title: Identifying the dominant prostate cancer focal lesion using image analysis and planning of a simultaneous integrated stereotactic boost.
abstract: BACKGROUND
  Prostate cancer is now the only solid organ cancer in which therapy is commonly applied to the whole gland. One of the main challenges in adopting focal boost or true focal therapy is in the accurate mapping of cancer foci defined on magnetic resonance (MR) images onto the computerised tomography (CT) images used for radiotherapy planning.
  
  
  METHODS
  Prostate cancer patients (n = 14) previously treated at the Edinburgh Cancer Centre (ECC) were selected for this study. All patients underwent MR scanning for the purpose of diagnosis and staging. Patients received three months of androgen deprivation hormone therapy followed by a radiotherapy planning CT scan. The dominant focal prostate lesions were identified on MR scans by a radiologist and a novel image analysis approach was used to map the location of the dominant focal lesion from MR to CT. An offline planning study was undertaken on suitable patients (n = 7) to investigate boosting of the radiation dose to the tumour using a stereotactic ablative body radiotherapy (SABR) technique.
  
  
  RESULTS
  The non-rigid registration algorithm showed clinically acceptable estimates of the location of the dominant focal disease on all CT image data of patients suitable for a boost treatment. Standard rigid registration was found to produce unacceptable estimates of the dominant focal lesion on CT. A SABR boost dose of 47.5 Gy was delivered to the dominant focal lesion of all patients whilst meeting all dose-volume histogram (DVH) constraints. Normal tissue complication probability (NTCP) for the rectum decreased from 1.28% to 0.73% with this method.
  
  
  CONCLUSIONS
  These preliminary results demonstrate the potential of this image analysis method for reliably mapping dominant focal disease within the prostate from MR images onto planning CT images. Significant dose escalation using a simultaneous integrated SABR boost was achieved in all patients.
authors.affiliation: a Department of Oncology Physics , Edinburgh Cancer Centre, Western General Hospital , Crewe Road South, Edinburgh , UK.
authors.forename: Yang
authors.initials: Y
authors.lastname: Feng
authors.affiliation: a Department of Oncology Physics , Edinburgh Cancer Centre, Western General Hospital , Crewe Road South, Edinburgh , UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Welsh
authors.affiliation: a Department of Oncology Physics , Edinburgh Cancer Centre, Western General Hospital , Crewe Road South, Edinburgh , UK.
authors.forename: Kim
authors.initials: K
authors.lastname: McDonald
authors.affiliation: a Department of Oncology Physics , Edinburgh Cancer Centre, Western General Hospital , Crewe Road South, Edinburgh , UK.
authors.forename: Linda
authors.initials: L
authors.lastname: Carruthers
authors.affiliation: a Department of Oncology Physics , Edinburgh Cancer Centre, Western General Hospital , Crewe Road South, Edinburgh , UK.
authors.forename: Kun
authors.initials: K
authors.lastname: Cheng
authors.affiliation: a Department of Oncology Physics , Edinburgh Cancer Centre, Western General Hospital , Crewe Road South, Edinburgh , UK.
authors.forename: Dean
authors.initials: D
authors.lastname: Montgomery
authors.affiliation: e Royal (Dick) School of Veterinary Studies, University of Edinburgh , Edinburgh , UK.
authors.forename: Jessica
authors.initials: J
authors.lastname: Lawrence
authors.affiliation: e Royal (Dick) School of Veterinary Studies, University of Edinburgh , Edinburgh , UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Argyle
authors.affiliation: d School of Engineering and Physical Sciences, Heriot Watt University , Edinburgh , UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: McLaughlin
authors.affiliation: b Department of Clinical Oncology , Edinburgh Cancer Centre, Western General Hospital , Crewe Road South, Edinburgh , UK.
authors.forename: Duncan B
authors.initials: DB
authors.lastname: McLaren
authors.affiliation: a Department of Oncology Physics , Edinburgh Cancer Centre, Western General Hospital , Crewe Road South, Edinburgh , UK.|c School of Engineering, the University of Edinburgh, the King's Buildings , Mayfield Road, Edinburgh , UK.
authors.forename: William H
authors.initials: WH
authors.lastname: Nailon
mesh_terms: D000465:Algorithms; D000726:Androgen Antagonists / Q000627:therapeutic use; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging; D008297:Male; D010865:Pilot Projects; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000532:radiotherapy*; D000069473:Radiation Dose Hypofractionation; D011880:Radiotherapy Planning, Computer-Assisted; D014057:Tomography, X-Ray Computed
chemical_list: D000726:Androgen Antagonists