Transcript Slide 1

THE POLARIZATION SPECTROSCOPY CAMERA – A PROMISING TOOL FOR
ASSESSMENT OF ERYTHEMATEOUS REACTIONS TO TOPICALLY APPLIED AGENTS
B.M MAGNUSSON1, G.E NILSSON2 and C. ANDERSON1
1Department
of Biomedicine and Surgery, Division of Dermatology,
2Department of Biomedical Engineering, Division of Biomedical Instrumentation,
Linköping University Hospital, Sweden.
Erythema is often used as an end point for percutaneous penetration. The erythemateous reaction of topically applied model agent
methyl-nicotinate (MN) was evaluated by a new portable, non-invasive tissue viability imaging technique (TiVi) for the investigation of
microvascular tissue blood concentration. In comparison with other traditional techniques, TiVi automatically captures up to 12
images of the microcirculation per minute with a user-friendly computerized system which also can analyze large amounts of data.
TiVi is based on polarization spectroscopy of blood in
superficial skin tissue. Lineraly polarized light incindent on the
skin is partly reflected by the surface layers and partly
backsscattered from the dermal tissue. Use of orthogonal
polarization filters over both the light source and the light
device in the camera suppresses the reflection from the
surface, and only the depolarized light backscattered from the
dermal matrix reaches the light sensitive array. By separating
the colour planes of an image acquired in this manner and
applying a dedicated image processing algorithm,
spectroscopic information about the amount of red blood cells
(RBC) in the underlying tissue can be discovered. The
algorithm is based on a theory that utilises the differences in
light absorption of RBC and dermal tissue in the red and green
wavelength regions.
0 sec (image 3)
Step 1: Capture the images
Step 2: Select regions of interest (ROI)
Step 3: Display the results
100 sec (image 13)
200 sec (image 23)
Erythema intensity for a ROI as a function of time
in a single individual.
300 sec (image 33)
Seven healthy volunteers participated in this technology
evaluation study. MN solutions were applied to skin occlusively
in order to minimise environmental influences using Finn
Chambers on Scanpor® application systems (Epicutan,
Tuusula, Finland). The application site was the ventral surface
of the forearm and the back (20 µl 10 mM MN for 30 sec). TiVi
measurement was performed directly after the application and
then every 10 seconds for the following 30 minutes.
Erythema area for a ROI as a function of time
in a single individual.
Comparison of photographic and
spectroscopic data for 2 selected ROI
from 0 to 300 sec.
RESULTS
Intensity
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TiVi-Value
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File Number
The TiVi user interface displayed for one individua.l
Intraindividual variablity at the eight
application sites in a single individual.
Interindividual variablity in seven volunteers
(mean of eight application sites).
CONCLUSION
 The results show moderate intraindividual differences but wide variability between individuals.
 The erythemateous reaction could easily be quantified as to area and intensity with a broad capacity to kinetic analysis.
 The TiVi technique has the capability to analyze large amounts of data during an erythemateous reaction.
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