How does skin pigmentation affect exposure factors?

• A. Need 50% more exposure
• B. Need 100% more exposure
• C. No change in exposure factors
• D. Need less exposure

Answer: (C)

Skin pigmentation does not meaningfully change exposure factors in diagnostic radiography. The X-ray beam interacts mainly with the underlying tissues—soft tissue, fat, muscle, bone—and the epidermal layer containing melanin is very thin compared with those tissues. In the diagnostic energy range, the attenuation differences caused by melanin are small enough that they don’t require adjusting kVp, mA, or exposure time. Technique charts are built around patient size, thickness, and overall density, not skin color, so no change in exposure factors is needed for different skin tones. If you tried to tweak exposure for pigment, you’d introduce inconsistency across patients and could compromise image quality or dose management.