文章：

新型算法规划参数对螺旋断层放疗计划剂量学质量、照射时间及投照精度的影响

Influence of the Planning Parameters of a New Algorithm on the Dosimetric Quality, Beam-On Time and Delivery Accuracy of Tomotherapy Plans

原文发布日期：15 May 2024

DOI: 10.3390/cancers16101883

类型: Article

开放获取: 是

英文摘要：

Background: This work aimed to determine the optimum VOLOTMUltra algorithm parameters for tomotherapy treatments. Methods: 1056 treatment plans were generated with VOLOTMUltra for 36 patients and six anatomical locations. The impact of varying four parameters was studied: the accelerated treatment (AT), leaf open/close time (LOT) cutoff, normal tissue objective (NTO) weight, and number of iterations. The beam-on time and dosimetric metrics were quantified for the target volumes and organs at risk (OARs). Delivery quality assurance measurements were obtained for 36 plans to assess the delivery accuracy. Results: The mean beam-on time for the helical tomotherapy and TomoDirect (TD) plans decreased by 26.6 ± 2.8% and 17.4 ± 4.3%, respectively, when the accelerated treatment parameter was increased from 0 to 10, at the expense of the planning target volume (PTV) coverage (2% lower D98%) and OAR dose (up to 15% increase). For TD plans, it seems preferable to systematically use an AT value of 10. Increasing the number of iterations beyond six seems unnecessary. In this study, an NTO weight of approximately 10 appears to be ideal and eliminates the need to use rings in the treatment plan. Finally, no correlation was found between the leaf open/close time cutoff and the delivery accuracy, while a leaf open/close cutoff of 60 ms seemed to degrade dosimetry quality. Conclusion: Optimal values for the AT, LOT cutoff, NTO weight, and number of optimization rounds were identified and should help improve the management of patients whose tomotherapy treatments are planned with VOLOTMUltra.

摘要翻译： 

背景：本研究旨在确定螺旋断层放疗治疗中VOLOTMUltra算法的最佳参数设置。方法：针对36例患者及六个解剖部位，使用VOLOTMUltra生成了1056个治疗计划。通过调整四个参数研究其影响：加速治疗参数、叶片开闭时间阈值、正常组织目标权重及迭代次数。量化分析了靶区及危及器官的照射时间与剂量学指标，并对36个计划进行实施质量验证以评估照射精度。结果：当加速治疗参数从0增至10时，螺旋断层放疗与TomoDirect计划的平均照射时间分别减少26.6±2.8%和17.4±4.3%，但导致计划靶区覆盖率下降（D98%降低2%）及危及器官剂量增加（最高达15%）。对于TomoDirect计划，系统采用加速治疗参数值10更为适宜。迭代次数超过6次未见明显获益。本研究中正常组织目标权重约10为理想值，可避免在治疗计划中使用剂量环结构。叶片开闭时间阈值与照射精度无显著相关性，但60毫秒的阈值会降低剂量学质量。结论：本研究明确了加速治疗参数、叶片开闭时间阈值、正常组织目标权重及优化迭代次数的最佳取值，有助于提升采用VOLOTMUltra计划的螺旋断层放疗患者的治疗管理质量。

原文链接：

Influence of the Planning Parameters of a New Algorithm on the Dosimetric Quality, Beam-On Time and Delivery Accuracy of Tomotherapy Plans