Transcript Слайд 1 - Eventry

Saratov
State University
Department of Optics
& Biophotonics
Optical properties of the human nasal polyps
in the spectral range from 300 to 2500 nm
Darya N.
Ekaterina A. Kolesnikova1, Aliya A. Muldasheva2, Julia P. Ireneva2,
Alexey N. Bashkatov1, Elina A. Genina1, Vyacheslav I. Kochubey1, Anatoly B. Knyazev2,
Valery V. Tuchin1
Zmeeva1,
1-Saratov State University, 2-Saratov State Medical University
Results
Rt
Tt
Tc
0,1
0,01
1E-3
1E-4
Materials and methods
0
500
1000
Fig.2. The geometry of
the
collimated
transmittance
measurements. Diameter
of the incident beam is 2
mm.
Inverse Monte Carlo (IMC)
The computer program package for determination of absorption and
scattering tissue properties has been developed. This inverse Monte
Carlo method based on the solution of direct problem by Monte Carlo
simulation and minimization of the target function
F  a , s , g    Rtexp  Rtcalc  a , s , g    Tcexp  Tccalc  a , s , g   
exp
 Tt calc  a , s , g  
2
with the boundary condition
0  g  0.98
0,10
0,08
0,06
0,04
1500
2000
0,02
0
2500
500
2
1000
1500
2500
B
60
1,0
50
Anisotropy factor
Absorption coefficient, 1/cm
2000
Wavelength, nm
A
40
30
20
10
0
0
500
1000
1500
2000
2500
0,8
0,6
0,4
0,2
0,0
0
500
Wavelength, nm
C
320
280
240
200
160
120
80
40
0
500
1000
1500
2000
1000
1500
2000
2500
Wavelength, nm
2500
Reduced scattering coefficient, 1/cm
Scattering coefficient, 1/cm
Fig.1. The geometry of the
measurements in A) transmittance
mode, B) reflectance mode. 1 - the
incident beam (diameter 1-4 mm);
2 - the tissue sample; 3 - the
entrance port (square 2516 mm);
4 - the transmitted (or diffuse
reflected) radiation; 5 - the
integrating sphere (IS) (inner
diameter is 150 mm); 6 - the exit port
(diameter 28 mm)
t
0,12
Wavelength, nm
 Experimental setup
T
0,14
0,00
1E-5
 For this study twenty samples of human nasal polyps have been used. The
samples were kept in saline during 48 hours at temperature 4-5°C until
spectrophotometric measurements. The size of the samples were approximately
15×15 mm, the average thickness was 1.0±0.5 mm. For mechanical support, the
tissue samples have been sandwiched between two glass slides
Measurement of the total reflectance, total and collimated transmittance have
been performed using a commercially available spectrophotometer LAMBDA 950
(PerkinElmer , USA) in the spectral range 300-2500 nm
All measurements were performed at room temperature (about 20°C)
Inverse Monte Carlo technique has been used for processing the experimentally
measured spectra of the tissue samples
2
0,16
Penetration depth, cm
Motivation
The knowledge of tissue optical properties is
necessary for the
development of the novel optical technologies of photodynamic and
photothermal therapy, optical tomography, optical biopsy, etc. Numerous
investigations related to determination of tissue optical properties are
available however the optical properties of many tissues have not been
studied in a wide wavelength range.
Goal of the study is to investigate of optical properties of human nasal
polyps in the wavelength range from 350 to 2500 nm
D
160
140
120
100
80
60
40
20
0
0
500
Wavelength, nm
E
1000
1500
2000
2500
Wavelength, nm
F
Fig.3. The typical spectra of sample of human nasal polyp. Rt is
total reflectance; Tt is total transmittance and Tc is collimated
transmittance (A); the wavelength dependence of penetration
depth (B), the absorption spectrum (C), the wavelength
dependence of scattering anisotropy factor (D), the scattering
coefficient spectrum (E), and the reduced scattering coefficient
spectrum (F) of human nasal polyps. IS, IMC, data averaged for
20 samples.
Summary
The analysis of the results has shown that investigated spectra
depend on scattering coefficient of collagen fibers and absorption
bands of interstitial matrix water. The absorption bands of
oxyhemoglobin at the wavelengths 415, 540 and 570 nm are well
seen
Our results can be used for the development of new methods
and optimization of the existing ones of therapy of rhinologic
diseases