title: Respiratory motion variability of primary tumors and lymph nodes during radiotherapy of locally advanced non-small-cell lung cancers.
abstract: OBJECTIVE
  The need for target adjustment due to respiratory motion variation and the value of carina as a motion surrogate is evaluated for locally advanced non-small-cell lung cancer.
  
  
  METHODS
  Using weekly 4D CTs (with audio-visual biofeedback) of 12 patients, respiratory motion variation of primary tumors (PT), lymph nodes (LN) and carina (C) were determined.
  
  
  RESULTS
  Mean (SD) 3D respiratory motion ranges of PT, LN and C were 4 (3), 5 (3) and 5 (3) mm. PT and LN (p = 0.003), and LN and C motion range were correlated (p = 0.03). Only 20 %/5 % of all scans had variations >3 mm/5 mm. Large respiratory motion range on the initial scan was associated with larger during-treatment variations for PT (p = 0.03) and LN (p = 0.001). Mean (SD) 3D relative displacements of PT-C, LN-C and PT-LN were each 6 (2) mm. Variations of displacements >3 mm/5 mm were observed in 28 %/6 % of scans for PT-LN, 20 %/9 % for PT-C, and 20 %/8 % for LN-C.
  
  
  CONCLUSIONS
  Motion reassessment is recommended in patients with large initial motion range. Relative motion-related displacements between PT and LN were larger than PT and LN motion alone. Both PT and C appear to be comparable surrogates for LN respiratory motion.
authors.affiliation: Department of Radiation Oncology, Virginia Commonwealth University, 401 College Street, PO Box 980058, Richmond, VA, 23298, USA. nuzhatjan@gmail.com.
authors.forename: Nuzhat
authors.initials: N
authors.lastname: Jan
authors.affiliation: Department of Radiation Oncology, Virginia Commonwealth University, 401 College Street, PO Box 980058, Richmond, VA, 23298, USA. gdhugo@vcu.edu.
authors.forename: Geoffrey D
authors.initials: GD
authors.lastname: Hugo
authors.affiliation: Department of Biostatistics, Virginia Commonwealth University, One Capital Square, Richmond, VA, 23298, USA. ndmukhopadhy@vcu.edu.
authors.forename: Nitai
authors.initials: N
authors.lastname: Mukhopadhyay
authors.affiliation: Department of Radiation Oncology, Virginia Commonwealth University, 401 College Street, PO Box 980058, Richmond, VA, 23298, USA. eweiss@mcvh-vcu.edu.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Weiss
mesh_terms: D059925:Anatomic Landmarks / Q000000981:diagnostic imaging; D016477:Artifacts; D001676:Biofeedback, Psychology; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000532:radiotherapy* / Q000556:secondary / Q000628:therapy; D002356:Cartilage / Q000000981:diagnostic imaging; D059248:Chemoradiotherapy; D056973:Four-Dimensional Computed Tomography; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy* / Q000628:therapy; D015182:Lymphatic Irradiation / Q000379:methods; D008207:Lymphatic Metastasis / Q000532:radiotherapy*; D009038:Motion; D011880:Radiotherapy Planning, Computer-Assisted; D012119:Respiration; D015656:Respiratory Mechanics; D014132:Trachea / Q000000981:diagnostic imaging