Theoretical Framework for Radiation Shielding Optimisation Using Locally Available Materials in Nigerian Nuclear Medicine Facilities

Background: The expansion of nuclear medicine facilities in Nigeria requires cost-effective radiation shielding solutions. Dependence on imported lead and specialised concretes imposes high costs. A theoretical framework for optimising shielding designs using locally available Nigerian materials is a significant scientific contribution. Aim: This study developed and validated a theoretical framework for radiation shielding optimisation using locally available materials in Nigerian nuclear medicine facilities. Methods: Monte Carlo N-Particle Transport Code simulations were developed to model gamma and neutron shielding performance of locally available materials including Nigerian granite, laterite, barite-aggregate concrete, and palm kernel shell composites. Material attenuation coefficients were measured by transmission experiments and used to validate simulation models. Multi-objective genetic algorithm optimisation minimised shielding mass and cost while meeting IAEA dose rate requirements. Results: Barite-aggregate concrete from locally sourced Nasarawa State barite achieved shielding performance within 8% of commercial imported equivalents at 67% lower material cost. Optimised multi-layer configurations using granite facing and barite inner layers reduced total shield mass by 22% compared with uniform concrete. Monte Carlo predictions matched experimental measurements within 5%. Conclusion: Locally sourced Nigerian materials can provide cost-effective nuclear medicine shielding solutions. The optimisation framework enables site-specific design and significantly reduces facility construction costs. Keywords: radiation shielding, Monte Carlo simulation, nuclear medicine, locally available materials, Nigeria.