Purpose: Irregular breathing can exacerbate errors in medical imaging and radiotherapy. The audiovisual biofeedback (AV) system has been proposed to facilitate regular patient respiration. The purpose of this work was to identify predictive factors from two lung cancer studies to extract information regarding each study's results and conduct to determine how to produce maximal respiratory guidance effectiveness for future studies. Methods: An analysis of respiratory regularity was performed on respiratory traces from two AV biofeedback lung cancer studies: one from a recent study performed at Stanford (Stanford study) and another, retrospectively, using data from George, et al (2006) (VCU study). Stanford study: 10 lung cancer patients, each had their external respiratory motion monitored whilst they breathed both with and without the guidance of AV biofeedback. VCU study: 24 lung cancer patients. Each patient participated in up to 5 study sessions, received training with the AV biofeedback system and shorter study sessions. Breathing regularity was quantified as the root mean square error (RMSE) of displacement and period. Results: The VCU study demonstrated AV biofeedback to be effective in producing regular respiration over free breathing (reduction in RMSE of 20% (p < 0.001) and 14% (p = 0.06) for displacement and period, respectively). However, the Stanford study did not (no reduction in RMSE displacement and reduction of RMSE in period by 31% (p = 0.17)). Distinguishing features in the conduct between these two studies was the AV biofeedback training, and the repeated and shorter sessions provided in the VCU study. Conclusion: This is the first study to retrospectively analyze the conduct and results from AV biofeedback studies and demonstrate the importance of patient familiarity and training with the AV biofeedback system. This will be used to develop ideal training and information for patients to maximize the efficiency of future AV biofeedback sessions. This work was supported by Sydney Medical School New Staff/Early; Career Researcher Scheme grant, NIH/NCI R01CA93626 and an NHMRC Australia Fellowship.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging