title: CT-fluoroscopy guided interstitial brachytherapy with image-based treatment planning for unresectable locally recurrent rectal carcinoma.
abstract: OBJECTIVE
  The aim of the study is to develop high-dose-rate (HDR) conformal interstitial brachytherapy by means of combined CT-fluoroscopy guidance with CT-based treatment planning for locally recurrent rectal carcinoma.
  
  
  METHODS
  Brachytherapy needle insertion was guided with a helical CT scanner providing continuous fluoroscopy reconstruction. A video monitor placed adjacent to the CT gantry simultaneously allowed the operator to see the process of needle insertion. Final CT images were transferred by an online system to the treatment-planning computer, which reconstructed the implant needles and organ contours. The doses in planning target volume were normalized and geometrically optimized. The patients received a brachytherapy dose at 5 Gy twice daily with a hypofractionated accelerated schedule at a total dose of 30-50 Gy with or without external radiation therapy. Eighteen patients were treated with this procedure.
  
  
  RESULTS
  Ten to thirty-six needles (average, 17.3) were successfully placed to the planning target volume in each patient. The average time for CT fluoroscopy was 357 seconds for each procedure. No accident was seen at needle insertion, but 2 patients developed incomplete peroneal nerve palsy after needle removal, but gradually recovered. CT-based treatment planning was faster and more accurate than projection reconstruction with conventional radiograms. Analysis of the dose volume histogram showed conformal dose distribution to the target, while avoiding normal structures.
  
  
  CONCLUSIONS
  CT fluoroscopy guidance ensures safety and increases the accuracy of needle placement in brachytherapy. Conformal high-dose-rate (HDR) interstitial brachytherapy with CT-based treatment planning is a method worth considering for locally recurrent rectal cancer.
authors.affiliation: Department of Radiation Oncology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan. hsakurai@med.gunma-u.ac.jp
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Sakurai
authors.forename: Norio
authors.initials: N
authors.lastname: Mitsuhashi
authors.forename: Koichi
authors.initials: K
authors.lastname: Harashima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Muramatsu
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Yoshizumi
authors.initials: Y
authors.lastname: Kitamoto
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Jun-ich
authors.initials: JI
authors.lastname: Saitoh
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Nonaka
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Akimoto
authors.forename: Yuko
authors.initials: Y
authors.lastname: Nakayama
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakano
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D001918:Brachytherapy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D020266:Radiotherapy, Conformal / Q000379:methods*; D011882:Radiotherapy, High-Energy; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods