Hounsfieldasteikolla
The Hounsfieldasteikolla, known in English as the Hounsfield scale, is a quantitative measurement system used in computed tomography (CT) to express the radiodensity of tissues relative to water. Radiodensity is measured in Hounsfield units (HU). Water is defined as 0 HU, air approximately –1000 HU, and dense bone can reach values of +1000 HU or higher. The scale is centered on the attenuation coefficient of water at a given energy level, typically 70 keV for diagnostic CT.
The scale was introduced by Sir Sir Godfrey Hounsfield, one of the pioneers of computed tomography, in
In clinical practice the scale is used for lesion detection, assessing tumor density, guiding biopsy, and monitoring