The abilities of the optical probe for fluorescence-guided stereotactic biopsy were investigated by means of a multifiber probe under 532 or 632.8 nm excitation. The set of multilayered phantoms representing a border between normal brain-tissue and a tumor with photosensitizer and gold nanoparticles (spheres or stars) in different concentrations were made to investigate the macroscopic parameters observed during the neurosurgical biopsy sample collection by means of the optical probe. These investigantions will allow to define the border of a brain tumor and control the type of tissue being collected by a stereotactic cannula during surgery. The impact of gold nanospheres and gold nanostars added in different concentrations to the bottom-layer of phantom was analyzed by fluorescence quenching or enhancement due to energy transfer between nanoparticles and fluorescent molecules. The results allow determining the tumor border and to make the biopsy uptake more efficient by observing the character of signal change while penetrating a tumor and while going out of it.

Modern methods of laser photonics, which make it possible to measure the dynamics of micro-deformations of volumetric objects without contact and with high sensitivity, find increasing application in a wide variety of fields. Particularly attractive is the use of such a delicate, non-perturbing technique in medicine. The article reports on experiments using laser photonics methods in dental implantology, which allowed to give practical medical recommendations. In the work, a study was made of the possibilities of holographic and speckle interferometry methods for measuring the deformation of the jaw bone tissue with a step-by-step installation of cylindrical and conical mini implants. The possibility of determining the relaxation time of deformations after the installation of mini implants was demonstrated. The purpose of this work is to justify the possibility and feasibility of using laser photonics  to solve this medical problem.

The use of multicomponent methods of special treatment (surgery, polychemotherapy, radiation therapy, laser photodynamic therapy) in oncology requires the control of doses in the tumor and healthy organs with high accuracy. A method of direct dosimetry using fiber-optic scintillation dosimeter MCD-4 is proposed. The dosimeter is fixed on endostats and is visualized on CT/MRI. The coordinates are entered into the anatomical units and dosimetry calculations, the data are mapped, the doses are adjusted on medical grounds. The developed technique of direct dosimetry allows monitoring of the contact radiation therapy (CRT) procedure in real time and making the necessary changes and corrections during the treatment. The refinement of the absorbed dose values using calculations and direct dosimetry minimizes the risk of complications and ensures the possibility of effective use of other treatment methods, including photodynamic therapy, after CRT.

Laser hyperthermia is one of the promising methods for treatment of oncological diseases. For routine clinical use of hyperthermia, it is necessary to control the uniformity and localization of heat within the tumor. Local heating can be achieved by using special thermal agents, such as nanoparticles doped with rare-earth ions. Measurement of the temperature of the thermal agents will allow timely regulation of the applied laser radiation excitation power and optimization of the hyperthermia process.

The paper presents the results of a study on the non-invasive determination of the YPO₄ nanoparticles doped with Nd³+ temperature with sensitivity of 0.2% °С^-1 in 30-60°С temperature range. The temperature of the nanoparticles was calculated from the Nd³+ luminescence spectra in the 800-1000 nm range under excitation into ⁴F_5/2 energy state by 805 nm laser. A calibration procedure for recalculating the ratio of the luminescence intensities from the Stark sublevels of the ⁴F_3/2 Nd³+ state into the values of the real NP temperature in accordance with the Boltzmann distribution is given. An algorithm for calculating luminescence intensities for individual Stark components is proposed. After calculating the intensities corresponding to each individual Stark component, all the intensities related to the transition from the upper and lower Stark sublevels of the ⁴F_3/2 state are summed, and then their ratio is calculated. The resulting ratio is normalized to the value of the ratio at room temperature and, in accordance with the calibration dependence, is recalculated into the NP heating temperature. It was demonstrated that the investigated 1%Nd³+:YPO₄ nanoparticles can be used as "primary” thermometers that do not require additional recalibration to evaluate the temperature in the range used for hyperthermia.

Photodynamic therapy is a relevant and promising area for research in the field of clinical neuroonocology. Application of modern developments in the field of laser technologies and new photosensitizers allows us to refer to this field as to high-tech. According to various authors, the inclusion of photodynamic therapy in combined and complex treatments of patients with malignant brain tumors allows achieving overall survival median of patients from 11 to 26 months for primary form of glioblastoma, and from 7.5 to 15 months - for recurrent forms of glioblastoma. Certain results have been achieved in the treatment of patients with metastatic brain lesion. In this publication the authors analyzed and systematized the results of the main clinical studies in the field of fluorescent diagnostics and intraoperative photodynamic therapy of primary, recurrent and metastatic forms of malignant brain tumors.

Abstract

This clinical case demonstrates the feasibility of photodynamic therapy (PDT) as a method of choosing the treatment of recurrent lung cancer in inoperable patients with ineffective chemoradiotherapy. An operation was performed on the patient with a diagnosis of pT4N0M0 central cancer of the lower lobe of the right lung after 2 courses of neoadjuvant chemotherapy in October 2015: an expanded combined lower bilobectomy of the right lung, with resection of the pericardium and left atrium. Then 4 courses of adjuvant chemotherapy (cisplatin + vinorelbine) and a course of radiotherapy on the mediastinum area up to a total dose of 45 Gy were carried out. After 2 months, a metastatic lesion of bifurcation lymph nodes with invasion of the mucosa of the tracheal bifurcation, involving the distal trachea, proximal right and left main bronchi was detected. The result of histological analysis: G2 squamous cell carcinoma without keratinization. From Dec 2016 to Jun 2017, the patient underwent 5 courses of PDT, as a result of which a significant cytoreductive effect and stabilization of the process were achieved. The continuation of the PDT treatment is planned.