According to NCRP 102, what is the minimum HVL at 70 kVp?

The correct answer represents the established guidelines set by the National Council on Radiation Protection and Measurements (NCRP) regarding the minimum half-value layer (HVL) for X-ray beam filtration at 70 kVp. According to NCRP Report 102, the minimum HVL should exceed 2.0 mm of aluminum (Al).

The HVL is a measure of the thickness of material needed to reduce the intensity of the X-ray beam by half and is an important factor in radiation safety. Adequate filtration in the X-ray beam helps to reduce patient exposure to unnecessary low-energy photons that contribute to patient dose without providing additional diagnostic benefit. Adhering to the specified minimum HVL ensures that the beam is adequately filtered for effective imaging while maintaining radiation safety standards.

Options that suggest a higher or lower HVL than 2.0 mm Al are not in alignment with the guidelines outlined in NCRP 102 and reflect either unnecessary complexity in filtration or insufficient protection against radiation.