December 16, 2008

Hounsfield Unit

What is Hounsfield Unit?

  • CT number
  • Unit used to measure attenuation of tissue on CT
  • A representative of relative attenuation coefficient of tissues, using water as a reference
  • Water is defined as zero Hounsfield unit
  • Matters with higher physical density (g/cm3), higher electron density (e/cm3) than water will have higher HU; and vice versa
  • HU depends on kV peak (used in CT image acquisition) and filtration technique (used in CT image reconstruction)
  • HU values on an image are only approximate (because it will change if kV changes)
Who is Hounsfield?
  • Godfrey Hounsfield is a British electrical engineer
  • He shared a 1979 Nobel Prize in physiology or medicine with Allan Cormack for the development of computed tomography (CT)
Huda W, et al. Review of radiology physics. 2003

No comments:

Post a Comment