title: Computed tomography-ultrasound fusion brachytherapy: description and evolution of the technique.
abstract: OBJECTIVE
  In this manuscript, we describe our computed tomography (CT)-ultrasound (US) fusion prostate brachytherapy method and report the updated dosimetry result and trend.
  
  
  METHODS
  This cohort of 132 consecutive patients received CT-US fusion prostate brachytherapy from the first author (DBF) from December 2002 to August 2006. The technique consists of a hybrid preplanned and intraoperative dynamic dosimetry method, which initially delivers a standard preplanned source distribution, and then uses interval CT-based source identification dosimetry, fused to an identically spaced intraoperative US volume study series, to direct remedial sources that correct initial dosimetry deficiencies.
  
  
  RESULTS
  The median and minimum prostate Day 0 prostate volume of interest receiving 100% of prescribed dose (V(100)) results in this patient cohort measured 98.26% and 92.61%, respectively, with all Day 0 prostate dose received by 90% of the volume of interest (D(90)) results exceeding 100% of the prescribed dose, and the maximum Day 0 prostate D(90) value measuring 128% of the prescribed dose. During the period of this analysis, a trend to the decreased quantity of dynamic remedial millicuries per case was identified, with the total sources decreasing from 116% to 106% of the preplanned level, resulting in minimal V(100) and D(90) decreases, while continuing to exceed the minimum Day 0 dosimetry requirements.
  
  
  CONCLUSIONS
  CT-US fusion dynamic prostate brachytherapy represents a consistent prostate brachytherapy dosimetry delivery mechanism, creating a tight lower and upper bound to the final Day 0 prostate V(100) and D(90) parameters. The practice and pitfalls of this technique are discussed in detail.
authors.affiliation: Department of Radiation Oncology, Radiation Medical Group, Inc., San Diego, CA 92101, USA. dfuller@rmgmed.com
authors.forename: Donald B
authors.initials: DB
authors.lastname: Fuller
authors.forename: Haoran
authors.initials: H
authors.lastname: Jin
mesh_terms: D001918:Brachytherapy / Q000379:methods*; D006801:Humans; D008297:Male; D011467:Prostate / Q000000981:diagnostic imaging*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography