Sato Kiyokazu, Takeda Ken, Dobashi Suguru, Kadoya Noriyuki, Ito Kengo, Chiba Mizuki, Kishi Kazuma, Yanagawa Isao, Jingu Keiichi
Radiation Technology, Tohoku University Hospital.
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2017;73(1):57-65. doi: 10.6009/jjrt.2017_JSRT_73.1.57.
Our aim was to investigate the feasibility of a three-dimensional (3D) -printed head-and-neck (HN) immobilization device by comparing its positional accuracy and dosimetric properties with those of a conventional immobilization device (CID). We prepared a 3D-printed immobilization device (3DID) consisting of a mask and headrest with acrylonitrile-butadiene-styrene resin developed from the computed tomography data obtained by imaging a HN phantom. For comparison, a CID comprising a thermoplastic mask and headrest was prepared using the same HN phantom. We measured the setup error using the ExacTrac X-ray image system. Furthermore, using the ionization chamber and the water-equivalent phantom, we measured the changes in the dose due to the difference in the immobilization device material from the photon of 4 MV and 6 MV. The positional accuracy of the two devices were almost similar in each direction except in the vertical, lateral, and pitch directions (t-test, p<0.0001), and the maximum difference was 1 mm, and 1°. The standard deviations were not statistically different in each direction except in the longitudinal (F-test, p=0.034) and roll directions (F-test, p<0.0001). When the thickness was the same, the dose difference was almost similar at a 50 mm depth. At a 1 mm depth, the 3DID-plate had a 2.9-4.2% lower dose than the CID-plate. This study suggested that the positional accuracy and dosimetric properties of 3DID were almost similar to those of CID.
我们的目的是通过比较三维（3D）打印的头颈部（HN）固定装置与传统固定装置（CID）的位置精度和剂量学特性，来研究其可行性。我们使用从HN体模成像获得的计算机断层扫描数据，制备了一种由丙烯腈-丁二烯-苯乙烯树脂制成的包含面罩和头枕的3D打印固定装置（3DID）。为了进行比较，使用相同的HN体模制备了一种由热塑性面罩和头枕组成的CID。我们使用ExacTrac X射线图像系统测量了摆位误差。此外，我们使用电离室和水等效体模，测量了由于固定装置材料差异导致的4 MV和6 MV光子剂量变化。除了垂直、横向和俯仰方向外，两种装置在各个方向上的位置精度几乎相似（t检验，p<0.0001），最大差异为1 mm和1°。除了纵向（F检验，p=0.034）和滚动方向（F检验，p<0.0001）外，各方向的标准差在统计学上没有差异。当厚度相同时，在50 mm深度处剂量差异几乎相似。在1 mm深度处，3DID板的剂量比CID板低2.9 - 4.2%。这项研究表明，3DID的位置精度和剂量学特性与CID几乎相似。
