Dose-area product measurements in paediatric radiography.

The dose-area product (DAP) could provide a useful quantity for monitoring doses for paediatric radiography, because it is a sensitive parameter, which is simple to record. A study of DAP measurements has been carried out for single radiographic projections for paediatric patients and comparisons made with measurements of entrance dose. The technique has been used to investigate doses for examinations performed with and without a grid. There is a linear relationship between DAP and entrance dose, with a variation of +/- 20% for pelvis, abdomen, spine and skull radiographs, but data for chests are more scattered. Logarithm of the DAP is linearly related to an equivalent patient diameter and reference levels could be set in terms of DAP either by patient age range or size. Effective doses determined from DAPs were 0.1-0.3 mSv for abdomen, pelvis and spine anteroposterior radiographs for 5-15 year olds, and less than 0.03 mSv for 0 and 1 year olds. Doses for examinations performed without a grid were only 20% of those for which a grid was used in the X-ray room studied. Significant reductions in doses for paediatric radiology can be achieved, where the use of grids can be avoided.