Journal of Medical Physics and Applied Sciences

Description

Radiological applications are indispensable in modern healthcare, industry and research, offering invaluable benefits from medical imaging and cancer treatment to nuclear energy production and space exploration. However, these applications also expose humans and the environment to harmful ionizing radiation, necessitating the development of advanced shielding materials. Traditional materials such as lead and concrete have served as effective radiation barriers, but they have limitations like high toxicity, significant weight and limited adaptability to modern requirements. This has driven researchers and engineers to describe novel materials that provide effective radiation shielding while overcoming the shortcomings of traditional options. Lead, long regarded as a gold standard for radiation shielding, has several inherent disadvantages. It is highly toxic, posing environmental and health risks during mining, processing and disposal. Additionally, its high density makes lead-based shields cumbersome, limiting their portability and application in lightweight systems like wearable protective gear. Concrete, another commonly used material, is bulky and has variable shielding properties due to the heterogeneity of its composition. These limitations highlight the urgent need for innovative shielding solutions that are safer, lighter and more adaptable to modern technologies. Metal Matrix Composites (MMCs) have emerged as promising candidates for radiation shielding. These materials combine a metal matrix, such as aluminum or magnesium, with high atomic number fillers like tungsten or bismuth to improve radiation attenuation. MMCs are lightweight compared to traditional lead-based shields, making them suitable for aerospace and mobile medical applications. Additionally, they offer improved mechanical strength and corrosion resistance, which are vital for long-term deployment in challenging environments such as space or nuclear facilities.

Polymer-based shielding materials

Polymers are another category of materials gaining attention for radiation shielding applications. While polymers alone do not offer significant protection against high-energy radiation, their properties can be improved by incorporating additives like boron, bismuth, or tungsten. For instance, boron-infused polyethylene is particularly effective in neutron shielding, as boron atoms have a high neutron absorption cross-section. Polymer-based shields are lightweight, flexible and customizable, making them ideal for wearable protective gear and specialized applications in medical and industrial settings. Nanotechnology has opened new frontiers in the development of radiation shielding materials. Nanomaterials like graphene oxide and carbon nanotubes offer unique properties, such as high strengthto- weight ratios and tunable radiation attenuation capabilities. These materials can be engineered to provide targeted protection against specific types of radiation, such as gamma rays or neutrons. For e.g, composite shields incorporating graphene oxide have demonstrated superior performance in blocking high-energy photons while maintaining lightweight and flexible characteristics. Furthermore, the incorporation of nanoparticles like tungsten oxide or bismuth oxide into polymer matrices has been shown to improve radiation shielding without compromising mechanical properties. With increasing emphasis on sustainability, researchers are exploring eco-friendly alternatives to traditional radiation shielding materials.

Bio-inspired and hybrid materials

Nature has inspired the development of novel shielding materials that mimic biological structures. For e.g, researchers are studying the microstructure of materials like nacre (motherof- pearl) to develop hybrid shields with improved strength and radiation attenuation. These bio-inspired materials combine lightweight, flexible polymer matrices with high-density fillers arranged in layered or hierarchical patterns, mimicking natural designs. Such materials offer a balance of mechanical robustness and effective shielding, making them suitable for diverse applications, including personal protective equipment and space analysing. Space analysing presents unique challenges for radiation shielding due to the high levels of cosmic radiation and the need for lightweight materials. Traditional shielding options are often too heavy for spacecraft, prompting the development of advanced materials tailored for extraterrestrial environments. Hydrogen-rich materials, such as polyethylene-based composites, are particularly effective in mitigating cosmic radiation due to hydrogen's ability to attenuate high-energy protons. Moreover, researchers are investigating the use of regolith, the loose material found on the surfaces of celestial bodies like the Moon and Mars, as a potential in-situ resource for building radiation shields. These innovations are critical for ensuring the safety of astronauts during long-duration missions.

Advancements in material science have enabled the creation of smart shielding materials capable of adapting to changing radiation environments. These materials incorporate responsive components that can dynamically adjust their properties, such as thickness or composition, in response to varying radiation levels.