At high energy levels (more than 70 keV), which tissue type exhibits greater attenuation?

• A. Bone
• B. Soft tissue
• C. Cartilage
• D. Fat

Answer: (B)

At high energy levels, such as those above 70 keV, bone exhibits greater attenuation compared to other tissue types, including soft tissue. The reason for this is that bone is denser and contains a higher atomic number compared to soft tissues, which commonly consist of lighter elements like carbon, hydrogen, and oxygen.

When X-ray photons pass through different types of tissues, their energy is partially absorbed—this absorption is influenced by the composition and density of the tissue. Because bone has a greater density and contains minerals like calcium, it is more effective at attenuating X-ray beams at higher energies.

Soft tissue, while it does attenuate X-rays, does so to a lesser extent than bone. The difference in attenuation between these tissues becomes more pronounced as the energy increases because bone's composition allows it to interact more effectively with the high-energy photons, resulting in greater absorption of those photons compared to soft tissues.

Therefore, when considering the arrangement and density of various tissues at high energy levels, bone clearly demonstrates a higher attenuation rate than soft tissue.