Comparative Analysis of Monte Carlo and Regulatory Methods for Gamma Radiation Shielding in Medical Concrete Barriers

Year 2026, Volume: 13 Issue: 1 , 374 - 390 , 31.03.2026

Zaw Lin Oo , Theint Win Laı , Aung Moe

https://doi.org/10.54287/gujsa.1858958

https://izlik.org/JA65LR46UU

Abstract

This study compares computational approaches for gamma radiation shielding design in medical concrete barriers, focusing on high-activity Cobalt-60 (Co-60) teletherapy sources—still relevant in resource-limited settings despite the global shift to linear accelerators. An open-source Python-based Monte Carlo framework was developed to model photon transport through standard concrete (density 2.35 g/cm³), incorporating NIST XCOM energy-dependent cross-sections, explicit dual gamma emissions of Co-60 (1.173 MeV and 1.332 MeV), material composition effects, and buildup factors using ANSI/ANS-6.4.3 Berger parameters. The framework was validated against NIST XCOM data (agreement <3% at Co-60 energies), narrow-beam Beer-Lambert law (<2% deviation), and OpenMC benchmarks using the ENDF/B-VIII.0 nuclear data library (agreement within 1.2–8%, ~7.4% difference at 195 cm). Compared to the conservative NCRP Report 49 regulatory method—which employs simplified assumptions and built-in safety margins for compliance—the Monte Carlo approach required 195 cm of concrete for a representative 10,000 Ci Co-60 source at 5 m from an occupied area (dose constraint 0.1 μSv/h), versus 147 cm by NCRP 49—a 33% difference. This arises mainly from explicit dual-energy modeling (~15%), detailed buildup inclusion in thick shields (~65%), and precise cross-sections (~20%). While NCRP 49 (and successor NCRP 151) provides practical, conservative tools for routine shielding design, Monte Carlo simulations deliver enhanced physical accuracy for thick barriers and high-activity sources. The findings advocate complementary use: regulatory methods for compliance documentation and Monte Carlo for design optimization. This work offers an accessible open-source Python tool and evidence-based recommendations for clinical shielding workflows, while noting Co-60’s ongoing relevance in select global contexts (IAEA DIRAC data).

Keywords

Radiation Shielding , Monte Carlo Simulation , Co-60 Therapy , Concrete Barriers , Medical Physics , Regulatory Compliance

Ethical Statement

This is a computational and theoretical study that did not involve human participants, animal subjects, or collection of personal data. Therefore, formal ethical review and approval were not required. All simulations were performed using in-house developed code and publicly available reference data. The authors declare no conflicts of interest regarding the publication of this article.

Supporting Institution

This research was supported by institutional resources from the Department of Atomic Energy, Myanmar. Technical and methodological support was provided by Ascend International Preparatory College (core algorithm development) and colleagues from the Ministry of Science and Technology. This study received no specific external grant or funding from commercial or public agencies.

Project Number

0001

Thanks

The authors gratefully acknowledge the support and resources provided by the Department of Atomic Energy, Myanmar. We extend our sincere appreciation to Ascend International Preparatory College for the core algorithm support. We also thank our colleagues in the Ministry of Science and Technology for their insightful discussions and technical assistance, particularly regarding Monte Carlo implementation and validation. Special thanks are due to the open-source scientific community for the Python libraries that enabled the computational framework developed herein. The constructive feedback from anonymous reviewers, which significantly strengthened the manuscript, is also acknowledged with gratitude. Any errors or omissions remain solely the responsibility of the authors.

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