Emission computed tomography (ECT) is a type of

tomography Tomography is imaging by sections or sectioning that uses any kind of penetrating wave. The method is used in radiology, archaeology, biology, atmospheric science, geophysics, oceanography, plasma physics, materials science, astrophysics, ...

involving

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consi ...

emissions. Types include positron emission tomography (PET) and Single-photon emission computed tomography (SPECT). The imaging agent used in SPECT emits

gamma rays A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...

, as opposed to the positron emitters (such as ¹⁸F) used in PET. There are a range of radiotracers (such as ^99mTc, ¹¹¹In, ¹²³I, ²⁰¹Tl) that can be used, depending on the specific application.

References

Tomography 3D nuclear medical imaging {{med-diagnostic-stub