The systems of biological objects images multispectral processing are usually applied for both medical diagnostic devices and devices providing the environmental state control. The basic component of each multispectral processing system is spectral selective element, for example, diffraction grating. Nowadays the acousto-optic tunable filters (AOTF) are often used as selective elements in such systems. The problem of interconnection of spatial and spectral information which can be transferred by means of AOTF, is the principal consideration subject in the present paper. The problem of the corresponding kind of information choice as kind of priority, is solved by means of the hierarchy system organization. It has been shown that increasing of spectral information is accompanied by spatial information losses only along one coordinate. It is necessary to form the system design by such way that information losses would be only at expense of the less valuable information. It is especially important for the multispectral processing of images obtained by the methods of microscopy.

Selective Laser Trabeculoplasty (SLT) is a treatment option for open-angle glaucoma, however, it lacks an instant evidence for successful irradiation. So far ophthalmologists use the visible appearance of permanent champagne like bubbles as an indicator for appropriate pulse energy. We hypothesize that micro bubbles, which take place far below the appearance of macro bubbles already trigger the therapeutic benefit. Here we present two techniques for real-time detection of the onset of micro bubbles. The trabecular meshwork of freshly enucleated porcine eye globes was irradiated, in contrast to conventional SLT, with a series of 15 pulses with a pulse duration of 1.7 μs and with increasing energy at a repetition rate of 100 Hz per each spot of 200 μm in diameter. Both observation methods, an optoacoustic and an optical, are equally capable of detecting micro bubble nucleation, with sensitivities over 0.83 and specificities over 0.89. We demonstrated an accurate method for detection of micro bubble formation in SLT. In case that the therapeutically demanded pressure reduction is already achieved with these micro bubbles, which needs to be proved clinically, then the methods presented here can be used in a feedback loop controlling the laser irradiation. This will unburden the clinicians from any dosing during SLT.

Selective retina therapy (SRT) is a short pulse (μs-regime) alternative to conventional laser photocoagulation (LPC) for treatment of retinal diseases. LPC leads to collateral damage of retinal layers adjacent to the retinal pigment epithelium (RPE), including healthy, non-regenerative photoreceptors due to the high thermal load, whereas in SRT, RPE cells are destroyed by microbubbles without damaging the neuronal retina. A novel experimental SRT laser operating at 532 nm wavelength can deliver 2 – 20 μs pulse sequences. Its tight integration into an upgraded diagnostic SPECTRALIS system combines beam control for treatment planning with real-time optical coherence tomography (OCT) overexposure protection of the photoreceptors. This “Spectralis Centaurus” system, was built and preliminary tested on porcine ex-vivo samples, reaching an unprecedented accuracy with unique planning and follow-up capabilities for upcoming clinical cellular level micro-surgery. The combination of OCT with SRT selectively limits cell death to the RPE by precisely controlling energy deposition while optically monitoring tissue response.

Femtosecond laser is routinely used in Ophthalmology to cut donor and patient’s cornea in lamellar or penetrating keratoplasty. Different cut shapes can be chosen, on the basis of the specific patient’s pathology and morphology and on surgeon’s skills. Different cut geometries provide different internal load resistance of the cornea, and this can affect the surgical outcomes. This work aims to qualitatively evaluate the biomechanical load resistance of the different configurations that are currently used in laser assisted keratoplasty, in order to support the surgeon’s choice. A 3D finiteelement biomechanical model of the human cornea was developed and different geometric configurations were designed, taking into account the possible different orientations of the cornea lamellae. We evidenced a different wound resistance to internal loads in the different laser trephined profiles, as well as a different distribution of the stresses in relation to the donor cornea orientation. The analyzed profiles are the mushroom, top hat and anvil. The anvil profile resulted more resistant to the increasing internal pressure, in accordance with the clinical results. The anvil profile enabled the apposition of a restricted number of sutures and early suture removal, thanks to its greater mechanical load resistance. These advantages can contribute to a faster visual recovery in patients undergoing penetrating keratoplasty.

Laser-generated fenestration is an alternative option for the intraoperative and selective modification of a endovascular endograft, especially in cases where patients are unsuitable for a standard endovascular aneurysms repair. Recently, diode laser approach has been proposed as a substitution of mechanical fenestration. In fact, using a near infrared wavelength (810 nm), the stent graft fabric can be successfully perforated. In this work we report an ex-vivo study providing the harmlessness of laser irradiation effects on biological tissue surrounding the endograft wall. 225 samples of human aortic tissue were irradiated varying energy and pulse duration of an 810 nm diode laser. Irradiated tissues were analyzed under histological examination. Thermal damage was evidenced in the 7.5% of the irradiated samples, typically in the contact area between the laser fiber tip and the aortic wall. These experiments suggest that the diode laser can be safely used for the proposed surgical application.

In this study, we aimed to develop a novel femtosecond laser-based technique for individual embryo tagging. We have demonstrated for the first time the possibility to create individual alphanumeric codes be means of femtosecond laser microsurgery directly on embryo’s outer shell. Femtosecond laser pulses (wavelength of 514 nm, pulse duration of 280 fs, repetition rate of 2.5 kHz, pulse energy of 20 nJ) were applied for precise alphanumeric code engraving on the zona pellucida of mouse embryos at the zygote stage. The code consisted of 4-5 characters (numerical and/or alphabetical) typically. Embryo quality assessment was performed every 24 hours post laser-assisted marking by light microscopy and compared with that of non-treated control embryos. The codes engraved could be clearly recognized until the thinning of the zona pellucida prior to hatching. No differences in morphology and developmental rates of laser-treated embryos and control embryos were found. Our results demonstrate the suitability of femtosecond laser as a novel tool for noninvasive embryo tagging, enabling embryo identification from day 0.5 post coitum to at least early blastocyst stage. The technique proposed is relatively fast, reliable and simple, and can be fully automated in the future. It can be performed in a contactless mode under sterile conditions and does not require any additional equipment (except microscope) to visualize the code and to identify the embryo. As far as femtosecond lasers offer several important advantages (such as high precision, minimal invasiveness, versatility etc.) over conventional milli/microsecond lasers we believe that further advances in ultrafast laser technology aimed at reducing complexity, size and high price of femtosecond lasers will help them gain popularity in the field of assisted reproduction.

Thermography is used in many application areas like non-destructive testing, architecture or zoology. Approaches to use thermography for medical diagnostics are usually focused on the detection of tumors. The usefulness and specificity for this purpose has been debated. Nevertheless it seems reasonable to evaluate the applicability of thermography as a tool for determining temperature distributions on the surface of, e.g., light diffusers or biological tissue in the field of laser medicine. The assessment of tissue-heating in treatments like interstitial photodynamic therapy (iPDT) is of particular interest since additional tissue damage due to tissue heating is usually undesired and has thus to be avoided. Monte Carlo based simulations of the expected heat distribution in tissue are based on idealized setups. They usually omit certain characteristics of fibers, like inhomogeneities in a light diffuser or losses at components such as internal mirrors, that might potentially result in local hot spots and therefore in heating beyond an acceptable temperature. Experimental techniques based on thermocouples, or similar point-based temperature measurement devices, provide only a limited view of the temperature distribution inside or at the surface of the treated tissue. As a high resolution non-contact wide-field technique thermography although has some limitations. We present an evaluation of the usefulness of thermographic methods for recording the heat distribution on tissue and tissue phantom surfaces during laser treatment in an iPDT-like setup and compare the results with Monte Carlo based simulations.

