Natural rubber block as gamma radiation shielding for medical applications

Abstract

In this study, a prototype of commercialized-style radiation shielding blocks based on natural rubber mixed with radiation shielding substance (i.e. lead and tungsten compound) was developed. The gamma shielding test was carried out using 137 Cs (662 keV) source and 60Co (1173, 1332 keV) source. The results reveal that based on the gamma attenuation property and forming capability, the optimum formula was a shielding block with 60% lead oxide, which was able to completely shield gamma radiation (> 99%). In comparison with a radiation shielding block with lead oxide, a radiation shielding block with tungsten oxide showed similar characteristics. Due to the higher price of tungsten oxide, natural rubber block with lead oxide is preferred. However, with an environmental concern, natural rubber block with tungsten oxide is selected. Moreover, it was found that the mechanical properties of these radiation shielding blocks (including hardness, tensile strength and elongation at break) were reduced with increasing of the amount of radiation shielding substance mixed in the radiation shielding blocks. However, the reduction of these mechanical properties does not affect the actual utilization since these radiation shielding blocks are normally not subjected to any strong force or pressure. In addition, the SEM images showed the uniform dispersion of radiation shielding substances in the rubber block texture.