Determination of Dosimetric Parameters of the Second Model of Pd-103 Seed Manufactured at Agricultural, Medical and Industrial Research School

Document Type: Original Paper

Authors

1 Associate Professor, Radiation Application Research School, Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran, Tehran, Iran

2 Assistant Professor, Agricultural, Medical and Industrial Research School, Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran, Karaj, Iran

3 M. Sc. in Medical Applications of Radiation, Nuclear Engineering Dept, Faculty of Engineering, Science and Research Unit, Islamic Azad University, Tehran, Iran

4 B. Sc. in Physics, Agricultural, Medical and Industrial Research School, Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran, Karaj, Iran

5 M. Sc. in Medical Physics, Medical Physics Dept., Faculty of Medical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran

Abstract

Introduction: The use of low energy isotopes such as  103 Pd in brachytherapy for the treatment of cancers 
such as prostate, eye, head, neck, breast and cervix is increasing. In this regard, different models of Pd-
103  seeds  have  been  designed  and  manufactured  at  the  Agricultural,  Medical  and  Industrial  Research 
School (AMIRS) of Atomic Energy Organization of Iran. In this research, the dosimetric parameters of 
the second model of Pd-103 seed manufactured at AMIRS have been calculated and measured.  
Materials and Methods: The dosimetric parameters of the second Pd-103 seed manufactured at AMIRS 
were determined according to TG-43U1 protocol using Monte Carlo calculations (MCNP4C computer 
code)  and  measurements  performed  using  TLD-GR200A  dosimeters  in  a  Perspex  phantom.  The 
parameters  include  dose  rate  constant,  geometry  function,  radial  dose  function,  anisotropy  function, 
anisotropy factor and anisotropy constant. 
Results:  It  was  found  that  by  using  MCNP4C  code  the  calculated  dose  rate  constant  in  water  and 
Perspex  was  0.706±0.001   and  0.501±0.001  cGyh -1 U -1 , respectively.  Using  the  calculated  geometry 
function,  the  radial  dose  function  and  the  anisotropy  function  were  determined  by  experimental  and 
theoretical methods in water and Perspex phantom. Also, the calculated value of anisotropy constant in 
water was equal to 0.88. 
Discussion and Conclusion: A discrepancy of less than 10% between the calculated and the measured 
values indicates a reasonable agreement between the simulation and the measurement method. Also, the 
dosimetric parameters of this seed have been compared to the dosimetric parameters of the first Pd-103 
seed  manufactured  at  AMIRS  and  some  other  seeds.  The  obtained  results  indicate  that  the  seeds 
manufactured at AMIRS have acceptable dosimetric parameters suitable for brachytherapy applications. 
 

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