title: Four-dimensional measurement of the displacement of metal clips or postoperative surgical staples during 320-multislice computed tomography scanning of gastric cancer.
abstract: OBJECTIVE
  To investigate the respiratory motion of metal clips or surgical staples placed in the gastric wall for planning of radiation therapy in gastric cancer patients.
  
  
  METHODS
  This study examined 15 metal markers in the gastric walls of 12 patients with gastric cancer treated with external-beam photon RT. Motion assessment was analyzed in 41 respiratory phases covering 20 s acquired with computed tomography (CT) in the RT position using 320-multislice CT. The intra-fraction displacement was assessed in the cranio-caudal (CC), antero-posterior (AP), and right-left (RL) directions.
  
  
  RESULTS
  Motion in the CC direction showed a very strong correlation (R2 > 0.7) with the respiratory curve in all 15 markers. The mean (+/- SD) intra-fractional gastric motion (maximum range of displacement) was 12.5 (+/- 3.4) mm in the CC, 8.3 (+/- 2.2) mm in the AP, and 5.5 (+/- 3.0) mm in the RL direction. No significant differences in magnitude of motion were detected in the following: a) among the upper (n = 6), middle (n = 4), and lower (n = 5) stomach regions; b) between metal clips (n = 5) and surgical staples (n = 10); and c) between full (n = 9) and empty (n = 6) stomachs.
  
  
  CONCLUSIONS
  Motion in primary gastric tumor was evaluated with 320-multislice CT. According to this study, the 95th percentile values from the cumulative distributions of the RL, AP, and CC direction were 6.3 mm, 9.0 mm, and 13.6 mm, respectively.
authors.affiliation: Department of Radiology, University of Tokyo Hospital, Tokyo, Japan. yamachan07291973@yahoo.co.jp
authors.forename: Hideomi
authors.initials: H
authors.lastname: Yamashita
authors.forename: Kae
authors.initials: K
authors.lastname: Okuma
authors.forename: Wataru
authors.initials: W
authors.lastname: Takahashi
authors.forename: Akira
authors.initials: A
authors.lastname: Sakumi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Haga
authors.forename: Kenji
authors.initials: K
authors.lastname: Ino
authors.forename: Masaaki
authors.initials: M
authors.lastname: Akahane
authors.forename: Kuni
authors.initials: K
authors.lastname: Ohtomo
authors.forename: Keiichi
authors.initials: K
authors.lastname: Nakagawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D056973:Four-Dimensional Computed Tomography; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D009068:Movement; D061330:Multidetector Computed Tomography; D009367:Neoplasm Staging; D011184:Postoperative Period; D011379:Prognosis; D011880:Radiotherapy Planning, Computer-Assisted; D012119:Respiration; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy / Q000601:surgery; D017792:Surgical Stapling
chemical_list: D008670:Metals