title: Prediction of lung density changes after radiotherapy by cone beam computed tomography response markers and pre-treatment factors for non-small cell lung cancer patients.
abstract: OBJECTIVE
  This study investigates the ability of pre-treatment factors and response markers extracted from standard cone-beam computed tomography (CBCT) images to predict the lung density changes induced by radiotherapy for non-small cell lung cancer (NSCLC) patients.
  
  
  METHODS
  Density changes in follow-up computed tomography scans were evaluated for 135 NSCLC patients treated with radiotherapy. Early response markers were obtained by analysing changes in lung density in CBCT images acquired during the treatment course. The ability of pre-treatment factors and CBCT markers to predict lung density changes induced by radiotherapy was investigated.
  
  
  RESULTS
  Age and CBCT markers extracted at 10th, 20th, and 30th treatment fraction significantly predicted lung density changes in a multivariable analysis, and a set of response models based on these parameters were established. The correlation coefficient for the models was 0.35, 0.35, and 0.39, when based on the markers obtained at the 10th, 20th, and 30th fraction, respectively.
  
  
  CONCLUSIONS
  The study indicates that younger patients without lung tissue reactions early into their treatment course may have minimal radiation induced lung density increase at follow-up. Further investigations are needed to examine the ability of the models to identify patients with low risk of symptomatic toxicity.
authors.affiliation: Institute of Clinical Research, University of Southern Denmark, Odense, Denmark; Laboratory of Radiation Physics, Odense University Hospital, Denmark. Electronic address: uffe.bernchou@rsyd.dk.
authors.forename: Uffe
authors.initials: U
authors.lastname: Bernchou
authors.affiliation: Institute of Clinical Research, University of Southern Denmark, Odense, Denmark; Department of Oncology, Odense University Hospital, Denmark.
authors.forename: Olfred
authors.initials: O
authors.lastname: Hansen
authors.affiliation: Department of Oncology, Odense University Hospital, Denmark.
authors.forename: Tine
authors.initials: T
authors.lastname: Schytte
authors.affiliation: Laboratory of Radiation Physics, Odense University Hospital, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Bertelsen
authors.affiliation: Department of Radiation Oncology, Princess Margaret Hospital, Toronto, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Hope
authors.affiliation: Department of Radiation Oncology, Princess Margaret Hospital, Toronto, Canada.
authors.forename: Douglas
authors.initials: D
authors.lastname: Moseley
authors.affiliation: Institute of Clinical Research, University of Southern Denmark, Odense, Denmark; Laboratory of Radiation Physics, Odense University Hospital, Denmark.
authors.forename: Carsten
authors.initials: C
authors.lastname: Brink
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*; D054893:Cone-Beam Computed Tomography / Q000379:methods; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology / Q000528:radiation effects*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: Computed tomography; Cone beam; Density change; Lung cancer; Response modelling