Krishnan Jayapalan, Shetty Jayarama, Rao Suresh, Hegde Sanath, Shambhavi C
Department of Radiation Oncology, Mangalore Institute of Oncology, Mangalore, Karnataka, India.
Department of Radiation Oncology, K. S. Hegde Medical Academy, Mangalore, Karnataka, India.
J Med Phys. 2017 Jan-Mar;42(1):14-17. doi: 10.4103/jmp.JMP_112_16.
The aim of this study was to evaluate the impact of conformity index in the unified dosimetry index (UDI) score for two different planning techniques namely intensity-modulated radiotherapy (IMRT) and Rapid Arc. Rapid Arc and IMRT plans of 57 patients were evaluated and compared using UDI score which incorporates four indices. To determine the impact of conformity index on the IMRT and Rapid Arc plans, UDI at conformity index one of all plan (UDI) score was calculated by assuming conformity index is equal to one. Mean and standard deviations of all indices were calculated. Rapid Arc technique plans of different treatment sites of all patients scored lesser UDI than IMRT plans, and the conformity index of Rapid Arc plan was significantly better than IMRT plan. The average dose gradient, homogeneity, coverage, and conformity index of all sites with Rapid Arc plans were 0.212 ± 0.05, 1.123 ± 0.03, 0.959 ± 0.03, and 1.056 ± 0.09; with IMRT plans were 0.190 ± 0.05, 1.113 ± 0.04, 0.950 ± 0.04, and 1.172 ± 0.16, respectively. UDI score value with actual conformity index of Rapid Arc and IMRT plans differed significantly ( < 0.001). However, UDI score values with assumed conformity index equal to one did not differ significantly ( = 0.528). In the comparison of IMRT and Rapid Arc plans using the UDI score, the impact of conformity index was significant.
本研究的目的是评估适形指数在统一剂量学指数（UDI）评分中对两种不同放疗计划技术（即调强放疗（IMRT）和容积旋转调强放疗（Rapid Arc））的影响。使用包含四个指数的UDI评分对57例患者的Rapid Arc和IMRT计划进行评估和比较。为了确定适形指数对IMRT和Rapid Arc计划的影响，通过假设适形指数等于1来计算所有计划在适形指数为1时的UDI（UDI）评分。计算所有指数的均值和标准差。所有患者不同治疗部位的Rapid Arc技术计划的UDI评分低于IMRT计划，且Rapid Arc计划的适形指数明显优于IMRT计划。Rapid Arc计划所有部位的平均剂量梯度、均匀性、靶区覆盖率和适形指数分别为0.212±0.05、1.123±0.03、0.959±0.0 和1.056±0.09；IMRT计划分别为0.190±0.05、1.113±0.04、0.950±0.04和1.172±0.16。Rapid Arc和IMRT计划实际适形指数的UDI评分值差异显著（<0.001）。然而，假设适形指数等于1时的UDI评分值差异不显著（=0.528）。在使用UDI评分比较IMRT和Rapid Arc计划时，适形指数的影响显著。
