Comparison of entrance surface doses of some X ray examinations with CEC reference doses.

Entrance surface dose (ESD) measurements have been carried out in Nigeria as part of the ongoing dose reduction programme. Thermoluminescence dosemeters (TLD) were used to measure skin entrance doses for four common radiographic views in three hospitals. The mean ESD for the PA chest examination in all the participating hospitals was in the range 0.12 - 4.46 mGy. The mean ESD for the AP skull. PA skull and LAT skull were 8.55, 5.17 and 6.97 mGy respectively. The mean ESD values are greater than the CEC reference doses, except for rooms 1 and 2 in UCH where the entrance surface doses for PA chest examination are below the CEC reference dose. The QA test results show non-compliance of the accuracy of tube voltage with acceptance limit in three rooms. The timer accuracy is also not within the acceptance limit in two rooms. The reproducibility of both the kVp and timer in all the rooms is good.