Fixed-jaw technique to improve IMRT plan quality for the treatment of cervical and upper thoracic esophageal cancer
Fixed-jaw technique to improve IMRT plan quality for the treatment of cervical and upper thoracic esophageal cancer
复制标题
固定颌技术提高宫颈癌和上胸段食管癌IMRT计划质量
DOI：
10.1002/acm2.12704
复制
发表时间：
2019-08-28
影响因子：
2.1
通讯作者：
Li, Jinkai
中科院分区：
文献类型：
--
作者：
Song, Wei;Lu, Hong;Li, Jinkai
本研究的目的是探讨颈部和胸上段食管癌（EC）患者接受调强放疗时，固定颌技术（FJT）相对于传统分野技术（SFT）的潜在优势。为15例颈段和上胸段EC患者生成SFT和FJT计划。比较了剂量学参数和递送效率。定义了以监测单元（MU）数量加权的钳口开口与多叶准直器（MLC）孔径的面积比（AR），以评价通过MLC的透射对PTV50.4外剂量梯度的影响，并分析了梯度指数（GI）与AR之间的相关性。FJT方案的GI和AR均优于FJT方案（P < 0.001）。FJT和SFT计划中的GI和AR分别为0.883和0.836，P <0.001。FJT计划肺平均剂量（D-mean）V-5Gy ~ V-40 Gy和体部平均剂量（D-mean）V-5Gy ~ V-50 Gy ~ PTV50.4均低于SFT计划（P < 0.05）。FJT计划显示脊髓PRV和心脏的剂量呈减少趋势，但只有心脏D均值的差异达到统计学显著性（P < 0.05）。FJT计划使MU和子野数分别减少5.5%和17.9%，分娩时间略缩短0.23min（P < 0.05）。两个计划的伽马指数通过率都在95%以上。FJT结合靶区分割可以提供上级器官的风险保留和类似的靶区覆盖，而不影响输送效率，应该是颈部和上胸部EC患者的首选调强放射治疗计划方法。
The purpose of this study was to investigate the potential advantages of the fixed-jaw technique (FJT) over the conventional split-field technique (SFT) for cervical and upper thoracic esophageal cancer (EC) patients treated with intensity-modulated radiotherapy. The SFT and FJT plans were generated for 15 patients with cervical and upper thoracic EC. Dosimetric parameters and delivery efficiency were compared. An area ratio (AR) of the jaw opening to multileaf collimator (MLC) aperture weighted by the number of monitor units (MUs) was defined to evaluate the impact of the transmission through the MLC on the dose gradient outside the PTV50.4, and the correlation between the gradient index (GI) and AR was analyzed. The FJT plans achieved a better GI and AR (P < 0.001). There was a positive correlation between the GI and AR in the FJT (r = 0.883, P < 0.001) and SFT plans (r = 0.836, P < 0.001), respectively. Moreover, the mean dose (D-mean), V-5Gy-V-40Gy for the lungs and the D-mean, V-5Gy-V-50Gy for the body-PTV50.4 in the FJT plans were lower than those in the SFT plans (P < 0.05). The FJT plans demonstrated a reduction trend in the doses to the spinal cord PRV and heart, but only the difference in the heart D-mean reached statistical significance (P < 0.05). The FJT plans reduced the number of MUs and subfields by 5.5% and 17.9% and slightly shortened the delivery time by 0.23 min (P < 0.05). The gamma-index passing rates were above 95% for both plans. The FJT combined with target splitting can provide superior organs at risk sparing and similar target coverage without compromising delivery efficiency and should be a preferred intensity-modulated radiotherapy planning method for cervical and upper thoracic EC patients.