Entrance Surface Dose Assessment for Postero-Anterior Erect Chest X-ray Examinations of Adult Patients in a Selected Teaching Hospital in Sri Lanka

Abstract

The amount of radiation received by the patient who is undergoing X-ray examination needs to be quantified to estimate the possibility of harm. Patient doses in radiography primarily depend on the Entrance Surface Dose (ESD) and the sensitivity of the organs and tissues that are irradiated during the radiographic examination. This study aimed to assess the ESDs to the patients of age over 18years, who are undergoing Postero-Anterior (PA) erect chest X-ray examinations at the Kurunegala Teaching Hospital, Sri Lanka and to determine whether the estimated mean ESD value is higher than the recommended value of International Atomic Energy Agency (IAEA) or not. A quantitative study was done on a convenience sample of fifty (50) patients selected separately for two (2) X-ray machines using an indirect method to estimate the ESD. Mean ESD value was calculated for each machine and finally this calculated value was compared with the recommended mean value given by IAEA using the Z-test. The results have shown that the estimated mean ESDs of 0.018 mGy and 0.023 mGy were less than the recommended value of 0.4 mGy. It is concluded that, the variations in the ESD were due to the patient thickness, the different technical characteristics of radiographic equipment and exposure parameters employed by the radiographers. This emphasizes the need for introducing a standard protocol among the radiographic staff and using the quality radiographic equipment.