Daria K. Tuchina, Alexey N. Bashkatov,
Elina A. Genina, Valery V. Tuchin
Department of Optics and Biophotonics of Saratov State University,
Saratov, Russia
Saratov Fall Meeting 2012
Saratov State University
Department of Optics and
Biophotonics
For the last two decades the optical method as a tool for clinical
functional imaging of physiological conditions, cancer diagnostics
and therapies is of great interest due to its unique informative features,
simplicity, safety and low cost in contrast to conventional X-ray
computed tomography, magnetic resonance imaging and ultrasound.
However, the main limitations of the optical imaging techniques are
connected with strong light scattering in tissue. Optical clearing is
perspective technique for solution of the problem. However, in spite
of numerous investigations, optical clearing of skin tissue has not be
studied in detail.
Goal of the study is to investigate of optical clearing of skin by
PEG-300
Saratov Fall Meeting 2012
Saratov State University
Department of Optics and
Biophotonics
Twelve samples of intact rat skin were used in the in vitro
experiments. Before experiments hairs and hypodermic fatty layer
were removed. The area of the samples was about 10 × 20 mm.
Collimated transmittance spectra of the skin samples were measured
by USB4000-Vis-NIR spectrometer (Ocean Optics, USA)
concurrently with administration of PEG-300 in the spectral range
400-1000 nm.
All measurements were performed at room temperature (about 20°C).
Refractive index of PEG-300 was measured as 1.465.
Saratov Fall Meeting 2012
Saratov State University
Department of Optics and
Biophotonics
Saratov Fall Meeting 2012
Saratov State University
Department of Optics and
Biophotonics
Dynamic of collimated transmittance of the rat skin sample
placed in PEG-300
Saratov Fall Meeting 2012
Saratov State University
Department of Optics and
Biophotonics
Spectra of collimated transmittance of the rat skin sample
placed in PEG-300 measured at different time intervals
concurrently with administration of PEG-300
Saratov Fall Meeting 2012
Saratov State University
Department of Optics and
Biophotonics
The time dependence of attenuation coefficient during optical
clearing of the rat skin sample placed in PEG-300
Saratov Fall Meeting 2012
Saratov State University
Department of Optics and
Biophotonics
Spectra of light attenuation coefficient during optical clearing
of the rat skin sample placed in PEG-300 measured at
different time intervals
Saratov Fall Meeting 2012
Saratov State University
Department of Optics and
Biophotonics
Degree of optical clearing of skin tissue was estimated as:
 t (t) -  t (t  0)
K(t) 
 t (t  0)
µt(t=0) is attenuation coefficient at t = 0
µt(t) is the time-dependent attenuation coefficient
Saratov Fall Meeting 2012
Saratov State University
Department of Optics and
Biophotonics
The equation was used to calculate parameter A, which characterizes maximum
of degree of optical clearing of skin tissue, and parameter τ, which characterizes
time of optical clearing of skin tissue:
 t (t) -  t (t  0)
K(t) 
 A(1  exp( t /  ))
 t (t  0)
The solution of the problem is minimization of the target function:
Nt
f ( A, )   ( A(1  exp( ti /  ))   t (ti )) 2
i 1
Nt is the number of time points obtained at registration of the time
dependence of collimated transmittance, µt is experimental values of the
time-dependent attenuation coefficient
Saratov Fall Meeting 2012
Saratov State University
Department of Optics and
Biophotonics
A
0.381
τ, min
8.691
Saratov Fall Meeting 2012
Saratov State University
Department of Optics and
Biophotonics
Acknowledgements
Grant #224014 Network of Excellence for
Biophotonics (PHOTONICS4LIFE) of the Seventh
Framework Programme of Commission of the
European Communities
Grants # 11-02-00560 and 12-02-92610-КО of
Russian Foundation of Basis Research
Russian Federation governmental contacts
02.740.11.0770, 02.740.11.0879, 11.519.11.2035, and
14.B37.21.0728
Saratov Fall Meeting 2012