Comparative evaluation of transmission properties of water-equivalent materials

Tissue equivalent materials, or phantoms, have as their main performance requirement the effective atomic number and/or its linear attenuation coefficient equal to the material to be simulated. The present work presents an initial phase of characterization of samples of water-equivalent materials. A set of samples was produced and submitted to tests of radiation transmission and evaluation of their mass density. Their properties were compared to water at different applied voltages. The transmission curves were estimated as thicknesses that correspond to approximately the water thickness for different values of the transmission factor under four different voltages. It was noted that the densities of all samples are larger than that of water. Systematically are needed thicknesses of the samples slightly smaller then of the water for the representation of the same transmission factor. (author)