title: Assessment of ovarian movement on consecutive pelvic MRI examinations in patients with gynaecological malignancies: what is the planning organ-at-risk volume for radiotherapy?
abstract: OBJECTIVE
  The aims of this study are to assess the extent of ovarian movement on consecutive MRI examinations in patients with gynaecological malignancies and to define potential safety volumes around the ovaries that may avoid ovarian ablation during pelvic irradiation.
  
  
  METHODS
  Patients with cervical, vaginal and endometrial cancer who underwent MRI examinations of the pelvis before and during radiotherapy were included in the study. The position of the ovaries was retrospectively determined on two consecutive axial and sagittal T(2) weighted MRI examinations of the pelvis. Ovarian movement was determined in craniocaudal, anteroposterior and mediolateral directions. Safety volumes were calculated by computing elliptical volumes based on the derived 95% and 99% reference intervals.
  
  
  RESULTS
  30 patients with a gynaecological malignancy were included. Both ovaries could be identified on the MRI examinations in all cases. The safety volumes around the ovaries encompassing 95% and 99% of ovarian movement were 11 and 25 cm(3) (95%), and 24 and 54 cm(3) (99%), for the left and right ovary, respectively.
  
  
  CONCLUSIONS
  Adding a safety volume around the ovaries may reduce the high radiation dose to the ovaries. This could potentially avoid ovarian ablation, reducing significant fertility morbidity.
authors.affiliation: Department of Radiology, Addenbrooke's Hospital and University of Cambridge, Cambridge, UK. nickypeters@gmail.com
authors.forename: N H G M
authors.initials: NH
authors.lastname: Peters
authors.forename: A J
authors.initials: AJ
authors.lastname: Patterson
authors.forename: G
authors.initials: G
authors.lastname: Horan
authors.forename: D
authors.initials: D
authors.lastname: Gregory
authors.forename: E
authors.initials: E
authors.lastname: Sala
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D009068:Movement; D058958:Organs at Risk / Q000033:anatomy & histology* / Q000528:radiation effects; D010053:Ovary / Q000033:anatomy & histology* / Q000528:radiation effects; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D012016:Reference Values; D014594:Uterine Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D014625:Vaginal Neoplasms / Q000473:pathology / Q000532:radiotherapy*