Ekaterina A. Kolesnikova 1 , Aleksandr S.Kolesnikov 1 , Urszula Zabarylo 2 ,

1. Saratov State University Department of Optics and Biophotonics Ekaterina A. Kolesnikova1, Aleksandr S.Kolesnikov1, Urszula Zabarylo2, Olaf Minet2, Elina A. Genina1, Alexey N. Bashkatov1, Valery V. Tuchin1,3,4 1SaratovStateUniversity, 2Medizinische Physik und Optische Diagnostik, Charité – Universitätsmedizin Berlin, 3Institute of Precision Mechanics and Control RAS, 4Optoelectronics and Measurement Techniques Laboratory e-mail: ekaterina.a.kolesnikova@mail.ru OPTICAL CLEARING OF HUMAN SKIN FOR THE ENHANCEMENT OF OPTICAL IMAGING OF PROXIMAL INTERPHALANGEAL JOINTS Saratov Fall Meeting 2013

2. Saratov State University Department of Optics and Biophotonics The transillumination optical imaging is a prospective technique for the diagnosis of rheumatoid arthritis in humans. But the relatively low contrast and poor spatial resolution of the result images limits the usage of the technique for the finding of differences between healthy and pathology joints. Goal of the study is to enhance the technique by reduction of skin light scattering at using of optical clearing method Motivation Saratov Fall Meeting 2013

3. Saratov State University Department of Optics and Biophotonics Materials and methods Experimental setup The beam of the laser diodes was focused upon a spot diameter of ≤1 mm on the finger surface illuminating LEDs (670, 820, and 904 nm) Using laser diodes of a fixed power, the exposure time depends on the diameter of the finger and the manifestation of rheumatoid arthritis finger monochromatic digital CCD camera of an 8 bit dynamic range and variable exposure time Fig. 1. The exterior of the experiment (left image) and the transillumination system with 3 laser diodes (right image). Saratov Fall Meeting 2013

4. Saratov State University Department of Optics and Biophotonics Materials and methods Tested specimens The experiments were carried out in vivo with human skin. Female (25 years) participated in the experiments. Proximal interphalangeal(PIP) joints of index finger (1.6 cm) and middle finger (1.8 cm) were investigated The scattered light images obtained by transillumination were taken from the PIP joints of index finger and middle finger to study the possibility of optical clearing application in optical diagnosis of rheumatoid arthritis Optical clearing agents Dehydrated glycerol and hand cream with urea (5%) were used as OCAs. Refractive indices of glycerolare: 1.469 at 670 nm 1.466 at 820 nm 1.465 at 904 nm Saratov Fall Meeting 2013

5. Saratov State University Department of Optics and Biophotonics Materials and methods Contrast calculation Contrast was calculated in region of interest (ROI) near the middle of the finger joint (fig.2) with special software designed in LabView programming environment Fig.2. An image of ROI for the contrast calculation (blue rectangle) Saratov Fall Meeting 2013

6. Saratov State University Department of Optics and Biophotonics Results Fig.3. An image of finger joint under the action of glycerol in a transmission mode: left image – before agent application, right image – 60 min after agent application. Wavelength is 670 nm. Saratov Fall Meeting 2013

7. Saratov State University Department of Optics and Biophotonics Results Fig.4. An image of finger joint under the action of glycerol in a transmission mode: left image – before agent application, right image – 60 min after agent application. Wavelength is 820 nm. Saratov Fall Meeting 2013

8. Saratov State University Department of Optics and Biophotonics Results Fig.5. An image of finger joint under the action of glycerol in a transmission mode: left image – before agent application, right image – 60 min after agent application. Wavelength is 904 nm. Saratov Fall Meeting 2013

9. Saratov State University Department of Optics and Biophotonics Results Fig.6. An image of finger joint under the action of hand cream in a transmission mode: left image – before agent application, right image – 60 min after agent application. Wavelength is 670 nm. Saratov Fall Meeting 2013

10. Saratov State University Department of Optics and Biophotonics Results Fig.7. An image of finger joint under the action of hand cream in a transmission mode: left image – before agent application, right image – 60 min after agent application. Wavelength is 820 nm. Saratov Fall Meeting 2013

11. Saratov State University Department of Optics and Biophotonics Results Fig.8. An image of finger joint under the action of hand cream in a transmission mode: left image – before agent application, right image – 60 min after agent application. Wavelength is 904 nm. Saratov Fall Meeting 2013

12. Saratov State University Department of Optics and Biophotonics Results Table 1. Contrast in a ROI near the middle of the joint for the case of glycerol topical application Saratov Fall Meeting 2013

13. Saratov State University Department of Optics and Biophotonics Results Table 2. Contrast in a ROI near the middle of the joint for the case of hand cream with 5% urea application Saratov Fall Meeting 2013

14. Saratov State University Department of Optics and Biophotonics Summary Thus, our results shows that glycerol and hand cream with 5% urea allow obtaining of more distinct image of finger joint. In that way we may conclude that investigated OCAs at topical applications to skin can be effectively used as enhancer for the technique for the finding of differences between healthy and pathology joints in transillumination mode. Saratov Fall Meeting 2013

15. Saratov State University Department of Optics and Biophotonics Acknowledgements • Thisresearch was supportedby: • Grant of President of RF NSH-1177.2012.2 • FiDiPro, TEKES Program (40111/11), Finland • RFState contracts№ 14.512.11.0022 and 14.B37.21.0728 Saratov Fall Meeting 2013

16. Thanks for your attention!