Dose Area Product (DAP) Meters



As an aside: suppose we did not have a 10cm air gap between the image receptor and the patient. The SSD would then be 59cm.

The SFR would be = 59cm x (15.25cm/100cm) or 9cm.

This would result in an exposed area of 3.14 x 9² or 254cm², and a skin exposure of 500Rcm²/254cm² or 2 Roentgens.

Eliminating that 10cm gap reduces patient exposure from 2.8 R to 2 R, almost a 30% reduction. This stands as a reminder of the importance of good exposure geometry...