Which material tends to produce the lowest remnant beam signal due to high attenuation properties?

Which material tends to produce the lowest remnant beam signal due to high attenuation properties?

• A. Bowel gas
• B. Bone
• C. Air
• D. Soft tissue

Answer: (B)

Remnant beam signal reflects how much X-ray makes it through a material. Attenuation grows with density and atomic number, so the transmitted intensity follows I = I0 e^{-μx}. Bone has a high density and high effective atomic number, giving a large attenuation coefficient μ; even a typical thickness reduces the beam a lot, leaving a very small remnant signal. In contrast, air (bowel gas) attenuates very little, so most of the beam passes through and the remnant signal remains strong, and soft tissue attenuates less than bone but more than air. Thus bone produces the smallest remnant beam due to its high attenuation properties.

Remnant beam signal reflects how much X-ray makes it through a material. Attenuation grows with density and atomic number, so the transmitted intensity follows I = I0 e^{-μx}. Bone has a high density and high effective atomic number, giving a large attenuation coefficient μ; even a typical thickness reduces the beam a lot, leaving a very small remnant signal. In contrast, air (bowel gas) attenuates very little, so most of the beam passes through and the remnant signal remains strong, and soft tissue attenuates less than bone but more than air. Thus bone produces the smallest remnant beam due to its high attenuation properties.