Primary shielding stops which?

• A. Scatter and leakage
• B. The primary beam
• C. All radiation
• D. Operator exposure

Answer: (B)

The main idea is that the primary shield is placed directly in the path of the X-ray beam that is generated to form the image. Its purpose is to attenuate that useful, primary beam so that, once it exits the shielding, its intensity is reduced to a safe level in areas where people may be present. It is not meant to stop all radiation or the scatter produced after the beam passes through the patient, nor the leakage from the tube housing. Scatter and leakage require other protective measures (secondary barriers and appropriate shielding design) because they originate after the primary beam is produced. So the best description is that primary shielding stops the primary beam.