Field-in-field breast planning for a jawless, double-stack MLC LINAC using flattening-filter-free beams
Field-in-field breast planning for a jawless, double-stack MLC LINAC using flattening-filter-free beams
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DOI：
10.1002/acm2.12722
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发表时间：
2019-10-16
影响因子：
2.1
通讯作者：
Cai, Bin
中科院分区：
文献类型：
--
作者：
Morris, Robert;Laugeman, Eric;Cai, Bin
背景：本研究旨在开发一种高效的野战(FIF)计划技术，并结合日食治疗计划系统(TPS)来确定使用Halcyon治疗递送系统进行乳腺癌3D治疗的可行性。方法在Halcyon治疗计划系统上制定10个治疗计划，并与相同患者临床提交的TrueBeam计划进行比较，该计划使用平坦化的6 MV和10 MV射野。入选本研究的患者接受了简单的乳房切向照射，没有接受锁骨上或内乳房淋巴结的放射治疗。规划目标体积(PTV)范围为519毫升至1211毫升，平均目标体积为877毫升。研究了几种规划技术，包括准直器、门架旋转和FIF段的数量，以及动态平坦束(DFB)的使用--动态平坦束(DFB)是一种预定义的MLC图案，旨在标准水模上提供10厘米深的平坦束轮廓。为了进行比较，临床交付的TrueBeam计划保持不变，只是将目标覆盖范围正常化，以便更容易地比较这两种治疗交付技术。结果使用医生定义的PTV，标准化后98%的体积被95%的处方剂量覆盖，Halcyon计划被放射肿瘤学家认为在临床上是可以接受的，并与TrueBeam计划相当。在试验患者中产生的全球平均最大剂量在TrueBeam和Halcyon计划之间是相同的(Rx的108%)，平均PTV剂量分别为102.5%和101.6%。结论本研究为使用Halcyon直线加速器进行三维适形乳腺放射治疗提供了一种实用而有效的计划方法。当归一化到临床期望的覆盖率时，热点被维持在可接受的水平，总体计划质量与传统C-Arm LINAC提供的计划相当。
Background This study intends to develop an efficient field-in-field (FiF) planning technique with the Eclipse treatment planning system (TPS) to determine the feasibility of using the Halcyon treatment delivery system for 3D treatment of breast cancer. Methods Ten treatment plans were prepared on the Halcyon treatment planning system and compared to the same patients' clinically delivered TrueBeam plans which used flattened 6 MV and 10 MV beams. Patients selected for this study were treated via simple, tangential breast irradiation and did not receive radiotherapy of the supraclavicular or internal mammary lymph nodes. Planning target volumes (PTV) volumes ranged from 519 cc to 1211 cc with a mean target volume of 877 cc. Several planning techniques involving collimator, gantry rotation, and number of FiF segments were investigated as well as the use of the dynamically flattened beam (DFB) - a predefined MLC pattern that is designed to provide a flattened beam profile at 10 cm depth on a standard water phantom. For comparison, the clinically delivered TrueBeam plans remained unaltered except for normalization of the target coverage to more readily compare the two treatment delivery techniques. Results Using the physician defined PTV, normalized such that 98% of the volume was covered by 95% of the prescribed dose, the Halcyon plans were deemed clinically acceptable and comparable to the TrueBeam plans by the radiation oncologist. Resulting average global maximum doses in the test patients were identical between the TrueBeam and Halcyon plans (108% of Rx) and a mean PTV dose of 102.5% vs 101.6%, respectively. Conclusions From this study a practical and efficient planning method for delivering 3D conformal breast radiotherapy using the Halcyon linear accelerator has been developed. When normalized to the clinically desired coverage, hot spots were maintained to acceptable levels and overall plan quality was comparable to plans delivered on conventional C-arm LINACs.