title: In vivo diode dosimetry vs. computerized tomography and digitally reconstructed radiographs for critical organ dose calculation in high-dose-rate brachytherapy of cervical cancer.
abstract: OBJECTIVE
  To investigate the correlation between the dose predicted by the treatment planning system using digitally reconstructed radiographs or three-dimensional (3D)-reconstructed CT images and the dose measured by semiconductor detectors, under clinical conditions of high-dose-rate brachytherapy of the cervix uteri.
  
  
  METHODS
  Thirty-two intracavitary brachytherapy applications were performed for 12 patients with cancer of the cervix uteri. The prescribed dose to Point A was 7 Gy. Dose was calculated for both International Commissioning on Radiation Units and Measurements (ICRU) bladder and rectal points based on digitally reconstructed radiographs and for 3D CT images-based volumetric calculation of the bladder and rectum. In vivo diode dosimetry was performed for the bladder and rectum.
  
  
  RESULTS
  The ICRU reference point and the volumes of 1, 2, and 5cm(3) received 3.6±0.9, 5.6±2.0, 5.1±1.7, 4.3±1.4 and 5.0±1.2, 5.3±1.3, 4.9±1.1, and 4.2±0.9 Gy for the bladder and rectum, respectively. The ratio of the 1cm(3) and the ICRU reference point dose to the diode dose was 1.8±0.7 and 1.2±0.5 for the bladder and 1.9±0.6 and 1.7±0.5 for the rectum, respectively.
  
  
  CONCLUSIONS
  3D image-based dose calculation is the most accurate and reliable method to evaluate the dose given to critical organs. In vivo diode dosimetry is an important method of quality assurance, but clinical decisions should be made based on 3D-reconstructed CT image calculations.
authors.affiliation: Department of Oncology, King Faisal Specialist Hospital & Research Center, Jeddah, Saudi Arabia. ashrafhassouna@hotmail.com
authors.forename: Ashraf H
authors.initials: AH
authors.lastname: Hassouna
authors.forename: Yasir A
authors.initials: YA
authors.lastname: Bahadur
authors.forename: Camelia
authors.initials: C
authors.lastname: Constantinescu
authors.forename: Mohamed E
authors.initials: ME
authors.lastname: El Sayed
authors.forename: Hussain
authors.initials: H
authors.lastname: Naseem
authors.forename: Adly F
authors.initials: AF
authors.lastname: Naga
mesh_terms: D001918:Brachytherapy / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D009929:Organ Size; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D012007:Rectum / Q000000981:diagnostic imaging / Q000473:pathology; D012666:Semiconductors; D014057:Tomography, X-Ray Computed; D001743:Urinary Bladder / Q000000981:diagnostic imaging / Q000473:pathology; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy*