title: Inter-application displacement of brachytherapy dose received by the bladder and rectum of the patients with inoperable cervical cancer.
abstract: BACKGROUND
  The aim of the study was to examine on the CT basis the inter-application displacement of the positions D0.1cc, D1cc and D2cc of the brachytherapy dose applied to the bladder and rectum of the patients with inoperable cervical cancer.
  
  
  METHODS
  This prospective study included 30 patients with cervical cancer who were treated by concomitant chemo-radiotherapy. HDR intracavitary brachytherapy was made by the applicators type Fletcher tandem and ovoids. For each brachytherapy application the position D0.1cc was determined of the bladder and rectum that receive a brachytherapty dose. Then, based on the X, Y, and Z axis displacement, inter-application mean X, Y, and Z axis displacements were calculated as well as their displacement vectors (R). It has been analyzed whether there is statistically significant difference in inter-application displacement of the position of the brachytherapy dose D0.1cc, D1cc and D2cc of the bladder and rectum. The ANOVA test and post-hoc analysis by Tukey method were used for testing statistical importance of differences among the groups analyzed. The difference among the groups analyzed was considered significant if p < 0.05.
  
  
  RESULTS
  There are significant inter-application displacements of the position of the brachytherapy dose D0,1cc, D1cc and D2cc of the bladder and rectum.
  
  
  CONCLUSIONS
  When we calculate the cumulative brachytherapy dose by summing up D0,1cc, D1cc and D2cc of the organs at risk for all the applications, we must bear in mind their inter-application displacement, and the fact that it is less likely that the worst scenario would indeed happen.
authors.affiliation: Centre for Radiotherapy, International Medical Centre Banja Luka, Banja Luka, Bosnia and Herzegovina.
authors.forename: Goran
authors.initials: G
authors.lastname: Marosevic
authors.affiliation: Gynaecology and Obstetrics Clinic, University Clinical Centre Tuzla, Tuzla, Bosnia and Herzegovina.
authors.forename: Dzenita
authors.initials: D
authors.lastname: Ljuca
authors.affiliation: Department for Radiotherapy, University Clinical Centre Tuzla, Tuzla, Bosnia and Herzegovina.
authors.forename: Hasan
authors.initials: H
authors.lastname: Osmic
authors.affiliation: Department for Radiotherapy, University Clinical Centre Tuzla, Tuzla, Bosnia and Herzegovina.
authors.forename: Semir
authors.initials: S
authors.lastname: Fazlic
authors.affiliation: Centre for Radiotherapy, International Medical Centre Banja Luka, Banja Luka, Bosnia and Herzegovina.
authors.forename: Oliver
authors.initials: O
authors.lastname: Arsovski
authors.affiliation: Centre for Radiotherapy, International Medical Centre Banja Luka, Banja Luka, Bosnia and Herzegovina.
authors.forename: Dusan
authors.initials: D
authors.lastname: Mileusnic
keywords: brachytherapy; inoperable cervical cancer; inter-application variations