  We have previously described RapidBrachyMCTPS, a brachytherapy treatment
planning toolkit consisting of a graphical user interface (GUI) and a
Geant4-based Monte Carlo (MC) dose calculation engine. This work describes the
tools that have recently been added to RapidBrachyMCTPS, such that it now
serves as the first stand-alone application for MC-based brachytherapy
treatment planning. Notable changes include updated applicator import and
positioning, three-plane contouring tools, and updated dose optimization
algorithms that, in addition to optimizing dwell position and dwell time, also
optimize the rotating shield angles in intensity modulated brachytherapy. The
main modules of RapidBrachyMCTPS were validated including DICOM import,
applicator import and positioning, contouring, material assignment, source
specification, catheter reconstruction, EGSphant generation, interface with the
MC code, and dose optimization and analysis tools. Two patient cases were
simulated to demonstrate these principles, illustrating the control and
flexibility offered by RapidBrachyMCTPS for all steps of the treatment planning
pathway. RapidBrachyMCTPS is now a stand-alone application for brachytherapy
treatment planning, and offers a user-friendly interface to access powerful MC
calculations. It can be used to validate dose distributions from clinical
treatment planning systems or model-based dose calculation algorithms, and is
also well suited to testing novel combinations of radiation sources and
applicators, especially those shielded with high-Z materials.
