Department of Physics and Engineering, University of Western Ontario, London, Ontario, Canada.
Radiother Oncol. 2011 Dec;101(3):431-7. doi: 10.1016/j.radonc.2011.08.030. Epub 2011 Oct 1.
To compare radiotherapy treatment plans for mid- and distal-esophageal cancer with primary involvement of the gastroesophageal (GE) junction using a novel IMRT & Arc technique (IMRT & Arc), helical tomotherapy (HT), and RapidArc (RA1 and RA2).
Eight patients treated on HT for locally advanced esophageal cancer with radical intent were re-planned for RA and IMRT&Arc. RA plans employed single and double arcs (RA1 and RA2, respectively), while IMRT&Arc plans had four fixed-gantry IMRT fields and a conformal arc. Dose-volume histogram statistics, dose uniformity, and dose homogeneity were analyzed to compare treatment plans.
RA2 plans showed significant improvement over RA1 plans in terms of OAR dose and PTV dose uniformity and homogeneity. HT plan provided best dose uniformity (p=0.001) and dose homogeneity (p=0.002) to planning target volume (PTV), while IMRT&Arc and RA2 plans gave lowest dose to lungs among four radiotherapy techniques with acceptable PTV dose coverage. Mean V(10) of the lungs was significantly reduced by the RA2 plans compared to IMRT&Arc (40.3%, p=0.001) and HT (66.2%, p<0.001) techniques. Mean V(15) of the lungs for the RA2 plans also showed significant improvement over the IMRT&Arc (25.2%, p=0.042) and HT (34.8%, p=0.027) techniques. These improvements came at the cost of higher doses to the heart volume compared to HT and IMRT&Arc techniques. Mean lung dose (MLD) for the IMRT&Arc technique (21.2 ± 5.0% of prescription dose) was significantly reduced compared to HT (26.3%, p=0.004), RA1 (23.3%, p=0.028), and RA2 (23.2%, p=0.017) techniques.
The IMRT&Arc technique is a good option for treating esophageal cancer with thoracic involvement. It achieved optimal low dose to the lungs and heart with acceptable PTV coverage. HT is a good option for treating esophageal cancer with little thoracic involvement as it achieves superior dose conformality and uniformity. The RA2 technique provided for improved treatment plans using additional arcs with low doses to the lungs at the cost of increased heart dose. Plan quality could still be improved through the use of additional arcs.
比较新型调强放疗和弧形技术（IMRT & Arc）、螺旋断层放疗（HT）和 RapidArc（RA1 和 RA2）治疗胃食管交界部（GE）原发性中下段食管癌的放射治疗计划。
对 8 例接受 HT 根治性治疗的局部晚期食管癌患者进行重新计划，采用 RA 和 IMRT & Arc。RA 计划采用单弧和双弧（RA1 和 RA2），而 IMRT & Arc 计划采用 4 个固定机架的调强放疗野和一个适形弧。分析剂量体积直方图统计、剂量均匀性和剂量均匀性，以比较治疗计划。
与 RA1 计划相比，RA2 计划在 OAR 剂量和 PTV 剂量均匀性和均匀性方面有显著改善。HT 计划为 PTV 提供了最佳的剂量均匀性（p=0.001）和剂量均匀性（p=0.002），而 IMRT & Arc 和 RA2 计划在四种放疗技术中为肺提供了最低的剂量，同时可接受的 PTV 剂量覆盖。与 IMRT & Arc（40.3%，p=0.001）和 HT（66.2%，p<0.001）技术相比，RA2 计划显著降低了肺的平均 V（10）。与 IMRT & Arc（25.2%，p=0.042）和 HT（34.8%，p=0.027）技术相比，RA2 计划的肺平均 V（15）也有显著改善。这些改善是以心脏体积的剂量升高为代价的，与 HT 和 IMRT & Arc 技术相比。与 HT（26.3%，p=0.004）、RA1（23.3%，p=0.028）和 RA2（23.2%，p=0.017）技术相比，IMRT & Arc 技术的平均肺剂量（MLD）（处方剂量的 21.2±5.0%）显著降低。
对于治疗有胸部受累的食管癌，IMRT & Arc 技术是一种很好的选择。它可以达到最优的肺部和心脏低剂量，同时可接受的 PTV 覆盖。HT 是治疗胸部受累较小的食管癌的一种很好的选择，因为它可以达到更好的剂量适形性和均匀性。RA2 技术通过使用额外的弧，在肺剂量较低的情况下提供了更好的治疗计划，但代价是心脏剂量增加。通过使用额外的弧，计划质量仍可以得到改善。
