title: Reproducibility of diaphragm position assessed with a voluntary breath-holding device.
abstract: OBJECTIVE
  To evaluate the reproducibility of diaphragm position in our new breath-holding radiotherapy for abdominal tumors using image-guided radiation therapy (IGRT) and a voluntary breath-holding device, Abches.
  
  
  METHODS
  Patients treated with abdominal tumors using IGRT with Abches were enrolled. Twenty patients without dementia or severe lung disease were analyzed. Each fraction of all patients was set up with kV cone-beam CT with reference to the vertebral bodies. Before daily treatment, electronic portal imaging device (EPID) images of the diaphragm at breath-holding exhale phase were acquired. The difference in the diaphragm position relative to the vertebral body was analyzed by comparing EPID images and the digitally reconstructed radiograph of the planning CT. We evaluated the reproducibility of two axes: superior-inferior (S-I) and right-left (R-L) with the EPID measurements.
  
  
  RESULTS
  The 443 irradiation data sets were analyzed. The interfractional reproducibility of the diaphragm relative to vertebral bodies was 1.7 ± 1.4 mm in the S-I and 1.4 ± 1.2 mm in the R-L direction.
  
  
  CONCLUSIONS
  This technique has good interfractional reproducibility and visibility of the diaphragm during irradiation. Its use is feasible in the routine clinical setting and irradiation.
authors.affiliation: Department of Radiotherapy, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa City, Ishikawa 920-8641, Japan. shigerad@staff.kanazawa-u.ac.jp
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Takamatsu
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takanaka
authors.forename: Tomoyasu
authors.initials: T
authors.lastname: Kumano
authors.forename: Eiichi
authors.initials: E
authors.lastname: Mizuno
authors.forename: Satoshi
authors.initials: S
authors.lastname: Shibata
authors.forename: Shizuko
authors.initials: S
authors.lastname: Ohashi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kurata
authors.forename: Shinichi
authors.initials: S
authors.lastname: Ueda
authors.forename: Naoki
authors.initials: N
authors.lastname: Hori
authors.forename: Saori
authors.initials: S
authors.lastname: Shouji
authors.forename: Kimiya
authors.initials: K
authors.lastname: Noto
authors.forename: Hironori
authors.initials: H
authors.lastname: Kojima
authors.forename: Osamu
authors.initials: O
authors.lastname: Matsui
mesh_terms: D000008:Abdominal Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D000368:Aged; D000369:Aged, 80 and over; D062485:Breath Holding; D054893:Cone-Beam Computed Tomography; D003964:Diaphragm / Q000000981:diagnostic imaging*; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D008297:Male; D008875:Middle Aged; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D061089:Radiotherapy, Image-Guided / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D013131:Spine / Q000000981:diagnostic imaging