We have developed a lipolysis laser system that can be commercialized using wavelengths of 1980 nm and 2300 nm with excellent absorption in fat and water. An 808 nm laser diode and Nd:YVO4 were used to generate a 1064 nm wavelength light source, which is used as pumping light for nonlinear crystals. The oven was designed and fabricated to precisely control the temperature of the nonlinear crystal and applied to the mid-infrared lipolysis laser system. The characteristics of the developed laser were validated by measuring the change of the wavelength depending on the temperature and the output according to the wavelength. We analyzed fat reduction efficacy appears for two selected wavelengths.

Automatic feedback temperature control has been proposed recently as a promising approach for retinal thermal laser therapy. It can regulate the retinal temperature increase to a pre-specified desired value, which can provide homogeneous temperature increase at the different irradiation sites as the feedback control can automatically set the required corresponding laser power. Therefore, we can avoid over treatment and its consequences due to the manual setting often provided by ophthalmologists in practice. However, in order to achieve successful automatic treatment, a mathematical model for the process is necessary to synthesize the feedback control algorithm. In this study, we develop a model, which can describe the dynamical relation between the temperature increase and the applied laser power at the different irradiation sites. We adopt the system identification approach, which is used to build mathematical models for dynamical systems based on experimental measurements. The identified model here can fit the rear-time data with an accuracy of about 91 ± 1.91%, which indicates its validity for effective feedback control. The control algorithm based on such models can achieve consistent irradiation time of about 50 ms in simulation

The conditions for deep, controlled, low-temperature (cavitational) laser dissection of biological tissues through the formation of a directional wave of enlightenment are considered.

A portable fluorescence meter with two photodetector channels was developed for risk assessment of cardiovascular diseases by in vivo measurement of advanced glycation end products (AGEs) content in the skin. One of the channels served to measure the intensity of the skin autofluorescence, and the other channel was used for normalization to the patient’s skin phototype by measuring the intensity of diffuse scattered radiation. A light-emitting diode with the peak wavelength 365 nm was used for excitation and silicon photodiodes with band filters served as photodetector assay. The AGEs measurements was performed for 70 patients with coronary heart disease and 100 practically healthy volunteers. The age grouping of patients have been used to reveal the trends in the variation of autofluorescence intensity with the factors of natural age degradation of skin collagen. It was shown that the pathologic process related to the metabolic stress directly determines the skin autofluorescence in patients with coronary heart disease.

Autosomal-dominant acute porphyria, a group of rare metabolic diseases, can lead to life-threatening neurovisceral attacks. Currently, no efficient screening test is available. Elevated urinary porphobilinogen (PBG) in addition to elevated porphyrins is highly specific for an attack of acute porphyria. This study proposes and evaluates a custom-made device, algorithm, and methods for a two-step quantification of urinary porphyrins and PBG. The first step is oxidation of the nonfluorescent porphyrinogens and subsequent fluorescence-spectroscopic determination of total urinary porphyrins (TUP) using second derivative spectral fitting. Photo-oxidation is compared with chemical oxidation methods. The second step is the quantification of porphobilinogen in case of elevated TUP. Heat-induced conversion products of PBG, namely uroporphyrin and porphobilin, are determined by fluorescence and absorption spectroscopy. The results of TUP quantification using the developed second derivative fitting algorithm show that both inaccuracy and imprecision were below 15% for concentrations of 0.2 μmol/L and higher. Heating of PBG generates porphobilin, which was detected using its absorption at 480 nm, and uroporphyrin, which was detected using its fluorescence at 615 nm. The change of fluorescence and absorption allows for a quantitative discriminability of PBG concentrations below 20 mg/L. For this indirect quantification of PBG, the resulting inaccuracy and imprecision are below 15% for both methods. The detection and quantification of TUP and porphobilinogen in urine with this proposed spectrophotometric approach is possible, requires only minimal sample processing and yields a result within 15 min, thus could be helpful in closing the screening gap for acute porphyria.

Nowadays, the ability to diagnose brain tumors intraoperatively and to delineate their margins, as accurately as possible, is of primordial importance during surgery. However, the exact tumor boundaries and the infiltrated tumor cells outside its solid volume are difficult to be found by the surgeon due to the similar visual appearances especially at the margins, leading in many cases to poor surgical outcomes and a high risk of recurrences. To solve this issue, our group develop a two-photon multimodal endomicroscope to analyze the endogenous fluorescence of cerebral tissues in order to provide reliable informations intraoperatively on the tissues nature at cellular level. For that, and in order to implement the imaging modality in our endomicroscope, we launched a study based on an original miniaturized scanning system to be coupled with our endomicroscope. In this work, we characterize a scanning system prototype based on an electrothermally-actuated scanning micro-mirror. This type of scanning devices can provide a wide linear scan range at a low driving voltage and a high stable scanning speed along a straight scan line which help to acquire high-quality images.

Basal cell carcinoma (BCC) is the most common type of cancer in the world. The very high incidence of this type of cancer has given rise to an increase in the number of new prospective treatment procedures. Previously we have described a fully automated multimodal instrument that combines autofluorescence microscopy with Raman spectroscopy for the investigation of the entire resection margins for surgically removed skin tissue samples. This multimodal spectral histopathology (MSH) instrument is capable of investigating surgical resection margins in 30 minutes, which is compatible with Mohs micrographic surgery (MMS). The instrument was first developed and optimized on spare frozen skin tissue samples obtained during MMS [1]. Here we present initial results using this MSH instrument when operated in a typical Mohs surgery clinic, using the real resected tissue. After MSH analysis, the samples were processed for frozen section histopathology, which was used to validate the MSH results. The paper aims to present the difficulties that are encountered during the implementation of the instrument into clinical practice. The operating procedure has been successfully adapted to perform measurements of fresh tissue samples intra-operatively, with an improved accuracy over frozen tissue samples.

Single and combined fiber optic probes for key spectroscopy methods (Raman scattering, Mid IR-absorption, Diffuse NIR-reflection, and auto-fluorescence) were compares to detect malignant tissue in clinical environment. All four methods were tested on cancer diagnostics on biopsies (stomach, colon and kidney) and bioliquids (serum, plasma and urine) of patients.

