Dipartimento di Fisiopatologia Clinica, Universita' degli Studi di Firenze, Firenze, Italy.
Med Phys. 2012 Feb;39(2):706-12. doi: 10.1118/1.3675973.
The aim of this study is to investigate the performance of Sentinel(™), a patient setup verification device based on a laser/camera system, when used on rigid-body phantoms.
The Sentinel system consists of a scanner unit, containing the laser and the camera, and surface-matching registration software. For the registration procedure, both a computed tomography (CT) and a Sentinel image can be used as a reference. Tests were performed on phantoms using an Elekta Synergy(®) beam modulator Linac equipped with a cone beam CT (CBCT), a HexaPOD RT couch top, and an iViewGT portal imaging system. Experiments conducted in this study tested reproducibility of the Sentinel surface acquisition and of set-up procedure, accuracy in quantifying known phantom mispositioning, and compared Sentinel, CBCT, and portal imaging system performance.
Reproducibility of surface acquisition and setup procedure was better than 0.5 mm and 0.5° and 1 mm and 0.4°, respectively. The system accuracy was better than 1 mm and 1° when a Sentinel image was used as reference. A global worsening of Sentinel performance was observed using as reference an external surface extracted from CT study. This effect is probably due to small differences in considered surfaces, caused by different imaging modalities. The results obtained by testing the system on rigid phantoms were comparable to those obtained using CBCT and better than those obtained with conventional portal imaging systems.
The Sentinel setup verification device is a reproducible and consistent system able to detect misalignments with accuracy better than 1 mm and 1°. When tested on rigid body phantoms, Sentinel and CBCT performed similarly. When compared to portal imaging, both Sentinel and CBCT were more accurate.
本研究旨在探讨 Sentinel（™）系统的性能，该系统基于激光/相机系统，用于刚体体模。
Sentinel 系统由一个扫描单元组成，包括激光和相机，以及表面匹配注册软件。对于注册过程，可以使用计算机断层扫描（CT）和 Sentinel 图像作为参考。在配备锥形束 CT（CBCT）的 Elekta Synergy（®）射束调制器直线加速器、HexaPOD RT 治疗床和 iViewGT 门控成像系统上对体模进行了测试。本研究中的实验测试了 Sentinel 表面采集和设置过程的重现性、定量已知体模错位的准确性，以及比较了 Sentinel、CBCT 和门控成像系统的性能。
表面采集和设置过程的重现性分别优于 0.5mm 和 0.5°、1mm 和 0.4°。当使用 Sentinel 图像作为参考时，系统的准确性优于 1mm 和 1°。当使用从 CT 研究中提取的外部表面作为参考时，Sentinel 性能会出现整体恶化。这种效应可能是由于不同成像模式导致的不同参考表面之间的微小差异造成的。在刚体体模上测试系统得到的结果与使用 CBCT 得到的结果相当，优于使用传统门控成像系统得到的结果。
Sentinel 定位验证设备是一种可重复且一致的系统，能够以优于 1mm 和 1°的精度检测到失准。在刚体体模上进行测试时，Sentinel 和 CBCT 的性能相似。与门控成像相比，Sentinel 和 CBCT 都更准确。
