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

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. (authors)