Burghelea Manuela, Bakkali Tahiri Jinane, Dhont Jennifer, Kyndt Martin, Gulyban Akos, Szkitsak Juliane, Bogaert Evelien, van Gestel Dirk, Reynaert Nick
Université libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), Institut Jules Bordet, Department of Medical Physics, Brussels, Belgium.
Université Libre De Bruxelles, Radiophysics and MRI physics laboratory, Brussels, Belgium.
Phys Imaging Radiat Oncol. 2023 Aug 14;28:100479. doi: 10.1016/j.phro.2023.100479. eCollection 2023 Oct.
4D Computed Tomography (4DCT) technology captures the location and movement of tumors and nearby organs at risk over time. In this study, a multi-institutional multi-vendor 4DCT audit was initiated to assess the accuracy of current imaging protocols.
Twelve centers, including thirteen scanners performed a 4DCT acquisition of a dynamic thorax phantom using the institution's own protocol with the in-house breathing monitoring system. Five regular and three irregular breathing patterns were used. Image acquisition and reconstruction were followed by automated image analysis with our in-house developed 4DCT QA program (QAMotion). CT number accuracy, volume deviation, amplitude deviation, and spatial integrity were assessed per pattern using both the segmented volumes and line profiles.
Regular breathing curves showed relatively accurate results across all institutions, with mean volume and CT number deviations and median amplitude deviation below 2%, 5 HU and 2 mm, respectively. Results obtained for irregular patterns showed more variation across the institutions. Volume and CT number deviations co-occurred with a blurring of the sphere, interpolation, or double-structure artifacts that were confirmed through the line profiles. For some of the irregular patterns, amplitude deviations up to 6 mm were observed. Maximum Intensity Projection (MaxIP) correctly captured the applied motion amplitude with deviations across all institutions within 2 mm except for double amplitude pattern.
All centers invited to participate in the audit responded positively, highlighting the need for a comprehensive yet easy-to-execute 4DCT quality assurance program. The largest variances between the results from one institution to another confirmed that a standardized 4DCT audit is warranted.
4D计算机断层扫描（4DCT）技术可随时间捕捉肿瘤及附近危险器官的位置和运动情况。在本研究中，启动了一项多机构多供应商的4DCT审核，以评估当前成像方案的准确性。
12个中心，包括13台扫描仪，使用机构自身的方案及内部呼吸监测系统对动态胸部体模进行4DCT采集。采用了5种规律呼吸模式和3种不规律呼吸模式。图像采集和重建后，使用我们内部开发的4DCT质量保证程序（QAMotion）进行自动图像分析。使用分割体积和线轮廓对每种模式的CT值准确性、体积偏差、幅度偏差和空间完整性进行评估。
在所有机构中，规律呼吸曲线显示出相对准确的结果，平均体积和CT值偏差以及中位幅度偏差分别低于2%、5 HU和2 mm。不规律模式的结果在各机构间显示出更大的差异。体积和CT值偏差伴随着球体模糊、插值或双重结构伪影出现，这些通过线轮廓得到了证实。对于一些不规律模式，观察到幅度偏差高达6 mm。最大强度投影（MaxIP）正确捕捉了所施加的运动幅度，除双幅度模式外，所有机构的偏差均在2 mm以内。
所有受邀参加审核的中心都做出了积极回应，突出了全面且易于执行的4DCT质量保证计划的必要性。各机构结果之间的最大差异证实了进行标准化4DCT审核的必要性。
