THE ADEQUACY OF THE SHIELDING MATERIALS AND TECHNIQUES EMPLOYED AT SELECTED X-RAY CENTERS IN IBADAN

X-rays play a vital role in medical diagnosis and therapy. Exposure to radiation can however cause a variety of biological mutations. The effects of exposure to radiation could be as severe as leading to rapid death when the whole body is irradiated with large doses. They could also be so minimal and almost negligible for a variable period of time after low doses until delayed effects of radiation manifests in a group of the exposed individuals.

As a result, x-rays pose a threat to the safety of workers, their patients and members of the general public if they are not adequately shielded so that they only interact with the targeted areas. This emphasises the need for a radiation protection system which allows for diverse beneficial applications of radiation while simultaneously ensuring that detrimental effects of radiation are prevented or minimised. This study presents the results of an evaluation of the adequacy of shielding at selected x-ray centres in Ibadan, Oyo State, Nigeria.

The major parameters recorded at the various centres visited are the Kilo Voltage peak (KVp), milliamperes-second (mAs) and relative positions of the measuring points to the x-ray source. The background dose rate is measured at each point and the dose rate is measured again during exposure. To improve the degree of accuracy and precision, multiple readings are obtained at each point and the mean value is computed. The data obtained is then employed to determine the shielding adequacy at each point and the overall shielding adequacy at each centre.

The average exposure dose rates at public access areas are generally reported to be below the recommended dose rate limit of 0.5 μSv/h. This largely implies ideal shielding at public access areas. However, at controlled areas, particularly within the console operating areas, the average exposure dose rates are found to be substantially higher than the recommended limits. This stresses the need for enhanced shielding at those areas.