Fuangrod Todsaporn, Greer Peter B, Simpson John, Zwan Benjamin J, Middleton Richard H
Faculty of Engineering and Built Environment, School of Electrical Engineering and Computer Science, University of Newcastle , Callaghan, Australia.
Radiation Oncology, Calvary Mater Newcastle Hospital, Waratah, Australia.
Int J Health Care Qual Assur. 2017 Mar 13;30(2):90-102. doi: 10.1108/IJHCQA-03-2016-0028.
Purpose Due to increasing complexity, modern radiotherapy techniques require comprehensive quality assurance (QA) programmes, that to date generally focus on the pre-treatment stage. The purpose of this paper is to provide a method for an individual patient treatment QA evaluation and identification of a "quality gap" for continuous quality improvement. Design/methodology/approach A statistical process control (SPC) was applied to evaluate treatment delivery using in vivo electronic portal imaging device (EPID) dosimetry. A moving range control chart was constructed to monitor the individual patient treatment performance based on a control limit generated from initial data of 90 intensity-modulated radiotherapy (IMRT) and ten volumetric-modulated arc therapy (VMAT) patient deliveries. A process capability index was used to evaluate the continuing treatment quality based on three quality classes: treatment type-specific, treatment linac-specific, and body site-specific. Findings The determined control limits were 62.5 and 70.0 per cent of the χ pass-rate for IMRT and VMAT deliveries, respectively. In total, 14 patients were selected for a pilot study the results of which showed that about 1 per cent of all treatments contained errors relating to unexpected anatomical changes between treatment fractions. Both rectum and pelvis cancer treatments demonstrated process capability indices were less than 1, indicating the potential for quality improvement and hence may benefit from further assessment. Research limitations/implications The study relied on the application of in vivo EPID dosimetry for patients treated at the specific centre. Sampling patients for generating the control limits were limited to 100 patients. Whilst the quantitative results are specific to the clinical techniques and equipment used, the described method is generally applicable to IMRT and VMAT treatment QA. Whilst more work is required to determine the level of clinical significance, the authors have demonstrated the capability of the method for both treatment specific QA and continuing quality improvement. Practical implications The proposed method is a valuable tool for assessing the accuracy of treatment delivery whilst also improving treatment quality and patient safety. Originality/value Assessing in vivo EPID dosimetry with SPC can be used to improve the quality of radiation treatment for cancer patients.
目的 由于复杂性不断增加，现代放射治疗技术需要全面的质量保证（QA）计划，而迄今为止这些计划通常侧重于治疗前阶段。本文的目的是提供一种用于个体患者治疗QA评估和识别“质量差距”以持续改进质量的方法。
设计/方法/途径 应用统计过程控制（SPC）通过体内电子射野影像装置（EPID）剂量测定来评估治疗实施情况。构建移动极差控制图，基于90例调强放射治疗（IMRT）和10例容积调强弧形治疗（VMAT）患者初始数据生成的控制限来监测个体患者的治疗性能。使用过程能力指数基于三种质量类别评估持续治疗质量：特定治疗类型、特定治疗直线加速器和特定身体部位。
发现 确定的IMRT和VMAT治疗的控制限分别为χ通过率的62.5%和70.0%。总共选择了14名患者进行初步研究，结果表明所有治疗中约1%包含与治疗分次之间意外解剖变化相关的误差。直肠癌和盆腔癌治疗的过程能力指数均小于1，表明有质量改进的潜力，因此可能受益于进一步评估。
研究局限性/影响 该研究依赖于在特定中心接受治疗的患者的体内EPID剂量测定的应用。用于生成控制限的抽样患者限于100名患者。虽然定量结果特定于所使用的临床技术和设备，但所描述的方法一般适用于IMRT和VMAT治疗QA。虽然需要更多工作来确定临床意义水平，但作者已经证明了该方法用于特定治疗QA和持续质量改进的能力。
实际意义 所提出的方法是评估治疗实施准确性的宝贵工具，同时还能提高治疗质量和患者安全性。
原创性/价值 用SPC评估体内EPID剂量测定可用于提高癌症患者放射治疗的质量。
