ESTIMATION OF PATIENT RADIATION DOSES FOR SELECTED X-RAY EXAMINATIONS AND CENTRES IN NORTH-CENTRAL, NIGERIA.

Abstract

The risk of occurrence of cancer in developed and developing nations has become a major concern in the scientific and medical circle. Cancer induction is therefore one of the risk to guard against during medical X-ray exposure. Constant assessment of radiological procedure are thereby crucial in ensuring radiation doses to patients are as low as reasonably achievable. The aim of this study is to determine the patient radiation dose during some X-ray diagnostic procedure in selected centres in North central, Nigeria. These centres include; general hospital Minna (GHM), general hospital Ilorin (GHI) and general hospital Kubwa, FCT (GHK) with a total of 552 patients. The focus to skin distance (FSD), tube potential (kVp) and tube loading (mAs) were measured from the X-ray machine and used to calculate the entrance surface dose, effective dose, absorbed organ dose and the cancer risk index using the Caldose_X 5.0 software. The entrance surface dose (ESD) was also computed using mathematical formula for comparison purpose. Data on sex, age, body mass index (BMI) were recorded for the patients.The obtained results were compared with the documents of international atomic energy agency (IAEA) and other previous studies. The highest and lowest values obtained for ESD were7.10 mGy and 1.00 mGy for GHI and GHM respectively for Caldose_X software while for mathematical estimation, 6.76 mGy and 0.56mGy for GHK and GHM respectively. The effective doses (mSv) for GHI, GHK and GHM ranged from 0.28-0.66, 0.1-0.59 and 0.06-0.37 respectively and the pelvis and breast are with the highest and lowest absorbed organ dose of 2.82 mGy and 0.004 mGy for GHI and GHM respectively. The low dose obtained at GHM is traceable to good radiological practices. The absorbed organ doses when compared with international commission on radiological protection (ICRP) were all within the risk estimates of 35 cancer cases per million cases. The effective dose and ESD shows that for the exception of a few, the patients in selected Nigerian hospitals have their dose within established diagnostic reference levels. For radiation risks and variations in patients dose to be within the recommended limit, quality assurance should be emphasized.