TY - JOUR
A1 - Selvam, T
A1 - Shrivastava, Vandana
A1 - Chourasiya, Ghanashyam
A1 - Babu, D. Appala
T1 - Monte Carlo-based revised values of dose rate constants at discrete photon energies
Y1 - 2014/1/1
JF - Journal of Medical Physics
JO - J Med Phys
SP - 4
EP - 9
VL - 39
IS - 1
UR - http://www.jmp.org.in/article.asp?issn=0971-6203;year=2014;volume=39;issue=1;spage=4;epage=9;aulast=Selvam
DO - 10.4103/0971-6203.125473
N2 - 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%.
ER -