A 1-mm Pb flat contact shield reduces dose to female reproductive organs by about what percent?

A 1-mm Pb flat contact shield reduces dose to female reproductive organs by about what percent?

• A. 50%
• B. 10%
• C. 90 to 95%
• D. 100%

Answer: (A)

Attenuation of X-rays by lead governs how much a shield can reduce dose. A 1-millimeter lead flat contact shield intercepts a significant portion of the primary beam directed at the reproductive organs and also cuts down some of the scatter that would reach them. But in diagnostic radiography, not all dose to the gonads comes from the portion of the beam that passes straight through the shield—there’s still transmission through the shield and, more importantly, dose from scatter within the patient and room, which the shield cannot eliminate. With typical diagnostic energies and a flat contact shield, this combination yields about half of the gonadal dose being blocked. That’s why the practical reduction is around 50%, making that option the best estimate among the choices. The other options would imply much greater or complete elimination of dose, which isn’t achievable with a 1-mm shield in real-world geometry and energies.

Attenuation of X-rays by lead governs how much a shield can reduce dose. A 1-millimeter lead flat contact shield intercepts a significant portion of the primary beam directed at the reproductive organs and also cuts down some of the scatter that would reach them. But in diagnostic radiography, not all dose to the gonads comes from the portion of the beam that passes straight through the shield—there’s still transmission through the shield and, more importantly, dose from scatter within the patient and room, which the shield cannot eliminate. With typical diagnostic energies and a flat contact shield, this combination yields about half of the gonadal dose being blocked. That’s why the practical reduction is around 50%, making that option the best estimate among the choices. The other options would imply much greater or complete elimination of dose, which isn’t achievable with a 1-mm shield in real-world geometry and energies.