information about patient, acceleration and plan. Modern machines can provide this information in DICOM format, but Monte Carlo codes are not able to treat it. Purpose To provide a tool to automatically read the data on patient anatomy, including RT structures, and the RT plan parameters and prepare the corresponding Monte Carlo jobs. Materials and methods We have developed in GAMOS/Geant4 framework a set of tools based on DCMTK to read a patient anatomy in DICOM format and transform the Hounsfield values into Geant4 materials. The DICOM RT Structure files are also read and combined with the anatomy to identify the voxels that are included in each structure. Another tool converts the many parameters of a RT plan into Monte Carlo parameters. Several utilities help the user check for the correct interpretation of the DICOM parameters. Results The tool has been applied to read many different DICOM patient anatomies from different providers. A full radiotherapy treatment has been simulated and the dose calculated and written in DICOM format has been compared with the one obtained using the vendor TPS. Conclusion A simple way is provided to automatically convert a radiotherapy treatment in DICOM format to GAMOS/Geant4 parameters so that real clinical treatments can be easily simulated.