A study of effective atomic number and electron density of gel dosimeters and human tissues for scattering of gamma rays: momentum transfer, energy and scattering angle dependence

摘要

The objective of this work was to study water- and tissue-equivalent properties of some gel dosimeters, human tissues and water, for scattering of photons using the effective atomic number (Z (eff)). The Rayleigh to Compton scattering ratio (R/C) was used to obtain Z (eff) and electron density (N (e) ) of gel dosimeters, human tissues and water considering a 10(-2)-10(9) momentum transfer, q ((-1)). In the present work, a logarithmic interpolation procedure was used to estimate R/C as well as Z (eff) of the chosen materials in a wide scattering angle (1A degrees-180A degrees) and energy range (0.001-100 MeV). The Z (eff) of the chosen materials was found to increase as momentum transfer increases, for q > similar to 1 (-1). At fixed scattering angle and energy, Z (eff) of the material first increases and then becomes constant for high momentum transfers (q aeyen 3 (-1)), which indicates that Z (eff) is almost independent of energy and scattering angle for the chosen materials. Based on the Z (eff) data and the continuous momentum transfer range (10(-2)-10(9) (-1)), MAGIC, PAGAT and soft tissue were found to be water-equivalent materials, since their differences (%) relative to water are significantly low (aecurrency sign3.2 % for MAGIC up to 10(3) (-1), aecurrency sign2.9 % for PAGAT up to 10(9) (-1), and aecurrency sign3.8 % for soft tissue up to 10(9) (-1)), while the Fricke gel was not found to be water equivalent. PAGAT was found to be a soft tissue-equivalent material in the entire momentum transfer range (< 4.3 %), while MAGAT has shown to be tissue equivalent for brain (aecurrency sign8.1 % up to 10 (-1)) and lung (< 8.2 % up to 10 (-1)) tissues. The Fricke gel dosimeter has shown to be adipose tissue equivalent for most of the momentum range considered (< 10 %).