German Cancer Research Center (DKFZ), Department of Medical Physics in Radiation Oncology (E040), Im Neuenheimer Feld, Heidelberg, Germany.
Phys Med. 2011 Oct;27(4):224-32. doi: 10.1016/j.ejmp.2010.10.005. Epub 2010 Nov 4.
In conformal radiotherapy, careful setup of the patient and setup verification prior to irradiation is essential. The technical performance of a commercial 3D-surface imaging system (Galaxy, LAP Laser, Lüneburg, Germany) for patient setup correction was evaluated. The system reconstructs a 3D-surface model by scanning the patient with a laser line while a camera records its reflections. This surface model is then compared with a reference model and a setup correction with 6 degrees of freedom is derived. The calibration stability of the system was investigated using the daily check phantom of the manufacturer. The accuracy and reproducibility of the system were investigated with an anthropomorphic phantom by performing 1D- and 3D-shifts with and without breathing of the phantom, respectively. In addition, measurements in a healthy volunteer were performed. With a few exceptions, the day-by-day variations of the calibration were <0.5mm in LAT and LNG direction and <1.5mm in VRT direction, respectively. Besides day-by-day variations, also baseline-shifts of up to 3mm were observed. The lowest observed accuracy of the system in detecting pre-defined shifts of the rigid phantom was found in lateral direction. Here, mean deviations of -0.15 ± 0.46 mm for 1D-shifts and -0.12 ± 0.26 mm for 3D-shifts were found. For the ventilated phantom, the lowest observed accuracy was found in vertical direction with mean deviations of 1.16 ± 0.6mm for 1D-shifts and -0.45 ± 0.57 mm for 3D-shifts. In a healthy volunteer, the accuracy was lowest in longitudinal direction with 1.7 ± 1.5mm. The overall technical accuracy of the surface imaging system can be considered to be acceptable for application in fractionated radiotherapy. For special radiotherapy techniques such as SBRT, an increased accuracy might be necessary. To define the clinical role of the system, patient studies for different target locations are required.
在适形放疗中，患者的仔细设置和照射前的设置验证至关重要。评估了一种商用 3D 表面成像系统（Galaxy、LAP Laser、Lüneburg、德国）用于患者设置校正的技术性能。该系统通过扫描患者的激光线，同时使用相机记录其反射，来重建 3D 表面模型。然后，将该表面模型与参考模型进行比较，并得出 6 自由度的设置校正。使用制造商的日常检查体模研究了系统的校准稳定性。通过对无呼吸和有呼吸的模拟体模进行 1D 和 3D 移位，分别研究了系统的准确性和可重复性。此外，还对一名健康志愿者进行了测量。除了少数例外，校准的日变化在 LAT 和 LNG 方向上分别小于 0.5mm，在 VRT 方向上小于 1.5mm。除了日变化外，还观察到基线移位高达 3mm。在检测刚性模拟体的预定义移位方面，系统的最低观察到的准确性在横向方向上。在这里，1D 移位的平均偏差为-0.15 ± 0.46mm，3D 移位的平均偏差为-0.12 ± 0.26mm。对于通气模拟体，1D 移位的最低观察到的准确性为垂直方向，平均偏差为 1.16 ± 0.6mm，3D 移位的平均偏差为-0.45 ± 0.57mm。在健康志愿者中，纵向方向的准确性最低，为 1.7 ± 1.5mm。表面成像系统的整体技术准确性可认为适用于分次放疗。对于特殊放疗技术，如 SBRT，可能需要更高的准确性。要确定系统的临床作用，需要针对不同的靶区进行患者研究。
