The application of self-made adjustable wedge plate in radiotherapy positioning

Objective To investigate the repeatability of precise radiotherapy placement of self-made adjustable angle wedge plate, negative pressure vacuum pad and common soft pillow, corresponding to 3 groups. The study is demonstrated with a thermoplastic membrane immobilization technology in kyphotic deformity patients with head and neck cancer (including primary and secondary), respectively. Methods From Jun 2014 to Apr 2016, 48 cases of severe head and neck cancer patients received radiotherapy humpback who were randomly divided into 3 groups. Combined with thermoplastic head and neck shoulder film position fixation, the right foot direction at the end of the skull styloid process layer center was set as a reference point. On the left foot at the end of the direction of styloid process layer center, localization of the origin of the coordinate system in patients around the head and foot, dorsoventrally (x, y, z) analysis of the direction change of position measurement was performed. Results There was no significant difference between the adjustable angle wedge plate and negative pressure vacuum pad groups of the coordinate system (P>0.05). Compared with common soft pillow group, three dimensional positioning errors and three dimensional coordinate system transfer errors of the adjustable angle wedge plate and negative pressure vacuum pad groups were statistically significantly different (t=-6.99 to -2.69, -5.13 to -2.71, P<0.05). Conclusions The self-made adjustable angle wedge plate has good repeatability, saves time and money, is simple and durable on precise radiotherapy positioning of kyphotic deformity patients with head and neck cancer. Key words: Head and neck neoplasms; Self-made adjustable angle wedge plate; Radiotherapy positioning repeatability/errors; Kyphotic deformity