title: A retrospective analysis of rectal and bladder dose for gynecological brachytherapy treatments with GZP6 HDR afterloading system.
abstract: OBJECTIVE
  The aim of this work is to evaluate rectal and bladder dose for the patients treated for gynecological cancers.
  
  
  BACKGROUND
  The GZP6 high dose rate brachytherapy system has been recently introduced to a number of radiation therapy departments in Iran, for treatment of various tumor sites such as cervix and vagina.
  
  
  METHODS
  Our analysis was based on dose measurements for 40 insertions in 28 patients, treated by a GZP6 unit between June 2009 and November 2010. Treatments consisted of combined teletherapy and intracavitary brachytherapy. In vivo dosimetry was performed with TLD-400 chips and TLD-100 microcubes in the rectum and bladder.
  
  
  RESULTS
  The average of maximum rectal and bladder dose values were found to be 7.62 Gy (range 1.72-18.55 Gy) and 5.17 Gy (range 0.72-15.85 Gy), respectively. It has been recommended by the ICRU that the maximum dose to the rectum and bladder in intracavitary treatment of vaginal or cervical cancer should be lower than 80% of the prescribed dose to point A in the Manchester system. In this study, of the total number of 40 insertions, maximum rectal dose in 29 insertions (72.5% of treatment sessions) and maximum bladder dose in 18 insertions (45% of treatments sessions) were higher than 80% of the prescribed dose to the point of dose prescription.
  
  
  CONCLUSIONS
  In vivo dosimetry for patients undergoing treatment by GZP6 brachytherapy system can be used for evaluation of the quality of brachytherapy treatments by this system. This information could be used as a base for developing the strategy for treatment of patients treated with GZP6 system.
authors.affiliation: Medical Physics Research Center, Faculty of Medicine, Pardise Daneshgah, Mashhad University of Medical Sciences, Azadi Square, Mashhad, Iran.
authors.forename: Mohammad Taghi
authors.initials: MT
authors.lastname: Bahreyni Toossi
authors.affiliation: North Khorasan University of Medical Sciences, Bojnurd, Iran.
authors.forename: Mahdi
authors.initials: M
authors.lastname: Ghorbani
authors.affiliation: Cancer Research Center, Radiation Oncology Department, Omid Hospital, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Yasha
authors.initials: Y
authors.lastname: Makhdoumi
authors.affiliation: Reza Radiotherapy and Oncology Center, Fallahi No. 2, Mashhad, Iran.
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Taheri
authors.affiliation: Cancer Research Center, Radiation Oncology Department, Omid Hospital, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Homaee Shandiz
authors.affiliation: Cancer Research Center, Radiation Oncology Department, Omid Hospital, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Siavash
authors.initials: S
authors.lastname: Zahed Anaraki
authors.affiliation: Comprehensive Cancer Center of Nevada, Las Vegas, NV, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Soleimani Meigooni
keywords: Bladder dose; Brachytherapy; GZP6 afterloading unit; Rectal dose