Radiation Risk Assessment from Background Radiation Exposures in Selected Hospitals in South – South Nigeria

Aim: This work was carried out to determine the radiation risk from background ionizing radiation exposures of selected hospitals in South-South, Nigeria.

Study Design: This study was purely an experimental work.

Place and Duration of Study: This study was carried out at University of Port Harcourt Teaching hospital (UPTH), University of Uyo Teaching hospital (UUTH) and Braithwaite Memorial Specialist Hospital (BMSH) between June, 2016 and February, 2017.

Methodology: The in-situ measurement of indoor and outdoor exposure dose rates of the three hospitals were measured with well calibrated radiation meters (Radalert-100 and Digilert-200) and Global positioning system (GPS) for exact position measurement. The radiation meters were set to measure the exposure rate in milli-Roetgen per hour. The measurements were carried out within the radiology department and some other departments of the hospital.

Result: The average indoor and outdoor exposure dose rates measured at University of Uyo Teaching hospital were 0.013±0.003 and 0.015±0.003 mRh-1, average indoor and outdoor exposure rates measured at the University of Port Harcourt Teaching hospital were 0.015±0.005 and 0.015±0.005 mRh-1 and the average indoor and outdoor exposure dose rates for Braithwaite Memorial Specialist Hospital were 0.014±0.003 mRh-1 and 0.013±0.003 mRh-1. The world standard threshold value for exposure dose rate is 0.013 mRh-1, the values show that University of Uyo Teaching hospital indoor are within this range, while the others are higher. The average indoor and outdoor absorbed dose rate for all the hospitals exceeded the world average of 89 nGyh-1. Also the results for average excess lifetime cancer risk (ELCR) calculated for indoor and outdoor for the hospitals show that ELCR for both indoor and outdoor exposures were all higher than the world acceptable value of 0.29x10-3, but the annual effective dose levels for the hospitals both indoor and outdoor were all below the 1 mSvy-1 maximum permissible limit for the public set by the International Commission on Radiological Protection (ICRP).

Conclusion: There is need for the management of the hospitals to monitor radiation levels in order to take necessary precautions to avoid radiation levels getting to unacceptable levels.