An radiographer acquires an optimal wrist image at 60 kVp and 2.5 mAs. If the same projection is acquired at 72 kVp and 5 mAs, which outcome is most likely?

• A. Quantum mottle on a radiography
• B. Geometric distortion
• C. Excessive patient dose
• D. Loss of spatial resolution

Answer: (C)

When thinking about technique factors, the key idea is that the dose to the patient is mainly governed by the amount of radiation produced, which is controlled by mAs. Increasing mAs directly increases the number of photons reaching the patient, and thus the energy deposited in the tissues. Kilovoltage peak (kVp) changes the energy of the photons and how deeply they penetrate; higher kVp makes the beam more penetrating and can reduce dose per photon to some extent, but it also lowers image contrast.

In this scenario, going from 60 kVp with 2.5 mAs to 72 kVp with 5 mAs doubles the photon flux (mAs doubles) and adds higher-energy photons. The increase in mAs tends to raise the entrance dose overall, and the modest gain in photon energy from the higher kVp doesn’t offset that rise enough. Therefore the most likely outcome is an excessive patient dose.

Quantum mottle would be more likely if mAs were too low, causing noisy image; geometric distortion and loss of spatial resolution are tied to geometry, focal spot, motion, or collimation rather than this specific change in exposure factors.