Tomografia

Tomography, or tomografia, is an imaging method that reconstructs cross-sectional or volumetric representations of an object's interior from projections acquired around an angle. The central idea is to obtain many 2D measurements that, when combined, separate signals from different depths and reduce superimposition. Reconstruction algorithms, such as filtered back projection or iterative techniques, estimate the values in each voxel.

In medicine, X-ray computed tomography (CT) is the most common form of tomography, producing detailed images of bone and soft tissue. Magnetic resonance tomography builds images by measuring magnetic properties of tissues. Emission tomography, including positron emission tomography (PET) and single-photon emission computed tomography (SPECT), maps metabolic activity. Other tomographic methods include ultrasound tomography and optical tomography for specialized applications.

The development of CT in the 1970s by Godfrey Hounsfield and Allan Cormack, for which they shared the Nobel Prize, marked a turning point in diagnostic imaging.

Applications span clinical diagnosis, treatment planning, neuroscience, radiation therapy, and industrial nondestructive testing. Limitations include radiation exposure in X-ray methods, motion artifacts, and trade-offs between resolution, noise, and acquisition time. Advances aim to reduce dose, improve speed, and combine structural and functional information in hybrid systems.