Evaluation of tissue blood supply during esophagectomy using fluorescent diagnostics and diffuse scattering spectroscopy in visible region.

Background: The success of the surgical treatment of a tumor or obstruction of the esophagus with subsequent anastomosis application depends on the level of blood supply to the stitched tissues. Intraoperative assessment of blood flow is widely used in medicine and can be used as a diagnostic method that affects the outcome of surgery and reduces the frequency of postoperative complications for the patient.

Methods: In this work, the assessment of blood supply during esophageal resection operations was carried out using two techniques sequentially: fluorescent diagnostics with indocyanine green and measurement of hemoglobin oxygen saturation by diffuse scattering spectroscopy in the visible wavelength range.

Attenuation correction technique for fluorescence analysis of biological tissues with significantly different optical properties.

During intraoperative fluorescence navigation to remove various neoplasms and during pharmacokinetic studies of photosensitizers in laboratory animals, in many cases, the ratio of photosensitizer accumulation in the tumor and normal tissue can reach ⩾ 10-fold, which inevitably changes their optical properties. At the same time, the tumor formation process causes various metabolic and structural changes at cellular and tissue levels, which lead to changes in optical properties. A hardware-software complex for the spectral-fluorescence studies of the content of fluorochromes in biological tissues with significantly different optical properties was developed, and it was tested on optical phantoms with various concentrations of photosensitizers, absorbers, and scatterers.

Optimization of upconversion luminescence excitation mode for deeper in vivo bioimaging without contrast loss or overheating.

Upconversion nanoparticles have attracted considerable attention as luminescent markers for bioimaging and sensing due to their capability to convert near-infrared (NIR) excitation into visible or NIR luminescence. However, the wavelength of about 970 nm is commonly used for the upconversion luminescence excitation, where the strong absorption of water is observed, which can lead to laser-induced overheating effects. One of the strategies for avoiding such laser-induced heating involves shifting the excitation into shorter wavelengths region.