Third and second harmonic generation (THG/SHG) microscopy is a novel imaging technique that has been suggested as a promising clinical tool, mainly for cancer diagnosis. Here, we test for the first time a compact, transportable ex-vivo THG/SHG microscope (Tritos Diagnostics B.V.) for clinical use. In lung surgery, immediate feedback on the nature of the excised tissue is important. We will present the first results of an ongoing study in which we image both lung tumor tissue immediately after excision and frozen section biopsies, and compare the images to the golden standard histology. Prior to this study, we performed a set of experiments collecting 3D images of mouse lung tissue to show that the combination of THG and SHG microscopy reveals key lung morphology components.

Photodynamic therapy (PDT) is emerging as a common and efficacious method for basal cell carcinoma (BCC) treatment, and new non-invasive imaging technologies can further enhance it. Optical coherence angiography (OCA) was employed in this study. OCA is a non-invasive, label-free, real-time bioimaging method that has proven to be a helpful tool for visualizing normal and pathological vasculature, including vascular damage evaluation after using a vasculature-targeted therapy for predicting its success. In experimental study, it was shown that both the tumor and peritumorous vessels stasis (disappearance in OCA images) in 24 hours post treatment play significant roles in PDT success. On controllable mouse ear tumor model the following practical and robust OCA-based criterion of PDT success was formulated: there should be no visibly perfused vessels on OCA images inside the tumor borders, whereas in the 2 mm near-tumor proximity regions the vascular density should not exceed 1% from OCA image area in 24 hours post PDT. The criterion obtained on the experimental model was translated to clinical study. OCA monitoring of basal cell carcinoma reaction to PDT has shown that dramatic decrease in the vascular density in the tumor in 24 hours post PDT can predict tumor non-recurrence with high diagnostic accuracy for 12 months follow-up. The strong reaction of peritumorous vessels in 24 hours post PDT is associated with hypertrophic scar formation in 3-6 months, but the weak reaction of peri-tumorous vascular reaction leads to normotrophic scar formation.

Photodynamic therapy (PDT) utilizes the combined action of photosensitizer, light, and molecular oxygen to generate reactive singlet oxygen (¹O₂) to treat various diseases. Photosensitizer is a key component in PDT and its singlet oxygen quantum yield determines the effectiveness of its photodynamic reaction. This study evaluated the singlet oxygen production of a novel water soluble chlorin photosensitizer (YLG-I) using a ¹O₂-specificfluorescence probe - Singlet Oxygen Sensor Green reagent (SOSG). The spectra and singlet oxygen luminescence in different solvents were evaluated using mTHPC as a reference. It was estimated and verified that the singlet oxygen quantum yield of the new photosensitizer YLG-I was at the same level of the potent chlorin sensitizer mTHPC. Preliminary evaluation suggested that YLG-I was a promising photosensitizer for PDT.

The utility to perform treatment planning for transbronchial light delivery is investigated using Monte Carlo simulations. Optical properties of pig and human lungs were determined, and dose volume histograms determined. These dose volume histograms indicate for example the minimum photosensitizer specific uptake ratio required to achieve selective tumour destruction.

Gastrointestinal cancerous lesions were induced in laboratorial animals using prolonged exposure to social (overpopulation) and chemical stress (nitrosamine diet), mimicking typical stress factors for humans in the big cities. Twenty laboratorial rats with developed stress-induced neoplasia in gastrointestinal tract were used. Three of them formed control group - without application of exogenous contrast fluorescent marker. Exogenous fluorescent spectroscopic measurements were used to evaluate gastrointestinal tract (GIT) neoplasia development noninvasively using excitation at 405 nm and emission was detected in the region of 500-850 nm using microspectrometer. We used as exogenous fluorescent marker protoporphyrin IX applying its precursor delta aminolevulinic acid in a dose of 20mg/kg, in laboratorial rats with stress-induced neoplasia. Spectroscopic analysis of primary gastric tumours and their metastases spreading in rats’ liver was carried out on animals in vivo, as excitation and emission light were delivered by fiberoptic probe 6+1 to the organs investigated during open surgery procedure. Biochemical indicators detected malignant alterations presence in GIT were also evaluated and used as complementary indices for lesions’ growth. Fluorescent observation using exogenous fluorophore addressed the exact area and borders of neoplastic lesions in stomach and liver. In some cases in inflammatory areas significant accumulation of delta-ALA had place, which lead to false-positive fluorescent signal of protoporphyrin IX in these tissues. Photodiagnostics accuracy of 93% was reached for cancerous cases and 87% for gastric pre-cancer lesions evaluation. Very good correlation between fluorescence data and histology examination of the lesions investigated was achieved as well.

We propose a new approach to monitoring of photodynamic therapy (PDT) of glioblastoma with the use of targeted nanoconstructs containing a photosensitizer (PS) benzoporphyrin derivative (BPD) and IRDye800 dye, antibodies for efficient accumulation of the drug in a tumor, and a chemotherapeutic agent for combined effect on tumor cells. Monitoring of PDT is based on the simultaneous fluorescent and optoacoustic (OA) imaging. Fluorescent imaging provides visualization of fluorescence agents with high molecular sensitivity, and monitoring of the effectiveness of PDT by PS photobleaching. OA allows to examine the vascular pattern of the tumor environment, as well as assess the tumor depth. IRDye800 is a better contrast agent in comparison to BPD due to red shifted spectral characteristics and higher fluorescence quantum yield. The results of numerical simulations have been verified in phantom studies using fluorescence and optoacoustic experimental setups and an agar phantom with optical characteristics similar to those of murine brain.

Interstitial photodynamic therapy (iPDT) is currently being investigated as a light-based treatment option for highly malignant brain tumours (glioblastomas/GBM). To obtain a sufficient irradiation of the tumour, quantitative knowledge about the light propagation in the tissue is required for the light dosimetry calculations underlying the clinical treatment planning. To individualize the light dosimetry calculations, the optical properties of the irradiated tissue need to be determined in-vivo. A novel approach for this purpose is based on the direction-resolved light detection within the tissue, using a rotating optical side-view probe. During measurement, the tissue is irradiated via a separate interstitially placed light applicator, and from the angular dependence of the recorded signal the optical tissue properties are calculated, based on a solution of the radiative transfer equation (RTE). Measurements were performed on liquid tissue phantoms and biological tissue samples. As a result, an over- and underestimation of the calculated optical absorption and scattering coefficients may arise in some situations, but the effective attenuation coefficient remains largely unaffected and corresponds well with literature values.

Photodynamic therapy (PDT) and/or photodetection (PDD) based on protoporphyrin IX (PpIX) are used in many medical fields. However, the endogenous production of PpIX in the tissue after administration of its precursor, 5-aminolevulinic acid (ALA), is frequently insufficient and, in particular, inhomogeneous, leading to unsatisfactory treatment outcomes or false negatives. Photobiomodulation (PBM), which is based on the application of a sub-thermal dose of red or near infrared light (typically in the range of 600 – 900 nm), is known to modulate, among others, the cell metabolism, as demonstrated by an increased production of adenosine triphosphate and changes of the mitochondrial potential. Yet, the precise mechanism of PBM and, furthermore, the optimal irradiation conditions are to be determined. In the work reported here, we have studied the dependence of the endogenous PpIX production by U-87 glioma cells on various PBM irradiation protocols (wavelengths, irradiations, light doses). We have shown that PBM can increase, and even homogenize the endogenous production of PpIX in these cells. Therefore, combining PBM with PDT or PDD could lead to more potent and satisfying cancer treatments or detections outcomes, in particular in neurosurgery, dermatology, and urology.

