Dosimetric Comparison between the Intensity Modulated Radiation Therapy and Volumetric Modulated arc Therapy for Prostate Cancer- A Case Study

Abstract

Purpose: The main purpose of this study is to perform the dosimetric comparison between Intensity modulated radiation therapy (IMRT) and Volumetric modulated arc therapy (VMAT) for the prostate cancer by using dose-volume histograms (DVH). Methods: IMRT plan and VMAT plan were generated using 7 fields and 2 arcs, respectively, for the total dose of 76 Gy. Planning target volume (PTV) was evaluated for the maximum dose, mean dose, minimum dose, and conformity index. Rectum and bladder were evaluated for V70Gy, V50Gy, and V30Gy. The number of MUs between IMRT and VMAT plan was evaluated too. Results: The PTV dose evaluation showed that VMAT plan produced values closer to the prescription dose than did IMRT plan. The conformity index was also slightly better in VMAT plan (1.15) than in IMRT plan (1.17). The relative volume of bladder receiving radiation was always lower in VMAT plan for all parameters. However, IMRT was better than VMAT at V70Gy and V30Gy, whereas VMAT was better at V50Gy. The MUs were higher in IMRT plan (812) when compared to the one in VMAT plan (560). Conclusion: Both the VMAT and IMRT produced clinically acceptable treatment plan for the prostate cancer. Based on the single case in this study, VMAT produced slightly favorable dosimetric results.