Abstract：
OBJECTIVE: To investigate dosimetric differences in organs at risk (OARs) and cardiac substructures in patients with locally advanced non-small cell lung cancer (NSCLC) between the adaptive radiotherapy (ART) and non-ART groups.
METHODS: Thirty patients were treated with definitive radiotherapy +/- chemotherapy. Cardiac substructures including the left anterior descending coronary artery (LAD) and large vessels, were contoured. Eight patients experienced tumor shrinkage and were replanned (ART). Cumulative plans after ART were compared to the original plans (not considering volume reduction) in terms of dosimetric parameters. The cumulative plans of the ART group (n=8) and non-ART group (n=22) were compared in terms of the same dosimetric parameters.
RESULTS: Within the ART group, the following parameters were found to be significantly improved after re-planning: mean lung dose (MLD) (13.79 Gy vs. 15.6 Gy), V20Gy both lungs (17.88% vs. 27.38%), ipsilateral MLD (20.87 Gy vs. 24.44 Gy), and esophagus mean dose (20.79 Gy vs. 24.2 Gy). No dosimetric differences were observed in heart substructures. Dosimetric parameters, particularly LAD, were significantly worse in the ART group than in the non-ART group. This is probably because this OAR was not considered in the plan optimization after re-planning, because it was not routinely contoured as an OAR.
CONCLUSIONS: Our analysis showed an improvement in dosimetric parameters in the lungs and esophagus in the ART group. This approach may lead to a possible reduction in toxicity. Contouring of cardiac substructures could lead to a plan optimization of their parameters and eventually reduce the risk of cardiac toxicities in these patients.
METHODS: Thirty patients were treated with definitive radiotherapy +/- chemotherapy. Cardiac substructures including the left anterior descending coronary artery (LAD) and large vessels, were contoured. Eight patients experienced tumor shrinkage and were replanned (ART). Cumulative plans after ART were compared to the original plans (not considering volume reduction) in terms of dosimetric parameters. The cumulative plans of the ART group (n=8) and non-ART group (n=22) were compared in terms of the same dosimetric parameters.
RESULTS: Within the ART group, the following parameters were found to be significantly improved after re-planning: mean lung dose (MLD) (13.79 Gy vs. 15.6 Gy), V20Gy both lungs (17.88% vs. 27.38%), ipsilateral MLD (20.87 Gy vs. 24.44 Gy), and esophagus mean dose (20.79 Gy vs. 24.2 Gy). No dosimetric differences were observed in heart substructures. Dosimetric parameters, particularly LAD, were significantly worse in the ART group than in the non-ART group. This is probably because this OAR was not considered in the plan optimization after re-planning, because it was not routinely contoured as an OAR.
CONCLUSIONS: Our analysis showed an improvement in dosimetric parameters in the lungs and esophagus in the ART group. This approach may lead to a possible reduction in toxicity. Contouring of cardiac substructures could lead to a plan optimization of their parameters and eventually reduce the risk of cardiac toxicities in these patients.
摘要：
目的：研究局部晚期非小细胞肺癌（NSCLC）患者适应性放疗（ART）和非ART组的危险器官（OARs）和心脏亚结构的剂量学差异。
方法：30例患者接受确定性放疗+/-化疗。心脏亚结构，包括左冠状动脉前降支（LAD）和大血管，轮廓。八名患者经历了肿瘤缩小并进行了重新扫描（ART）。在剂量参数方面,将ART后的累积计划与原始计划(不考虑体积减少)进行比较。根据相同的剂量学参数比较了ART组（n=8）和非ART组（n=22）的累积计划。
结果：在ART组中，重新计划后发现以下参数显着改善：平均肺剂量（MLD）（13.79Gyvs.15.6Gy)，V20Gy双肺（17.88%vs.27.38%），同侧MLD（20.87Gyvs.24.44Gy)，和食道平均剂量（20.79Gyvs.24.2Gy)。在心脏亚结构中未观察到剂量学差异。剂量测定参数,尤其是LAD,ART组比非ART组明显更差。这可能是因为在重新规划后的计划优化中没有考虑到这个OAR，因为它通常没有像OAR一样轮廓。
结论：我们的分析显示ART组肺和食道的剂量学参数有所改善。这种方法可能导致毒性的可能降低。心脏亚结构的轮廓可以导致其参数的计划优化，并最终降低这些患者的心脏毒性风险。
方法：30例患者接受确定性放疗+/-化疗。心脏亚结构，包括左冠状动脉前降支（LAD）和大血管，轮廓。八名患者经历了肿瘤缩小并进行了重新扫描（ART）。在剂量参数方面,将ART后的累积计划与原始计划(不考虑体积减少)进行比较。根据相同的剂量学参数比较了ART组（n=8）和非ART组（n=22）的累积计划。
结果：在ART组中，重新计划后发现以下参数显着改善：平均肺剂量（MLD）（13.79Gyvs.15.6Gy)，V20Gy双肺（17.88%vs.27.38%），同侧MLD（20.87Gyvs.24.44Gy)，和食道平均剂量（20.79Gyvs.24.2Gy)。在心脏亚结构中未观察到剂量学差异。剂量测定参数,尤其是LAD,ART组比非ART组明显更差。这可能是因为在重新规划后的计划优化中没有考虑到这个OAR，因为它通常没有像OAR一样轮廓。
结论：我们的分析显示ART组肺和食道的剂量学参数有所改善。这种方法可能导致毒性的可能降低。心脏亚结构的轮廓可以导致其参数的计划优化，并最终降低这些患者的心脏毒性风险。
