Which two tissues have approximately the same radiographic density?

Which two tissues have approximately the same radiographic density?

• A. Muscle and Water
• B. Muscle and Fat
• C. Fat and Water
• D. Muscle, Fat, and Water

Answer: (A)

Radiographic density reflects how much an tissue attenuates X-rays, which depends on its density and composition. Muscle and water have nearly the same attenuation because muscle is largely water content, giving it a similar effective density to pure water (roughly 1.0 g/cm³, with muscle around ~1.04 g/cm³). Fat has a lower density and attenuation due to its lipid content, so it appears less dense on radiographs. Because of this, the two tissues with approximately equal radiographic density are muscle and water.

Radiographic density reflects how much an tissue attenuates X-rays, which depends on its density and composition. Muscle and water have nearly the same attenuation because muscle is largely water content, giving it a similar effective density to pure water (roughly 1.0 g/cm³, with muscle around ~1.04 g/cm³). Fat has a lower density and attenuation due to its lipid content, so it appears less dense on radiographs. Because of this, the two tissues with approximately equal radiographic density are muscle and water.