title: Elastic image registration for guiding focal laser ablation of prostate cancer: preliminary results.
abstract: OBJECTIVE
  To guide ultrasound-driven prostate photodynamic therapy using information from MRI-based treatment planning.
  
  
  METHODS
  Robust points matching (RPM) and thin plate splines (TPS) are used to solve correspondences and to map optimally positioned landmarks from MR images to transrectal ultrasound (TRUS) images. The algorithm uses a reduced number of anatomical markers that are initialized on the images.
  
  
  RESULTS
  Both phantom and patient data were used to evaluate precision and robustness of the method. Mean registration error (±standard deviation) was of 2.18±0.25 mm and 1.55±0.31 mm for patient prostate and urethra, respectively. Repeated tests with different markers initialization conditions showed that the quality of registration was neither influenced by the number of markers nor to the human observer.
  
  
  CONCLUSIONS
  This method allows for satisfyingly accurate and robust non rigid registration of MRI and TRUS and provides practitioners with substantial help in mapping treatment planning from pre-operative MRI to interventional TRUS.
authors.affiliation: Inserm, U703, F-59000 Lille, France.
authors.forename: Nasr
authors.initials: N
authors.lastname: Makni
authors.forename: Philippe
authors.initials: P
authors.lastname: Puech
authors.forename: Pierre
authors.initials: P
authors.lastname: Colin
authors.forename: Abdelrahmene
authors.initials: A
authors.lastname: Azzouzi
authors.forename: Serge
authors.initials: S
authors.lastname: Mordon
authors.forename: Nacim
authors.initials: N
authors.lastname: Betrouni
mesh_terms: D006801:Humans; D008297:Male; D019047:Phantoms, Imaging; D011471:Prostatic Neoplasms / Q000473:pathology*; D015203:Reproducibility of Results