Which of the following will INCREASE attenuation of x-rays inside the body?

• A. increasing kVp and correcting the mAs
• B. decreasing kVp and correcting the mAs
• C. increasing SID and correcting the mAs
• D. using more added filtration

Answer: (B)

Lower energy x-ray beams are more readily absorbed by body tissues, so attenuation increases as photon energy decreases. When you lower the kVp, the average photon energy drops, raising the chance of interactions like the photoelectric effect in tissues. To keep image receptor exposure consistent, you typically compensate by increasing the mA (or exposure time), which means more photons are sent toward the body. The combination of lower energy photons and more photons overall leads to greater attenuation inside the body.

Raising kVp makes photons more penetrating, reducing attenuation. Increasing SID mainly affects receptor exposure without changing how much the beam is attenuated within the body. Adding filtration removes the lower-energy photons, which decreases attenuation in tissue.