title: Audiovisual Biofeedback Improves Cine-Magnetic Resonance Imaging Measured Lung Tumor Motion Consistency.
abstract: OBJECTIVE
  To assess the impact of an audiovisual (AV) biofeedback on intra- and interfraction tumor motion for lung cancer patients.
  
  
  METHODS
  Lung tumor motion was investigated in 9 lung cancer patients who underwent a breathing training session with AV biofeedback before 2 3T magnetic resonance imaging (MRI) sessions. The breathing training session was performed to allow patients to become familiar with AV biofeedback, which uses a guiding wave customized for each patient according to a reference breathing pattern. In the first MRI session (pretreatment), 2-dimensional cine-MR images with (1) free breathing (FB) and (2) AV biofeedback were obtained, and the second MRI session was repeated within 3-6 weeks (mid-treatment). Lung tumors were directly measured from cine-MR images using an auto-segmentation technique; the centroid and outlier motions of the lung tumors were measured from the segmented tumors. Free breathing and AV biofeedback were compared using several metrics: intra- and interfraction tumor motion consistency in displacement and period, and the outlier motion ratio.
  
  
  RESULTS
  Compared with FB, AV biofeedback improved intrafraction tumor motion consistency by 34% in displacement (P=.019) and by 73% in period (P<.001). Compared with FB, AV biofeedback improved interfraction tumor motion consistency by 42% in displacement (P<.046) and by 74% in period (P=.005). Compared with FB, AV biofeedback reduced the outlier motion ratio by 21% (P<.001).
  
  
  CONCLUSIONS
  These results demonstrated that AV biofeedback significantly improved intra- and interfraction lung tumor motion consistency for lung cancer patients. These results demonstrate that AV biofeedback can facilitate consistent tumor motion, which is advantageous toward achieving more accurate medical imaging and radiation therapy procedures.
authors: Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, Sidney, NSW, Australia.
authors: Danny
authors: D
authors: Lee
authors: School of Mathematical and Physical Sciences, The University of Newcastle, Newcastle, NSW, Australia; Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, NSW, Australia.
authors: Peter B
authors: PB
authors: Greer
authors: Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, NSW, Australia.
authors: Joanna
authors: J
authors: Ludbrook
authors: Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, NSW, Australia.
authors: Jameen
authors: J
authors: Arm
authors: Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, NSW, Australia.
authors: Perry
authors: P
authors: Hunter
authors: Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, Sidney, NSW, Australia.
authors: Sean
authors: S
authors: Pollock
authors: Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, Sidney, NSW, Australia.
authors: Kuldeep
authors: K
authors: Makhija
authors: Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, Sidney, NSW, Australia.
authors: Ricky T
authors: RT
authors: O'brien
authors: Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, Sidney, NSW, Australia; Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia.
authors: Taeho
authors: T
authors: Kim
authors: Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, Sidney, NSW, Australia. Electronic address: paul.keall@sydney.edu.au.
authors: Paul
authors: P
authors: Keall
mesh_terms: D056228:Feedback, Sensory / Q000502:physiology*; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy; D019028:Magnetic Resonance Imaging, Cine; D009068:Movement; D012119:Respiration