Yao Wenyan, Dong Shuhui, Xu Peixun, Zhong Ziyue, Li Zongtai, Zhou Yupeng, Fang Yongwen, Lin Zhiyue, He Mengxue, Hu Jiang, Xia Weixiong, Xu Senkui
Sun Yat-Sen University Cancer Center, Guangzhou, 510060, China.
State Key Laboratory of Oncology in South China, Guangzhou, 510060, China.
BMC Cancer. 2025 Sep 2;25(1):1414. doi: 10.1186/s12885-025-14850-1.
To investigate the anatomical and dosimetric differences in target areas and organs at risk (OARs) after adjusting the radiotherapy schedule for nasopharyngeal carcinoma (NPC).
In total, 34 patients who underwent radiotherapy for NPC were selected. A new localization computed tomography (CT) scan was performed after 25th and before 26th fraction. The target area and organs at risk were redrawn based on the new CT, and the radiotherapy plan was redesigned for the seven remaining rounds of radiotherapy. Plan consists of the old image and old plan, Plan consists of the new image and new plan, and Plan consists of the new image and old plan. Data on the volume and dose of target areas and organs at risk were collected for two schedule sets.
In the re-scan CT, the volume of Planning Target Volume for Nodal Region Right (PTVnd (R)), Planning Target Volume for Nodal Region Left (PTVnd (L)), left parotid and right parotid decreased significantly (P < 0.05). Additionally, the centroids of the left and right parotid moved towards the centre, abdomen and head. Compared to Plan the D and V of PTVnd (R) and PTVnd (L) of Plan was significantly lower, also significant differences were observed in the D and D of the left and right parotid, and the D of the spinal cord (P < 0.05). In comparison with Plan and Plan, except for the D and D of Planning Target Volume nodal extension (PTVnx) and the D of PTVnd (R), significant dosimetric differences were observed in the target area and all organs at risk indicators (P < 0.05). In the re-designed plan, the exposure dose to organs at risk was reduced.
Due to significant anatomical changes in the volume and position of both target volumes and organs at risk during the later fractions of radiotherapy for NPC, the dose coverage of lymph-node regions can no longer meet clinical requirements. Adaptive radiotherapy ensures adequate target coverage while simultaneously reducing the dose to surrounding critical structures.
探讨调整鼻咽癌（NPC）放疗计划后靶区及危及器官（OARs）的解剖学和剂量学差异。
共选取34例接受NPC放疗的患者。在第25次分割后和第26次分割前进行一次新的定位计算机断层扫描（CT）。根据新的CT重新勾画靶区和危及器官，并为剩余的7轮放疗重新设计放疗计划。计划包括旧图像和旧计划、计划包括新图像和新计划、计划包括新图像和旧计划。收集两个计划组的靶区和危及器官的体积和剂量数据。
在重新扫描的CT中，右侧淋巴结区计划靶体积（PTVnd（R））、左侧淋巴结区计划靶体积（PTVnd（L））、左侧腮腺和右侧腮腺的体积显著减小（P < 0.05）。此外，左侧和右侧腮腺的质心向中心、腹部和头部移动。与计划相比，计划中PTVnd（R）和PTVnd（L）的D和V显著降低，左侧和右侧腮腺的D以及脊髓的D也观察到显著差异（P < 0.05）。与计划和计划相比，除了计划靶体积淋巴结延伸（PTVnx）的D和D以及PTVnd（R）的D外，在靶区和所有危及器官指标中均观察到显著的剂量学差异（P < 0.05）。在重新设计的计划中，危及器官的照射剂量降低。
由于NPC放疗后期靶区和危及器官的体积和位置发生显著解剖学变化，淋巴结区域的剂量覆盖不再满足临床要求。自适应放疗可确保靶区得到充分覆盖，同时降低对周围关键结构的剂量。
