For many years, photobiomodulation in cancer patients has been used empirically, based on the positive clinical experience. When using PBM for the prevention and treatment of early radiation toxicity, exposure can occur directly in the area of the tumor site. For that reason, the data is need about a potential influence of low-intensity red light as on the normal as well on the tumor cells exposed to ionizing radiation. The aim of the work was to study the effects of photobiomodulation (PBM) in the red spectrum (640 nm) with fluences from 3 mJ/cm2 to 2 J/cm2 in combination with ionizing radiation at doses of 2–6 Gy against human BJ-5ta-hTERT cells – postnatal fibroblasts. The cells were exposed to low-intensity red light before or after their exposure to IR, the viability of the cells was determined by MTT-test 24 hours after the last exposure. The effects of PBM depend on the fluence of PBM, the dose of IR and the sequence of the actions of these physical factors on cells. The adaptive effect of PBM was observed only for high fluences – 1 and 2 J/cm2 when exposed to PBM and subsequent irradiation of IR. At the same time, the stimulating effect of PBM was observed only for low fluences from 3 to 300 mJ/cm2 under IR irradiation and subsequent (after 1 hour) exposure to PBM. These data should be taken into account when using PBM for the correction of adverse events of radiation therapy in a clinic.
The possibilities of optoacoustic microscopy for comparison of vascular network of different tumor models as well as for investigation of tumor vessels response to radiation therapy were demonstrated.
Using optoacoustic microscopy, a radiation-induced increase in the fragmentation of experimental tumor small vessels, as well as the formation of large hemoglobin-containing structures were revealed within first days after treatment.
Development of a number of diseases is accompanied by changes in the blood vessels’ structure and the investigation of tissue vascular pattern remains one of the most essential problems in experimental and clinical medicine. Hybrid methods of optoacoustic (OA) imaging enable label-free optical-contrast angiography at optical penetration depths with ultrasonic resolution. We used OA to study vascular network of experimental tumor during growth and after treatment as well as to study the dynamics of blood content of human skin during functional tests. Optoacoustic angiography was performed using raster-scan system in reflection mode with 532 nm laser source and wideband PVDF detector. The sensitivity of the system allowed to visualize 50 µm blood vessels at up to 2.1 mm depth. Minimally detected diameter of blood vessel located at the surface of a soft tissue was 15 µm. Imaging of colon tumor models CT26 and HT-29 revealed peculiarities of vascular system development. Irradiation-induced increase of small tumor vessels segments number and parallel decrease in the number of large hemoglobin-containing structures were demonstrated. The fraction of blood-filled vessels of the human skin was assessed during cuff occlusion and temporarily filling with blood became clearly visible on OA images. To study the effects of local mechanical compression on human skin vasculature we varied external pressure and revealed the gradual drop in OA signal from blood vessels. We demonstrated the possibilities of raster-scan angiography for in vivo analysis of vessels structure, for monitoring of neoangiogenesis and for dynamical investigation of blood content under external actions.
The aim of the work was studying the effects of photobiomodulation in doses of less than 1 J/cm2 in combination with gamma-irradiation to Hela Kyoto cells. Tumor cells were irradiated with 640 nm LED at different energy densities before and after to gamma-irradiation. Cells viability was determined 24 h after exposure for each gamma-irradiation dose and PBM mode. There was a statistically significant decrease in a number of viable tumor cells for samples that were exposed to PBM prior to gamma-irradiation and a statistically significant increase in a number of viable tumor cells for samples that were exposed to PBM after gamma-irradiation.
The aim of this study was to compare the effectiveness of low-intensity LED radiation of the red and infrared spectra for the correction of mucositis in patients receiving radiation and chemoradiation therapy for oral and pharyngeal cancer at an energy density of less than 1 J/cm2. The study included 106 patients who received radiation and chemoradiation therapy for oral cavity and pharyngeal cancer, who were randomly divided into three groups. In the first (37 patients) correction of mucositis was carried out in accordance with the clinic's standards, in the second (36 patients) and the third (33 patients), patients additionally received exposure to the oral cavity with low-intensity LED radiation at a wavelength of 635 nm at a dose of 0,3 J/cm2 (prophylactic regimen) and 0.45 J/cm2 (treatment regimen). When exposed to a wavelength of 780 nm, the dose was 0.6 J/cm2 with a prophylactic regime and 0.8 J/cm2 with a therapeutic regimen, respectively. Exposure to low-level LED irradiation at a wavelength of 635 nm significantly reduced the frequency and severity of radiation mucositis, increased the time until the onset of its first symptoms, reduced the duration of severe mucositis (grade 3) and reduced the patients' need for painkillers, including narcotic analgesics compared with the group receiving standard prophylaxis and correction of mucositis. Photobiomodulation at a wavelength of 780 nm, compared with the standard correction group, significantly increased the time to the onset of the first symptoms of mucositis and decreased the severity of pain.
