Assessing radiological properties of novel tissue equivalent materials for heterogeneous pediatric head phantom: Experimental insights and Monte Carlo simulations

Abstract

This study addresses the need for realistic substitute materials in pediatric head CT to enhance imaging safety. Epoxy resin-based composites were developed to mimic cranial bone, brain tissue, cerebrospinal fluid and eye lens. Radiological properties were validated using Monte Carlo simulations and XMuDat software, with CT numbers measured on a 64-detector CT scanner at 80, 100, and 120 kVp. A comparison was applied against standard tissues from the International Commission on Radiation Units and Measurements (ICRU). For cranial bone, a composite of 70 % epoxy resin and 30 % calcium carbonate achieved a density of 1.65 g/cm³ and Z_eff = 11.02, with deviations in mass attenuation coefficients from ICRU standard ranging from 17.4 % at 40 keV to 1.2 % at 150 keV. Brain matter (95 % resin, 5 % acetone) achieved Z_eff = 6.19, with deviations from the ICRU standard ranging from 13.7 % to 5.5 %. CSF (80 % resin, 15 % silica, 5 % acetone) closely matched water, with deviations from the water standard ranging from 3.4 % to 1.1 %. Eye lens (95 % resin, 5 % sodium bicarbonate) achieved Z_eff = 6.47, with deviations from ICRU standard ranging from 7.5 % to 4.2 %. These results demonstrate the potential of epoxy resin-based substitutes to approximate ICRU standard tissues supporting safer pediatric radiology protocols customized to this sensitive population.