Saratov State University Department of Optics and Biophotonics

Saratov State University, Department of Optics and Biophotonics MONITORING OF MUSCLE OPTICAL CLEARING USING OCT Marina D. Kozintseva 1, Vyacheslav I. Kochubey 1, Alexey N. Bashkatov 1, Elina A. Genina 1, Valery V. Tuchin 1, 2, 3 1 Saratov State University, Department of Optics and Biophotonics, 83, Astrakhanskaya Street, Saratov 410012, Russia 2 Institute of Precise Mechanics and Control of RAS, 24, Rabochaya Street, Saratov 410028, Russia 3 University of Oulu, P. O. Box 4500, Oulu 90014, Finland marin 15121991@mail. ru Saratov Fall Meeting 2014

Motivation • The possibility of selective translucence of the superficial skin layers is very useful in developing functional imaging and therapeutic techniques. A potential benefit of the optical clearing is the improvement of laser therapeutic techniques that enable sufficient light penetration to a target embedded in tissue. Combination of optical clearing with laser radiation can reduce the laser fluences required for a therapeutic effect. However, in spite of numerous investigations deal with transport of glucose solution within biological tissue the problem of estimating the diffusion coefficient of the agent in muscle has not been studied in details. • Goal of the study is to measure the diffusion coefficient of 40% glucose solution into muscle tissue in vitro Saratov Fall Meeting 2014

Materials and Methods • For this study ten beef muscle tissue samples have been used. All the tissue samples were cut into pieces with the area about 20˟ 15 mm 2. For mechanical support, the tissue samples were placed in bath where the aqueous 40% glucose solution was flowed in. • Experiments were provided with the Spectral Radar OCT system (THORLABS, USA) All measurements were performed at room temperature (about 20°C) • As a clearing agent 40% glucose solution was used. Refractive index of the solution is 1, 391. It has been measured using Abbe refractometer at wavelength 589 nm Saratov Fall Meeting 2014

Experimental setup (а) (b) • Figure 1. Optical Coherence Tomography (OCT): (a) general view of the OCT technique; (b) tissue samples on the OCT object stage. Saratov Fall Meeting 2014

Method for determination of glucose diffusion coefficient where ∆z = |z 1 – z 2| • Figure 2. Estimation of the total attenuation coefficient μt of the tissue on the different depths: the black line describes the signal at the beginning (0 sec) of the experiment, the red line – on the 600 sec, the green line – on the 5400 sec. Saratov Fall Meeting 2014

Results: glucose diffusion Figure 3. B-scan of intact muscle tissue sample in vitro Figure 5. B-scan of muscle tissue sample in vitro treated by 40% glucose solution Saratov Fall Meeting 2014

Results: glucose diffusion Tissue Thicknes Diffusion sample s, mm coefficient, Tissue Thicknes sample s, mm cm 2/sec Diffusion coefficient, cm 2/sec 1 1, 97 3. 04 10 -5 6 1, 93 2. 48 10 -6 2 2, 17 4. 99 10 -6 7 1, 78 2. 54 10 -6 3 1, 93 3. 83 10 -6 8 1, 95 2. 51 10 -6 4 1, 88 2. 48 10 -6 9 1, 50 2. 57 10 -6 5 1, 73 6. 49 10 -7 10 1, 77 2. 44 10 -6 Averaged diffusion coefficient <D> = (2, 98± 0, 94) 10 -6 cm 2/sec Saratov Fall Meeting 2014

Thank you for your attention! Saratov Fall Meeting 2014