Vergalasova Irina, Light Kim, Chino Junzo, Craciunescu Oana
Department of Radiation Oncology, Rutgers, The Cancer Institute of New Jersey, New Brunswick, NJ, USA.
Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA.
Med Dosim. 2017;42(3):230-237. doi: 10.1016/j.meddos.2017.05.002. Epub 2017 Jul 12.
The aim of this study was to quantitatively compare dosimetric criteria between intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans for patients undergoing radiation treatment of gynecologic carcinoma with a simultaneous integrated boost (SIB) technique. IMRT and VMAT plans were retrospectively analyzed for 20 patients. The elective volume was planned to receive 45 Gy in 25 fractions of 1.8 Gy, with the integrated boost volume (involved nodes) receiving 55 Gy simultaneously. The same dose constraints were employed during the optimization of both techniques. IMRT plans consisted of 9 to 11 fields at equally spaced gantry angles. VMAT plans consisted of 3 full arcs of 360°. A large variety of dose metrics across planning target volume (PTV), PTV, bladder, rectum, sigmoid, bowel, kidneys, and femoral heads were extracted per patient, per plan. Conformity and homogeneity indices were also calculated and compared for each target volume. The total number of monitor units as well as the integral dose was also compared between IMRT and VMAT. The Wilcoxon signed rank test was performed to evaluate any significant differences between parameters, with an applied Bonferroni correction to account for multiple testing (significance level, p < 0.0006). The results demonstrate the equivalence of the 2 planning techniques across all studied parameters, with the exception of the expected decrease in monitor units that VMAT is capable of achieving. The findings of this study suggest that IMRT and VMAT are both acceptable options for applying simultaneous integrated boost techniques for the treatment of gynecologic cancers. The technique of choice will be dependent on departmental resources and should be considered on a case-by-case basis.
本研究的目的是定量比较采用同步整合加量（SIB）技术进行妇科癌症放射治疗的患者，其调强放射治疗（IMRT）计划与容积调强弧形放疗（VMAT）计划之间的剂量学标准。对20例患者的IMRT和VMAT计划进行回顾性分析。计划对选择性靶区给予45 Gy，分25次，每次1.8 Gy，同时对整合加量靶区（受累淋巴结）给予55 Gy。在两种技术的优化过程中采用相同的剂量限制。IMRT计划由9至11个射野组成，机架角等间隔分布。VMAT计划由3个360°的完整弧形组成。为每位患者的每个计划提取了多种跨越计划靶区（PTV）、膀胱、直肠、乙状结肠、肠、肾脏和股骨头的剂量指标。还计算并比较了每个靶区的适形指数和均匀性指数。同时比较了IMRT和VMAT之间的监测单位总数以及积分剂量。采用Wilcoxon符号秩检验评估参数之间的任何显著差异，并应用Bonferroni校正来处理多重检验（显著性水平，p < 0.0006）。结果表明，除了VMAT能够实现的监测单位预期减少外，两种计划技术在所有研究参数上均等效。本研究结果表明，IMRT和VMAT都是应用同步整合加量技术治疗妇科癌症的可接受选择。选择的技术将取决于科室资源，应根据具体情况考虑。