Bladder cancer, occurring at different times after radiation therapy for tumors of the pelvic organs (cervical cancer, uterus cancer, prostate cancer) is a specific problem of oncourology. The main visual manifestations of the adverse events of radiation therapy in early time after irradiation are pronounced edema and hyperemia of the bladder mucosa, in the case of severe complications – hemorrhages. In years after radiation exposure atrophic changes of the mucous membrane, telangiectasia and reduction of the capacity of the bladder occur; late complications of a severe degree manifest as ulcers and fistulas. The main clinical symptoms of bladder cancer are hematuria and dysuria. The cystoscopy still remains the “gold standard” for its diagnosis, but this method appears to have significant limitations if a tumor arises in bladder tissue suffering from radiation exposure. In this case, the clinical symptoms and the cystoscopic picture can be regarded as manifestations of the side effects of RT, especially in case of grade 3 and 4 of complication. Optical methods may play a key role for distinguishing between a metachronous bladder cancer and severe complications of radiation therapy. Optical coherence tomography (OCT) has a spatial resolution corresponding to several micrometers and makes it possible to assess the structure of biological tissues at a depth of up to 2 mm. Besides, polarization-sensitive methods OCT (CP OCT) allow evaluating the state of the connective tissue matrix which loses orderliness and organized structure of the arrangement of collagen fibers and bundles in malignant tumors. The study presents the case reports of bladder cancer which arose against the radiation-induced changes of bladder tissue after previous irradiation for cervical cancer and were diagnosed by optical coherence tomography.
The objective of the study is the quantitative analysis of the dose-time dependences of changes occurring in collagen of bladder and rectum after gamma-irradiation using optical methods [nonlinear microscopy in a second harmonic generation (SHG) detection regime and cross-polarization optical coherence tomography (CP OCT)]. For quantitative assessment of the collagen structure, regions of interest on the SHG-images of two-dimensional (2-D) distribution of SHG signal intensity of collagen were chosen in the submucosa. The mean SHG signal intensity and its standard deviation were calculated by ImageJ 1.39p (NIH). For quantitative analysis of CP OCT data, an integral depolarization factor (IDF) was calculated. Quantitative calculation of the SHG signal intensity and the IDF can provide additional information about the processes of the collagen radiation-induced degradation and subsequent remodeling. High positive correlation between the mean SHG signal intensity and the mean IDF of bladder and rectum demonstrates that CP OCT can be used as an “optical biopsy” in the grading of collagen radiation damage.
The ability for noninvasive visualization of functional changes of a tumor’s oxygenation and circulatory system offers new advantages for prognosis and monitoring of the treatment efficacy. The results of breast cancer oxygen state study under chemotherapy action obtained by diffuse optical spectroscopy (DOS) in combination with Doppler ultrasonic imaging are presented. Complex use of optical and ultrasound methods gives complementary information about the size of the tumor node, peculiarities of its vascular bed, rate of its blood flow as well as oxygenation, and provide a picture of the tumor response to treatment. Comparison with tumor pathologic response allowed to identify differences in the changes of these parameters depending on the degree of pathological tumor response to chemotherapy. It was demonstrated that fourth and fifth degrees of therapeutic pathomorphism may be predicted by the increase of oxygen saturation level after the first cycle of chemotherapy. If the reduction or absence of the oxygen saturation dynamics is observed, first or second degree of pathological tumor response can be expected. Additional ultrasound investigation of the tumors may be useful for observation of the dynamics of tumor blood flow thereby for understanding the reasons of induced chemotherapy oxygenation changes. The proposed approach based on DOS and ultrasonography may be applied for monitoring of breast tumors under therapy and prediction of their sensitivity.
Effective breast cancer treatment requires the assessment of metabolic changes of tumor tissue during chemo- and hormonotherapy for prediction tumor response. Evaluation of the dynamics of tumor oxygen state (by diffuse optical spectroscopy imaging) and tumor vasculature (by ultrasound investigation in power Doppler mode) was performed before treatment beginning and before the second cycle of chemotherapy in 16 patients who received preoperative chemotherapy. Changes of these indicators were compared then with tumor pathologic response. Breast tumors demonstrated different dynamics of tumor oxygenation depending on the changes of tumor tissue. The increase of the tumor oxygenation after the first cycle of chemotherapy was observed in five of six patients with grade 4 and 5 of pathologic tumor response. Decrease of the oxygenation level was revealed in one patient with the 4th degree of tumor response. Variable changes of the oxygenation level were mentioned in the patients with moderate (the 3d degree) tumor response. Tumor oxygenation decreased or was unchanged in case of 1 or 2 degree of tumor response in five of six cases. The study of the tumor blood vessels didn't reveal any correlation between vasculature changes and tumor response under the performed treatment. The trend of tumor oxygenation in early time after treatment beginning might be a predictive criterion of tumor sensitivity to chemotherapy.
