title: A study of the effect of setup errors and organ motion on prostate cancer treatment with IMRT.
abstract: OBJECTIVE
  To assess the influence of setup errors and organ motion in terms of the probability of tumor control and normal-tissue complications by tumor control probability and normal-tissue complication probability.
  
  
  METHODS
  Twelve patients were treated for prostate cancer with intensity-modulated radiation therapy. Two orthogonal portal images were taken daily. All patients underwent three computed tomography scans during the 8-week treatment time (i.e., baseline, intermediate, and final). The original treatment plans were re-evaluated, taking into account setup errors and organ motion.
  
  
  RESULTS
  The mean shifts +/- standard deviation of the whole patient population in the lateral, anterior-posterior, and craniocaudal direction were 1.0 +/- 1.5 mm, 0.9 +/- 2.1 mm, and 1.9 +/- 2.1 mm, respectively. In most of the recalculated dose-volume histograms, the coverage of clinical target volume was granted despite organ motion, whereas the rectal wall histograms were often very different from the planned ones.
  
  
  CONCLUSIONS
  We have studied the impact of prostate and rectum motion, as well as setup errors, on dose-volume histograms. The estimate of these effects may have implications for predictive indications when planning intensity-modulated radiation therapy treatments on prostate.
authors.affiliation: Laboratorio di Fisica Medica e Sistemi Esperti, Istit4uto Regina Elena, Rome, Italy. landoni@ifo.it
authors.forename: Valeria
authors.initials: V
authors.lastname: Landoni
authors.forename: Bianca
authors.initials: B
authors.lastname: Saracino
authors.forename: Simona
authors.initials: S
authors.lastname: Marzi
authors.forename: Michaele
authors.initials: M
authors.lastname: Gallucci
authors.forename: Maria G
authors.initials: MG
authors.lastname: Petrongari
authors.forename: Enrico
authors.initials: E
authors.lastname: Chianese
authors.forename: Michaela
authors.initials: M
authors.lastname: Benassi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Iaccarino
authors.forename: Antonella
authors.initials: A
authors.lastname: Soriani
authors.forename: Giorgio
authors.initials: G
authors.lastname: Arcangeli
mesh_terms: D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009068:Movement; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D011859:Radiography; D050397:Radiotherapy, Intensity-Modulated; D012007:Rectum / Q000000981:diagnostic imaging; D012062:Relative Biological Effectiveness; D013679:Technology, Radiologic / Q000379:methods