ESTRO 2023 - Abstract Book

S395

Sunday 14 May 2023

ESTRO 2023

This mono-center, cross-sectional study was conducted within the Multi-OutcoMe EvaluatioN of radiation Therapy Using the MR-linac (MOMENTUM) study (NCT04075305). Eligible patients received treatment on a 1.5T Unity MR-linac (Elekta, Stockholm). An MR safe video monitor (BOLDscreen 32, Cambridge Research Systems Ltd) was installed at the end of the bore and patients were using an MR safe mirror (glasses) to view calming video content (i.e., nature or travel documentaries) on the screen behind them (Figure 1). Patient experience was captured by means of an adaptation of a validated questionnaire (5-point Likert scale), and anxiety by means of the State Trait and Anxiety Inventory (STAI) (4-point Likert scale), at first and third treatment fraction. The STAI questionnaire results in a total score of 20–80 where a higher score represents more anxiety. An MR-conditional pulse oximeter (NONIN Medical Inc, USA) was used to capture continuous heart rate as explorative marker for stress. Ten-minute measurements after start of the first MRI-scan were used to calculate the heart rate mean (HRM) and the heart rate standard deviation (HRSD). Results Between November 2021 and October 2022, 45 patients were included. The majority was male (n=41, 94%) with a median age of 73 (range 55-82). MRgRT was most frequently delivered to prostate lesion (n=30,67%), pancreas (n=5,11%), and lymph nodes (n=5,11%). The mean treatment time was 39 minutes (standard deviation 20). Response rates varied from 82%-89%. During first and third fraction, respectively 18 (40%) and 16 (36%) patients preferred to look at calming content. Of those patients, 17/18 (94%) and 15/15 (100%) could look at the screen comfortably. Overall patient experience of the treatment was good (Figure 2); 35/39 (90%) felt calm during treatment. Mean STAI-scores at first treatment were 33 (95% confidence interval (CI) 29-36) before and 29 (95%CI 26–32) after treatment. Mean STAI-scores at third treatment were 30 (95% CI 27 33) before and 29 (95%CI 26-32) after treatment. During first treatment the mean of HRM was 72 (95% CI 68 -77) and the mean of HRSD was 1.69 (95% CI 1.39–1.98) measurements did not differ significantly between first (n=36) and third fraction (n=26). Conclusion This study shows that it is feasible for patients to look at an in-room video monitor during MR-Linac treatment comfortably. Patient experience was good, and anxiety-levels were low. Heart-rate monitoring during treatment on the MR-linac was feasible. In future, the video monitor setup on the MR-linac could facilitate biofeedback-guided respiratory gating workflows.