X-RAY SHIELDING BARRIER ESTIMATION: A CASE STUDY OF RADIOLOGY DEPARTMENT, AHMADU BELLO UNIVERSITY TEACHING HOSPITAL, SHIKA – ZARIA

ABSTRACT

The shielding barrier already constructed in the general radiography, fluoroscopy and mammography rooms of Ahmadu Bello University Teaching Hospital, Shika and the general radiography room of Barau Dikko Specialist Hospital, Kaduna was evaluated. The evaluation was based on the shielding code called XRAYBARR, which is a routine to calculate radiation shielding requirements for diagnostic radiology installations. This code uses distances to the occupied area, x-ray tube information, workload and use factor, and with the design dose limit and occupancy factor specified, to calculate the barrier thickness required to reduce the total annual dose to acceptable limit. Area survey of the already constructed shielding barrier was also carried out using TLDs. The calculated values from XRAYBARR and the measured values from TLD readings were compared to the shielding design already constructed. The results showed that the ratio of the measured to design dose was less than 1(<1) for all the rooms indicating that the measured dose beyond the barriers were lower than the design dose limit. The ratio of the calculated to the design shielding barrier thickness was less than 1(<1) indicating that the shielding already provided in the rooms were adequate. The general radiography rooms in both hospitals were also compared. The area survey from TLD measurements and the calculated shielding barrier thickness from XRAYBARR when compared to the design dose and design barrier thickness were found to be satisfactory.