In this study we present a complex approach to photodynamic therapy (PDT) with chlorin based photosensitizers including Monte Carlo based planning and prediction of optical diagnostics results, intra-procedure dual-wavelength fluorescence monitoring allowing to evaluate PS accumulation and photobleaching, and monitoring of tissue response with optical coherence tomography (OCT). The approach was employed to compare the effects of different PDT regimens in normal and tumor tissues and the results of non-invasive optical diagnostics were matched with results of histologic examination, including hematoxylin-eosin and Mallory staining. The considered doses are in the range 50-150 J/cm² for normal tissues and 150-275 J/cm² for tumor tissues, single wavelength (405 and 660 nm) and dual-wavelength regimes are studied.

Blue LED light (420 nm) has successfully been used to induce hemostasis through a photo-thermo-coagulation process: light absorption by hemoglobin triggers a local temperature increase, leading to a coagulation effect. Besides hemoglobin, there are other macromolecules, such as cytochromes, that are able to absorb blue light: after irradiation, these ubiquitous cellular components can trigger one or more intracellular pathway that modulates the healing process, in combination with the coagulation effect. The aim of this study is to investigate the molecular effects of 30s treatment with a Blue LED device in two different murine model wounds. In the first model we studied a superficial wound, and in particular the inflammatory response by an immunohistochemical and morphological analysis of the many cellular types involved in this phase of the healing process. The second model is a full-thickness wound: a customized ELISA kit enabled to study EGF, bFGF, VEGF, TNF-α, MMP-2 and PRO-MMP-9 at different postoperative time points (1, 3, 6, 9, 24 hours and 7 and 14 days after the treatment). A modulation of these parameters was evidenced in the early phase of the wound healing process, while at longer follow up times no differences are pointed out.

The current report intended to inspect the photobiomodulatory effects of 632.8 nm laser on cellular parameters on artificially injured human monolayer skin fibroblast cells growing in vitro. To accomplish the specified objectives, a scratch (1-2 mm) was generated on monolayered human skin fibroblast cells. Further, cells were illuminated with a single dose of 632.8 nm (He-Ne laser; 1.5 cm beam spot; 11.8mW power; 6.68 mWcm^-2) at 5 and 7 Jcm^-2. Alterations due to red light laser irradiation were appraised by quantifying cytochrome c oxidase activity and Adenosine triphosphate synthesis in wounded skin fibroblast cells at various time points. Elevated ATP synthesis via cytochrome c oxidase activity was noticed in wounded cells following single exposure of 632.8 nm at 5 Jcm^-2. In a nutshell, the low level laser therapy boosts numerous cellular processes in wounded fibroblast cells culminating in enhanced tissue repair.

Glucocorticoids are considered gold standard treatment for Duchenne muscular dystrophy (DMD). Moreover, treatment with non-steroidal anti-inflammatory drugs (NSADs) may also have positive effects on management of the muscular symptoms of this disease. However, prolonged use of these drugs leads to development of important adverse effects. In addition, the use of photobiomodulation therapy (PBMT) has demonstrated an important role in delay muscular impairments in disease progression, with protective effect on the skeletal muscle without adverse effects reported. Therefore, we compared the effects of PBMT, glucocorticoids and NSAIDs applied alone or combined in mdx mice. The pharmacological treatment was performed with oral drugs (Prednisone and ibuprofen) every day during 14 consecutives weeks. The PBMT was performed using a cluster probe with 9 diodes (1 laser diode of 905 nm, 4 LED diodes of 875 nm, and 4 LED diodes of 640 nm) on only 1 point on the ventral region of the animal’s tibialis anterior muscle. The results showed that glucocorticoids and PBMT improving the functional performance, compared to placebo-control group. However, PBMT was also better than the other groups of treatment. In this way, we believe that the promising and optimistic results about the PBMT in skeletal muscle of mdx mice may in the future contribute to this therapy to be considered a safe alternative for patients with DMD in a washout period (between treatment periods with glucocorticoids), allowing them to remain receiving effective and safe treatment in this period, avoiding at this way periods without administration of any treatment.

Keloids are an exuberant response to cutaneous wound healing, characterized by an exaggerated synthesis of collagen probably due to the increase of fibroblasts activity and their proliferation rate. Currently, there are not definitive treatments or pharmacological therapies able to prevent keloid formation and its recurrence. In the last years, physical treatments have been proposed and among them the photobiomodulation therapy. In this work, the effects of Blue LED light (410-430 nm wavelength, 0.69 W/cm² power density, 5÷60s treatment time) were evaluated on seven boundary keloid tissues by using two different colorimetric assays. Micro-Raman spectroscopy was used to explore direct effects of the Blue LED light on the endogenous cellular redox system and in particular to probe any variation in the oxidation state of the photosensitive heme-protein Cytochrome C (Cyt C) upon irradiation. We also investigated the effects of Blue LED light on membrane currents correlated to cell cycle modulation by patch-clamp recordings. Twenty-four hours after irradiation, a significant reduction of cell metabolism and proliferation was observed. The decrease in cell metabolism was maintained up to 48 hours when we found also an increased reduction in cell proliferation. Electrophysiological recordings showed an enhancement of voltage-dependent outward currents elicited by a depolarizing ramp protocol after a 30s irradiation. Data indicates that Blue LED light irradiation directly affects human keloid fibroblasts: it possesses a long lasting inhibitory effect on cell metabolism and proliferation whereas acutely increases membrane currents. Similar responses were obtained in our recent works conducted on human keloid tissues. The proposed photomodulation treatment by using Blue LED light represents a non-invasive approach in the management of hypertrophic scars and keloids.

This paper describes the further investigation into the capabilities of the already established noncontact optoacoustic method to measure temperature profiles in cell cultures during controlled heating. The technic is scalable in spatial and temporal resolution. The intra and extracellular medium is heated by a thulium laser (wavelength 1.94 μm; power up to 25W). With a second Q-switched thulium laser (2.01 μm; up to 3 mJ) the sample medium temperature is simultaneously probed in the dish (20 mm diameter) via the photoacoustic effect. The pressure waves emitted due to the thermoelastic expansion of water are measured with an ultrasonic hydrophone at the side of the dish. The amplitudes of the waves are temperature dependent and are used to calculate the temperature/time course at 10 locations. Temperatures of up to 70°C with a heating power of up to 25 W after 5 s were measured, as well as lateral temperature profiles over time. Measurements in water show temperature fluctuations likely due to thermal convection and water circulation. Since measurements in agar do not show similar temperature fluctuations, this theory seems to be confirmed. In conclusion optoacoustics can serve as a real-time non-contact technique to determine temperature changes in cell and organ cultures as well as in vivo and during hyperthermia based therapies.

