Faculty of Physics/Medical Physics, Heinrich-Heine-University Düsseldorf, Germany; Department of Radiotherapy and Radiation Oncology, University Hospital of Düsseldorf, Germany.
Department of Radiotherapy and Radiation Oncology, University Hospital of Düsseldorf, Germany.
Z Med Phys. 2019 Aug;29(3):229-238. doi: 10.1016/j.zemedi.2018.09.001. Epub 2018 Oct 9.
The University Hospital of Düsseldorf, Germany (UKD) recently installed the Respiratory Gating for Scanners module (RGSC) (Varian Medical Systems, Palo Alto, USA). The aim of this article is to report on the commissioning and clinical implementation of the RGSC system. The steps encompassed the validation of the manufacturer's specifications including functionality tests using a commercial and in-house developed breathing phantom, to establish calibration procedures, and clinical workflow analysis involving breath acquisition and patient data evaluation. In this context also the RGSC signal without motion was performed to assess the calibration procedure. Reproducibility test were conducted as well with breathing phantoms. Fifteen clinical breath curves were examined in order to assess the impact of treatment related uncertainties such as noises of the CT, patient positioning, movement of the CT table, unintended patient motion. Finally, different binning approaches were assessed and the effect on the CT reconstructions and methodic advantages were investigated. All technical specifications of the manufacturer were confirmed. A baseline drift of 1.83mm of the measured breath curve occurred during longitudinal movement of the CT table. This drift is smaller if the direction of table motion coincides precisely with the level of calibration. If the calibration is carried out on extensions for patient positioning we measured a baseline drift up to 6mm. It was found that especially for a combination of a ceiling mounted IR-camera and amplitude based 4D-CT reconstructions, precise calibration is prerequisite. The evaluations of patient breath curves and corresponding CT reconstructions revealed patient specific aspects and variations, respectively. Consequently patient selection criteria need to be established in parallel with the technical implementation and validation phase of respiratory gating.
德国杜塞尔多夫大学医院（UKD）最近安装了呼吸门控扫描模块（RGSC）（美国瓦里安医疗系统公司，帕洛阿尔托）。本文旨在报告 RGSC 系统的调试和临床实施情况。该过程包括验证制造商的规格，包括使用商业和内部开发的呼吸体模进行功能测试，以建立校准程序，并进行涉及呼吸采集和患者数据评估的临床工作流程分析。在这种情况下，还进行了没有运动的 RGSC 信号评估以评估校准程序。还对呼吸体模进行了重复性测试。为了评估与治疗相关的不确定性（例如 CT 噪声、患者定位、CT 台移动、患者意外移动）的影响，检查了 15 条临床呼吸曲线。最后，评估了不同的 binning 方法，并研究了它们对 CT 重建的影响和方法学优势。制造商的所有技术规格均得到确认。在 CT 台的纵向运动过程中，测量呼吸曲线会发生 1.83mm 的基线漂移。如果台运动的方向与校准水平精确一致，则漂移较小。如果在用于患者定位的扩展部分进行校准，则我们测量到的基线漂移最大可达 6mm。结果发现，特别是对于安装在天花板上的红外摄像机和基于幅度的 4D-CT 重建的组合，精确的校准是先决条件。对患者呼吸曲线和相应的 CT 重建的评估分别揭示了患者特定的方面和变化。因此，需要在呼吸门控的技术实施和验证阶段的同时，建立患者选择标准。
