title: Comparison of dose and catheter optimization algorithms in prostate high-dose-rate brachytherapy.
abstract: OBJECTIVE
  The purpose of this work was to compare the hybrid inverse treatment planning optimization (HIPO), inverse dose-volume histogram-based optimization (DVHO), and fast simulated annealing stochastic algorithm (IPSA). The catheter optimization algorithm HIPO was also compared with the Centroidal Voronoi Tessellation (CVT) algorithm.
  
  
  METHODS
  In this study, eight high-dose-rate prostate cases were randomly selected from an anonymized bank of patients. Oncentra Prostate v4.1 was used to run DVHO and the HIPO catheter optimization (HIPO_cat), whereas Oncentra Brachy v4.3 was used for the remaining. For fixed catheter configurations, DVHO plans were compared with IPSA and HIPO. For catheter positions optimization, CVT and HIPO_cat algorithms were compared with standard clinical template plans. CVT catheters were further restrained to the template grid (CVT_grid) and compared with HIPO_cat.
  
  
  RESULTS
  For dose optimization, IPSA and HIPO were not different from each other. The urethra D10 and the computation time were found significantly better with IPSA and HIPO compared with DVHO (p < 0.0001). All other dosimetric indices were not statistically different from each others (p > 0.05). For catheter placement, CVT plans were better, whereas HIPO_cat plans were significantly worse (p < 0.05) than standard clinical plans. CVT_grid plans were similar to clinical plans and fulfilling American Brachytherapy Society guidelines down to 12 catheters, whereas HIPO_cat plans do not for all catheter numbers. The CVT algorithm run time was significantly faster than HIPO_cat (p < 0.0001).
  
  
  CONCLUSIONS
  Dose optimization engines IPSA, DVHO, and HIPO give similar dosimetric results. The CVT approach was found to be better than HIPO_cat and was able to reduce the number of catheters significantly.
authors.affiliation: Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer de l'Université Laval, Université Laval, Québec, Canada; Département de radio-oncologie et Axe Oncologie du Centre de recherche du CHU de Québec, CHU de Québec, Québec, Canada.
authors.forename: Eric
authors.initials: E
authors.lastname: Poulin
authors.affiliation: Département de radio-oncologie et Axe Oncologie du Centre de recherche du CHU de Québec, CHU de Québec, Québec, Canada.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Varfalvy
authors.affiliation: Département de radio-oncologie et Axe Oncologie du Centre de recherche du CHU de Québec, CHU de Québec, Québec, Canada.
authors.forename: Sylviane
authors.initials: S
authors.lastname: Aubin
authors.affiliation: Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer de l'Université Laval, Université Laval, Québec, Canada; Département de radio-oncologie et Axe Oncologie du Centre de recherche du CHU de Québec, CHU de Québec, Québec, Canada. Electronic address: beaulieu@phy.ulaval.ca.
authors.forename: Luc
authors.initials: L
authors.lastname: Beaulieu
mesh_terms: D000465:Algorithms; D001918:Brachytherapy / Q000379:methods*; D057785:Catheters; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012189:Retrospective Studies
keywords: Dose optimization; HDR brachytherapy; Inverse planning; Needle planning