使用基于叶片开启时间的剂量重建工具对螺旋断层放射治疗中的颅脊髓照射进行质量保证。

Quality assurance of craniospinal irradiation in helical tomotherapy using a dose reconstruction tool based on leaf open time.

作者信息

Wang Xiunan, Ni Wenjie, Ge Yongqing, Liu Bo, Wang Qin, Song Linan, Yang Hui, Jin Yizhen, Mu Xiaofeng

机构信息

Department of Radiation Oncology, Beijing Shijitan Hospital of Capital Medical University, Beijing, China.

出版信息

J Appl Clin Med Phys. 2025 Jul;26(7):e70139. doi: 10.1002/acm2.70139.

DOI:10.1002/acm2.70139

PMID:40653775

Abstract

OBJECTIVE

The delivery quality assurance (DQA) of craniospinal irradiation (CSI) due to the target length results in no ideal verification devices. Delivery Analysis (DA) could calculate the dose distribution based on the measured multi leaf open time in helical tomotherapy (HT). This study aimed to evaluate the efficacy of DA for DQA of CSI in HT.

MATERIAL AND METHODS

32 CSI plans were classified into two groups based on γ analysis of the PTV-cranial and PTV-spine plans using a 2D ionization chamber matrix (MatriXX). Plans with γ passing rates ≥ 95% at 3%/2 mm were classified as the passed group, while those < 95% were classified as the failed group. Receiver operating characteristic (ROC) curves identified optimal passing rate threshold for DA in HT. Logistic regression analyzed risk factors for DQA failure, and failed plans were reoptimized according to the adjusted parameter.

RESULTS

For PTV-cranial plans, 30 passed and two failed; for PTV-spine plans, 21 passed and 11 failed. ROC analysis revealed areas under the curve of 0.858 (PTV-cranial, threshold: 89.0%) and 0.714 (PTV-spine, threshold: 86.0%). Logistic regression identified planned modulation factor (MF-plan; p = 0.046; p = 0.023) and actual modulation factor (MF-actual; p = 0.027; p = 0.008) as independent risk factors for DQA failure in both MatriXX and DA. Additionally, beam on time (p = 0.043), gantry period (p = 0.007) and maximum leaf open time (p = 0.007) were identified as independent risk factors for DA. Reoptimization of failed plans with MF-plan = 2.6 significantly improved passing rates in DA (73.70% ± 13.30% vs. 88.20% ± 12.30%; p = 0.010) and MatriXX (91.20% ± 2.60% vs. 96.10% ± 1.40%; p < 0.001).

CONCLUSION

Delivery Analysis could be a feasible tool for DQA of CSI in HT. Increasing the MF-plan is recommended to enhance the passing rate.

摘要

目的

由于靶区长度原因，颅脊髓照射（CSI）的剂量输送质量保证（DQA）没有理想的验证设备。剂量输送分析（DA）可根据螺旋断层放疗（HT）中测量的多叶准直器开启时间计算剂量分布。本研究旨在评估DA在HT中对CSI进行DQA的有效性。

材料与方法

根据使用二维电离室矩阵（MatriXX）对PTV-颅脑和PTV-脊柱计划进行的γ分析，将32个CSI计划分为两组。在3%/2毫米条件下γ通过率≥95%的计划被分类为通过组，而<95%的计划被分类为失败组。受试者操作特征（ROC）曲线确定了HT中DA的最佳通过率阈值。逻辑回归分析了DQA失败的风险因素，并根据调整后的参数对失败计划进行重新优化。

结果

对于PTV-颅脑计划，30个通过，2个失败；对于PTV-脊柱计划，21个通过，11个失败。ROC分析显示曲线下面积分别为0.858（PTV-颅脑，阈值：89.0%）和0.714（PTV-脊柱，阈值：86.0%）。逻辑回归确定计划调制因子（MF-计划；p = 0.046；p = 0.023）和实际调制因子（MF-实际；p = 0.027；p = 0.008）是MatriXX和DA中DQA失败的独立风险因素。此外，射束开启时间（p = 0.043）、机架旋转周期（p = 0.007）和最大叶准直器开启时间（p = 0.007）被确定为DA的独立风险因素。将MF-计划 = 2.6的失败计划重新优化后，DA中的通过率显著提高（73.70%±13.30%对88.20%±12.30%；p = 0.010），MatriXX中的通过率也显著提高（91.20%±2.60%对96.10%±1.40%；p < 0.001）。