Computed Tomography (CT Scan)
A diagnostic medical imaging modality combining rotating X-ray tubes and digital detectors with filtered back-projection algorithms to produce 3D cross-sectional tissue images.
Governing formula
Hounsfield Unit HU = 1000 × (μ_tissue - μ_water) / (μ_water - μ_air)
SI unit
Hounsfield Units (HU, Water = 0, Air = -1000, Bone = +1000)
In depth
Measures X-ray linear attenuation coefficients μ across hundreds of projection angles. Computed algorithms calculate cross-sectional attenuation density maps quantified in standardized Hounsfield Units (HU).
Examples in the real world
Emergency head CT scans detecting acute intracranial hemorrhages within minutes.