Silvestri Valerio, Raspanti Davide, Guerrisi Maria Giovanna, Falco Maria Daniela
Department of Radiation Oncology, "SS. Annunziata" Hospital, "G. D'Annunzio" University, Via De' Vestini, 66100 Chieti, Italy; Medical Physics Unit, "Tor Vergata" University, Rome, Italy.
Tema Sinergie S.p.A, Faenza, Italy.
Phys Med. 2023 Apr;108:102570. doi: 10.1016/j.ejmp.2023.102570. Epub 2023 Mar 28.
To determine the error detection sensitivity of a commercial log file-based system (LINACWatch®, LW) for integration into clinical routine and to compare it with a measurement device (OCTAVIUS 4D, Oct4D) for IMRT and VMAT delivery QA.
76 VMAT/IMRT plans (H&N, prostate, rectum and breast) preliminarily classified according to their Modulation Complexity Score (MCS) calculated by LW, were considered. Receiver Operating Characteristic (ROC) Curves were used to establish gamma criteria for LW. 12 plans (3 for each site) were intentionally modified in order to introduce delivery errors regarding MLC, jaws, collimator, gantry and MU (for a total set of 168 incorrect plans) and irradiated on Oct4D; the corresponding log files were analysed by LW. Each incorrect plan was compared to the error-free plan using γ-index analysis for MLC, jaws and MU errors investigation and Root-Mean-Square (RMS) values for gantry and collimator errors investigation.
MCS ranges values were: 0.10-0.20 for H&N, 0.21-0.40 for prostate and rectum, 0.41-1.00 for breast. From ROC curves, the Gamma Passing Rate (GPR) thresholds were: 87%, 92%, 99% for H&N, prostate and rectum, and breast, respectively. The 1.5%/1.5 mm/local criteria were adopted for the γ-analysis. LW sensitivity in detecting the introduced errors was higher when compared to Oct4D: 48.5% vs 30.4% respectively.
LW can be considered useful complement to phantom-based delivery QA of IMRT/VMAT plans. The MCS tool is effective in detecting over or under modulated plans prior to pre-treatment QA. However, rigorous and routinely machine QCs are recommended.
确定一种基于商业日志文件的系统（直线加速器监测系统，LINACWatch®，LW）在整合到临床常规流程中的错误检测灵敏度，并将其与用于调强放疗（IMRT）和容积调强弧形放疗（VMAT）剂量验证（QA）的测量设备（OCTAVIUS 4D，Oct4D）进行比较。
考虑了76个VMAT/IMRT计划（头颈部、前列腺、直肠和乳腺），这些计划根据LW计算的调制复杂度评分（MCS）进行了初步分类。使用接收者操作特征（ROC）曲线来确定LW的伽马标准。故意修改了12个计划（每个部位3个），以引入关于多叶准直器（MLC）、光阑、准直仪、机架和监测单位（MU）的照射错误（总共168个错误计划），并在Oct4D上进行照射；LW分析了相应的日志文件。使用γ指数分析对每个错误计划与无错误计划进行比较，以调查MLC、光阑和MU错误，并使用均方根（RMS）值调查机架和准直仪错误。
MCS范围值为：头颈部0.10 - 0.20，前列腺和直肠0.21 - 0.40，乳腺0.41 - 1.00。从ROC曲线来看，伽马通过率（GPR）阈值分别为：头颈部87%，前列腺和直肠92%，乳腺99%。γ分析采用1.5%/1.5毫米/局部标准。与Oct4D相比，LW检测引入错误的灵敏度更高：分别为48.5%和30.4%。
LW可被视为IMRT/VMAT计划基于模体的剂量验证的有用补充。MCS工具在治疗前QA之前检测调制过度或不足的计划方面是有效的。然而，建议进行严格且常规的机器质量控制。
