As beam restriction tightens, receptor exposure what happens to receptor exposure?

• A. Receptor exposure increases
• B. Receptor exposure increases as a result of focusing of x-rays
• C. Receptor exposure decreases
• D. Receptor exposure is not affected

Answer: (C)

Tightening beam restriction reduces the field size, so the image receptor receives photons from a smaller area. With fewer photons reaching the receptor and less tissue to scatter them, receptor exposure decreases. If you wanted the same receptor exposure with a smaller field, you’d need to increase the technique factors (like mA·s or kVp) to compensate.