Risk Assessment of Occupational Exposure of Workers Engaged in Radiation Practice without Monitoring Devices

Objective: This study was carried out to evaluate occupational dose of personnel, engaged in radiation work without wearing monitoring device, at five diagnostic centres in Abeokuta, Ogun State metropolis, namely, Rainbow, New image, Bethel, Akinolugbade and Abiolad.

Materials and Methods: Thermoluminescent dosimeters (TLDs) obtained from Radiation Protection Services, Lagos State University (LASU), Ojo were used for dose measurements. LASU is accredited by the Nigerian Nuclear Regulatory Authority (NNRA) to provide radiation monitoring services. The TLDs were distributed to each of the centre for personnel and area (control and supervised) monitoring. The period of exposure of the TLDs was three months. The exposed TLDs were returned to LASU for processing. The effective dose received by personnel per quarter was extrapolated to annual effective dose to make comparison with the International Commission on Radiation Protection (ICRP) recommended dose limit. The stochastic effect of the measured dose was also estimated.

Results: Annual effective dose received by all personnel ranged from 1.16 - 2.54 mSv. While the highest value was obtained by personnel at Bethel diagnostic centre, the lowest value was obtained at Akinolugbade. The risk of cancer associated with these values, estimated for a million population, was 112 and 61 at Bethel and Akinolugbade respectively.

Conclusion: This study showed that the annual effective doses to personnel at these centres were below the ICRP recommended dose of 20 mSv per annum. However, the Managements of these diagnostic centres should provide monitoring devices for their radiation workers in line with NNRA authorization requirements.