A study of scatter in diagnostic X-ray rooms.

An important part of determining the radiation protection requirements during X-ray room design is the calculation of the amount of scatter inside and outside the planned locations of the shielding barriers. In this work, a Monte Carlo code has been developed to calculate the percentage scatter so that the current data can be consolidated and new data can be provided as required. Calculations have been compared with measurements to show that they are representative of scatter found in X-ray rooms. Scatter from the dose-area product meter and the collimator system were found to provide large contributions to the measured scatter. A fluoroscopy room containing a C-arm X-ray set was modelled with the Monte Carlo code. The scatter dose was calculated at an X-ray room entrance behind the protective screen, acting as a secondary barrier, at the radiographer's console. The variation of scatter with the position of the protective screen was studied. An empirical calculation, which provided reasonable agreement with the Monte Carlo calculations, was found by using new data for the variation of scatter from concrete with field size. If a door was placed in the X-ray room entrance behind the protective screen, the results showed that it would not need to be lead lined.