Biomedical Engineering Reference
In-Depth Information
faster image capture because it does not require the reference mirror movement
that is necessary in current “time-domain” systems [
157
]. It appears that FD-OCT
can result in as many as 60,000,000 A-scans per second [
158
]. The major benefit
of FD-OCT is that it permits point-to-point registration and can give accurate
volumetric analysis. Not only has technology already improved upon OCT, but it
has also made imaging scans easier and clearer than ever before. Ultrahigh-speed
FD-OCT allows imaging of large areas of the retina and rapid three-dimensional
volume rendering of optic nerve head and fovea [
159
]. Scientists and researchers
have already begun refining the technique of OCT to view biological tissues as they
are in the body. This represents a transition in technology from two-dimensional
imaging to three-dimensional screening of large retinal volumes that is also an
achievement in the efficiency of three-dimensional imaging [
159
]. Furthermore,
OCT has been improved upon to speed up imaging scans and increase clarity of
the image. This new technology is definitely a more efficient method compared to
standard procedures [
159
]. Every photon that is emitted is detected, thus increasing
efficiency by a factor of a 100 and 50. This is extremely beneficial because the
imaging speed is increased without decreasing the quality of the image. This new
progress made in OCT is going to make it easier for medical practitioners to perform
quick and easy noninvasive procedures.
Research and development concerned with the improvement of fundamental
characteristics such as imaging resolution, speed, and sensitivity are very active.
Some of the technology and application areas currently having great impact on
the field are ultrahigh-resolution system [
160
]; polarization-sensitive imaging;
high-speed, high-sensitivity optical spectral-domain systems such as SS-OCT and
FD-OCT; and novel approaches like full-field or wide-field OCT [
161
-
164
].
Another active area of research involved the use of external contrast agents
to enhance both penetration, through reduced scattering (optical clearing), and
contrast through enhanced refractive index variation, which can enable the enhanced
visualization of selected features such as abnormal tissues, microvasculature, etc.
[
165
-
167
]. There are numerous research applications of this technology in a
broad range of fields. In addition, advances in technology are continuing. More
research remains to be done, and numerous clinical studies must be performed in
order to determine where OCT can play a role in clinical medicine, apart from
ophthalmology. However, unique capabilities of OCT imaging suggest that it will
have significant impact on fundamental research as well as on medicine.
5.8
Conclusion
OCT is a high-resolution, noninvasive, 3D imaging technique with great potential
in both clinical and fundamental research application in many areas. Its wide
range of current applications covers from medical diagnosis and surgical guidance
to the characterization of polymer microstructures and reading of multilayered
storage media, etc., which indicate that OCT will play a major role in practical
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