Room: Davidson Ballroom A
Purpose: Deep Inspiration Breath Hold (DIBH) treatment is often used to reduce cardiac toxicity in left-sided breast radiotherapy. This work evaluates the application of Breath Well (BW), a novel, visual feedback system to DIBH treatment to improve breathhold reproducibility and stability. Herein, we present our initial experience with the first two enrolled patients in the clinical trial.
Methods: BW was used to provide visual feedback for left-sided breast cancer patients. During simulation, a baseline breathhold was recorded for each patient as the â€œtarget zoneâ€? for treatment. Before treatment, patients maintained a ten-second breathhold without visual feedback to capture uncoached breaths. The first two seconds of each breath were discounted to accommodate chest recoil. Breathhold reproducibility was quantified for 42 uncoached and 336 coached breaths in two ways: the interbreath standard deviation and range of mean chest wall displacement. Breathhold stability was taken to be the mean standard deviation of each intrabreath chest wall displacement. Parameters were tested for statistical significance using a Wilcoxon test. BW-measured chest wall position was correlated with clinically-commissioned AlignRT.
Results: Standard deviation of chest wall position was reduced with the addition of visual feedback from 4.2 mm to 0.7 mm (p << 0.001). Similarly, breathhold range was reduced from 15.5 mm to 4.3 mm with coaching. Interestingly, changes in intrabreath stability were not found to be statistically significant between uncoached and coached breathing (p = 0.958). Finally, BW allowed chest wall monitoring in the presence of electron accessories which obstruct the ceiling-mounted cameras employed by AlignRT.
Conclusion: DIBH of left-sided breast cancer reduces cardiac dose significantly. Visual feedback for patients may improve reproducibility of breathhold levels and improve dosimetric outcomes. The compact design of Breath Well holds great promise for improving DIBH treatments in the future.
Funding Support, Disclosures, and Conflict of Interest: One of the authors is a founder and director of Opus Medical, the company that markets the Breathe Well product, which provided device and technical support.