title: Inter-institutional variation of implant activity for permanent prostate brachytherapy.
abstract: OBJECTIVE
  Despite the existence of guidelines for permanent prostate brachytherapy, it is unclear whether there is interinstitutional consensus concerning the parameters of an ideal implant.
  
  
  METHODS
  Three institutions with extensive prostate brachytherapy expertise submitted information regarding their implant philosophy and dosimetric constraints, as well as data on up to 50 radioiodine implants. Regression analyses were performed to reflect each institution's utilization of seeds and implanted activity.
  
  
  RESULTS
  Despite almost identical implant philosophy, target volume, and dosimetric constraints, there were statistically significant interinstitutional differences in the number of seeds and total implant activity across the range of prostate volumes. For larger volumes, the variation in implanted activity was 25%; for smaller glands, it exceeded 40%.
  
  
  CONCLUSIONS
  There remain wide variations in implanted activity between institutions espousing seemingly identical implant strategies, prescription, and dosimetry constraints. Brachytherapists should therefore be wary of using nomograms generated at other institutions.
authors.affiliation: Department of Radiation Oncology, University of Massachusetts Medical School, Worcester, MA 01605, USA. aronwij@ummhc.org
authors.forename: Jesse N
authors.initials: JN
authors.lastname: Aronowitz
authors.forename: Juanita M
authors.initials: JM
authors.lastname: Crook
authors.forename: Jeff M
authors.initials: JM
authors.lastname: Michalski
authors.forename: John E
authors.initials: JE
authors.lastname: Sylvester
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Merrick
authors.forename: Christie
authors.initials: C
authors.lastname: Mawson
authors.forename: David
authors.initials: D
authors.lastname: Pratt
authors.forename: Devi
authors.initials: D
authors.lastname: Naidoo
authors.forename: Wayne M
authors.initials: WM
authors.lastname: Butler
authors.forename: Kathryn
authors.initials: K
authors.lastname: Karolczuk
mesh_terms: D001918:Brachytherapy / Q000379:methods*; D003625:Data Collection; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008297:Male; D049451:Nomograms; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage