title: The Vienna applicator for combined intracavitary and interstitial brachytherapy of cervical cancer: design, application, treatment planning, and dosimetric results.
abstract: OBJECTIVE
  To present a combined intracavitary and interstitial dedicated applicator and magnetic resonance imaging (MRI) treatment planning for cervical cancer brachytherapy.
  
  
  METHODS
  A modified ring applicator allows interstitial needles to be implanted in parallel to the intrauterine tandem. MRI treatment planning based on a standard loading pattern with stepwise dwell weight adaptation and needle loading is performed to achieve optimal dose coverage and sparing of organs at risk. Dose constraints are applied for dose-volume histogram parameters.
  
  
  RESULTS
  The use of additional interstitial needles provides prescription dose up to 15 mm lateral to point A. Twenty-two patients with high-risk clinical target volumes of mean 44 cm3 were treated with a mean prescribed total dose of 85 Gy (biologically equivalent to 2 Gy fractionation, alpha/beta = 10 Gy) and 93% coverage (V100). The dose to organs at risk was within standard limits for intracavitary brachytherapy alone.
  
  
  CONCLUSIONS
  A combined interstitial-intracavitary applicator results in reproducible implants for cervical cancer brachytherapy. MRI-based treatment planning based on a target concept, dose-volume constraints, and limitations for the relative dwell weight allows for an increase in target coverage, treated volume, and total dose without increasing the dose to critical structures.
authors.affiliation: Department of Radiotherapy and Radiobiology, Medical University of Vienna, Vienna, Austria. Kirisits@meduniwien.ac.at
authors.forename: Christian
authors.initials: C
authors.lastname: Kirisits
authors.forename: Stefan
authors.initials: S
authors.lastname: Lang
authors.forename: Johannes
authors.initials: J
authors.lastname: Dimopoulos
authors.forename: Daniel
authors.initials: D
authors.lastname: Berger
authors.forename: Dietmar
authors.initials: D
authors.lastname: Georg
authors.forename: Richard
authors.initials: R
authors.lastname: Pötter
mesh_terms: D001918:Brachytherapy / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D011446:Prospective Studies; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy*