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Hounsfield Unit

Aka: Hounsfield Unit

Definition
1. XRay attenuation unit used in CT Scan interpretation
2. Characterizes the relative density of a substance
3. Each pixel is assigned a value between -1k to 1k
Indication
1. Computed Tomographic Scanning (CT Scan)
Substance densities in Hounsfield Units
1. Air: -1000
2. Fat: -50
3. Water: 0
4. Soft tissue such as muscle: +40
5. Calculus: +100 to +400
6. Bone: +1000
References
1. Hounsfield (1980) Med Phys 7:283-90

Hounsfield unit (C1552985)
Definition (NCI)	Term given to the dimensions of the quantifier of x-ray attenuation, CT number. (Dr. Joseph A. Thie)
Definition (HL7V3.0)	1
Definition (HL7V3.0)	1
Concepts	Quantitative Concept (T081)
HL7	[HNSF'U], [hnsf'U]
English	Hounsfield Unit, HU, Hounsfield unit
Sources	Derived from the NIH UMLS (Unified Medical Language System)

Family Practice Notebook

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Although access to this page is not restricted, the information found here is intended for use by medical providers.

This page was written by Scott Moses, MD, last revised on 10/21/2007 and last published on 5/14/2013.

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