Possibilities of Laser Spectroscopy Methods for Prediction of the Radiotherapy Results

In this paper, possibilities of laser fluorescence spectroscopy to predict the reactions of the oral cavity cancer to radiation treatment are considered. A theoretically substantiated assumption about the link between the tumor’s consumption of an exogenous photosensitizer and its radioresistance is proposed. The first experience with the use of the Radahlorin photosensitizer is described; preliminary results of the 5 patients study are presented. As a result different photosensitizer consumptions versus different treatment outcomes are discussed. Keywords: laser fluorescence spectroscopy, photosensitizer, oral cavity cancer, radiotherapy, cross-resistanc

Лазерная флуоресцентная спектроскопия и оптическая тканевая оксиметрия в диагностике фиброза кожи

There are currently no effective measures to combat fibrosis in modern medical practice. One of the reasons for that is the late diagnosis associated with the lack of available clinical biomarkers and effective methods of non-invasive detection of the process. Fibrosis of the skin is characterized by fibrosis of the dermis, underlying tissues and is represented by a wide range of nosologies. Scleroderma and scars are of the greatest interest for the study. Skin changes in the development of bleomycin-induced fibrosis was studied in the experimental model using laser fluorescence spectroscopy and optical tissue oximetry. A significant increase in the rates of endogenous fluorescence of porphyrins, caused by inflammation and hypoxia, was detected at 7 and 21 days. An increased intensity of endogenous collagen fluorescence and a decreased specific oxygen uptake due to excess accumulation of the extracellular matrix were recorded on the 21st day after bleomycin treatment. Synchronous measurements of the collagen fluorescence and the specific oxygen uptake allowed to correlate the obtained data and the phases of the fibrogenic response described morphologically. The results allow to judge the severity of inflammation and hypoxia in the process of the fibrosis development. The objective and quantitative nature of the recorded parameters makes it possible to develop criteria for diagnosing the phases of fibrosis development.В современной медицинской практике нет эффективных мер борьбы с фиброзом. Одна из причин – поздняя диагностика, связанная с отсутствием доступных клинических биомаркеров и эффективных методов неинвазивного обнаружения этого процесса. Фиброзирующие заболевания кожи характеризуются фиброзом дермы, подлежащих тканей и представлены широким спектром нозологий. Наибольший интерес для изучения представляют склеродермия и рубцы кожи. На экспериментальной модели методами лазерной флуоресцентной спектроскопии и оптической тканевой оксиметрии изучены изменения кожи в рамках развития блеомицин-индуцированного фиброза. Выявлен достоверный рост показателей эндогенной флуоресценции порфиринов на 7 и на 21 сут, вызванный воспалением и гипоксией. Зафиксированы повышение интенсивности эндогенной флуоресценции коллагена и снижение показателей удельного потребления кислорода на 21 сут исследования, связанные с избыточным накоплением межклеточного матрикса. Синхронные измерения флуоресценции коллагена и удельного потребления кислорода позволили провести корреляцию с фазами фиброгенного ответа, описанного морфологически. Полученные результаты позволяют судить о выраженности воспаления и гипоксии в процессе развития фиброза. Объективный и количественный характер регистрируемых параметров дает возможность разработки критериев для диагностики фаз развития фиброза

Laser fluorescence spectroscopy and optical tissue oximetry in the diagnosis of skin fibrosis

There are currently no effective measures to combat fibrosis in modern medical practice. One of the reasons for that is the late diagnosis associated with the lack of available clinical biomarkers and effective methods of non-invasive detection of the process. Fibrosis of the skin is characterized by fibrosis of the dermis, underlying tissues and is represented by a wide range of nosologies. Scleroderma and scars are of the greatest interest for the study. Skin changes in the development of bleomycin-induced fibrosis was studied in the experimental model using laser fluorescence spectroscopy and optical tissue oximetry. A significant increase in the rates of endogenous fluorescence of porphyrins, caused by inflammation and hypoxia, was detected at 7 and 21 days. An increased intensity of endogenous collagen fluorescence and a decreased specific oxygen uptake due to excess accumulation of the extracellular matrix were recorded on the 21st day after bleomycin treatment. Synchronous measurements of the collagen fluorescence and the specific oxygen uptake allowed to correlate the obtained data and the phases of the fibrogenic response described morphologically. The results allow to judge the severity of inflammation and hypoxia in the process of the fibrosis development. The objective and quantitative nature of the recorded parameters makes it possible to develop criteria for diagnosing the phases of fibrosis development

Non-invasive Optical Methods in Quantitative Minimal Erythema Dose Assessment in Vivo: Comparison of Preclinical and Clinical Data

Even in modern dermatology clinics, the determination of the severity of ultraviolet (UV)-induced erythema and assessment of individual photosensitivity based on the calculation of minimal erythema dose (MED) is still performed visually, which is subjective, and associated with high variability of the results and frequent errors when it done be untrained personnel. The application of non-invasive quantitaitve methods such as laser fluorescence spectroscopy (LFS) and optical tissue oximetry (OTO) could be a solution of these problems. In is well known that acute UV skin damage is associated with structural alterations, vasodilatation and inflammatory response. Moreover, porphyrins which have well-known autofluorescent properties play a role in the chemoattraction of immune cells to the area of local inflammation caused by UV. Using LFS in the preclinical part of the study on ICR mice (N = 25) time-dependent dynamic changes in the fluorescence parameters of porphyrins were found. Optical parameters were in a good agreement with histological findings. Statistically significant correlation was found between the severity of inflammatory infiltrate and the tissue content index (η) of porphyrins. During the clinical part of the study on healthy volunteers (n = 14) the analysis of endogenous fluorescence and microcirculation characteristics by LFS and OTO revealed the correlation relationship between the intensity of endogenous fluorescence of porphyrins and oxygen consumption with a dose of UV radiation. The correlation of the porphyrins fluorescence with a dose of UV was also demonstrated. Overall results have fundamental value and should be investigated and applied in clinical practice to objectively assess and predict MED. © 2021, Springer Nature Switzerland AG

Non-invasive Optical Methods in Quantitative Minimal Erythema Dose Assessment in Vivo: Comparison of Preclinical and Clinical Data

Even in modern dermatology clinics, the determination of the severity of ultraviolet (UV)-induced erythema and assessment of individual photosensitivity based on the calculation of minimal erythema dose (MED) is still performed visually, which is subjective, and associated with high variability of the results and frequent errors when it done be untrained personnel. The application of non-invasive quantitaitve methods such as laser fluorescence spectroscopy (LFS) and optical tissue oximetry (OTO) could be a solution of these problems. In is well known that acute UV skin damage is associated with structural alterations, vasodilatation and inflammatory response. Moreover, porphyrins which have well-known autofluorescent properties play a role in the chemoattraction of immune cells to the area of local inflammation caused by UV. Using LFS in the preclinical part of the study on ICR mice (N = 25) time-dependent dynamic changes in the fluorescence parameters of porphyrins were found. Optical parameters were in a good agreement with histological findings. Statistically significant correlation was found between the severity of inflammatory infiltrate and the tissue content index (η) of porphyrins. During the clinical part of the study on healthy volunteers (n = 14) the analysis of endogenous fluorescence and microcirculation characteristics by LFS and OTO revealed the correlation relationship between the intensity of endogenous fluorescence of porphyrins and oxygen consumption with a dose of UV radiation. The correlation of the porphyrins fluorescence with a dose of UV was also demonstrated. Overall results have fundamental value and should be investigated and applied in clinical practice to objectively assess and predict MED