Recently proposed in vivo label-free optical coherence angiography techniques based on phase and amplitude speckle variability often require additional signal pre- and post processing operations to enhance vessel-contrast. We observe here 1) contrast enhancement by optimizing the signal normalization/weighing before processing; 2) algorithm based on Kasai estimator for phase compensation between processed A-scans to reduce masking role of motion artifacts; and 3) image projection through the imaging depth for en face plotting. We demonstrate the efficiency of proposed additional algorithms as for the microcirculation imaging of hamsters cheek in vivo as for the preliminary microcirculation imaging of patients after radiotherapy. This technical framework complete in details our recent publications on M-Mode like OCT algorithms and its implementation.
The aim of the work was to study the participation of hydrogen peroxide in reaction of cervical cancer cell line HeLa Kyoto on cisplatin action. Determination of hydrogen peroxide level was performed using genetically encoded fluorescent sensor HyPer2. The dependence of cell viability on cisplatin concentration was determined using MTT assay. Mechanisms of cell death as well as HyPer2 reaction was revealed by flow cytometry after 6-hours of incubation with cisplatin in different concentrations. Cisplatin used in low concentrations had no effect on hydrogen peroxide level in HeLa Kyoto cells. Increase of HyPer2 fluorescence was detected only after exposure with cisplatin in high concentration. The reaction was not the consequence of cell death.
Adverse events in normal tissues after irradiation of malignant tumors are of great importance in modern radiation oncology. Second harmonic generation (SHG) microscopy allows observe the structure of collagen fibers and bundles without additional staining. The study objective was evaluation the dose-time dependences of the structural changes occurring in collagen of rat rectum and bladder after gamma-irradiation. Animals were irradiated by a local field at single doses of 10 Gy and 40 Gy. The study of collagen state was carried out in a week and a month after radiation exposure. Paraffin-embedded material was sectioned on the slices 10 mkm thick and SHG-imaging was performed by LSM 510 Meta (Carl Zeiss, Germany). Excitation was implemented with a pulsed (100-fs) titanium-sapphire laser at a wavelength of 800 nm and a pulse repetition frequency of 80 MHz, registration was performed at two wavelengths: 362-415 nm according to collagen fluorescence and 512-576 nm according to myoglobin fluorescence. In a week after irradiation, sings of epithelial damage and edema of submucosal layer, more significant after the dose of 40 Gy were observed on LSM-images. The SHG signal decreased at this time reflecting the processes of collagen degradation independently either in bladder or in rectum. In a month after radiation the increase of size and number of collagen-bearing structures was observed, more essential after irradiation in a dose of 40 Gy. LSM microscopy with SHG allows evaluate changes of normal tissues after ionizing radiation and get information in addition to standard and special histological staining.
Diffuse Optical Tomography (DOT) is based on acquiring information from multiply scattered light which penetrates
into the tissue up to depths of several centimeters. This technique allows for imaging of absorbing and scattering
inclusions inside tissue and distinguishing between them after computer processing of an image. An experimental setup
for multicolor frequency-domain diffuse optical tomography (FD DOT) to visualize neoplasia of breast tissue and to
estimate its size has been created. A breast is scanned in the transilluminative configuration by a single source and
detector pair. Illumination at three wavelengths (684 nm, 794 nm, and 850 nm) which correspond to different parts of the
absorption spectrum provides information about concentration of the main absorbers (oxygenated hemoglobin,
deoxygenated hemoglobin, and fat/water). Source amplitude modulation at 140 MHz increases spatial resolution and
provides separate reconstruction of scattering and absorption coefficients. In vivo study of breast carcinoma has been
performed. Maps of 2D distributions of reconstructed absorption and scattering coefficients and concentration of
hemoglobin have been obtained. An increase of absorption and scattering coefficient, total hemoglobin concentration and
decrease of blood oxygen saturation is observed in the tumor area in comparison with the surrounding tissue. We can
conclude that FD DOT technique confirms a possibility of detecting neoplastic changes.
We present the results in optical coherence tomography (OCT) visualization of structural changes in human oral cavity and pharyngeal mucosa for 14 patients in the process of radiation and chemoradiation therapy. Typical mucosal changes are seen as a decrease in the tissue layer contrast progressing to a complete contrast loss as severe mucosal damage occurs. Similar evolution in OCT images was observed for all patients. OCT changes can be seen prior to visual mucosal changes and increased as more mucosal damage occurs. Moreover, OCT was able to obtain information on the specific features of the patient response depending on the irradiation method and the individual radiosensitivity.
We present pilot results in optical coherence tomography (OCT) visualization of normal mucosa radiation damage. 15 patients undergoing radiation treatment of head and neck cancer were enrolled. OCT was used to monitor the mucositis development during and after treatment. OCT can see stages of radiation mucositis development, including hidden ones, before any clinical manifestations.
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