title: Real-time intraoperative evaluation of implant quality and dose correction during prostate brachytherapy consistently improves target coverage using a novel image fusion and optimization program.
abstract: OBJECTIVE
  Our purpose was to describe the process and outcome of performing postimplantation dosimetric assessment and intraoperative dose correction during prostate brachytherapy using a novel image fusion-based treatment-planning program.
  
  
  METHODS
  Twenty-six consecutive patients underwent intraoperative real-time corrections of their dose distributions at the end of their permanent seed interstitial procedures. After intraoperatively planned seeds were implanted and while the patient remained in the lithotomy position, a cone beam computed tomography scan was obtained to assess adequacy of the prescription dose coverage. The implanted seed positions were automatically segmented from the cone-beam images, fused onto a new set of acquired ultrasound images, reimported into the planning system, and recontoured. Dose distributions were recalculated based upon actual implanted seed coordinates and recontoured ultrasound images and were reviewed. If any dose deficiencies within the prostate target were identified, additional needles and seeds were added. Once an implant was deemed acceptable, the procedure was completed, and anesthesia was reversed.
  
  
  RESULTS
  When the intraoperative ultrasound-based quality assurance assessment was performed after seed placement, the median volume receiving 100% of the dose (V100) was 93% (range, 74% to 98%). Before seed correction, 23% (6/26) of cases were noted to have V100 <90%. Based on this intraoperative assessment and replanning, additional seeds were placed into dose-deficient regions within the target to improve target dose distributions. Postcorrection, the median V100 was 97% (range, 93% to 99%). Following intraoperative dose corrections, all implants achieved V100 >90%.
  
  
  CONCLUSIONS
  In these patients, postimplantation evaluation during the actual prostate seed implant procedure was successfully applied to determine the need for additional seeds to correct dose deficiencies before anesthesia reversal. When applied, this approach should significantly reduce intraoperative errors and chances for suboptimal dose delivery during prostate brachytherapy.
authors.affiliation: Department of Radiation Oncology, Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York. Electronic address: zelefskm@mskcc.org.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Zelefsky
authors.affiliation: Department of Radiation Oncology, Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York.
authors.forename: Gilad N
authors.initials: GN
authors.lastname: Cohen
authors.affiliation: Department of Radiation Oncology, Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York.
authors.forename: Amandeep S
authors.initials: AS
authors.lastname: Taggar
authors.affiliation: Department of Radiation Oncology, Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York.
authors.forename: Marisa
authors.initials: M
authors.lastname: Kollmeier
authors.affiliation: Department of Radiation Oncology, Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York.
authors.forename: Sean
authors.initials: S
authors.lastname: McBride
authors.affiliation: Department of Radiation Oncology, Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York.
authors.forename: Gig
authors.initials: G
authors.lastname: Mageras
authors.affiliation: Department of Radiation Oncology, Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York.
authors.forename: Marco
authors.initials: M
authors.lastname: Zaider
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000295:instrumentation / Q000379:methods*; D054893:Cone-Beam Computed Tomography; D005500:Follow-Up Studies; D006801:Humans; D007430:Intraoperative Care / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010347:Patient Care Planning; D056888:Patient Positioning; D011467:Prostate / Q000000981:diagnostic imaging / Q000528:radiation effects; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D019736:Prostheses and Implants; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014463:Ultrasonography