Alexander Vavilov Optical topography principles and example of
an application. Bachelor Thesis Work
Slide 2
Contents: Hitachi ETG-4000 Device Description Fields of use The
Principle of Technology Visual Stimulus experiment overview
Conclusion
Slide 3
Hitachi ETG-4000 Device Description The ETG-4000 is a device
that measures relative changes in tissue concentration of
oxy-hemoglobin and deoxy-hemoglobin and total hemoglobin (it is
proportional to the level of blood) in the cerebral cortex by
beaming near-infrared light, that can penetrate the body
efficiently, and is absorbed by the hemoglobin in the blood. The
ETG-4000 displays the changes of overall Hemoglobin concentration
in time- course graphs, 2D topography images and 3D topography
images based on the data from multiple point measurements.
Slide 4
Infant Hospital, Trieste, Italy Biomedical Research Center, La
Corua, Spain Brain Computer Interface research, Graz,
AustriaDepartment of Experimental Psychology University of Tartu,
Estonia Field of use
Slide 5
> < 1 mm bundle type fiber element wire 30.. 50 m from
laser 4 mW to diode 1 pW adult Optical Topography principle
Operation Principle ETG-4000 The principle of technology
Slide 6
The light is transmitted at one end of the tissue and collected
at the back end. Light propagated through tissue (Io) and
transmitted at the output (I) traversing a distance L allows for
chromophore concentration [C] calculations using Beer Lamberts Law.
The principle of technology A -Absorption spectrum Io - Light
propagated through tissue I Light transmitted at the output
Extintion coefitient [C] - Chromophore concentration L -
distance
Slide 7
In case of head model we need to measure the light on the same
side of tissue. The principle of technology OD - the change in the
optical density Extintion coefitient [C] - Chromophore
concentration L - distance
Slide 8
Absorption Spectra of Hemoglobin Wavelength (nm) Molar
absorption coefficient (mM -1 mm -1 ) Oxy Hb Deoxy Hb 830695 The
principle of technology
Hitachi ETG-4000 optical topography system, which is used in
medicine as well as in chemistry, is a good example of successful
cooperation in the fields of electronics, physics and chemistry.
Conclusion It has made it possible to get such a glimpse of the
working brain, which has not been possible to get ever before.