How does increasing mA affect X-ray production?

• A. Increases the number of photons produced, but lowers patient dose.
• B. Increases exposure time without changing photon count.
• C. Increases focal spot size.
• D. Increases the number of photons produced and patient dose.

Answer: (D)

Increasing mA raises the tube current, so more electrons strike the target each second. Each of those collisions produces x-ray photons, so the beam has more photons overall. That higher photon output means the patient receives a greater dose. Focal spot size isn’t affected by changing mA, since it’s a tube-geometry property that influences image sharpness, not the number of photons. If exposure time is kept the same, increasing mA increases the total exposure proportionally (mA × time). In short, raising mA boosts both photon production and patient dose.