Radio-frequency (RF) catheter ablation is routinely used in the clinics to treat arrhythmias, neoplastic lesions and other dysfunctional tissues. It is based on scarring the target tissue via localized heating induced by medium frequency alternating current in the proximity of a metallic ablation catheter. The outcome of RF interventions strongly relies on the temperature distribution within the treated tissue as well as on the exposure time, which cannot be efficiently monitored with existing clinical tools. Optoacoustic (OA) tomography has recently been shown to provide unique capabilities for RF ablation monitoring such as high spatio-temporal resolution, hand-held operation feasibility and high sensitivity to temperature changes and tissue coagulation. However, shallow light penetration in biological tissues strongly limits the accessible regions, particularly for cardiac procedures, while internal illumination through the catheter induces strong responses in the metallic parts that hamper soft tissue visualization. Herein, we present a new endocardial catheter based on saline irrigation that delivers electric current while being transparent for light. The new design averts OA image artifacts due to the presence of metallic electrodes while retaining the ablation efficiency.

Laser-induced forward transfer (LIFT) has been used in recent years for the flexible and gentle 3D-bioprinting of cells with superior cell survival rates relative to other methods [1]. One drawback of the current state-of-the-art nanosecond laser based cell printing is the fact that material from an inorganic sacrificial layer, which is required for laser energy absorption, is transferred to the printed target structure, where it contaminates the printed construct [2]. Furthermore, existing LIFT based technologies transfer multiple cells at a time, i.e. with a single laser pulse. However, living cells in a functional in vitro microenvironment are exposed to multiple biophysical, biochemical and biological signals. Therefore, a 3D-bioprinting technique providing single cell resolution is desirable for a number of applications, e.g. the investigation of cell-cell interactions and cell niches, which has not yet been achieved using laser based bioprinting. Here we present a new femtosecond laser-based method for the efficient and precise single cell printing and sorting, which avoids the use of non-biological inorganic absorption layers. An ultrashort laser pulse (λ = 1030 nm, 600 fs, few μJ) is focused underneath a cell layer, which is suspended on top of a hydrogel reservoir. Nonlinear absorption leads to plasma ionization and rapid cavitation bubble expansion, which generates a jet of material, transferring cell-laden hydrogel from a gel/cell reservoir to an acceptor stage [3]. In addition, to the effective sacrificial-layer free transfer of multiple cells, individual cells can be selected based on their morphology and phenotype, and transferred to the acceptor slide, isolated from the remaining cells. Furthermore, laser-induced single cell printing efficiencies close to 100% were achieved for the first time.

Determining the light propagation in heterogeneous media is a challenging task which can only be approximated by solving the Boltzmann transport equation via diffusion theory. However, diffusion theory becomes very inaccurate at interfaces, boundaries, sources, and sinks, which are present in heterogeneous media. Monte Carlo methods are able to converge to the correct solution by simulating a sufficiently high number of photons, at the cost of increased runtime. Therefore, it is important to optimize the Monte Carlo simulator, thereby allowing more photons to be simulated and a more accurate solution within a given runtime. FullMonte is a full-featured simulator that uses processor-optimized operations to achieve the highest performance of any 3D tetrahedral Monte Carlo light propagation software to date. This paper presents two medical use cases which benefit from FullMonte, highlights new features and explains the optimizations that lead to its high performance.

Laser irradiation has been recognized as a promising tool across a number of biomedical applications. However, understanding the molecular mechanisms and cellular responses remains incomplete. Here, we investigated the mechanism involved in the apoptotic process in human hepatic cells under laser irradiation. Our data show that the laser-mediated alternation of mitochondrial membrane potential leads apoptosis in Huh7 and Alexander cells. Contrary, HepG2 cells are resistant to laser induced cell death. The observed link between mitochondrial membrane potential and cytotoxicity could be a fundamental phenomenon in laser-induced cell apoptosis.

Interstitial Photodymanic Therapy (iPDT) selectively treats malignant brain cancer. A photoactive drug, which accumulates specifically in tumour cells, is delivered to the patient. By irradiation of the targeted brain region with low power laser light, radical oxygen is generated, leading to apoptosis or necrosis. For the illumination, glass fibers are connected to a laser source and inserted through boreholes into the human skull. At the distal fiber end, light is decoupled from the fiber and spread into the surrounding tissue. Various approaches target the decoupling process from the fiber core to the surrounding tissue including the use of polymer diffusers, surface roughening or internal glass modification using ultrafast laser sources. While the manufacturing process is a widely debated topic, the measurement of the radiation profile of the fibers is rarely discussed. Therefore, this study targets the introduction of a novel method, using a plain camera sensor, which was brought in close contact to the fibre diffuser surface. Thereby, an angle-resolved profile should be accessible. The gained profiles were afterwards compared to the state-of-the-art method, a camera setup recording an image of the diffuser surface through an optical lens, as well as to an integrating sphere, collecting all emitted rays along the diffuser length. The results showed that the main characteristics are similar in between all three methods, however its development strongly differs. This could be explained by the limitations of the camera setup, which is limited by the acceptance angle of the used camera lens. Rays emitted under a flat angle from the fibre surface miss the lens aperture and won’t be detected. For the camera sensor and the integrating sphere setup, those rays are detected. The results show a dependency of the radiation profile on the selected method. The novel camera sensor method allows an angle-resolved measurement detecting almost the full radiation profile. Furthermore, a simulation model can be easily established, which could be used to predetermine the radiation profile of manufactured diffusers.

Fluorescence-guided intervention is increasingly considered for real-time intra-operative oncological applications. Herein we propose a novel composite phantom for standardization and quality control, which could serve as a framework toward good clinical practices.

Melanoma is one of the most severe types of skin cancer. Although it is generally believed that ultraviolet radiation (UVR) is the main environmental causative risk factor in the induction of melanoma, the cells of origin and mechanisms of melanoma remain unclear. Recent studies show that the melanocyte stem cells in the hair follicles could be the cells of origin of melanoma upon exposure to ultraviolet radiation. Red hair is usually considered as one of the risk factors for melanoma. Therefore, it is of interest to investigate the UV transmission characteristics of hairs from red-hair individuals. In this article, the measurement techniques using a micro-spectrophotometer for studying the transmission characteristics of human hair are demonstrated. Several hair samples from a red-haired adult are studied. The results show that non-medullated red hair has relatively superior transmission properties to the medullated red hair in the UV wavelength range. It has also been found that light blond hair has a noticeably lower attenuation coefficient in the ultraviolet-A (UVA) wavelength range than the light yellow and red hair from the same red-haired individual. Our findings support the hypothesis that the colorless hair may transmit sufficient UV photons to harm the melanocyte stem cells in the hair follicles, ultimately resulting in melanoma.

