title: Treatment planning for resected abdominal tumors: differences in organ position between diagnostic and radiation-planning computed tomography scans.
abstract: OBJECTIVE
  To evaluate whether organ location, determined from preoperative diagnostic computed tomography scans (CTs), accurately reflects organ location when patients are positioned for radiation therapy.
  
  
  METHODS
  We identified patients with upper abdominal malignancies treated with surgery and/or radiation therapy. Comparisons of organ position relative to fixed bony landmarks were made among preoperative diagnostic CTs, postoperative diagnostic CTs, and radiation-planning CTs. We studied 18 patients who had CTs differing only in scanning technique, 11 patients who had CTs differing only in operative state, and 7 patients with CTs differing in both scanning technique and operative state.
  
  
  RESULTS
  For patients with diagnostic CTs and radiation-planning CTs that were either both preoperative or both postoperative, mean organ position, measured relative to a fixed bony landmark, ranged from 1.9 to 3.2 cm superior on radiation-planning CTs compared with diagnostic CTs (p < 0.0001). Mean organ position ranged from 0.9 to 1.7 cm posterior on radiation-planning CTs compared with diagnostic CTs (p < or = 0.008). Shifts in the right-left direction were small and variable. For patients with pre- and postoperative diagnostic CTs, organ shifts were variable and not significant. Organ shifts for patients with preoperative diagnostic CTs and postoperative radiation-planning CTs were similar to shifts observed for the first group.
  
  
  CONCLUSIONS
  Relative to bony landmarks, there are superior and posterior shifts in organ position for radiation-planning CTs compared with diagnostic CTs. These shifts should be considered during treatment planning for resected abdominal tumors.
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital/Dana Farber Cancer Institute, Boston, MA 02115, USA.
authors.forename: Aileen B
authors.initials: AB
authors.lastname: Chen
authors.forename: Joseph
authors.initials: J
authors.lastname: Killoran
authors.forename: Haesook
authors.initials: H
authors.lastname: Kim
authors.forename: Harvey
authors.initials: H
authors.lastname: Mamon
mesh_terms: D005260:Female; D005743:Gastrectomy; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging; D008099:Liver / Q000000981:diagnostic imaging; D008297:Male; D010180:Pancreatectomy; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D011860:Radiography, Abdominal; D011880:Radiotherapy Planning, Computer-Assisted; D013154:Spleen / Q000000981:diagnostic imaging; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D014057:Tomography, X-Ray Computed