A scale used in computed tomography to convert the linear attenuation coefficient measurements of an object into a universal radiodensity scale. The radiodensity of distilled water—at standard pressure and temperature—is defined as 0 HU; air is defined as -1000 HU; and the radiation density of compact bone is defined as +1000. The scale is named for Godfrey Hounsfield, one of the co-inventors of computed tomography.