Conversion coefficients from fluence and air kerma to personal dose equivalent for monoenergetic photons using analytical fit and Monte Carlo simulation

Abstract

The present study aims to calculate a new database of conversion coefficients from fluence and air Kerma to personal dose equivalent in two terms: absorbed dose and Kerma-approximations. In this work, we propose a new equation to perform an analytical fit of our Monte Carlo (MC) calculated conversion coefficients for photons for different angles. Also, we have calculated the conversion coefficients using the EGSnrc code. The conversion coefficients have been calculated for beams of monoenergetic photons from 0.015 to 10 MeV, incident on phantom ICRU for angles of incidence from 0° to a 75° in steps of 15°. Our computed values agree well when compared with those published for the ICRU 57 in Kerma-approximations with statistical uncertainties in the calculation around 2%. We can conclude from this work that the analytical approach is successful and powerful such as Monte Carlo methods to calculate the operational quantities.

Radiation Safety Assessment in Prostate Cancer Treatment: A Predictive Approach for I-125 Brachytherapy

“…Therefore, the external radiation dose rate is positively correlated with the sum of the source activities of the implanted radioactive nuclei and negatively correlated with the implantation depth of the radioactive source. In the predictive model, we must consider the initial dose rate of I-125 implantation [initial dose rate (D 0 ) in water = S k •Λ] [16][17][18][19][20] and the air-kerma strength and H*(10) conversion factor [21][22][23][24][25][26]. The equations for this are as follows:…”

“…where S k is the total air-kerma strength of all sources implanted; Λ is the dose rate constant, which is the dose rate of the unit air-kerma strength source on the horizontal axis 1 cm away from the water in the water phantom; and CF is the conversion factor that converts air-kerma strength into ambient dose rate equivalent H*(10) (Sv/Gy) [21][22][23][24][25][26]. The average energy of the I-125 source used in this study was 27.4 keV, and the dose rate conversion factor for the external photon air exposure dose rate was calculated from the ICRP-74 (ICRP, 1997) [14].…”

Physician scatter dose in interventional CT fluoroscopy

“… 28 and MDCT reported by Berg, 29 and (c) the analytical function relating Hp to surface air kerma for c‐arm procedures published by Kanti et al. 30 (Hp/Ka = 1.62, 1.52, and 1.71 for Hp(0.07), Hp(3) and Hp(10) respectively for thorax level, and Hp/Ka = 1.67, 1.56, and 1.80 respectively for eyes level) and for MDCT published by Kanti et al. 30 and Berg 29 (Hp/Ka = 1.55, 1.46, and 1.59 for Hp(0.07), Hp(3), and Hp(10) respectively for 120 kV and eye level).…”

“… 30 (Hp/Ka = 1.62, 1.52, and 1.71 for Hp(0.07), Hp(3) and Hp(10) respectively for thorax level, and Hp/Ka = 1.67, 1.56, and 1.80 respectively for eyes level) and for MDCT published by Kanti et al. 30 and Berg 29 (Hp/Ka = 1.55, 1.46, and 1.59 for Hp(0.07), Hp(3), and Hp(10) respectively for 120 kV and eye level). The surface air Kerma rate was obtained by dividing the total surface air kerma by the mean fluoroscopy time.…”

Neutron conversion coefficients of ambient dose equivalent and personal dose equivalent

“…So, the operational quantities seek to provide a reasonable estimate of the protection quantities. [4][5][6][7][8][9][10] The equivalent dose in the tissue or an organ, H, have given by: 𝐻 = ∑ 𝑤 𝑅 𝐷 𝑇,𝑅 𝑅 Eq .1 Where: DT,R is the main absorbed dose in the specified tissue or organ T from the radiation of type R. wR is the radiation weight factor for neutron given by Equation 2. 11 𝑤 𝑅 = , 𝐸 𝑛 > 50𝑀𝑒𝑉 )…”