This study was designed to find an effective way of ceramic brackets debonding through the laser irradiation on the interface between the teeth and the bracket. Various laser parameters were applied to remove orthodontic brackets. After debonding, the adhesive remnant index (ARI) and the degree of enamel fractures were examined with microscope. The laser-assisted debonding be capable of lowering the risk of enamel damage and the less adhesive residue. The results indicated that the line laser system can be successfully applied to ceramic bracket remove tool. This method is expected to be useful in the field of orthodontics.

A rapid and easy method for the monitoring of both live and dead bacteria in a sample is valuable in many fields of microbiological and pharmacodynamics studies, and for the monitoring of food safety and public health. Efficient, culture-independent detection of live and dead bacteria can be achieved using differentially staining fluorescent dyes SYTO 9 and propidium iodide (PI). Fluorescence microscopy and flow cytometry have been used extensively for detection of these live/dead cell fluorescence signals, however, both these methods require bulky equipment and are relatively expensive to implement. We are optimising a method to determine live and dead bacterial concentration that takes advantage of an inexpensive fibre-based fluorimeter, the optrode, which can measure fluorescence intensity in bacterial solutions in challenging working environments. The concentrations of live and dead bacteria were predicted using multivariate analysis of optrode-measured fluorescence spectra, which is then compared with results obtained from the flow cytometry measurements. The findings from this study will be used to establish a general method for the monitoring of live and dead bacteria using the optrode.

We report a development of hyperspectral polarization imaging approach for assessment of age-related skin changes. The degree of residual polarization is used as a quantitative marker of the age-related pathological malformations. The developed approach in frame of express analysis of the degree of residual polarization in each pixel of the image are shown.

Portwine stain (PWS) birthmarks are congenital vascular malformations of the skin. Pulse dye laser (PDL) is current treatment option for PWS. As a possible alternative, vascular targeting photodynamic therapy (PDT) is currently under formal clinical trials for the treatment of PWS in China. Color blanching is an important indicator of treatment effectiveness. There is a need to develop an objective and quantitative color analysis system for the evaluation of PWS color before and after PDT treatment.In this study, the CIE L*a*b* color space coordinate was used to quantify skin and PWS coloron digital color photos.A custom-made multi-color template (PWS Color Card) for the accurate color correction of digital photos. Hardware and software were developed and tested for quantitative PWS color and size analyses before and after PDT treatment. Results suggest that PWS color, its color blanching and treatment efficacy in PDT treatment can be quantitatively analyzed using digital photos in conjunction with suitable color analysis and color correction algorithm.

Background: The effect of tea on teeth under temperature conditions has not been studied previously. Model: The present study used an in vitro one-week immersed tooth model with different tea temperatures, hot and cold. An in vivo tea administration model, allowing rats to drink tea over the course of a week, was also performed. Methods: Elemental content of tea leaves was identified by ICP-MS, Laser-Induced Breakdown Spectroscopy (LIBS) for elemental spectrum analysis, Atomic Force Microscopy (AFM) for roughness analysis, scanning electron microscopy for ultrastructural assessment and histology used for structural assessments. Results: The LIBS analysis demonstrated a significant increase in the mineral elements (Zn, Mg, Ca, Sr and Fe) from tea in vivo. For in vitro, increases of Fe and K were significantly higher in the hot-tea group than in the cold-tea group, with a decrease of the elements in hydroxyapatite forming teeth, albeit not statistically significance, though. The LIBS showed that in vitro cold-tea group drastically increased Zn, C, Ca, Mn, Mg, P, Sr, Fe and K compared with cold-water. While in vitro hot-tea group was significantly increased in Mg, Ca, Sr, Fe and K compared with hot-water. The AFM did not show a significance difference among groups in vivo or in vitro, but in vivo tea presented a higher roughness compared with cold-tea, hot-tea and hot-water, indicating a polishing effect due to temperature and tea. Using scanning electron microscopy, hot-water induced cracks more than 1μm while cold-tea and hot-tea revealed extrinsic matter adhered to teeth. Histological analysis showed considerable increase in the percentage of mineralization from cold tea on the enamel surface. Conclusion: Under cold conditions, tea prompted an interaction of the inorganic components in teeth: Ca, Mg, P, Fe and K. An accumulation in the organic matrix was promoted by tea. However, high temperature facilitated deposition of metals associated with teeth staining. Moreover, under hot temperature teeth lost the mineral phase leading to demineralization. Even though green tea protects enamel, its potential is susceptible to prompting demineralization over dental structures under high temperatures.

A technique is presented for solving the problem of the thermomechanical effect of a pulsed laser beam on an absorbing medium, based on the numerical simulation of three-dimensional equations of the motion of continuous media in the Lagrange form. The structure of the excited acoustic pulses is analyzed depending on the space-time characteristics of the laser pulses.

The paper describes the methodology and technical implementation of a multimodal approach for optical diagnostics in hepatopancreatobiliary organs focal and diffuse neoplasms. Fine needle aspiration biopsy technique and following cytological examination show its effectiveness and safety but its performing takes several days. However, the problem of real-time analysis of pathological changes in tissues remains relevant. The solution suggested is implementing of optical biopsy methods (namely fluorescence spectroscopy and diffuse reflectance spectroscopy) in the form of fiber-optic probe compatible with standard biopsy fine needles. The special device was designed for this purpose to conduct optical measurements and compare the results with ones obtained by conventional biopsy. The proposed methodology seems promising for developing new diagnostic criteria for clinical practice.

An introduction of innovative minimally invasive methods like multimodal optical coherence tomography (OCT) with polarization-sensitivity and angiography modes for intrasurgical guidance appears to be a critical challenge for the modern neurooncology. This study aimed to develop a new instrument for targeted stereotactic brain biopsy based on cross-polarization (CP) OCT realized in standard biopsy needle to increase the safety of ongoing neurosurgical procedures. Experimental studies in vivo on the healthy rat’s brain allow detecting blood vessels in the process of moving the biopsy needle along the brain surface and detect tissue type (cerebral cortex or white matter) when the needle went inside the brain. The images was assessed by visual criteria. However, CP OCT signal quantification methods will increase the sensitivity/specificity for the tissue type differentiation and blood vessels detection. The potential of CP OCT as an effective instrument for OCT-guided stereotactic biopsy of brain tumors was demonstrated.

This study aimed to investigate the effects of PBMT with a synergistic combination of lasers and light emitting diodes (LEDs) with three different wavelengths and three doses on cytochrome c oxidase activity in intact skeletal muscle, and also to determine the time-window between irradiation and increased activity on cytochrome c-oxidase in skeletal muscle fibers. Male Wistar rats (240 ± 20g) were divided into two groups (placebo and PBMT) where seven different experimental time-points were tested. Transcutaneous PBMT was irradiated at tibialis anterior muscles employing a cluster with 9 diodes (1 laser diode of 905nm, 4 LED diodes of 875nm, 4 LED diodes of 640nm – manufactured by Multi Radiance Medical™), with different doses (1, 3 and 10 J). Then muscles were removed at different experimental time-points (5, 10, 30 minutes, 1, 2, 12 and 24 hours) and the analyses of cytochrome c oxidase expression were performed by immunohistochemistry. PBMT with 10 J dose increased cytochrome c oxidase expression with significant difference (p<0.05) when compared to the placebo group at all time-points tested. The 3 J dose showed significant differences (p<0.05) when compared to the placebo group from 30 mins to 12 h time-points, and the 1J dose showed significant differences (p<0.05) when compared to the placebo group from 30 mins to 24 h. PBMT with the combination of super-pulsed laser, red and infrared LEDs can increase cytochrome c-oxidase activity in intact skeletal muscle mainly with 10 J dose fulfilling the time-response window from 5 minutes until 24 hours after irradiation.

