What is the impact of exposure factor selection on patient dose without compromising diagnostic quality?

• A. Lower kVp and higher mA reduce skin dose.
• B. Higher kVp and lower mA can reduce skin dose; choose settings that maintain diagnostic quality with the lowest feasible dose.
• C. Dose is independent of exposure factors.
• D. Always maximize kVp and mA for best image.

Answer: (B)

Optimizing exposure factors to keep the patient’s dose as low as possible while still producing a usable image is the key idea. Using a higher kilovolt peak (kVp) and a lower milliamperage (mA) or shorter exposure time lets you maintain the same level of image receptor exposure with fewer photons overall. The beam energy is higher, so fewer photons are needed to achieve adequate detector exposure, which reduces the entrance skin dose. Of course, you balance this against image quality, because too high a kVp can reduce image contrast; you should pick the highest kVp that still yields acceptable diagnostic quality. The opposite approach—lowering kVp while raising mA—drives up the patient dose and can degrade or unnecessarily complicate image quality. The aim is to adjust factors so you get the needed diagnostic information with the lowest feasible dose, in line with ALARA.