title: Construction and evaluation of an anatomically correct multi-image modality compatible phantom for prostate cancer focal ablation.
abstract: OBJECTIVE
  Focal therapy using lasers is emerging as an alternative strategy for prostate cancer treatment. However, to our knowledge no anatomically correct models are available to test imaging and ablation techniques. Animal models present ethical, anatomical and cost challenges. We designed and validated an inexpensive but anatomically correct prostate phantom incorporating tumor, rectum and urethra that can be used for simulated and experimental magnetic resonance guided focal intervention. Our secondary aim was to asses the phantom using other imaging modalities.
  
  
  METHODS
  The phantom, which was constructed of ballistic gel, includes an 80 gm prostate with urethra, tumor, perineum and rectum. Gadolinium was added to make the gel visible to magnetic resonance imaging. To recreate a tumor an irregularly shaped 5 cc volume of coagulable gel was inserted into the prostate phantom. The phantom was evaluated using magnetic resonance, computerized tomography and transrectal ultrasound. Thermal ablation was delivered via interstitial placement of laser fibers. Magnetic resonance thermometry was done to record real-time tissue temperatures during thermal ablation.
  
  
  RESULTS
  With all modalities tested the phantom emulated human prostate anatomy. The coagulable gel tumor allowed us to generate focal thermal lesions. The phantom had magnetic resonance imaging properties comparable to in vivo properties, allowing ablative zones to be accurately assessed and magnetic resonance thermometry to be done.
  
  
  CONCLUSIONS
  The phantom is a useful tool to test different aspects of thermal focal ablation for prostate cancer using multiple imaging modalities, particularly magnetic resonance. It is inexpensive and easily constructed, and may be considered a valuable model to train on and teach focal therapy.
authors.affiliation: Surgical Oncology, Urology Division, University Health Network, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Uri
authors.initials: U
authors.lastname: Lindner
authors.forename: Nathan
authors.initials: N
authors.lastname: Lawrentschuk
authors.forename: Robert A
authors.initials: RA
authors.lastname: Weersink
authors.forename: Orit
authors.initials: O
authors.lastname: Raz
authors.forename: Eugen
authors.initials: E
authors.lastname: Hlasny
authors.forename: Marshall S
authors.initials: MS
authors.lastname: Sussman
authors.forename: Sean R
authors.initials: SR
authors.lastname: Davidson
authors.forename: Mark R
authors.initials: MR
authors.lastname: Gertner
authors.forename: John
authors.initials: J
authors.lastname: Trachtenberg
mesh_terms: D004867:Equipment Design; D005682:Gadolinium; D005782:Gels; D006801:Humans; D053783:Magnetic Resonance Imaging, Interventional; D008297:Male; D008953:Models, Anatomic; D019047:Phantoms, Imaging; D011467:Prostate / Q000473:pathology / Q000601:surgery; D011471:Prostatic Neoplasms / Q000473:pathology / Q000601:surgery*; D015641:Radiography, Interventional; D012007:Rectum / Q000033:anatomy & histology; D018084:Ultrasonography, Interventional; D014521:Urethra / Q000033:anatomy & histology
chemical_list: D005782:Gels; D005682:Gadolinium