Net image receptor dose and patient skin dose differ in what way?

• A. Net Image Receptor Dose Is Energy Deposited in the Detector; Patient Skin Dose Is Energy Incident on the Skin.
• B. They Are the Same Thing
• C. Net Dose Is the Patient's Skin Dose
• D. Net Dose Has Nothing to Do with Dose Optimization

Answer: (A)

The main idea is that two different measures of exposure are being compared: how much energy is deposited in the image receptor versus how much energy actually hits the patient’s skin. Net image receptor dose refers to the energy absorbed by the detector material to create the image. Patient skin dose (entrance skin dose) is the energy that impinges on the skin surface. They differ because the x-ray beam must pass through the patient before reaching the detector, so attenuation and scattering in the patient reduce the energy that makes it to the detector. The detector then absorbs only a portion of that transmitted energy, depending on its materials and efficiency, to form the image. So energy deposited in the detector and energy incident on the skin are related but not the same. This distinction is important for dose optimization: you aim for enough image receptor exposure to get a good image while keeping the patient’s entrance skin dose as low as reasonably achievable.