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What is the CT number for bone?

  1. 20

  2. 0

  3. 1000

  4. -200

The correct answer is: 1000

The CT number for bone is defined by its high density, which results in a significantly high value on the Hounsfield scale, which is utilized in computed tomography (CT) imaging. Bone is considerably denser than soft tissue and water, resulting in a CT number around +1000. This density is due to the mineral content in bone, primarily calcium, which absorbs more X-ray radiation compared to less dense substances. In contrast, water is assigned a CT number of 0 on this scale, and fat typically has negative values, while air has significantly low values. Understanding the CT numbers assigned to various substances is crucial in interpreting CT images effectively, as they provide information on the composition and density of the tissues being scanned. This knowledge is vital for radiographers when making assessments based on CT images.