Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan; Department of Radiation Oncology, Institute of Biomedical & Health Science, Hiroshima University, Hiroshima, Japan.
Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan; Department of Radiation Oncology, Institute of Biomedical & Health Science, Hiroshima University, Hiroshima, Japan.
Phys Med. 2019 Feb;58:54-58. doi: 10.1016/j.ejmp.2019.01.012. Epub 2019 Jan 25.
The aim of this study was to perform a comparison between robust optimization and planning target volume (PTV)-based optimization plans using volumetric modulated arc-therapy (VMAT) by evaluating perturbed doses induced by localization offsets for setup uncertainties in larynx cancer radiation therapy.
Ten patients with early-stage (T1-2N0) glottis carcinoma were selected. The clinical target volume (CTV), carotid arteries, and spinal cord were contoured by a radiation oncologist. PTV-based and robust optimization plans were normalized at D to the PTV and D to the CTV, respectively. Both optimization plans were evaluated using perturbed doses by specifying user defined shifted values from the isocenter. CTV dose (D, D, and D), homogeneity index (HI) and conformity index (CI, CI, and CI), as well as doses to the carotid arteries and spinal cord were compared between PTV-based and robust optimization plans.
The robust optimization plans exhibited superior CTV coverage and a reduced dose to the carotid arteries compared to the PTV-based optimization plans (p < 0.05). HI, CI and the dose to the spinal cord did not significantly differ between the PTV-based and robust optimization plans (p > 0.05). The robust optimization plans showed better CI and CI compared to the PTV-based optimization plans (p < 0.05). Plan perturbed evaluations showed that the robust optimization plan has small variations in the doses to the CTV, carotid arteries, and spinal cord compared to the PTV-based optimization plan.
The robust optimization plan may be a suitable treatment method in radiotherapy for larynx cancer patient.
本研究旨在通过评估喉癌放射治疗中因定位偏移引起的摆位不确定性的受扰剂量，对基于容积调强弧形治疗（VMAT）的稳健优化与计划靶区（PTV）优化计划进行比较。
选择 10 例早期（T1-2N0）声门型癌患者。由放射肿瘤学家对临床靶区（CTV）、颈动脉和脊髓进行勾画。PTV 优化计划和稳健优化计划分别在 PTV 和 CTV 归一化为 D 和 D，对优化计划进行评估，并指定从等中心点偏移的用户定义值。比较 PTV 优化计划和稳健优化计划的 CTV 剂量（D、D 和 D）、均匀性指数（HI）和适形性指数（CI、CI 和 CI），以及颈动脉和脊髓的剂量。
与 PTV 优化计划相比，稳健优化计划显示出更好的 CTV 覆盖度，同时降低了颈动脉的剂量（p＜0.05）。HI、CI 和脊髓剂量在 PTV 优化计划和稳健优化计划之间无显著差异（p＞0.05）。与 PTV 优化计划相比，稳健优化计划具有更好的 CI 和 CI（p＜0.05）。计划受扰评估表明，与 PTV 优化计划相比，稳健优化计划的 CTV、颈动脉和脊髓剂量变化较小。
稳健优化计划可能是喉癌患者放射治疗的一种合适的治疗方法。
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