SOFT-RT: Software for IMRT simulations based on MCNPx code

Abstract

Intensity Modulated Radiation Therapy (IMRT) is an advanced treatment technique, widely used in external radiotherapy. This paper presents the SOFT-RT which allows the simulation of an entire IMRT treatment protocol. The SOFT-RT performs a full three-dimensional renderization of a set of patient images, including the definitions of region of interest with organs in risk (OIR), and the target tumor volume and margins (PTV). Thus, a more accurate analysis and planning can be performed, taking into account the features and orientation of the radiation beams. The exposed tissues as well as the amount of absorbed dose is depicted in healthy and/or cancerous tissues. As conclusion, SOFT-RT can predict dose on the PTV accurately, preserving the surrounding healthy tissues. SOFT-RT is coupled with SISCODES code. The SISCODES code is firstly applied to segment the set of CT or MRI patient images in distinct tissues pointing out its respective density and chemical compositions. Later, the voxel model is export to the SOFT-RT IMRT planning module in which a full treatment planning is created. All geometrical parameters are sent to the general-purpose Monte Carlo transport code-MCNP-to simulate the interaction of each incident beam towards to the PTV avoiding OIR. Computational simulations is running on MCNPx. The normalized dose results are exported to the SOFT-RT output-module, in which the three-dimensional model visualization is shown in a transparent glass procedure adopting gray scale for the dependence on the mass density of the correlated tissue; while, a color scale to depict dose values in a superimpose protocol.

Keywords: IMRT; MCNPx; SOFT-RT; Simulation; Voxel phantom.