If a chest radiograph requires 4 mAs at 72", the new mAs to use at 56" would be

Question

Quizplus · Accepted Answer

The mAs is directly proportional to the square of the distance. The new mAs can be calculated using the mAs-distance formula:

mAs1 / D1^2 = mAs2 / D2^2

where mAs1 = 4 mAs, D1 = 72", mAs2 is the new mAs, and D2 = 56".

Substituting the values and solving for mAs2, we get:

4 / 72^2 = mAs2 / 56^2
mAs2 = 4 x (56^2 / 72^2)
mAs2 = 2.4

Therefore, the new mAs to use at 56" would be 2.4 mAs.

If a Chest Radiograph Requires 4 MAs at 72", the New