The purpose of this study is to develop a method for characterisation of time-of-flight (ToF) imaging system for application in deep inspiration breath-hold radiotherapy (DIBH-RT). The performance of an Argos 3D P330 ToF camera (Bluetechnix, Austria) was studied for patient surface monitoring during DIBH-RT using a phantom to simulate the intra-patient and inter-patient stability of the camera. Patient setup error was also simulated by positioning the phantom at predefined shift positions (2, 5 and 10 mm) from the isocentre. The localisation accuracy of the phantom was measured using ToF imaging system and repeated using CBCT imaging alone (CBCT) and simultaneously using ToF imaging during CBCT imaging (ToF-CBCT). The mean and SD of the setup errors obtained from each of the imaging methods were calculated. Student t-test was used to compare the mean setup errors. Correlation and Bland-Altman analysis were also performed. The intra-and inter-patient stability of the camera were within 0.31 mm and 0.74 mm, respectively. The localisation accuracy in terms of the meanSD of the measured setup errors were 0.340.98 mm, 0.120.34 mm, and −0.241.42 mm for ToF, CBCT and ToF-CBCT imaging, respectively. A strong correlation was seen between the phantom position and the measured position using ToF (r = 0.96), CBCT (r = 0.99) as well as ToF-CBCT (r = 0.92) imaging. The limits of agreement from Bland Altman analysis between the phantom position and ToF, CBCT and ToF-CBCT measured positions were −1.52, 2.31 mm, −0.55, 0.78 mm; and −3.03, 2.55 mm, respectively. The sensor shows good stability and high accuracy comparable to similar sensors in the market. The method developed is useful for characterisation of an optical surface imaging system for application in monitoring DIBH-RT.

本研究的目的是开发一种用于表征飞行时间 (ToF) 成像系统的方法，以应用于深吸气屏气放射治疗 (DIBH-RT)。研究了 Argos 3D P330 ToF 相机（Bluetechnix，奥地利）的性能，用于 DIBH-RT 期间的患者表面监测，使用体模模拟相机的患者体内和患者间稳定性。还通过将体模定位在距等中心点的预定义移位位置（2、5 和 10 毫米）来模拟患者设置错误。使用 ToF 成像系统测量体模的定位精度，并重复使用 CBCT 成像（CBCT）和在 CBCT 成像期间同时使用 ToF 成像（ToF-CBCT）。计算了从每种成像方法获得的设置误差的平均值和 SD。学生 t 检验用于比较平均设置误差。还进行了相关性和 Bland-Altman 分析。摄像机的内部和患者间稳定性分别在 0.31 mm 和 0.74 mm 以内。对于 ToF、CBCT 和 ToF-CBCT 成像，以测量设置误差的均值 SD 计的定位精度分别为 0.340.98 mm、0.120.34 mm 和 -0.241.42 mm。使用 ToF (r = 0.96)、CBCT (r = 0.99) 以及 ToF-CBCT (r = 0.92) 成像时，模型位置与测量位置之间存在很强的相关性。Bland Altman 分析的模型位置与 ToF、CBCT 和 ToF-CBCT 测量位置之间的一致性限制为 -1.52、2.31 mm、-0.55、0.78 mm；和 -3.03, 2.55 毫米，分别。该传感器具有与市场上同类传感器相媲美的良好稳定性和高精度。