title: A simple technique to minimize needle displacement in gynecologic interstitial brachytherapy: Use of fully stretched elastic tapes.
abstract: Previous studies on reproducibility in gynecologic high-dose-rate interstitial brachytherapy (HDRIB) have reported caudal needle displacements as high as 14-27.9 mm. The needle-template units in these studies were, however, sutured to the perineum, which gradually moved away from the target due to edema. To overcome the caudal force from the edema, we have been using fully stretched elastic tapes that exert cranial force on the template. To evaluate the effectiveness of our technique, caudal needle displacements relative to the target were investigated using CT coordinates.
  
  
  
  Twenty-nine gynecologic cancer patients were treated using HDRIB. The template was pressed into the perineum using two elastic tapes. All patients underwent pretreatment and posttreatment CTs to obtain craniocaudal coordinates for the needles and the clinical target volume.
  
  
  
  The median displacements for the 533 needles relative to the clinical target volume were -0.8 mm (range, -5.7 to +4.7 mm). Absolute craniocaudal displacement >3 mm was observed in only 14.4% of the needles, with a maximum displacement of only 5.7 mm.
  
  
  
  The use of elastic tapes achieved smaller displacements compared to those in previous reports. This was a simple but effective technique to minimize needle displacement for gynecologic HDRIB.
authors.affiliation: Department of Radiation Oncology, Nippon Medical School, Tama Nagayama Hospital, Tama, Tokyo, Japan. Electronic address: nose-takayuki@nms.ac.jp.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nose
authors.affiliation: Department of Radiation Oncology, Cancer Institute Hospital of the Japanese Foundation for Cancer Research, Koto ward, Tokyo, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Onoe
authors.affiliation: Department of Radiation Oncology, Cancer Institute Hospital of the Japanese Foundation for Cancer Research, Koto ward, Tokyo, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Otani
authors.affiliation: Department of Radiation Oncology, Cancer Institute Hospital of the Japanese Foundation for Cancer Research, Koto ward, Tokyo, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Oguchi
authors.affiliation: Department of Radiation Oncology, Cancer Institute Hospital of the Japanese Foundation for Cancer Research, Koto ward, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamashita
mesh_terms: D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000379:methods*; D004548:Elasticity; D005260:Female; D005833:Genital Neoplasms, Female / Q000532:radiotherapy*; D006801:Humans; D008875:Middle Aged; D009339:Needles; D010388:Pelvis; D011475:Prosthesis Failure; D053832:Surgical Tape
keywords: Elastic tapes; Gynecologic cancer; Interstitial brachytherapy; Needle displacement; Radiotherapy