Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, USA.
ViewRay Inc., Mountain View, CA, USA.
Med Phys. 2021 Apr;48(4):1540-1545. doi: 10.1002/mp.14766. Epub 2021 Mar 6.
To modify and evaluate an automatic American College of Radiology (ACR) phantom analysis toolbox for ACR quality assurance (QA) on a low-field MR-guided radiotherapy system (ViewRay).
An open-source toolbox was modified for ACR QA of a 0.35T MRI system (ViewRay MRIdian). A total of 17 ACR datasets were evaluated, including 10 datasets acquired from different systems across the world, and seven datasets acquired at our center between 2014 and 2020. All required ACR tests, geometric accuracy (GA), high-contrast spatial resolution (HCSR), slice thickness accuracy (ST), slice position accuracy (SP), percent integral uniformity (PIU), percentage signal ghosting (PSG), and low-contrast object detectability (LCOD), were assessed manually and using the toolbox automatically. Measurements between manual and automatic analysis were compared. Precision, recall, and accuracy were calculated, where the manual results were used as the ground truth.
The software took less than 2 min to complete all seven tests, which usually requires 40 min or more if analyzed manually. Overall, the automatic measurement was consistent with the manual result. The absolute differences between the two measurements were 0.72 ± 0.66 (mm), 0.01 ± 0.03, 0.50 ± 0.60 (mm), 0.39 ± 0.41 (mm), 1.01 ± 1.00 (%), 0.0016 ± 0.0019, and 2.79 ± 2.29 for the seven tests. The precision of the automatic toolbox was 100% for all tests, indicating that a test would 100% pass a manual analysis if it had passed the automatic analysis. Recall and accuracy were ≥ 96% for GA, HCSR, SP, PIU, PSG, and LCOD tests, and 91% for the ST test.
An automatic ACR QA tool was adopted and evaluated for the low-field MR-guided radiotherapy (MRgRT) system. Overall, the toolbox provided comparable results as manual analysis, and reduced the processing time from over 40 min to <2 min. This toolbox holds the potential to be widely adopted either as a second check tool or partially replace human measurement for MRgRT programs using the same system.
修改并评估一个用于低场磁共振引导放射治疗系统（ViewRay）的美国放射学院（ACR）自动体模分析工具包，以进行 ACR 质量保证（QA）。
对一个开源工具包进行了修改，用于评估 0.35T MRI 系统（ViewRay MRIdian）的 ACR QA。共评估了 17 个 ACR 数据集，包括来自世界各地不同系统的 10 个数据集，以及我们中心在 2014 年至 2020 年间采集的 7 个数据集。所有必需的 ACR 测试，包括几何精度（GA）、高对比度空间分辨率（HCSR）、切片厚度精度（ST）、切片位置精度（SP）、整体积分均匀性（PIU）、百分比信号鬼影（PSG）和低对比度物体检测（LCOD），均进行了手动和自动分析。比较了手动和自动分析之间的测量结果。计算了精度、召回率和准确性，其中手动结果用作基准。
软件在不到 2 分钟的时间内完成了所有 7 项测试，如果手动分析则通常需要 40 分钟或更长时间。总体而言，自动测量与手动结果一致。两种测量之间的绝对差异分别为 0.72±0.66（mm）、0.01±0.03、0.50±0.60（mm）、0.39±0.41（mm）、1.01±1.00（%）、0.0016±0.0019 和 2.79±2.29，这是 7 项测试的结果。对于所有测试，自动工具的精度均为 100%，这意味着如果通过了自动分析，则测试将 100%通过手动分析。GA、HCSR、SP、PIU、PSG 和 LCOD 测试的召回率和准确性均≥96%，ST 测试的召回率和准确性为 91%。
采用了一种用于低场磁共振引导放射治疗（MRgRT）系统的自动 ACR QA 工具，并对其进行了评估。总体而言，该工具包提供了与手动分析相当的结果，并将处理时间从 40 多分钟缩短到不到 2 分钟。该工具包有可能被广泛采用，无论是作为第二检查工具，还是部分替代使用相同系统的 MRgRT 程序的人工测量。
