Attenuation in fat is described as:

Attenuation in fat is described as:

• A. Low
• B. Intermediate
• C. High
• D. Extremely high

Answer: (A)

Attenuation depends on how tissues interact with X-ray photons, which is largely determined by density and atomic composition. Fat has a lower density and fewer high‑atomic‑number elements than water or soft tissues, so it absorbs or deflects fewer photons. That means more photons pass through fat with less attenuation, which in CT shows up as lower attenuation values (around -100 HU). So fat is described as having low attenuation. In contrast, soft tissues attenuate more than fat, and bone attenuates the most, giving them higher appearance on CT.

Attenuation depends on how tissues interact with X-ray photons, which is largely determined by density and atomic composition. Fat has a lower density and fewer high‑atomic‑number elements than water or soft tissues, so it absorbs or deflects fewer photons. That means more photons pass through fat with less attenuation, which in CT shows up as lower attenuation values (around -100 HU). So fat is described as having low attenuation. In contrast, soft tissues attenuate more than fat, and bone attenuates the most, giving them higher appearance on CT.