The positioning accuracy of individualized open-face mask in patients with intracranial tumors receiving radiotherapy-a randomized controlled study

BACKGROUND: The thermoplastic head mask, combined with styrofoam, is a widely used immobilization method for patients undergoing radiotherapy for intracranial tumors at our center. However, a significant drawback of this technique is its full-face coverage, which often causes discomfort, making the mask feel overly constrictive. This can lead to breathing difficulties, nervousness, and anxiety. To address these issues, we designed an individualized open-face mask to improve patient comfort without compromising positioning accuracy. The aim of this study was to compare the positioning accuracy between the traditional head mask and the individualized open-face mask in patients receiving radiotherapy for intracranial tumors. METHODS: Patients with intracranial tumors undergoing radiotherapy were randomly assigned to either the traditional head mask (THM) group or the individualized open-face mask (IOFM) group in a 1:1 ratio. The IOFM was customized with an open area based on the patient's feedback. All patients received additional fixation with styrofoam. Cone beam computed tomography (CBCT) was performed once a week during radiotherapy to record set-up errors in three directions. The set-up errors and target zone flaring boundary values were compared between the two groups using a t-test. Patient comfort was evaluated using a modified Likert questionnaire during the first and sixth treatment sessions. RESULTS: A total of 103 patients were enrolled in this study, with 51 patients immobilized using the IOFM method and 52 using the THM method. The baseline characteristics of the two groups were well balanced. Analysis of the 593 CBCT data showed no significant differences in set-up errors between the IOFM and THM groups (X direction: 1.07±0.89 mm vs. 1.02±0.93 mm, p= 0.501; Y direction: 1.23±0.88 mm vs. 1.24±0.98 mm, p= 0.921; Z direction: 1.15±0.89 mm vs. 1.15±0.84 mm, p= 0.930; rotation error: 0.90±0.84° vs. 0.92±1.02°, p= 0.793). The set-up errors in the open area of the face were also not significantly different between the IOFM and THM groups (X direction: 1.39±1.10 mm vs. 1.28±1.14 mm, p= 0.204; Y direction: 1.77±1.36 mm vs. 1.62±1.29 mm, p= 0.160; Z direction: 1.38±0.90 mm vs. 1.25±0.94 mm, p= 0.085; rotation error: 1.13±0.93° vs. 1.11±1.03°, p= 0.875). The modified PTV boundaries in the X, Y, and Z directions were 2.67 mm, 3.12 mm, and 2.57 mm in the IOFM group, compared to 3.06 mm, 3.39 mm, and 2.37 mm in the THM group, respectively. Comfort scores were significantly higher in the IOFM group on both occasions compared to the THM group (32.39±1.31 vs. 30.54±2.03, p <0.001 and 32.25±2.19 vs. 30.77±1.17, p <0.001). CONCLUSION: The individualized open-face mask improves patient comfort without compromising positioning accuracy. It is a valuable approach that merits promotion and use in clinical settings for radiotherapy positioning.