title: Respiratory motion management using audio-visual biofeedback for respiratory-gated radiotherapy of synchrotron-based pulsed heavy-ion beam delivery.
abstract: OBJECTIVE
  To efficiently deliver respiratory-gated radiation during synchrotron-based pulsed heavy-ion radiotherapy, a novel respiratory guidance method combining a personalized audio-visual biofeedback (BFB) system, breath hold (BH), and synchrotron-based gating was designed to help patients synchronize their respiratory patterns with synchrotron pulses and to overcome typical limitations such as low efficiency, residual motion, and discomfort.
  
  
  METHODS
  In-house software was developed to acquire body surface marker positions and display BFB, gating signals, and real-time beam profiles on a LED screen. Patients were prompted to perform short BHs or short deep breath holds (SDBH) with the aid of BFB following a personalized standard BH/SDBH (stBH/stSDBH) guiding curve or their own representative BH/SDBH (reBH/reSDBH) guiding curve. A practical simulation was performed for a group of 15 volunteers to evaluate the feasibility and effectiveness of this method. Effective dose rates (EDRs), mean absolute errors between the guiding curves and the measured curves, and mean absolute deviations of the measured curves were obtained within 10%-50% duty cycles (DCs) that were synchronized with the synchrotron's flat-top phase.
  
  
  RESULTS
  All maneuvers for an individual volunteer took approximately half an hour, and no one experienced discomfort during the maneuvers. Using the respiratory guidance methods, the magnitude of residual motion was almost ten times less than during nongated irradiation, and increases in the average effective dose rate by factors of 2.39-4.65, 2.39-4.59, 1.73-3.50, and 1.73-3.55 for the stBH, reBH, stSDBH, and reSDBH guiding maneuvers, respectively, were observed in contrast with conventional free breathing-based gated irradiation, depending on the respiratory-gated duty cycle settings.
  
  
  CONCLUSIONS
  The proposed respiratory guidance method with personalized BFB was confirmed to be feasible in a group of volunteers. Increased effective dose rate and improved overall treatment precision were observed compared to conventional free breathing-based, respiratory-gated irradiation. Because breathing guidance curves could be established based on the respective average respiratory period and amplitude for each patient, it may be easier for patients to cooperate using this technique.
authors.affiliation: Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China; and School of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Pengbo
authors.initials: P
authors.lastname: He
authors.affiliation: Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
authors.affiliation: Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China.
authors.forename: Xinguo
authors.initials: X
authors.lastname: Liu
authors.affiliation: Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China.
authors.forename: Zhongying
authors.initials: Z
authors.lastname: Dai
authors.affiliation: Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Zhao
authors.affiliation: Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China.
authors.forename: Tingyan
authors.initials: T
authors.lastname: Fu
authors.affiliation: Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China.
authors.forename: Guosheng
authors.initials: G
authors.lastname: Shen
authors.affiliation: Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China; and School of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China; and School of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Qiyan
authors.initials: Q
authors.lastname: Huang
authors.affiliation: Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China; and School of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yuanlin
authors.initials: Y
authors.lastname: Yan
mesh_terms: D000328:Adult; D000465:Algorithms; D001676:Biofeedback, Psychology; D003198:Computer Simulation; D005260:Female; D063193:Heavy Ion Radiotherapy / Q000379:methods*; D006801:Humans; D008297:Male; D009068:Movement; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D015203:Reproducibility of Results; D012119:Respiration; D012542:Scattering, Radiation; D012984:Software; D017356:Synchrotrons; D055815:Young Adult