title: The effect of pro-qura case volume on post-implant prostate dosimetry.
abstract: OBJECTIVE
  To evaluate the effect of prostate brachytherapy case volume on postimplant dosimetric quality in Pro-Qura proctored programs.
  
  
  METHODS
  From August 1999 to December 2008, the computed tomography datasets for 6,600 prostate implants performed by 129 brachytherapists were submitted to Pro-Qura for dosimetric analysis. Brachytherapists were divided into three roughly equal-sized terciles based on total case volume. Postimplant computed tomography scans were obtained at a median of 30 days. Excellent target coverage was defined by a V100≥90% and D90≥100% minimum prescribed peripheral dose. To determine if the number of excellent implants improved with increasing case numbers, each brachytherapist's series of implants was bisected into early and late experience by a moveable critical point.
  
  
  RESULTS
  For the entire cohort, the mean V100 and D90 were 89.2% and 102.8%, respectively, with 47.7% of the implants scored as excellent. Brachytherapists in the highest-case tercile had a significantly greater fraction of excellent target coverage (57.9%) than did those in the two lower terciles (39.5% and 45.7%, p=0.015). Twenty-one (25.6%) of the 82 brachytherapists with sufficient case volume for dosimetric improvement analyses demonstrated quality improvement over time. Although there was no significant difference between prostate volume and seed strength, the number of seeds used was significantly greater in adequate implants.
  
  
  CONCLUSIONS
  The highest-volume brachytherapists were most likely to obtain excellent target coverage. We are encouraged that in general practice, nearly 48% of all implants were scored excellent. It is conceivable that with greater expert third-party involvement, an even greater percentage of cases with excellent target coverage will become reality.
authors.affiliation: Schiffler Cancer Center Wheeling Jesuit University, Wheeling, WV 26003, USA. gmerrick@urologicresearchinstitute.org
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Merrick
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Lief
authors.forename: Peter
authors.initials: P
authors.lastname: Grimm
authors.forename: John
authors.initials: J
authors.lastname: Sylvester
authors.forename: Wayne M
authors.initials: WM
authors.lastname: Butler
authors.forename: Zachariah A
authors.initials: ZA
authors.lastname: Allen
mesh_terms: D001918:Brachytherapy / Q000592:standards* / Q000706:statistics & numerical data; D002983:Clinical Competence / Q000592:standards* / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D011467:Prostate / Q000473:pathology; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D058996:Quality Improvement / Q000592:standards* / Q000706:statistics & numerical data; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden; D016526:Workload