Adjusting mAs Value for Mobile Chest X-ray
How would you adjust your mAs value if you changed the distance for a mobile chest x-ray?
1) 4) 9 mAs 2) 6.3) mAs 3) 7.6 mAs 4) 9.0 mAs
Answer:
To maintain the same image exposure when increasing the distance from 60 to 72 for a mobile chest x-ray, the mAs value needs to be adjusted to approximately 9.0 mAs using the inverse square law of radiation.
Explanation:
Inverse Square Law of Radiation
The inverse square law of radiation states that the intensity of radiation is inversely proportional to the square of the distance from the source. This means that as the distance increases, the intensity of radiation decreases.
Adjusting mAs Value
To adjust the mAs value when changing the distance from 60 to 72, we can use the formula mAs1 / mAs2 = (D1^2) / (D2^2), where mAs1 is the initial mAs value (6.3 mAs), D1 is the initial distance (60), mAs2 is the adjusted mAs value, and D2 is the new distance (72).
Plugging in the values: 6.3 mAs / mAs2 = (60^2) / (72^2)
mAs2 = 6.3 mAs * (72^2) / (60^2)
mAs2 = 6.3 mAs * 1.44
mAs2 = 9.07 mAs
Therefore, the adjusted mAs value would be approximately 9.0 mAs to maintain the same exposure for a mobile chest x-ray when changing the distance from 60 to 72.