title: Quantification of dose uncertainties in cumulated dose estimation compared to planned dose in prostate IMRT.
abstract: In prostate IMRT, the objectives were to quantify, for the bladder and the rectum: (i) the dose difference (DD) between the planned dose (PD) and the estimated cumulated dose (ECD) by deformable image registration (DIR); (ii) the dose accumulation uncertainties (DAU).
  
  
  
  A series of 24 patients receiving 80Gy in the prostate was used to calculate the ECDpts and the DDpts. To evaluate the DAU, a numerical phantom (ph) simulating deformations of main pelvic organs was used to calculate the ECDph using the same DIR method. A reference cumulated dose (RCDph) was calculated, based on the simulated deformations. The DAUph was defined by the differences between RCDph and ECDph.
  
  
  
  For the mean dose to the bladder, the standard deviation of DDpts was 6.9Gy (18.1Gy maximum) with a DAUph of 2.7Gy. For the rectum wall, it was 2.0Gy (4.2Gy maximum) with a DAUph of 1.2Gy. Volume differences between PDpts and ECDpts, along the dose-volume histogram, ranged from -30% to +37% and -14% to +14% for the bladder and rectum, respectively. The corresponding uncertainties ranged from -23% to +7% and -4% to +7% for the bladder and rectum, respectively.
  
  
  
  Large differences between planned and delivered doses to the bladder have been quantified and are higher than the uncertainties of the DIR method. For the rectum, the differences are smaller and close to the DIR uncertainties.
authors.affiliation: Université de Rennes 1, LTSI, Rennes, F-35000, France; INSERM, U1099, Rennes, F-35000, France. Electronic address: mohamed.hatem.nassef@gmail.com.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Nassef
authors.affiliation: Université de Rennes 1, LTSI, Rennes, F-35000, France; INSERM, U1099, Rennes, F-35000, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Simon
authors.affiliation: Université de Rennes 1, LTSI, Rennes, F-35000, France; INSERM, U1099, Rennes, F-35000, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Cazoulat
authors.affiliation: Université de Rennes 1, LTSI, Rennes, F-35000, France; INSERM, U1099, Rennes, F-35000, France.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Duménil
authors.affiliation: Centre Eugène Marquis, Département de Radiothérapie, F-35000, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Blay
authors.affiliation: Université de Rennes 1, LTSI, Rennes, F-35000, France; INSERM, U1099, Rennes, F-35000, France; Centre Eugène Marquis, Département de Radiothérapie, F-35000, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Lafond
authors.affiliation: Université de Rennes 1, LTSI, Rennes, F-35000, France; INSERM, U1099, Rennes, F-35000, France.
authors.forename: Oscar
authors.initials: O
authors.lastname: Acosta
authors.affiliation: Université Joseph Fourier, Grenoble, F-38041, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Balosso
authors.affiliation: Université de Rennes 1, LTSI, Rennes, F-35000, France; INSERM, U1099, Rennes, F-35000, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Haigron
authors.affiliation: Université de Rennes 1, LTSI, Rennes, F-35000, France; INSERM, U1099, Rennes, F-35000, France; Centre Eugène Marquis, Département de Radiothérapie, F-35000, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: de Crevoisier
mesh_terms: D054893:Cone-Beam Computed Tomography; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated; D012007:Rectum / Q000528:radiation effects; D035501:Uncertainty; D001743:Urinary Bladder / Q000528:radiation effects
keywords: Cumulative dose; Deformable image registration; IGRT; Phantom; Prostate