Objectives: This study aimed to assess the precision of dose delivery to the target in adaptive carbon ion radiotherapy (CIRT) for locally advanced non-small cell lung cancer (LA-NSCLC) in cumulative dosimetry.Methods:Forty-six patients who received CIRT were included (64 Gy[relative biological effectiveness, RBE] in 16 fractions) with treatment plan computed tomography (CT) and weekly CT scans. Offline adaptive radiotherapy (ART) was administered if the dose distribution significantly worsened. Daily doses were calculated from weekly CTs and integrated into plan CT scans using deformable image registration. The dosimetry parameters were compared between the as-scheduled plan and adaptive replan in patients receiving ART. Survival outcomes and toxicity were compared between the ART and non-ART groups.Results:ART was implemented for 27 patients in whom adaptive replans significantly increased the median V98%of the clinical tumor volume from 96.5% to 98.1% and D98%from 60.5 to 62.7 Gy(RBE) compared with the as-scheduled plans (p< 0.001). The conformity and uniformity of the dose distribution improved (p< 0.001), with no significant differences in the doses to normal tissues (lungs, heart, esophagus, and spinal cord) from the as-scheduled plans (p> 0.05). The ART and non-ART groups demonstrated comparable local control, progression-free survival, and overall survival (p> 0.05). No grade 3 or higher radiation-related toxicities were observed.Conclusions:ART enhanced target dose coverage while maintaining acceptable normal tissue exposure, supporting weekly CT monitoring integration during CIRT for the timely intervention for anatomical variations, ensuring precise dose delivery in LA-NSCLC.
目的：本研究旨在通过累积剂量学评估局部晚期非小细胞肺癌（LA-NSCLC）自适应碳离子放疗（CIRT）中靶区剂量投递的精确性。 方法：纳入46例接受CIRT治疗的患者（处方剂量64 Gy[相对生物效应，RBE]，分16次完成），所有患者均接受治疗计划计算机断层扫描（CT）及每周CT扫描。若剂量分布显著恶化，则实施离线自适应放疗（ART）。基于每周CT图像通过形变配准计算每日剂量并整合至计划CT中。在接受ART的患者中，比较计划方案与自适应重计划方案的剂量学参数。同时比较ART组与非ART组的生存结局及毒性反应。 结果：27例患者实施了ART，其自适应重计划方案相较于原计划方案，临床靶区中位V98%从96.5%显著提升至98.1%，D98%从60.5 Gy(RBE)提升至62.7 Gy(RBE)（p<0.001）。剂量分布的适形性与均匀性均得到改善（p<0.001），而正常组织（肺、心脏、食管和脊髓）的受照剂量与原计划相比无显著差异（p>0.05）。ART组与非ART组在局部控制率、无进展生存期和总生存期方面表现相当（p>0.05）。未观察到3级及以上放疗相关毒性反应。 结论：ART在保证正常组织受照剂量处于可接受范围内的同时，提高了靶区剂量覆盖度。该结果支持在LA-NSCLC的CIRT治疗中整合每周CT监测，以针对解剖结构变化及时干预，从而确保剂量投递的精确性。
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