Evaluation of laser-induced effects on multilayer tissues of hollow organs by determining their optical properties
Anna A. Krivetskaya1,2, Daniil M. Kustov1, Vladimir V. Levkin3, Sergey S. Kharnas3, and Tatiana A. Savelieva1,2
1 Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia
2 Institute of Engineering Physics for Biomedicine, National Research Nuclear University MEPhI, Moscow, Russia
3 Department of Faculty Surgery No. 1, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
Abstract
Nowadays, the assessment of the optical properties (absorption coefficient, scattering coefficient and anisotropy factor) of the separate layers of biological tissues is performed only on resected samples. One established approach for this task involves measurements using integrating spheres [1–3]. Determining these optical properties immediately before or during laser exposure in the course of treatment would enable personalization of the procedure. The aim of this investigation was to obtain a method for assessing optical properties that is suitable for real-time use in clinical settings by adapting the integrating-sphere measurement methodology to measurements with a fiber-optic spectrometer.
To acquire the initial values of the optical properties the modified two-stream Kubelka-Munk model was used. The layered assessment of optical properties was carried out using the developed method based on the inverse adding-doubling method. Verification of the developed algorithm for restoring the absorption coefficient, scattering coefficient and anisotropy factor was carried out using numerical modeling of light propagation in tissues using the Monte Carlo method, optical phantoms, and resected gastrointestinal tract samples. The approbation was performed on the diffuse reflection and transmission spectra recorded in laboratory and clinical conditions. In the first case, there were two sets of equipment: the spectrophotometer “Hitachi U-3400” with integrating sphere and setup with the optical-fiber spectrometer “LESA-01-BIOSPEC”. In the intraoperative conditions only fiber-optic equipment was used.
According to the results of the work, the developed method is suitable for the local layer-by-layer determination of the optical properties in vivo in real time and can be used to adjust the laser dose during photodynamic therapy.
The work was funded by the Russian Science Foundation, grant No. 25-25-00516.
[1] A. Bashkatov, E. Genina, V. Kochubey, V. Rubtsov, E. Kolesnikova, V. Tuchin, Optical properties of human colon tissues in the 350 – 2500 nm spectral range, Quantum Electronics, vol. 44, p. 779, (2014).
[2] A. Bashkatov, E. Genina, V. Kochubey, A. Gavrilova, S. Kapralov, V. Grishaev, V. Tuchin, Optical properties of human stomach mucosa in the spectral range from 400 to 2000 nm: Prognosis for gastroenterology, Medical Laser Appli-cation, vol. 22. pp. 95-104, (2007).
[3] R. Marchesini, E. Pignoli, S. Tomatis, S. Fumagalli, A.E. Sichirollo, S. Di Palma, M. Dal Fante, P. Spinelli, A.C. Croce, G. Bottiroli, Ex vivo optical properties of human colon tissue, Lasers in surgery and medicine, vol. 15(4), pp. 351–357, (1994).
Speaker
Anna Krivetskaya
Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia; Institute of Engineering Physics for Biomedicine, National Research Nuclear University MEPhI, Moscow, Russia
Russia
Discussion
Ask question