Low-level light therapy, which is a red or near-infrared light-employed therapeutic methodology, can act to help the brain repair in cases of traumatic brain injury and stroke. In this paper, we investigate the effects of near-infrared light therapy (NILT) for the recovery of blood flow of mice with cerebral hypoperfusion, which is a key mechanism leading to vascular dementia, induced by bilateral common carotid artery stenosis (BCAS). The mice are divided into three groups of 4-5 mice per group: a normal group (without BCAS operation), a BCAS group (without NILT), or a BCAS/NILT group. The LED with a peak wavelength of 810 nm and a power of 20 mW is arranged to illuminate on the top of the mouse head. The mice receive treatment from the LED source 3 times per week for one month. After the treatment, positron emission tomography is used to quantify the effects of NILT on whole brain and regional cerebral blood flow in the cortex, striatum, and hippocampus.

Selective retina therapy (SRT) is currently used in clinical studies to treat several chorioretinal diseases. For SRT a laser pulse duration of 1,7 μs is currently used. At this pulse duration the retinal pigment epithelium (RPE) cells are destroyed by transient microbubbles without damaging the neuronal retina. So far it is unclear whether slightly longer laser pulses are still acting thermomechanically or whether thermal effects show responsible for cell damage close above damage threshold. In order to investigate the damage threshold increase with pulse duration, a novel laser with adjustable pulse duration in the range of 2-20 μs was used to investigate RPE damage on ex-vivo porcine RPE explants. The specimen were fixed in an eye model and were exposed to laser pulse energies ranging from 15-150 μJ with a top hat square of 120×120μm², exhibiting a spatial intensity modulation factor of 1,3. Viability tests using binary evaluation result in threshold values with peak radiant exposures of 233 mJ/cm² and 389 mJ/cm² for 2 μs and 20 μs laser durations, respectively. An almost logarithmic increase of the threshold radiant exposure over pulse duration was found.

Photodynamic therapy (PDT) proved itself as a powerful tumor and non-tumor pathologies treatment tool. Photosensitizers (PS), which are employed as therapeutic agents for PDT, feature fluorescent properties. Thus, PDT provides the principles of theranostics when diagnostics is performed during treatment. The estimation of PS localization within the tissue is of critical importance for PDT planning. Fluorescence imaging is commonly applied for the monitoring of PS accumulation within the tissue, however, it does not provide with the in-depth PS distribution. Chlorinbased PS feature two pronounced peaks in their excitation spectra corresponding to 402 nm and 662 nm, which provides additional diagnostic possibilities. The ratio of fluorescence signals corresponding to different excitation wavelengths is shown to be a criterion for the evaluation of PS penetration depth after topical application and PS localization within the tissue after intravenous injection. The study is based on numerical simulation applying Monte Carlo technique. The results of numerical simulations are verified with phantom experiments results.

The preferential absorption of photon energy by hemoglobin, oxyhemoglobin and water at specific wavelengths (400 nm, 560-580 nm, 800-980 nm, 1064 nm) allows the use of laser radiation for the treatment of tumors and vascular lesions. Absorption of light energy by oxyhemoglobin at a wavelength of 1060 nm creates thermal energy, allowing to selectively damaged blood vessels with minimal damage to surrounding tissues. In this paper, were developed laser irradiation regimes to selective damage the tumor vessels using a semiconductor laser «Lakhta-Milon» at wavelength of 1060 nm with maximum power 20 W and pulse duration 10-50 ms. The calculations were based on the threshold for thermal vessels damage with various vessels sizes: less 8 μm, 10-30 μm, over 30-100 μm. Histological studies of carcinoid tumor after irradiation revealed that thermal damage of tumor vessels may be localized under pulsed irradiation without causing thermal tissue necrosis. The pulse irradiation modes developed in this work have potential applications in the method of laser airways recanalization for tumoral stenosis in therapeutic bronchoscopy.

Dual-wavelength photodynamic therapy is a photodynamic therapy (PDT) modality combining therapeutic effects of irradiation at two wavelengths of different region of visible range. In this paper we report on comparative analysis of single- and dual-wavelength PDT regimes based on multimodal optical monitoring of tissue response with histologic verification. Morphological and functional tissue responses to PDT procedure with chlorin-based photosensitizer (PS) were studied at the normal skin of a rabbit ear inner surface. Multimodal optical monitoring was performed by OCT and dual-wavelength fluorescence technique. The studied doses vary from 50 to 150 J/cm² delivered separately at 405 or 660 nm, or at both wavelengths together in the equal dose.

Development of new microperimetric tools dedicated for imaging of early functional changes in the retina may help in the monitoring of various ocular diseases progression e.g. Age-Related Macular Degeneration. Recently described two-photon vision may be applied to microperimetric devices. Many subjects with well-known disease history could be investigated with newly developed instrumentation that tests ability of human eye to perceive near infrared radiation. The main limitation of this new method is a very high cost of the femtosecond laser. Facing this problem, we try to replace the femtosecond laser with lower cost fiber-optic picosecond light source. To compare these two lasers, we constructed dedicated measurement system. We performed measurements of two-photon vision threshold on healthy subjects for two different light sources - sub picosecond Kerr mode-locking solid-state laser and fiber-based picosecond laser. Experiments were conducted for an open circle flickering stimulus with 0.5 deg. diameter, for retinal locations varying from 0 deg. to 5.8 deg., using 4-2-1 threshold strategy that is well-known from classical microperimetry. Values of obtained thresholds are only 5 times higher for the fiber laser than that obtained by using the femtosecond laser, while it was expected to be about over 16 times higher. This fact requires further investigations. Nevertheless, the idea of replacement of the latter laser by relatively cheap fiber-optic one in ophthalmic devices for two-photon vision studies seems to be potentially promising.

Using flow cytometry with a genetically encoded fluorescent sensor, vital dye and two types of apoptosis markers: PE Annexin V and TMRE, the participation of hydrogen peroxide (H₂O₂) in cisplatin-induced apoptosis was demonstrated. It was shown that cisplatin causes the increase of H₂O₂ level in early apoptotic cancer cells. Accumulation of H₂O₂ begins before the externalization of phosphatidylserine but after the loss of mitochondrial membrane potential. Scavenging of H₂O₂ prevents the cisplatin-induced apoptosis.

