ABSTRACT
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, OgunState 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 personnelat 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
ABSTRACT
Objective@#To determine the personal dose level of radiation workers in medical institutions at the municipal level and below in a city, and to provide a scientific support for strengthening the radiation protection in the city’s medical institutions.@*Methods@#Information of the successful applicants for the "Radiation Worker Permit" from 174 medical institutions at the municipal level and below was collected from October 1, 2011 to December 31, 2014. The annual effective dose was calculated based on the personal dose monitoring report, and indicators including sex, permit application time, hospital level, type of occupational radiation, length of radiation work, blood test, and micronucleated lymphocyte rate were analyzed.@*Results@#Of the 1 143 radiation worker permit applications submitted by medical institutions the municipal level and below in this city from 2011 to 2014, 1 123 provided at least one personal dose monitoring report. The annual effective dose of the radiation workers was 0-4.76 mSv (mean 0.31±0.40 mSv) , and the collective annual effective dose was 351.96 mSv. The annual effective dose was significantly different between radiation workers with different times of permit application, hospital levels, and types of occupational radiation (P<0.05) . Interventional radiology workers had the highest annual effective dose (0.63 mSv) , and annual effective dose was significantly different between interventional radiology workers with different lengths of radiation work (H=10.812, P<0.05) .@*Conclusion@#The personal radiation dose of radiation workers in medical institutions at the municipal level and below in this city is maintained at a relatively low level, suggesting that the occupational environment is relatively safe for these workers. However, more focus should be placed on clinical interventional radiology workers.