Yadav Girigesh, Bhushan Manindra, Dewan Abhinav, Saxena Upasna, Kumar Lalit, Chauhan Deepika, Raman Kothanda, Mitra Swarupa, Suhail Mahammood
Division of Medical Physics & Department of Radiation Oncology, Rajiv Gandhi Cancer Institute and Research Centre, Sector-5, Rohini, New Delhi 110085, India.
Rep Pract Oncol Radiother. 2017 Jan-Feb;22(1):1-9. doi: 10.1016/j.rpor.2016.09.002. Epub 2016 Oct 17.
Aim of the present study was to compare the dosimetric impact of different photon beam energies and number of arcs in the treatment of carcinoma cervix.
Carcinoma cervix is a common cancer in women worldwide with a high morbidity rate. Radiotherapy is used to treat such tumours. Volumetric Modulated Arc Therapy (VMAT) is considered superior to other techniques with multiple arcs and energies.
Twenty patients with carcinoma cervix underwent radiotherapy in a prospective observation study conducted at our institute. Volumetric modulated arc plans with 6 MV, 10 MV and 15 MV photon energies using single arc (SA) and dual arc (DA) were generated. Several physical indices for planning target volume (PTV) like , , , , , and total number of MUs were compared. Normal Tissue Integral Dose (NTID) and dose to a shell structure PHY and PHY were analyzed.
Comparable dose coverage to PTV was observed for all the energies and arcs. CI for DA (1.095) was better than SA (1.127), SA (1.116) and SA (1.116). Evaluated parameters showed significant reduction in OAR doses. Mean bladder dose for DA (41.90 Gy) was better than SA (42.48 Gy), SA (42.08 Gy) and SA (41.93 Gy). Similarly, -value for the mean rectal dose calculated was 0.001 (SA), 0.013 (DA) and 0.003 (DA) and subsequently favoured DA. Difference in NTID was very small.
The study showed no greater advantage of higher energy, and DA VMAT plan with 6 MV photon energy was a good choice of treatment for carcinoma cervix as it delivered a highly homogeneous and conformal plan with superior target coverage and better OAR sparing.
本研究的目的是比较不同光子束能量和弧数在宫颈癌治疗中的剂量学影响。
宫颈癌是全球女性常见的癌症，发病率很高。放射治疗用于治疗此类肿瘤。容积调强弧形放疗（VMAT）被认为优于其他具有多个弧和能量的技术。
在我们研究所进行的一项前瞻性观察研究中，20例宫颈癌患者接受了放射治疗。生成了使用单弧（SA）和双弧（DA）的6MV、10MV和15MV光子能量的容积调强弧形计划。比较了计划靶体积（PTV）的几个物理指标，如 、 、 、 、 、 以及总跳数。分析了正常组织积分剂量（NTID）和对壳结构PHY和PHY的剂量。
所有能量和弧的PTV剂量覆盖情况相当。双弧（1.095）的CI优于单弧（1.127）、单弧（1.116）和单弧（1.116）。评估参数显示危及器官剂量显著降低。双弧的平均膀胱剂量（41.90Gy）优于单弧（42.48Gy）、单弧（42.08Gy）和单弧（41.93Gy）。同样，计算出的平均直肠剂量的 -值分别为0.001（单弧）、0.013（双弧）和0.003（双弧），因此双弧更具优势。NTID的差异非常小。
该研究表明更高能量并无更大优势，6MV光子能量的双弧VMAT计划是宫颈癌治疗的一个良好选择，因为它能提供高度均匀且适形的计划，具有出色的靶区覆盖和更好的危及器官保护。
