Definition of optical coherence tomography imaging system

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Photonics Dictionary

optical coherence tomography imaging system: Optical coherence tomography (OCT) is an imaging technique used in medical diagnostics and biomedical research to obtain high-resolution, cross-sectional images of biological tissues. An OCT imaging system employs low-coherence interferometry to capture detailed, three-dimensional images of tissue microstructure with micrometer-scale resolution.

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Here is how an OCT imaging system typically works:

Light source: The system includes a broadband light source, often a superluminescent diode (SLD) or a swept-source laser. This light source emits a beam of near-infrared light with a broad spectrum of wavelengths.

Optical components: The light is directed through a series of optical components, including lenses, mirrors, and beam splitters, to split the beam into two paths: a sample arm and a reference arm.

Sample arm: In the sample arm, the light is focused onto the tissue being imaged. Scanning systems, such as galvanometer mirrors or optical scanning devices, are often used to raster scan the beam over the tissue surface, enabling cross-sectional imaging.

Reference arm: In the reference arm, a portion of the light is directed to a reference mirror. This mirror reflects the light back toward the beam splitter.

Interference: The light from the sample arm and the reference arm is recombined at the beam splitter and directed toward a detector. When the two beams recombine, they interfere with each other. The interference pattern carries information about the depth of structures within the tissue.

Detector: The interference pattern is detected by a photodetector, such as a photodiode or a CCD camera. The detector converts the interference pattern into an electrical signal.

Signal processing: The electrical signal is processed by a computer to generate cross-sectional images, known as A-scans, which represent the intensity of the light as a function of depth within the tissue. By acquiring multiple A-scans at different lateral positions, a 2D or 3D image of the tissue microstructure can be reconstructed.

OCT imaging systems offer non-invasive, high-resolution imaging capabilities that are valuable for various medical applications, including ophthalmology (e.g., retinal imaging), cardiology (e.g., imaging blood vessels), dermatology, gastroenterology, and oncology. They provide clinicians and researchers with detailed insights into tissue morphology and pathology, aiding in early disease detection, treatment monitoring, and research investigations.