tomografija

Tomografija, or tomography, is a family of imaging techniques that reconstruct cross‑sectional or volumetric images of an object from projections acquired around it. The goal is to visualize internal structures with greater detail than a single projection provides.

In typical tomography, a source and detector rotate around the subject while measurements collect line integrals of a property such as X‑ray attenuation or MR signal. Image reconstruction combines these projections to produce a two‑dimensional slice or a 3D volume.

Several modalities are described as tomography. Computed tomography (CT) uses X‑rays for rapid cross‑sectional imaging. Magnetic resonance tomography (MRT or MRI-based tomography) uses magnetic fields and radio waves. Positron emission tomography tomography (PET) imaging shows metabolic activity when combined with CT or MRI. Optical tomography, including diffuse optical tomography (DOT), images light propagation in tissue. Electron tomography, used in materials science and electron microscopy, reconstructs 3D structure from tilted TEM images.

Applications span medical diagnosis and treatment planning, industrial nondestructive testing, materials science, and archaeology. The technique can provide high spatial resolution and quantitative measurements but may involve radiation exposure (as with CT) and artifacts from motion or reconstruction assumptions.

History notes that the modern CT scanner was developed in the 1960s–1970s by Godfrey Hounsfield and Allan Cormack, with the first clinical CT in 1971. Since then, advances include iterative reconstruction, dual‑energy and spectral CT, and dose reduction strategies.