title: Effect of Gold Nanoparticle on Percentage Depth Dose Enhancement On Megavoltage Energy in MAGICA Polymer Gel Dosimeter.
abstract: BACKGROUND
  Radiation-sensitive polymer gels are among the most promising three-dimensional dose verification tools and tissue-like phantom developed to date.
  
  
  OBJECTIVE
  The aim of this study is an investigating of percentage depth dose enhancement within the gel medium with used of conformal distribution gold nanoparticle as contrast agents by high atomic number material.
  
  
  METHODS
  In this work the normoxic polymer gel dosimeter MAGICA tissue-equivalence was first theoretically verified using MCNPX Monte Carlo code and experimentally by percentage depth dose curves within the gel medium. Then gold nanoparticles (GNPs) of 50nm diameter with different concentrations of 0.1mM, 0.2mM, and 0.4mM were embedded in MAGICA gel and irradiated by 18MV photon beam.
  
  
  RESULTS
  Experimental results have shown dose increase of 10%, 2% and 4%   in 0.1mM, 0.2mM and 0.4mM concentrations, respectively. Simulation results had good agreement in the optimum concentration of 0.1mM. The largest error between experimental and simulation results was equal to 9.28% stood for 0.4mM concentration.
  
  
  CONCLUSIONS
  The results showed that the optimum concentration of gold nanoparticles to achieve maximum absorbed dose in both experimental and simulation was 0.1 mM and so it can be used for clinical studies.
authors.affiliation: Physics Department, Mazandaran University, Babolsar, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Mahdavi
authors.affiliation: Physics Department, Mazandaran University, Babolsar, Iran ; Para Medical Department, Babol University of Medical Sciences, Babol, Iran.
authors.forename: M
authors.initials: M
authors.lastname: KhademAbolfazli
authors.affiliation: Medical Physics Department, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: S-R-M
authors.initials: SR
authors.lastname: Mahdavi
authors.affiliation: Para Medical Department, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Gh
authors.initials: G
authors.lastname: Ataei
keywords: Gold nanoparticles; Percentage depth dose; Polymer gel dosimeter