Title: Analysis of statistical properties of laser speckles, forming in mucose of colon: Application in laser surgery.

Authors: Vladimir Rubtsov, Sergey Kapralov, Yuri Chalyk, Sergey Ulyanov

Statement of the problem

• Scattering of laser light from biological sample leads to formation of speckles. In the case of laser surgery, the localization of intensity may cause the essential inhomogeneity thermal effects of laser on processed area of human organ under the surgery treatment.

• Non-Gaussian statistics of scattered light may enhance the localization of light, which might be the critical factor for laser surgery.

Purpose of researches

• Analyze the statistics of speckle, forming in the mucose of colon.

• Suggest the way of speckle suppression to provide inhomogeneous illumination of processing organ under the surgery.

Collimated laser beam

Histological sample

microobjective

CMOS cameraPhoenix MuTech PC 1240

Scheme of experimental set-up

Device has been performed on the base of conventional microscope.CMOS camera is placed instead of ocular.

Speckles observed from a cut of skin. Compare with mucose scattering, slides # 8 - #39

Because of highly scattering, intensity fluctuations usually obey to negative exponent distribution (in the case of polarized speckles)

Algorithm of speckle processing

• Select central line from 2D speckle pattern• Chi-Square Test is performed • Hypothesis about negative-exponent statistics

of intensity fluctuations is performed

Scattering from the histological sample of mucose of colon.

Sample thickness is 50 um.

Realization #1

Realization #2

Realization #3

Realization #4

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #5

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #6

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #7

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #8

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #9

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #10

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Scattering from the histological sample of mucose of colon.

Sample thickness is 100 um.

Realization #1

Realization #2

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #3

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #4

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #5

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #6

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #7

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #8

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #9

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #10

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Scattering from the histological sample of mucose of colon.

Sample thickness is 150 um.

Realization #1

Realization #2

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #3

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #4

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #5

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #6

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #7

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #8

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #9

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Realization #10

Hypothesis about negative-exponent statistics of intensity fluctuations is rejected

Resume

• As it shown, statistics of speckle, forming in the mucose of colon, is non-gaussian one.

• It is expedient to use additional scattering gel (for example, mixture of Vaseline oil with TiO2 particles) to reduce speckle size and to make statics of speckle is gaussian one.