Fabrication of new non-hazardous tungsten carbide epoxy resin bricks for low energy gamma shielding in nuclear medicine

Introduction. The main aim of this study was to fabricate a lead-free tungsten carbide epoxy resin brick that has similar shielding properties to lead brick for low energy gamma shielding in nuclear medicine. The attenuation properties of bricks were characterized by using gamma transmission principle in Single-Photon Emission Computed Tomography (SPECT) scanner. Materials and methods. In this study, various percentage of tungsten carbide epoxy resin were fabricated into brick with thickness of 0.5 cm, 1.0 cm, 1.5 cm and 2.0 cm. Tungsten carbide epoxy resin and lead bricks were irradiated with gamma rays from 99mTc to evaluate the radiation attenuation properties. A detector was used to evaluate the gamma shielding performance at 140 keV. The activity of the radioactive source was measured and recorded. The radiation attenuation of tungsten carbide epoxy resin bricks was compared with lead brick of same size and thickness. The gamma transmission was evaluated by using SPECT. Results. Results showed that tungsten carbide epoxy resin brick attenuates more radiation than a lead brick of the same thickness. This study also found that tungsten carbide epoxy resin brick is an effective radiation shielding material compared to lead. The best tungsten carbide and epoxy resin combination was found with a mixture of 90%:10% by weight, respectively. The study showed that both half-value layer and mean free path are higher at thicker samples for all materials at 140 keV. This study found that tungsten carbide and tungsten carbide epoxy resin bricks have small half-value layer and mean free path compared to lead brick. The values were 0.07 cm and 0.06 cm for lead and tungsten carbide, respectively. Conclusion. This study showed that attenuation coefficient measurement can be performed using gamma transmission principle in SPECT. Tungsten carbide epoxy resin shows high potential to replace lead as radiation shielding material.