Imaging retinal and macular disease - OCT Flashcards
OCT is based on…
low-coherence interferometry
with OCT, what wavelength and type of light beam is directed at target area
830nm light beam (infra-red)
with OCT, what 2 things of the reflected light is used to produce images
Magnitude and relative location of the reflected light
with OCT, what does each imaged point generate
an axial A-scan
The more A-scans, the higher the resolution
how does a B scan get generated
As the scanning beam moves across the tissue a cross sectional
image is created = tomogram
A 3-D cube is a collection of…and what is this scan called
tightly packed B-scans
called C-scan
what is a single line scan
a single cross section area that’s taken
what is a Raster/Radial scan and what advantage does this have
a series of lines in a grid formation
10 x scans with 10 averages per scan = less definition but a volume created
which 2 types of “domains” does OCT work ok
Time domain
which 2 types of “domains” does OCT work ok
Time domain
Spectral domain
how does time domain (TD-OCT) work
uses a moving mirror to measure time taken for light to be reflected
400 A-scans per second
how many A-scans per second does time domain OCT produce
400 A-scans per second
how does Spectral domain OCT (SD- OCT) work
measures multiple wavelengths of reflected light across a spectrum
40,000 A-scans per second
Axial resolution of 4 to 7μm
Transverse resolution 15μm
how many A scans per second does Spectral domain OCT (SD- OCT) produce
40,000
what is the Axial and Transverse resolution of Spectral domain OCT (SD- OCT)
Axial resolution of 4 to 7μm
Transverse resolution 15μm
