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IntroductionThe primary aim of this study is to compare intensity modulated radiation therapy (IMRT) to volumetric modulated arc therapy (VMAT) for the radical treatment of prostate cancer using version 10.0 (v10.0) of Varian Medical Systems, RapidArc radiation oncology system. Particular focus was placed on plan quality and the implications on departmental resources. The secondary objective was to compare the results in v10.0 to the preceding version 8.6 (v8.6).MethodsTwenty prostate cancer cases were retrospectively planned using v10.0 of Varian's Eclipse and RapidArc software. Three planning techniques were performed: a 5-field IMRT, VMAT using one arc (VMAT-1A), and VMAT with two arcs (VMAT-2A). Plan quality was assessed by examining homogeneity, conformity, the number of monitor units (MUs) utilized, and dose to the organs at risk (OAR). Resource implications were assessed by examining planning and treatment times. The results obtained using v10.0 were also compared to those previously reported by our group for v8.6.ResultsIn v10.0, each technique was able to produce a dose distribution that achieved the departmental planning guidelines. The IMRT plans were produced faster than VMAT plans and displayed improved homogeneity. The VMAT plans provided better conformity to the target volume, improved dose to the OAR, and required fewer MUs. Treatments using VMAT-1A were significantly faster than both IMRT and VMAT-2A.Comparison between versions 8.6 and 10.0 revealed that in the newer version, VMAT planning was significantly faster and the quality of the VMAT dose distributions produced were of a better quality.ConclusionVMAT (v10.0) using one or two arcs provides an acceptable alternative to IMRT for the treatment of prostate cancer. VMAT-1A has the greatest impact on reducing treatment time.

This study aims to compare Intensity Modulated Radiation Therapy (IMRT) to Volumetric Modulated Arc Therapy (VMAT) for the treatment of prostate cancer. Particular focus was placed on the impact IMRT and VMAT have on departmental planning and treatment resources. Materials and Methods: Twenty prostate cancer cases were retrospectively planned to compare 5-field IMRT to VMAT using a single arc (VMAT-1A) and two arcs (VMAT-2A). The impact on departmental resources was assessed by comparing the time needed to generate the dose distributions and to deliver the treatment plan. A comparison of plan quality was also performed by comparing homogeneity, conformity, the number of monitor units (MUs) and dose to the organs at risk. Results: IMRT and VMAT-2A were able to produce adequate plans for all cases. Using VMAT-1A, planning guidelines were achieved in 8 of the 20 cases. IMRT provided an improved dose distribution and the best homogeneity to the planning target volume. Also, the IMRT plans were generated significantly faster than both VMAT techniques. VMAT planning provided significantly improved conformity and utilized significantly less MUs than IMRT. VMAT-1A treatments were significantly faster than both IMRT and VMAT-2A. VMAT plans delivered lower dose to the bladder and heads of femur, and an increased dose to the rectum in the low dose region. Conclusion: Bladder Volume (cm 3) Rectum Volume (cm 3) Case 1