Methods, Invited Lecture

INTERPLAY AMONG TEMPERATURE, THERMAL-STRESS AND STRAIN FIELDS IN LASER-ASSISTED MODIFICATION OF COLLAGENOUS TISSUES STUDIED BY SPECKLE-CONTRAST TECHNIQUE AND OPTICAL COHERENCE ELASTOGRAPHY

Vladimir Zaitsev, Institute of Applied Physics RAS, Russia
Olga I. Baum, Institute of Photon Technologies, FSRC “Crystallography and Photonics”, RAS, Moscow, Russia
Alexey V. Yuzhakov, Institute of Photon Technologies, FSRC “Crystallography and Photonics”, RAS, Moscow, Russia
Alexander P. Sviridov, Institute of Photon Technologies, FSRC “Crystallography and Photonics”, RAS, Moscow, Russia
Maria L. Novikova, Institute of Photon Technologies, FSRC “Crystallography and Photonics”, RAS, Moscow, Russia
Alexander L. Matveyev, Institute of Applied Physics RAS, Russia
Lev A. Matveev, Institute of Applied Physics RAS, Russia
Alexander A. Sovetsky, Institute of Applied Physics RAS, Russia
Emil N. Sobol, IPG Medical Corporation, Marlborough, Massachusetts, USA

ABSTRACT

Moderate heating of such collagenous tissues as cartilage and cornea by infrared laser irradiation can produce biologically non-destructive structural rearrangements and relaxation of internal stresses resulting allowing for the tissue reshaping. The reshaping results and biological properties of the tissue strongly depend on the laser-irradiation regime. Conventionally, influence of the heating on the tissue is discussed in terms of the Arrhenius probability and influence of direct heating. Here, we experimentally demonstrate an important role of thermally produced stresses in such tissue modification. We used a speckle-contrast technique based on monochromatic illumination of the tissue and strain mapping by means of optical coherence elastography (OCE). The speckle-based technique readily ensures en-face visualization of the irradiation-induced motion of scatterers via cross-correlation and speckle-contrast processing, whereas OCE ensures quantitative depth-resolved B-scans of irradiation-induced strain-evolution. The observations demonstrate an important contribution of thermal stresses along with straightforward heating. The used techniques can be used for real-time control of the reshaping procedures (e.g., for laser shaping of cartilaginous implants in otolaryngology and maxillofacial surgery) and optimization of the laser-irradiation regimes to ensure the desired reshaping using lower and biologically safer temperatures.

Representing author

photo

Dr. Vladimir Zaitsev

Institute of Applied Physics RAS, Leading Researcher
Nizhny Novgorod, Russia

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