Experimental Evaluation of MCDTK, the Monte Carlo DICOM Tool-Kit

Abstract

The Monte Carlo DICOM Tool-Kit (MCDTK) is a software suite designed for treatment plan dose verifica- tion, using the BEAMnrc and DOSXYZnrc Monte Carlo codes. MCDTK converts DICOM-format treatment plan information into Monte Carlo input files and compares the results of Monte Carlo treatment simulations with conventional treatment plan- ning dose calculations. In this study, a treatment is planned using a commercial treatment planning system, delivered to a pelvis phantom containing ten thermoluminescent dosimeters and simulated using BEAMnrc and DOSXYZnrc using inputs derived from MCDTK. The dosimetric accuracy of the Monte Carlo data is then evaluated via comparisons with the dose distribution obtained from the treatment planning system as well as the in-phantom point dose measurements. The simulated beam arrangement produced by MCDTK is found to be in ge- ometric agreement with the planned treatment. An isodose dis- play generated from the Monte Carlo data by MCDTK shows general agreement with the isodose display obtained from the treatment planning system, except for small regions around den- sity heterogeneities in the phantom, where the pencil-beam dose calculation performed by the treatment planning system is likely to be less accurate. All point dose measurements agree with the Monte Carlo data obtained using MCDTK, within confidence limits, and all except one of these point dose measurements show closer agreement with the Monte Carlo data than with the doses calculated by the treatment planning system. This study pro- vides a simple demonstration of the geometric and dosimetric accuracy of Monte Carlo simulations based on information from MCDTK.