title: Intrafractional organs movement in three-dimensional image-guided adaptive pulsed-dose-rate cervical cancer brachytherapy: assessment and dosimetric impact.
abstract: OBJECTIVE
  To prospectively evaluate the intrafractional movements of organs at risk (OARs) and their dosimetric impact during the delivery of pulsed-dose-rate brachytherapy in cervical cancer.
  
  
  METHODS
  An MRI on Day 1 was used for treatment planning in 19 patients. CT scans were acquired at Days 1, 2, and 3 with delineation of the OARs. The MRI plan was transferred to each CT. The intersection volume between the 10 Gy isodose and the OARs were monitored, reflecting movement. Lower dose evaluated in the maximally exposed 0.1 cm(3) of an organ and lower dose evaluated in the maximally exposed 2 cm(3) of an organ (D(2cm3)) were evaluated on each CT and compared. Results were averaged considering that each CT reflected one-third of the treatment course to evaluate the delivered dose.
  
  
  RESULTS
  No major movements of the sigmoid and bladder were observed, whereas the rectum got significantly closer to the implant at Day 2. The consequence was an increase of 6% ± 5.3 (3.7 Gy, α/β = 3 Gy) of the delivered D(2cm3) from the planned dose, in contrast to 0.2% ± 6.1 for the bladder and 1.1% ± 6.4 for the sigmoid. The increase of the D(2cm3) of the rectum was reported in 17 patients, ranging from 0.4 to 9.4 Gy, leading to a 10.5% overcoming of the dose constraint (75 Gy). Similar tendencies were reported for lower dose evaluated in the maximally exposed 0.1 cm(3) of an organ.
  
  
  CONCLUSIONS
  A significant systematic variation was observed for the rectum (+3.7 Gy). As significant random variations were observed, caution should be exercised when the planned D(2cm3) is close to the dose constraints.
authors.affiliation: Department of Radiation Oncology, Gustave Roussy Cancer Campus, Villejuif, France; Laboratory of Molecular Radiotherapy, UMR1030, Gustave Roussy Cancer Campus, Villejuif, France. Electronic address: renaud.mazeron@gustaveroussy.fr.
authors.forename: Renaud
authors.initials: R
authors.lastname: Mazeron
authors.affiliation: Department of Medical Physics, Gustave Roussy Cancer Campus, Villejuif, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Champoudry
authors.affiliation: Department of Radiation Oncology, Gustave Roussy Cancer Campus, Villejuif, France.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Gilmore
authors.affiliation: Department of Medical Physics, Gustave Roussy Cancer Campus, Villejuif, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Dumas
authors.affiliation: Department of Radiation Oncology, Gustave Roussy Cancer Campus, Villejuif, France.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Goulart
authors.affiliation: Department of Radiation Oncology, Gustave Roussy Cancer Campus, Villejuif, France.
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Oberlander
authors.affiliation: Department of Radiation Oncology, Gustave Roussy Cancer Campus, Villejuif, France.
authors.forename: Eleonor
authors.initials: E
authors.lastname: Rivin del Campo
authors.affiliation: Laboratory of Molecular Radiotherapy, UMR1030, Gustave Roussy Cancer Campus, Villejuif, France; Radiation Epidemiology Group - INSERM U1018, Gustave Roussy Cancer Campus, Villejuif, France.
authors.forename: Ibrahima
authors.initials: I
authors.lastname: Diallo
authors.affiliation: Laboratory of Molecular Radiotherapy, UMR1030, Gustave Roussy Cancer Campus, Villejuif, France; Department of Medical Physics, Gustave Roussy Cancer Campus, Villejuif, France.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Lefkopoulos
authors.affiliation: Department of Radiation Oncology, Gustave Roussy Cancer Campus, Villejuif, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Haie-Meder
mesh_terms: D001918:Brachytherapy / Q000379:methods*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058958:Organs at Risk / Q000528:radiation effects; D011446:Prospective Studies; D011880:Radiotherapy Planning, Computer-Assisted; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis / Q000532:radiotherapy*
keywords: Cervical cancer; Image-guided adaptive brachytherapy; Movements; Organs at risk; Uncertainty