title: Dosimetric analysis of rectal filling on rectal doses during vaginal cuff brachytherapy.
abstract: OBJECTIVE
  Several studies have analyzed the effect of bladder filling during vaginal cuff brachytherapy (VCB), but the effect of rectum filling has not been studied. We sought to evaluate the effects of rectal volume on rectal doses during postoperative VCB.
  
  
  METHODS
  Brachytherapy planning CT scans (334 sets) obtained from 92 consecutive patients treated with VCB were resegmented (bladder and rectum) and replanned retrospectively using the same parameters to homogenize data and improve analysis. Rectal volume and a set of values derived from dose-volume histograms (DVHs) were extracted (maximal dose [Dmax], D0.1cc, D1cc, and D2cc). Univariate and multivariate analyses were carried out to evaluate the association between rectal volume and DVH metrics after adjusting for other clinical factors.
  
  
  RESULTS
  A positive significant correlation was observed between rectal volume correlated and Dmax, D0.1cc, D1cc, and D2cc. Multiple linear regression models found that rectal volume, cylinder angle position, and cylinder diameter variables correlated significantly with the different DVH parameters analyzed. These variables explained the 14.5% and 18% of variance on regression models.
  
  
  CONCLUSIONS
  Larger rectal volumes are associated with higher rectal dose parameters during VCB fractions. Prospective studies are needed to investigate whether these data are linked to differences in rectal toxicity.
authors.affiliation: Department of Radiation Oncology, Complejo Hospitalario Universitario de Albacete (CHUA), Albacete, Spain. Electronic address: ssabaterm@gmail.com.
authors.forename: Sebastia
authors.initials: S
authors.lastname: Sabater
authors.affiliation: Department of Radiation Oncology, Hospital Universitari Sant Joan, Reus, Spain.
authors.forename: Meritxell
authors.initials: M
authors.lastname: Arenas
authors.affiliation: Department of Radiation Oncology, Complejo Hospitalario Universitario de Albacete (CHUA), Albacete, Spain.
authors.forename: Roberto
authors.initials: R
authors.lastname: Berenguer
authors.affiliation: C.S. General Ricardos, Area 11, Madrid, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Machin-Hamalainen
authors.affiliation: Department of Radiation Oncology, Complejo Hospitalario Universitario de Albacete (CHUA), Albacete, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Andres
authors.affiliation: Department of Radiation Oncology, Complejo Hospitalario Universitario de Albacete (CHUA), Albacete, Spain.
authors.forename: Ma Mar
authors.initials: MM
authors.lastname: Sevillano
authors.affiliation: Department of Radiation Oncology, Hospital Son Espases, Palma de Mallorca, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Jimenez-Jimenez
authors.affiliation: Department of Radiation Oncology, Hospital Central de Asturias, Oviedo, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Martos
authors.affiliation: Department of Radiation Oncology, Complejo Hospitalario Universitario de Albacete (CHUA), Albacete, Spain.
authors.forename: Veronica
authors.initials: V
authors.lastname: Lopez-Honrubia
authors.affiliation: Department of Radiation Oncology, Complejo Hospitalario Universitario de Albacete (CHUA), Albacete, Spain.
authors.forename: Jesus
authors.initials: J
authors.lastname: Fernandez-Lopez
mesh_terms: D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000379:methods*; D016889:Endometrial Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy* / Q000601:surgery; D005260:Female; D006801:Humans; D007044:Hysterectomy; D008875:Middle Aged; D009929:Organ Size; D058958:Organs at Risk / Q000503:physiopathology / Q000528:radiation effects; D011446:Prospective Studies; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant / Q000379:methods; D012007:Rectum / Q000473:pathology / Q000503:physiopathology / Q000528:radiation effects*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: Brachytherapy; Dilatation; Dose–volume histogram; Endometrial neoplasms; Rectum