Journal of Medical Physics
ORIGINAL ARTICLE
Year
: 2014  |  Volume : 39  |  Issue : 1  |  Page : 4--9

Monte Carlo-based revised values of dose rate constants at discrete photon energies


T Palani Selvam, Vandana Shrivastava, Ghanashyam Chourasiya, D. Appala Raju Babu 
 Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Health Safety and Environmental Group, Anushakti Nagar, Mumbai, Maharashtra, India

Correspondence Address:
Vandana Shrivastava
Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, CT and CRS Building, Anushakti Nagar 400 094, Mumbai, Maharashtra
India

Absorbed dose rate to water at 0.2 cm and 1 cm due to a point isotropic photon source as a function of photon energy is calculated using the EDKnrc user-code of the EGSnrc Monte Carlo system. This code system utilized widely used XCOM photon cross-section dataset for the calculation of absorbed dose to water. Using the above dose rates, dose rate constants are calculated. Air-kerma strength S k needed for deriving dose rate constant is based on the mass-energy absorption coefficient compilations of Hubbell and Seltzer published in the year 1995. A comparison of absorbed dose rates in water at the above distances to the published values reflects the differences in photon cross-section dataset in the low-energy region (difference is up to 2% in dose rate values at 1 cm in the energy range 30-50 keV and up to 4% at 0.2 cm at 30 keV). A maximum difference of about 8% is observed in the dose rate value at 0.2 cm at 1.75 MeV when compared to the published value. S k calculations based on the compilation of Hubbell and Seltzer show a difference of up to 2.5% in the low-energy region (20-50 keV) when compared to the published values. The deviations observed in the values of dose rate and S k affect the values of dose rate constants up to 3%.


How to cite this article:
Selvam T P, Shrivastava V, Chourasiya G, Babu DR. Monte Carlo-based revised values of dose rate constants at discrete photon energies.J Med Phys 2014;39:4-9


How to cite this URL:
Selvam T P, Shrivastava V, Chourasiya G, Babu DR. Monte Carlo-based revised values of dose rate constants at discrete photon energies. J Med Phys [serial online] 2014 [cited 2019 Jul 21 ];39:4-9
Available from: http://www.jmp.org.in/article.asp?issn=0971-6203;year=2014;volume=39;issue=1;spage=4;epage=9;aulast=Selvam;type=0