Beam restriction reduces the number of Compton interactions, affecting contrast how?

• A. Decreased contrast
• B. Increased contrast
• C. Increased exposure
• D. No change

Answer: (B)

Reducing beam size lowers scatter radiation. Scatter from Compton interactions adds a hazy fog that diminishes the differences between tissues, so image contrast drops. When you beam-restrict, fewer photons interact in the patient to produce scatter, and fewer scattered photons reach the detector. The remaining primary photons preserve the true differences in tissue attenuation, making structures stand out more clearly. So the net effect is increased image contrast.