title: Use of image coregistration in salvage prostate brachytherapy.
abstract: OBJECTIVE
  We describe a method of performing salvage prostate brachytherapy on patients whose initial implant was suboptimal. This technique uses an image correlation algorithm only previously used to fuse postimplant magnetic resonance and computed tomographic (CT) images. Here, the initial postimplant CT and the second preimplant volume study are coregistered to plan delivery of the salvage implant.
  
  
  METHODS
  Two early-stage patients had salvage implants performed with this technique, in which only a limited number of sources were visible on the ultrasound images. The dosimetric results of the first implant were displayed on the preplan generated for the second procedure. The planned total dose then was visualized prior to salvage implant.
  
  
  RESULTS
  The implants were performed without complication. Rectum and urethra doses remained acceptable. In each case, the improvement in coverage of the gland was dramatic (V80 coverage improved from 65.2% and 47.3% to 93.1% and 92.2%, respectively), precluding the need for further intervention.
  
  
  CONCLUSIONS
  Coregistration of the postimplant CT scan to an ultrasound volume study can be quantifiably and reliably performed. The resulting image set can be used to guide needle placement during a second salvage implant to achieve much improved dosimetric coverage of the gland.
authors.affiliation: University of Texas Health Science Center at San Antonio, Texas, USA.
authors.forename: W S
authors.initials: WS
authors.lastname: Bice
authors.forename: J E
authors.initials: JE
authors.lastname: Freeman
authors.forename: L F
authors.initials: LF
authors.lastname: Russell
authors.forename: G D
authors.initials: GD
authors.lastname: Case
authors.forename: D F
authors.initials: DF
authors.lastname: Dubois
authors.forename: J J
authors.initials: JJ
authors.lastname: Prete
authors.forename: B R
authors.initials: BR
authors.lastname: Prestidge
mesh_terms: D000465:Algorithms; D001918:Brachytherapy / Q000379:methods*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D010165:Palladium / Q000627:therapeutic use; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D011868:Radioisotopes / Q000627:therapeutic use; D011880:Radiotherapy Planning, Computer-Assisted; D016879:Salvage Therapy; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014463:Ultrasonography
chemical_list: D007457:Iodine Radioisotopes; D011868:Radioisotopes; D010165:Palladium