Scatter dose estimation based on dose-area product and the specification of radiation barriers.

Scatter dose as a function of dose-area product (DAP) has been studied over a range of tube potentials and scattering angles. Data are presented to permit the calculation of scatter dose from DAP at distances of 1 m or more from the patient. This method has been used to calculate absorbed dose to the walls of six existing X-ray rooms which are used for interventional radiology, angiography or barium contrast studies. These calculations have been compared with measurements using thermoluminescent dosemeters. The median ratio of measured to calculated dose was 0.50 and the maximum value was 1.26. It was concluded that the calculation of scatter dose from DAP using the factors derived in this report can be used as the basis for the specification of radiation protection barriers. The busiest room in this study in terms of DAP had a DAP rate of 224 Gy cm2 per day. From the scatter factors presented here, it was shown that the room walls did not need to have more than 1.2 mm of lead equivalence.