Objective  To produce three-dimensional (3D)-printed personalized radiotherapy headrests for patients with nasopharyngeal cancer and evaluate their effect in preventing radiotherapy setup errors by comparing them with standardized headrests.

  Methods  A total of 40 patients with nasopharyngeal carcinoma who underwent radiotherapy in Sichuan Provincial People's Hospital from April 2020 to August 2021 were selected and assigned into 3D-printed headrest group and standardized headrest group, 20 cases in each group. Cone beam CT (CBCT) was performed every week. Positioning error data of target area, cervical vertebrae region and C1-C7 single cervical vertebra in ascending, descending, and left-right directions were collected and analyzed with statistical software.

  Results  The setup error values in the 3D-printed headrest group were (0.87±0.78) mm on C1-C7 elevation, (1.09±0.86) mm in the entry/exit direction, and (0.88±1.18) mm in the left/right direction. The setup error values in the standardized headrest group were (1.01±0.83) mm on C1-C7 elevation, (1.27±0.92) mm in the entry/exit direction, and (1.08±0.89) in the left/right direction. In the 3D-printed headrest group, the overall cervical setup error values were (0.65±0.64) mm on C1-C7 elevation, (0.40±0.49) mm in the entry/exit direction, and (0.90±0.74) mm in the left/right direction. In the standardized headrest group, the overall cervical setup error values were (1.08±0.96) mm on C1-C7 elevation, (0.80±0.80) mm in the entry/exit direction, and (1.62±1.51) mm in the left/right direction. Although improvement in the overall setup error of the target area was noted with the 3D-printed headrests, this was not significant (P>0.05). However, a significant difference (P<0.05) in the improvement of setup errors of the cervical spine as a whole and in each vertebra was noted with the 3D-printed headrests.

  Conclusions  3D-printed personalized radiotherapy headrests improve radiotherapy setup errors while examining patients with nasopharyngeal cancer. Specifically, personalized headrests provide additional neck comfort, which meets the clinical requirements of precision radiotherapy. This is a promising field for further clinical research.