Comparative analysis of the transmission properties of tissue equivalent materials

Abstract

Phantom objects have as main requirement to have the effective atomic number and linear attenuation coefficient approximately equal to the human tissue to be simulated. The present work aims to characterize samples of materials radiologically equivalent to water for dose studies in patients in the diagnostic energy range. Water was chosen as reference material representing human tissue, which is composed mostly of it. A set of samples was formulated and submitted to radiation transmission tests in four different values of tension applied to an Xray tube. Mass densities of the samples were evaluated using the Arquimedes method. The samples were identified as A, B, C and D. By transmission curves, it was possible to estimate the samples transmission factors corresponding to the water transmission factor for different thicknesses. Moreover, the thicknesses of samples equivalent to water thickness for different values of transmission factor were also evaluated. All the samples densities were bigger than the density of water. For the same thickness of water and the samples, the radiation transmission of the developed materials are in better agreement for thicknesses of 10mm and 30 mm. The lowest percentage difference between the water transmission and the transmission of any of the samples obtained was approximately 0.6% for the sample A in the thickness of 30mm under voltage of 60 kV. The correspondence between the transmission factors and the thicknesses showed that the compounds studied in this work are potential materials to develop phantoms that simulate the transmission properties of human tissue.