Methodology for integrating MCNP6 Monte Carlo simulation into PLUNC for prostate brachytherapy planning

Brachytherapy is a well-established therapeutic technique for treating tumours involving the placement of radioactive encapsulated sources close to or in direct contact with a tumour. Considering this type of treatments, the purpose of this work is to incorporate Monte Carlo (MC) simulation into brachytherapy treatment planning. This approach allows for precise estimation of dose distribution in target organs as well as in Organs At Risk (OAR), due to the accuracy of the MC methods in describing dose deposition. To carry out this work, the medical image visualization and dose analysis tools provided by the open-source planner PlanUNC (PLUNC) were utilized. Additionally, a set of programs was developed which automatize the main steps of a treatment planning segmentation, from DICOM images, exporting geometries determining materials and seeds positions, creating an input file for the simulation code (MCNP6.2) and, finally, reading and visualization of the simulation results in the format of the used planning software. With this methodology, results of 3D dose distribution, isodoses curves, Dose-Volume Histograms (DVH), and absorbed dose in OAR were obtained. Thus, the integration of the MC simulation into PLUNC for brachytherapy treatments, has demonstrate its utility for this purpose, showing adaptability to different anatomical geometries and extensibility to various types of treatments. •More accuracy in patient dose estimation when using Monte Carlo simulation.•Methodology has been designed to incorporate Monte Carlo into brachytherapy planning.•Realistic simulations with patient CT images allows calculating dose distribution.•Adequate accuracies and computing times compared to real planning treatment.•In-depth analysis of medically valid outcome data for brachytherapy treatments.