3D打印头膜固定技术在头部肿瘤放疗的应用研究

Application of 3D printed head film fixation technology in radiotherapy for head tumors

目的为头部放疗患者定制个体化3D打印头膜,通过与热塑头膜对比,评价其材质的物理特性及该技术的摆位精准度。方法分别将3D打印头膜和热塑头膜置于固体水表面,通过电离室和胶片测量深度5cm处和表面剂量来进行剂量学评估。选取30例头部放疗患者随机分为对照组和试验组,分别采用热塑头膜和3D打印头膜进行固定,通过CBCT获取患者X、Y、Z方向的平移和旋转摆位误差来进行临床摆位误差评估。结果深度5cm处两种材质对射线衰减率均<1%。表面位置热塑头膜剂量升高27%,3D打印头膜升高18%。两组患者各取116组摆位误差数据,对照组和试验组X、Y、Z方向平均平移误差分别为1.29mm和1.16mm、1.42mm和1.24mm、1.38mm和1.16mm;平均旋转摆位误差分别为1.29°和1.08°、1.02°和0.96°、1.01°和1.00°。与对照组相比,试验组患者在Y、Z方向平移摆位误差和X方向旋转摆位误差不同(P<0.05),其他方向相近(P>0.05)。结论3D打印头膜体位固定技术符合现代放疗的精准摆位要求,具有较高的临床实用价值,可用于进一步临床研究。

Objective To customize the individualized 3D printed head film for patients with head tumors undergoing radiotherapy,and to evaluate the physical properties of the material and the precision of this technology compared with the thermoplastic head film.Methods The 3D printed head film and thermoplastic head film were placed on the solid water surface,and the depth and surface dose were measured at 5 cm by ionization chamber and film,respectively.Thirty patients with head tumors receiving radiotherapy were randomly divided into the control and experimental groups.The patients were fixed with thermoplastic head film and 3D printed head film.The translational and rotational errors in the x,y and z direction were obtained by CBCT.Results The radiation attenuation rate of two materials at the depth of 5 cm was less than 1%.The dose of thermoplastic head film in the surface position was increased by 27%,and increased by 18%in the 3D printed head film.In two groups,116 sets of setup errors were collected.The average translational setup errors in the control and experimental groups were 1.29 mm and 1.16 mm,1.42 mm and 1.24 mm,1.38 mm and 1.16 mm,respectively,and the average rotational setup errors were 1.29°and 1.08°,1.02°and 0.96°,1.01°and 1.00°,respectively.The translational setup errors in the y and z direction and rotational setup errors in the x direction significantly differed between the control and experimental groups(all P<0.05),but no statistical significance was found in the other direction(all P>0.05).Conclusion The 3D printed head film fixation meets the precise setup requirements of modern radiotherapy,which deserves further application in clinical trials.