title: Dose perturbation due to catheter materials in high-dose-rate interstitial (192)Ir brachytherapy.
abstract: OBJECTIVE
  Catheters made of either metal or plastic are currently used in brachytherapy treatment to insert radiative sources into patients. However, the radiation dose perturbations due to catheter attenuation are not taken into account in treatment planning. The purpose of this work is to quantify the effects of catheter composition on dose distribution and study their impacts on the overall treatment with high-dose-rate (192)Ir sources.
  
  
  METHODS
  Dose perturbations are first studied in a simplified case consisting of two parallel catheters. The catheter wall is either composed of stainless steel or polyoxymethylene. The attenuations are studied as the distance between the two catheters is varied from 5 to 30 mm. Dose perturbations resulting from irradiation are evaluated with a Monte Carlo GEANT4 dose calculation algorithm. The dose differences are further investigated with seven typical high-dose-rate prostate treatment plans involving 17 catheters.
  
  
  RESULTS
  The dose differences compared with water in the simplified case reach -4.3 ± 0.1% for stainless steel and 1.7 ± 0.5% for polyoxymethylene at 10 mm above the source when the catheters are separated by a distance of 5 mm. Dose perturbations are reduced in real treatment plans because of the contributions of the many dwell positions. Stainless steel and polyoxymethylene catheters induce on an average a dose difference of -1.3 ± 0.3% and 0.1 ± 0.2%, respectively in the target.
  
  
  CONCLUSIONS
  The dose differences reported in this work do not warrant any changes in the clinical procedures.
authors.affiliation: Département de Radio-oncologie et Centre de recherche du CHU de Québec, CHU de Québec, Québec, Canada; Département de physique, de génie physique et d'optique, et Centre de recherche sur le cancer de l'Université Laval, Université Laval, Québec, Canada; Department of Radiation Oncology (MAASTRO), GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Gaudreault
authors.affiliation: Department of Radiation Oncology (MAASTRO), GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Reniers
authors.affiliation: Department of Radiation Oncology (MAASTRO), GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands; Faculty of Physics, Department of Medical Physics, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Landry
authors.affiliation: Department of Radiation Oncology (MAASTRO), GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands; Medical Physics Unit, McGill University Health Centre and Department of Oncology, McGill University, Montréal, Québec, Canada.
authors.forename: Frank
authors.initials: F
authors.lastname: Verhaegen
authors.affiliation: Département de Radio-oncologie et Centre de recherche du CHU de Québec, CHU de Québec, Québec, Canada; Département de physique, de génie physique et d'optique, et Centre de recherche sur le cancer de l'Université Laval, Université Laval, Québec, Canada. Electronic address: beaulieu@phy.ulaval.ca.
authors.forename: Luc
authors.initials: L
authors.lastname: Beaulieu
mesh_terms: D000465:Algorithms; D001918:Brachytherapy / Q000379:methods*; D057785:Catheters; D004867:Equipment Design; D006801:Humans; D008297:Male; D009010:Monte Carlo Method; D011467:Prostate; D011829:Radiation Dosage; D011879:Radiotherapy Dosage; D012117:Resins, Synthetic; D013193:Stainless Steel
chemical_list: D012117:Resins, Synthetic; D013193:Stainless Steel; C010102:delrin
keywords: Catheters composition; Dose perturbations; HDR brachytherapy