Hounsfield

Hounsfield is a unit of measurement used in computed tomography (CT) scans, named after Sir Godfrey Hounsfield, a British engineer and Nobel laureate. The Hounsfield scale is a quantitative scale for describing radiodensity, which is used in evaluating CT scans.

History

The Hounsfield unit (HU) was named after Sir Godfrey Hounsfield, who shared the 1979 Nobel Prize in Physiology or Medicine with Allan McLeod Cormack for their development of the CT scanner. Hounsfield's work revolutionized the field of medical imaging, allowing for more precise diagnosis and treatment of many diseases.

Measurement

The Hounsfield scale measures the radiodensity of a specific area in a CT scan. The scale is defined such that the radiodensity of distilled water at standard temperature and pressure (STP) is zero HU, while the radiodensity of air at STP is -1000 HU. The radiodensity of other materials can be calculated relative to these values.

Clinical significance

In clinical practice, the Hounsfield scale is used to differentiate between different types of tissues in a CT scan. For example, bone typically has a high positive Hounsfield value, while air and fat have negative values. This allows physicians to identify abnormalities such as tumors, which may have a different radiodensity than the surrounding tissue.

See also

• Computed Tomography
• Radiodensity
• Medical imaging