title: Rectal contrast increases rectal dose during vaginal cuff brachytherapy.
abstract: OBJECTIVE
  To evaluate the impact of rectal dose on rectal contrast use during vaginal cuff brachytherapy (VCB).
  
  
  METHODS
  A retrospective review of gynecology patients who received some brachytherapy fractions with and without rectal contrast was carried out. Rectal contrast was instilled at the clinician's discretion to increase rectal visibility. Thirty-six pairs of CT scans in preparation for brachytherapy were analyzed. Pairs of CTs were segmented and planned using the same parameters. The rectum was always defined from 1 cm above the cylinder tip up to 1.5 cm below the last activated dwell source position. An individual plan was computed at every VCB fraction. A set of values (Dmax, D(0.1cc), D(1cc), and D(2cc)) derived from dose-volume histograms were extracted and compared according to the rectal status.
  
  
  RESULTS
  Rectal volume was 26.7% larger in the fractions with rectal contrast. Such an increase in volume represented a significant increase from 7.7% to 10.4% in all parameters analyzed except Dmax dose-volume histogram.
  
  
  CONCLUSIONS
  Avoiding rectal contrast is a simple way of decreasing the rectal dose parameters of VCB, which would mean a better therapeutic ratio. Results also suggest that action directed at maintaining the rectum empty might have the same effect.
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, Complejo Hospitalario Universitario de Albacete (CHUA), Albacete, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Andres
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, Complejo Hospitalario Universitario de Albacete (CHUA), Albacete, Spain.
authors.forename: Roberto
authors.initials: R
authors.lastname: Berenguer
authors.affiliation: Department of Radiation Oncology, Complejo Hospitalario Universitario de Albacete (CHUA), Albacete, Spain.
authors.forename: Marimar
authors.initials: M
authors.lastname: Sevillano
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: Gynecological Cancer Unit, Radiation Oncology Department, ICMHO, Hospital Clinic, University of Barcelona, IDIBAPS, Barcelona, Spain.
authors.forename: Angeles
authors.initials: A
authors.lastname: Rovirosa
authors.affiliation: Unidad de Medicina Molecular, Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Albacete, Spain; Unidad asociada de Biomedicina, UCLM-CSIC, Albacete, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Sanchez-Prieto
authors.affiliation: Department of Radiation Oncology, Hospital Universitari Sant Joan, Reus, Spain.
authors.forename: Meritxell
authors.initials: M
authors.lastname: Arenas
mesh_terms: D001918:Brachytherapy; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D005833:Genital Neoplasms, Female / Q000532:radiotherapy* / Q000601:surgery; D006801:Humans; D058958:Organs at Risk / Q000000981:diagnostic imaging*; D011829:Radiation Dosage; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D018714:Radiotherapy, Adjuvant; D012007:Rectum / Q000000981:diagnostic imaging* / Q000528:radiation effects; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods; D014621:Vagina
chemical_list: D003287:Contrast Media
keywords: Dose-volume histogram; Endometrial cancer; Rectal contrast; Vaginal cuff brachytherapy