Computed tomography | 合法醫療器材資訊網

Computedtomography(CT)scanning,alsoknownas,especiallyintheolderliteratureandtextbooks,computerizedaxialtomography(CAT)scanning,isa ...

Computed tomography (CT), also known as, especially in the older literature and textbooks, computerized axial tomography (CAT), is an imaging modality[1] that uses x-rays[2] to build cross-sectional images[3] ("slices") of the body. Cross-sections are reconstructed from measurements of attenuation coefficients[4] of x-ray beams passing through the volume of the object studied.

CT is based on the fundamental principle that the density of the tissue passed by the x-ray beam can be measured from the calculation of the attenuation coefficient[5]. Using this principle, CT allows the reconstruction of the density of the body, by a two-dimensional section perpendicular to the axis of the acquisition system.

The CT x-ray tube[6] (typically with energy levels between 20 and 150 keV[7]), emits N photons[8] (monochromatic) per unit of time. The emitted x-rays form ...