title: Evaluation of Focal Ablation of Magnetic Resonance Imaging Defined Prostate Cancer Using Magnetic Resonance Imaging Controlled Transurethral Ultrasound Therapy with Prostatectomy as the Reference Standard.
abstract: We evaluated magnetic resonance imaging controlled transurethral ultrasound therapy as a treatment for magnetic resonance imaging defined focal prostate cancer using subsequent prostatectomy and histology as the reference standard.
  
  
  
  Five men completed this pilot study, which was approved by the institutional review board. Prior to radical prostatectomy focal tumors identified by magnetic resonance imaging were treated by coagulating targeted subtotal 3-dimensional volumes of prostate tissue using magnetic resonance imaging controlled transurethral focused ultrasound. Treatment was performed with a 3 Tesla clinical magnetic resonance imaging unit combined with modified clinical planning software for high intensity focused ultrasound therapy. After prostatectomy whole mount histological sections parallel to the magnetic resonance imaging treatment planes were used to compare magnetic resonance imaging measurements with thermal damage at the cellular level and, thus, evaluate treatment and target accuracy.
  
  
  
  Three-dimensional target volumes of 4 to 20 cc and with radii up to 35 mm from the urethra were treated successfully. Mean ± SD temperature control accuracy at the target boundary was -1.6 ± 4.8C and the mean spatial targeting accuracy achieved was -1.5 ± 2.8 mm. Mean treatment accuracy with respect to histology was -0.4 ± 1.7 mm with all index tumors falling inside the histological outer limit of thermal injury.
  
  
  
  Magnetic resonance imaging guided transurethral ultrasound therapy is capable of generating thermal coagulation and tumor destruction in targeted 3-dimensional angular sectors out to the prostate capsule for prostate glands up to 70 cc in volume. Ultrasound parameters needed to achieve ablation at the prostate capsule were determined, providing a foundation for future studies.
authors.affiliation: Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Ramsay
authors.affiliation: Philips, Markham, Ontario, Canada.
authors.forename: Charles
authors.initials: C
authors.lastname: Mougenot
authors.affiliation: Philips Research North America, Cambridge, Massachusetts.
authors.forename: Robert
authors.initials: R
authors.lastname: Staruch
authors.affiliation: Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada.
authors.forename: Aaron
authors.initials: A
authors.lastname: Boyes
authors.affiliation: Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Kazem
authors.affiliation: Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Bronskill
authors.affiliation: Department of Anaesthesiology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto.
authors.forename: Harry
authors.initials: H
authors.lastname: Foster
authors.affiliation: Department of Anatomic Pathology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Linda
authors.initials: L
authors.lastname: Sugar
authors.affiliation: Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Masoom
authors.initials: M
authors.lastname: Haider
authors.affiliation: Department of Urology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Laurence
authors.initials: L
authors.lastname: Klotz
authors.affiliation: Department of Radiology and Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas. Electronic address: Rajiv.chopra@utsouthwestern.edu.
authors.forename: Rajiv
authors.initials: R
authors.lastname: Chopra
mesh_terms: D000368:Aged; D001707:Biopsy, Needle; D005500:Follow-Up Studies; D057086:High-Intensity Focused Ultrasound Ablation / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011300:Preoperative Care / Q000379:methods; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D018570:Risk Assessment; D012494:Sampling Studies; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013997:Time Factors; D016896:Treatment Outcome
keywords: high-intensity focused ultrasound ablation; magnetic resonance imaging; minimally invasive surgical procedures; prostatic neoplasms; transurethral resection of prostate