Receptor exposure is defined as the amount of radiation striking the image receptor.

• A. Amount of Radiation Striking the Image Receptor
• B. Visible Difference in Brightness Levels in the Image
• C. Amount of Magnification in the Digital Image
• D. Amount of Radiation Absorbed by the Patient

Answer: (A)

Receptor exposure is the amount of radiation that actually reaches the image receptor. This is determined by the exposure factors (like mA, exposure time, and kVp), distance from the x-ray source to the receptor, and filtration, all shaping how many photons arrive at the receptor to form an image. It is not about how much energy is absorbed by the patient (that’s patient dose), nor about the brightness or density differences you see on the image (those are visual manifestations of receptor exposure but not the definition itself), and it isn’t about magnification, which is a geometric effect of object-to-image distance and focal spot size.