Assessment of the integrity of structural shielding of four computed tomography facilitiesin the greater accra region of ghana

Abstract

The structural shielding thicknesses of the walls of four computed tomography (CT) facilities in Ghana were re-evaluated to verify the shielding integrity using the new shielding design methods recommended by the National Council on Radiological Protection and Measurements (NCRP). The shielding thickness obtained ranged from 120 to 155 mm using default DLP values proposed by the European Commission and 110 to 168 mm using derived DLP values from the four CT manufacturers. These values are within the accepted standard concrete wall thickness ranging from 102 to 152 mm prescribed by the NCRP. The ultrasonic pulse testing of all walls indicated that these are of good quality and free of voids since pulse velocities estimated were within the range of 3.496±0.005 km s21. An average dose equivalent rate estimated for supervised areas is 3.4±0.27 μ week21 and that for the controlled area is 18.0±0.15 μ week21, which are within acceptable values. © The Author 2013. Published by Oxford University Press. All rights reserved.