Hu Haili, Jueyi Zhou, Hao Jiang, Lai Jianjun
Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China.
Zhejiang Hospital, Hangzhou, Zhejiang, China.
Front Oncol. 2025 Jun 9;15:1610980. doi: 10.3389/fonc.2025.1610980. eCollection 2025.
The Serial function in the Monaco treatment planning system is essential for cardiac dose optimization in left breast cancer radiotherapy; however its optimal K-value for deep-inspiration breath-hold intensity-modulated radiotherapy (DIBH-IMRT) has not been established. This study aims to determine the evidence-based K-value configuration for clinical implementation.
41 left breast cancer patients undergoing DIBH-IMRT were retrospectively analyzed. Plans were stratified by Monaco-Serial K-values: Group A (K=1), B (2≤K ≤ 4), and C (K>4). Dosimetric parameters (heart, LAD, Lung-L) and dose-volume reduction rates (Groups B/C vs A) were compared. Correlations between K-values and DIBH-induced anatomical changes (Lung-L volume increment rate, Lung-L/Heart volume ratio, and Heart-Breast Distance increment) were assessed.
All plans satisfied target coverage. Group B achieved optimal cardiac protection: mean heart dose (273.9 ± 91.0 cGy), max heart dose (2676.2 ± 1380.7 cGy), and LAD doses (mean: 411.3 cGy; max: 1483.3 ± 736.3 cGy) significantly decreased versus Group A. Lung-L V500cGy in Group B increased marginally but within clinical tolerance. Correlation analysis confirmed that Group B achieved balanced control of mean/maximum heart doses, aligning with the expected effects of anatomical variations induced by the DIBH technique.
Adjusting Monaco-Serial K-value to 2≤K ≤ 4 provides optimal dose constraints for the heart and substructures while ensuring target coverage, making it the optimal parameter setting for left breast cancer DIBH-IMRT.
Monaco治疗计划系统中的序列功能对于左乳癌放疗中的心脏剂量优化至关重要；然而，其在深吸气屏气调强放疗（DIBH-IMRT）中的最佳K值尚未确定。本研究旨在确定基于证据的K值配置以用于临床实施。
回顾性分析41例行DIBH-IMRT的左乳癌患者。计划根据Monaco序列K值分层：A组（K = 1）、B组（2≤K≤4）和C组（K>4）。比较剂量学参数（心脏、左前降支、左肺）和剂量体积减少率（B/C组与A组）。评估K值与DIBH引起的解剖学变化（左肺体积增加率、左肺/心脏体积比和心脏-乳腺距离增加）之间的相关性。
所有计划均满足靶区覆盖。B组实现了最佳的心脏保护：与A组相比，平均心脏剂量（273.9±91.0 cGy）、最大心脏剂量（2676.2±1380.7 cGy）和左前降支剂量（平均：411.3 cGy；最大：1483.3±736.3 cGy）显著降低。B组中左肺V500cGy略有增加，但在临床耐受范围内。相关性分析证实，B组实现了对平均/最大心脏剂量的平衡控制，与DIBH技术引起的解剖学变化的预期效果一致。
将Monaco序列K值调整为2≤K≤4可为心脏及亚结构提供最佳剂量限制，同时确保靶区覆盖，使其成为左乳癌DIBH-IMRT的最佳参数设置。
