title: The dosimetric impact of single, dual, and triple tandem applicators in the treatment of intact uterine cancer.
abstract: OBJECTIVE
  To identify an optimal afterloading technique for high-dose-rate brachytherapy treatments in patients with medically inoperable uterine cancer.
  
  
  METHODS
  Eighteen treatment plans were generated using point and volume-based techniques for three patients using a single, dual, and triple tandem. Dosimetric parameters of the target and critical structures were evaluated.
  
  
  RESULTS
  Similar target coverage was achieved for each patient using volume-based planning; however, differences were evident when comparing point-based plans for the three applicators. In Patient 1, with a cylindrical uterus (8 cm by 4.5 cm), similar results were achieved with all three applicators (V95 [Single]=90.6%, V95 [Dual]=90.6%, and V95 [Triple]=91.5%). In Patient 2, who had a more spherical uterus (5 cm by 5.4 cm), the dual tandem was inferior to the others (V95=65.9% vs. 83.7% with triple and 85.8% with single tandem). Analysis of isodose distributions showed that the dual tandem failed to achieve adequate coverage of the central portion of the fundus. In Patient 3, who had a uterus (6 cm by 5.5 cm) in close proximity to the bladder (0.5 cm) and bowel, both the triple and dual tandem point-based plans achieved better coverage than the single tandem, given dose constraints on the bladder and bowel, with uterus V95 of 83.4% (Triple), 84.9% (Dual), and 73.7% (Single), respectively.
  
  
  CONCLUSIONS
  For inoperable uterine cancer, optimal high-dose-rate applicator selection depends on the anatomy and location of the uterus and critical organs. The triple tandem applicator provides greater latitude in dose and anatomic uterus coverage as compared with either single or dual tandem applicators.
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, MI.
authors.forename: Skyler B
authors.initials: SB
authors.lastname: Johnson
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, MI.
authors.forename: Jessica
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, MI.
authors.forename: Shruti
authors.initials: S
authors.lastname: Jolly
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, MI.
authors.forename: Bingqi
authors.initials: B
authors.lastname: Guo
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, MI.
authors.forename: Lisa
authors.initials: L
authors.lastname: Young
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, MI. Electronic address: joannp@med.umich.edu.
authors.forename: Joann I
authors.initials: JI
authors.lastname: Prisciandaro
mesh_terms: D001918:Brachytherapy / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D011874:Radiometry; D011880:Radiotherapy Planning, Computer-Assisted; D016896:Treatment Outcome; D014594:Uterine Neoplasms / Q000532:radiotherapy*
keywords: Brachytherapy; High-dose-rate; Tandem applicator; Uterine cancer