title: The first patient treatment of computed tomography ventilation functional image-guided radiotherapy for lung cancer.
abstract: OBJECTIVE
  Radiotherapy that selectively avoids irradiating highly-functional lung regions may reduce pulmonary toxicity. We report on the first clinical implementation and patient treatment of lung functional image-guided radiotherapy using an emerging technology, computed tomography (CT) ventilation imaging.
  
  
  METHODS
  A protocol was developed to investigate the safety and feasibility of CT ventilation functional image-guided radiotherapy. CT ventilation imaging is based on (1) deformable image registration of four-dimensional (4D) CT images, and (2) quantitative image analysis for regional volume change, a surrogate for ventilation. CT ventilation functional image-guided radiotherapy plans were designed to minimize specific lung dose-function metrics, including functional V20 (fV20), while maintaining target coverage and meeting standard constraints to other critical organs.
  
  
  RESULTS
  CT ventilation functional image-guided treatment planning reduced the lung fV20 by 5% compared to an anatomic image-guided plan for an enrolled patient with stage IIIB non-small cell lung cancer. Although the doses to several other critical organs increased, the necessary constraints were all met.
  
  
  CONCLUSIONS
  An emerging technology, CT ventilation imaging has been translated into the clinic and used in functional image-guided radiotherapy for the first time. This milestone represents an important first step toward hypothetically reduced pulmonary toxicity in lung cancer radiotherapy.
authors.affiliation: Department of Radiation Oncology, University of California Davis School of Medicine, Sacramento, USA. Electronic address: toyamamoto@ucdavis.edu.
authors.forename: Tokihiro
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Department of Digital Imaging, Philips Research, Hamburg, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Kabus
authors.affiliation: Philips Healthcare, Best, The Netherlands.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Bal
authors.affiliation: Radiation Physics Laboratory, Sydney Medical School, University of Sydney, Camperdown, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Keall
authors.affiliation: Department of Radiation Oncology, University of California Davis School of Medicine, Sacramento, USA.
authors.forename: Stanley
authors.initials: S
authors.lastname: Benedict
authors.affiliation: Department of Radiation Oncology, University of California Davis School of Medicine, Sacramento, USA.
authors.forename: Megan
authors.initials: M
authors.lastname: Daly
mesh_terms: D005240:Feasibility Studies; D056973:Four-Dimensional Computed Tomography / Q000379:methods*; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D011446:Prospective Studies; D011832:Radiation Injuries / Q000517:prevention & control; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D061089:Radiotherapy, Image-Guided / Q000379:methods*
keywords: 4D CT; Deformable image registration; Lung cancer; Lung functional imaging; Radiation pneumonitis