Optical nerve stimulation (ONS) using infrared laser radiation is a technique developing as a potential alternative to electrical stimulation of nerve tissue. This preliminary study proposes and explores a computer simulation tool for numerically optimizing laser and surface scanning parameters including laser power and surface scanning speed to be used in laser scanning subsurface ONS. This tool consisted of three parts, including the Monte Carlo simulations for generating laser energy distribution in the tissue sample, the laser-scanning model by moving the heat source at the surface, and the thermal transfer simulations to calculate the tissue temperature. In the simulations, the laser wavelength of 1490 nm was used and the surface scan was performed on both x and y axes. In addition, the tissue model was constructed in such a way that the nerve tissue extends over the y-axis. As a result of calculations, the nerve tissue temperature map was produced as a function of laser power and surface scanning speed. According to the temperature map, the optimal laser power to reach the nerve temperature at 43 °C was estimated to be 15 mW at the scanning speeds of 1.2 mm/s in the x-axis and 1.0 mm/s in the y-axis. With further development this simulation tool may hold promise in the development of an optical stimulus device.

The growing interest in the development of new wearable electronic devices for mobile healthcare provides great opportunities for the development of methods for assessing blood perfusion in this direction. Laser Doppler flowmetry (LDF) is one of the promising methods. A fine analysis of capillary blood ow structure and rhythm in the time and frequency domains, coupled with a new possibility of round-the-clock monitoring can provide valuable diagnostic information about the state of microvascular blood ow. In this study, wearable implementation of laser Doppler flowmetry was utilised for microcirculatory function assessment in patients with diabetes and healthy controls of two distinct age groups. Four wearable laser Doppler flowmetry monitors were used for the analysis of blood microcirculation. Thirty-seven healthy volunteers and 18 patients with type 2 diabetes mellitus participated in the study. The results of the studies have shown that the average perfusion differs between healthy volunteers of distinct age groups and between healthy volunteers of the younger age group and patients with diabetes mellitus. It was noted that the average level of perfusion measured on the wrist in the two groups of healthy volunteers has no statistically significant differences found in similar measurements on the fingertips. The wearable implementation of LDF can become a truly new diagnostic interface to monitor cardiovascular parameters, which could be of interest for diagnostics of conditions associated with microvascular disorders.

Presently, in the modern laser Doppler flowmetry (LDF) the distribution of blood perfusion and its changes along the Doppler shift frequencies are simply ignored and/or not properly addressed. Utilizing the registered power spectrum of photocurrent, we introduce an LDF signal processing approach suitable for expanding of diagnostic capabilities of the technique. In particular, we demonstrate that it is possible to determine how the oscillations of blood ow (cardiac, breathe, myogenic, etc.) are distributed along the Doppler shift frequency. Wavelet analysis is utilized to extract the oscillations corresponded to the particular frequency sub-bands of blood perfusion. The main purpose of this study is to identify influence of local pressure by fiber optic probe on cardiac oscillations and their distribution along frequency of Doppler shift.

Nd:YAG-laser associated to a photoabsorber, in the reduction of artificial caries in enamel was evaluated. Eighty bovine specimens with 6mm diameter and 2mm high were obtained and a half of the surface of each was protected as a control. Microdurometer and FTIR were performed initially and 8 groups (n=10) were obtained according to treatments: G1(- control): no-treatment; G2(+control): fluorophosphate; G3(Nd:YAG 60mJ/pulse, 10Hz, 48J/cm², non-contact); G4(photoabsorber + Nd:YAG 60mJ); G5(Nd:YAG 80mJ/pulse, 10Hz, 64J/cm²); G6(photoabsorber + Nd:YAG 80mJ); G7(Nd:YAG 100mJ/pulse, 10Hz, 80J/cm²); G8(photoabsorber + Nd:YAG 100mJ). De-remineralization cycle were performed for induction of artificial caries and to interferometer, microdurometer and FTIR. Microhardness data were submitted to 2-way ANOVA and Tukey/Dunnett tests 5%. Statistically differences were obtained in the photoabsorberfactor individually and in the interaction between laser and photoabsorber. There was a lower percentage of microhardness loss in the groups with photoabsorber; G8 presented microhardness similar to G2. FTIR data were submitted to T-test 5%. Compared with G2, higher concentrations of carbonate were found in G4, G6 and G8; phosphate in G8; lower Amide-I concentration at G8 and higher Carbonate/Phosphate ratio at G4 and G6. The interferometry results were submitted to 3-way ANOVA of repeated measures 5%. There were statistically differences in the photoabsorber-factor individually and in the time-factor. Photoabsorber decreased the demineralization; Nd:YAG-laser without photoabsorber were less effective than fluoride; Nd:YAG-laser 100mJ with photoabsorber was as effective as fluoride and; the Nd:YAG-laser, associated or not to the photoabsorber, was no more effective than fluoride in the reduction of artificial decay.

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 relevance and importance of the development of new areas of tumor therapy is defined in connection with a strong increase in the level of oncological diseases. The latest global cancer data indicates a high mortality rate: the incidence of cancer increases to 18.1 million new cases and 9.6 million cancer deaths in 2018. Advances in nanostructures and nanotechnologies at the molecular scale in future can revolutionize several aspects of the diagnosis and treatment of body tumors. Search of highly specific and highly effective new therapeutic compounds is one of the most important directions in treatment of oncological diseases by noninvasive way. Currently, in clinics method of photodynamic therapy (PDT) of tumors based on photosensitizers (PSs) and light irradiation is widely used. At its application, the cancer cells are unable to develop resistance to such method of destruction.

Multidimensional images are often used for the most convenient representation of the processes carrying out in the studied object. However, sometimes, especially in such areas as medical diagnostics or related ones, it is required to estimate quickly simultaneously several aspects of the observed process, and certain part of multidimensional image must be observed in details without influence of several excessive signal distribution along some dimensions. The acousto-optic method based on Bragg diffraction has been proposed for this problem solution which provides fast and automatic (controlled by software) way of multidimensional switching to its selective part or several parts. Especially this method is convenient in electrocardiography where signal processing produces such pictures as 3D mapping images or signal wavelet transform images. Information losses which appear due to this method application, have been estimated, and the ways of the method optimization from the point of view of maximum signal-to-noise ratio providing, have been proposed.

This study investigates that the light source can be transmitted deeper for photodynamic treatment of deep locations using the biological correlations of Focused Ultrasound and tissue. we used the phenomenon that Focused Ultrasound induced changes in tissue structure. Ultrasound interacts with tissue through both thermal and non-thermal mechanisms and generates a variety of biological effects. We measured 1. Monte Carlo Simulation to measurement of the relationship between the constitutional deformation of the tissue and the transmittance of the light source 2. Measurement of the effect of the scattering coefficient. 3. Measurement of biological tissue by constitution modification with biological characteristics of ultrasound. a chest tissue phantom was sampled, and a system was developed with FUS and Laser. In conclusion, we could detect the possibility that the light source could penetrate deeper into the region of the tissue after the FUS was irradiated.

This PDF file contains the front matter associated with SPIE Proceedings Volume 11079, including the title page, copyright information, table of contents, and author and committee lists.