(HIS) [Also Clinical Information System (CIS)] Information system to manage the administrative, financial and clinical aspects of a hospital.

In nuclear medicine a hot spot describes a strong activity enrichment in one or more ranges of the organ or body part which is examined.
A pinhole collimator may be used if images of a hot spot and the surrounding with very high resolution are necessary. Zoom magnification or a converging collimator also may be used to improve resolution and assign the hot spot.

(H) The Hounsfield scale displays radiodensity in a linear scale of gray shades expressed in Hounsfield units (HU). The Hounsfield scale is a quantitative transformation of the attenuation coefficient.
The Hounsfield value -1000 is defined as the radiodensity of air, 0 H that of distilled water at standard pressure and temperature, and denser tissues like for example cranial bone can reach 2000 H. The radiation attenuation of dental fillings or artificial implants depends on atomic number of the elements used. Titanium usually has an amount of +1000 HU. Iron steel can have a density greater than the highest range (traditional 3095 H) covered by the standard Hounsfield scale of a CT scanner. Areas with attenuation coefficients that exceed the scale's maximum are white areas in which no detail is visible.
Some CT machines are relatively tolerant, precise representing regions with very high densities. Sometimes, an option is available to select an extended CT number scale.

(HU) [CT scanner display unit] The arbitrary scale is defined by air, which has a CT number of -1000 HU, and water, with a CT number of 0 HU. It is named after Sir Godfrey Hounsfield, who developed the first clinical CT scanner.

See also Hounsfield Scale.

Hypaque 76 is a radiopaque contrast agent supplied as a 76 percent sterile aqueous solution providing 66 percent (w/v) diatrizoate meglumine and 10 percent (w/v) diatrizoate sodium.

GE Healthcare has discontinued Hypaque 76 for unknown reasons.