Which factor influences Modulation Transfer Function (MTF)?

• A. Spatial frequency
• B. Technologist experience
• C. Kilovoltage Peak (kVp)
• D. Milliampere-seconds (mAs)

Answer: (D)

MTF shows how well an imaging system reproduces contrast at different sizes of detail, plotted against spatial frequency. The factor that influences the MTF is spatial frequency because the curve describes how modulation (contrast transfer) changes as you try to reproduce finer details. The system tends to preserve contrast at low spatial frequencies (large details) but loses modulation at higher spatial frequencies (fine details) due to blur and sampling limits.

Exposure factors like kilovoltage and mA·s affect image brightness and noise, not the inherent transfer characteristics of the system. Technologist experience also doesn’t change the physical ability of the system to transfer modulation. So, spatial frequency is the element that directly governs how the MTF behaves.