title: Placement of empty catheters for an HDR-emulating LDR prostate brachytherapy technique: comparison to standard intraoperative planning.
abstract: OBJECTIVE
  We sought to determine whether placing empty catheters within the prostate and then inverse planning iodine-125 seed locations within those catheters (High Dose Rate-Emulating Low Dose Rate Prostate Brachytherapy [HELP] technique) would improve concordance between planned and achieved dosimetry compared with a standard intraoperative technique.
  
  
  METHODS
  We examined 30 consecutive low dose rate prostate cases performed by standard intraoperative technique of planning followed by needle placement/seed deposition and compared them to 30 consecutive low dose rate prostate cases performed by the HELP technique. The primary endpoint was concordance between planned percentage of the clinical target volume that receives at least 100% of the prescribed dose/dose that covers 90% of the volume of the clinical target volume (V100/D90) and the actual V100/D90 achieved at Postoperative Day 1.
  
  
  RESULTS
  The HELP technique had superior concordance between the planned target dosimetry and what was actually achieved at Day 1 and Day 30. Specifically, target D90 at Day 1 was on average 33.7 Gy less than planned for the standard intraoperative technique but was only 10.5 Gy less than planned for the HELP technique (p < 0.001). Day 30 values were 16.6 Gy less vs. 2.2 Gy more than planned, respectively (p = 0.028). Day 1 target V100 was 6.3% less than planned with standard vs. 2.8% less for HELP (p < 0.001). There was no significant difference between the urethral and rectal concordance (all p > 0.05).
  
  
  CONCLUSIONS
  Placing empty needles first and optimizing the plan to the known positions of the needles resulted in improved concordance between the planned and the achieved dosimetry to the target, possibly because of elimination of errors in needle placement.
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA; Dana-Farber Cancer Institute, Boston, MA; Harvard Medical School, Boston, MA. Electronic address: tniedermayr@partners.org.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Niedermayr
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA; Dana-Farber Cancer Institute, Boston, MA; Harvard Medical School, Boston, MA.
authors.forename: Paul L
authors.initials: PL
authors.lastname: Nguyen
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA; Dana-Farber Cancer Institute, Boston, MA; Harvard Medical School, Boston, MA.
authors.forename: Yonina R
authors.initials: YR
authors.lastname: Murciano-Goroff
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA.
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Kovtun
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA.
authors.forename: Emily
authors.initials: E
authors.lastname: Neubauer Sugar
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA.
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Cail
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA; Dana-Farber Cancer Institute, Boston, MA; Harvard Medical School, Boston, MA.
authors.forename: Desmond A
authors.initials: DA
authors.lastname: O'Farrell
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA; Dana-Farber Cancer Institute, Boston, MA; Harvard Medical School, Boston, MA.
authors.forename: Jorgen L
authors.initials: JL
authors.lastname: Hansen
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA; Dana-Farber Cancer Institute, Boston, MA; Harvard Medical School, Boston, MA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Cormack
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA; Dana-Farber Cancer Institute, Boston, MA.
authors.forename: Ivan
authors.initials: I
authors.lastname: Buzurovic
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA.
authors.forename: Luciant T
authors.initials: LT
authors.lastname: Wolfsberger
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA; Dana-Farber Cancer Institute, Boston, MA; Department of Urology, Brigham and Women's Hospital, Boston, MA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: O'Leary
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA; Dana-Farber Cancer Institute, Boston, MA; Department of Urology, Brigham and Women's Hospital, Boston, MA.
authors.forename: Graeme S
authors.initials: GS
authors.lastname: Steele
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA; Dana-Farber Cancer Institute, Boston, MA; Harvard Medical School, Boston, MA.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Devlin
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA; Dana-Farber Cancer Institute, Boston, MA; Harvard Medical School, Boston, MA.
authors.forename: Peter F
authors.initials: PF
authors.lastname: Orio
mesh_terms: D000368:Aged; D001918:Brachytherapy / Q000295:instrumentation / Q000379:methods*; D002408:Catheters, Indwelling; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy* / Q000601:surgery; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional
keywords: Brachytherapy; LDR; Low dose rate; Prostate