Biological Shielding Design Effectiveness of the Brachytherapy Unit at the Korle Bu Teaching Hospital in Ghana Using Mcnp5 Monte Carlo Code

Design objectives for brachytherapy treatment facilities require sufficient shielding to reduce primary and scatter radiation to design limit in order to limit exposure to patients, staff and the general public. The primary aim of this study is to verify whether shielding of the brachytherapy unit at the Korle Bu teaching Hospital in Ghana provides adequate protection in order to assess any radiological health and safety impact and also test the suitability of other available sources. The study evaluates the effectiveness of the biological shielding design of a Cs-137 brachytherapy unit at the Korle-Bu Teaching Hospital in Ghana using MCNP5. The facility was modeled based on the design specifications for LDR Cs-137, MDR Cs-137, HDR Co-60 and HDR Ir-192 treatment modalities. The estimated dose rate ranged from (0.01-0.15) μSv/h and (0.37-3.05) μSv/h for the existing initial and decayed activities of LDR Cs-137 for the public and controlled areas respectively, (0.03-0.57) μSv/h and (1.53-8.06) μSv/h for MDR Cs-137, (7.47-59.46) μSv/h and (144.87-178.74) μSv/h for HDR Co- 60, (0.13-6.95) μSv/h and (19.47-242.98) μSv/h for HDR Ir-192 for the public and controlled areas respectively. The results were verified by dose rates measurement for the current LDR setup at the Brachytherapy unit and agreed quiet well. It was also compared with the reference values of 0.5 μSv/h for public areas and 7.5 μSv/h for controlled areas respectively. It can be concluded that the shielding is adequate for the existing source.