In an automatic exposure control (AEC) test, if an exposure through 10 cm of aluminum results in a receptor exposure of 100 microgray, an exposure through 5 cm of aluminum should result in receptor exposure in which of the following?

In an automatic exposure control (AEC) test, if an exposure through 10 cm of aluminum results in a receptor exposure of 100 microgray, an exposure through 5 cm of aluminum should result in receptor exposure in which of the following?

• A. 25 Gy
• B. 50 Gy
• C. 100 Gy
• D. 200 Gy

Answer: (C)

Automatic exposure control works to keep the image receptor receiving a consistent level of exposure by automatically adjusting the technique when attenuation changes. If you replace 10 cm of aluminum with 5 cm, the beam is less attenuated and more radiation would reach the detector unless the system steps in. The AEC will counter this by reducing exposure time or beam intensity so that the receptor still receives the target amount. As a result, the measured receptor exposure stays the same as before (100 microgray in this setup). The takeaway is that a properly functioning AEC delivers a constant receptor dose despite changes in shielding or patient thickness.

Automatic exposure control works to keep the image receptor receiving a consistent level of exposure by automatically adjusting the technique when attenuation changes. If you replace 10 cm of aluminum with 5 cm, the beam is less attenuated and more radiation would reach the detector unless the system steps in. The AEC will counter this by reducing exposure time or beam intensity so that the receptor still receives the target amount. As a result, the measured receptor exposure stays the same as before (100 microgray in this setup). The takeaway is that a properly functioning AEC delivers a constant receptor dose despite changes in shielding or patient thickness.