Lasers in Medicine
Year:2024 | Volume:21 | Issue:1|Papers Count:6

2International Day of Light, May 26, is celebrated annually due to the invention of the first laser on this day by the famous physicist "Theodore Maiman" has been named International Day of Light by UNESCO. The International Day of Light is a global initiative supported by UNESCO to continue to celebrate the place of light in science, technology, culture and art, education and sustainable development. This day is a call to strengthen scientific cooperation and use its potential to strengthen peace and sustainable development. Laser has played a key role in the place in science and technology, and after the advent of laser, the century of science and technology was already named based on light. Today, we see that light plays an important role in various fields such as medicine and health, communication, energy, industry, intelligent systems, etc. One of the important features of science and technology based on light is the variety of topics and applications that make this field more attractive and universal. IDL is an opportunity to show the importance of light-based science and technology in which many countries and related centers in the world participate. The wide range of topics and applications related to light that covers many different parts of society from science, technology, art and culture may be a platform for the development of global communication. One of the important features of science and technology based on light is the variety of topics and applications, which makes this field more attractive and universal. IDL is an opportunity to show the importance of light-based science and technology in which many countries and related centers in the world participate. One of the important goals of holding IDL is to create a bridge between scientific, educational and artistic programs in response to the basic need for interdisciplinary interactions and the development of dialogue between society, scientists, decision makers, industrialists and policy makers and non-governmental institutions. IDL is valuable by emphasizing the place of light in people's lives to improve their quality of life in the world and move towards sustainable development. ACECR is proud to have established the first medical laser research center and the first quarterly scientific research in the Persian language of Laser Medicine in Iran in the last two decades by using light in biological, medical and health applications for research. It is hoped that with the publication of a variety of basic and clinical sciences, elite researchers, professors, and students throughout the country choose this scientific platform to publish their excellent clinical and research activities, and with this choice, share science in the scientific community

2Introduction: Optical sensors are an integral part of various devices in the field of biomedical diagnostics. In the meantime, photonic technologies have gained great popularity for use as sensors in medical applications and human health monitoring due to their many advantages such as high sensitivity, the possibility of integration with electronic devices, suitable compactness of the device, metal-free operation, cheap cost, and electromagnetic safety that photonic technologies provide, justify the need to study in the field of optical sensors. Analysis method:  In this study, the effect of the composition percentage of PbS and Ag2Se quantum dots, as well as the changes in the diameter and film doping density of Ag2Se quantum dots in the active region at different temperatures to maximize the responsivity has been studied. To achieve the responsivity of the photodetector based on the structure of quantum dots, first by solving the self-consistent Schrödinger and Poisson equations with the finite difference method, the electron density in each level and potential profile is obtained and the responsivity of the photodetector is calculated. Results: The obtained results show that with the increasing percentage of PbS quantum dots compared to Ag2Se quantum dots, the responsivity of the device decreases. By increasing the film doping density of the Ag2Se quantum dots, initially due to the increase of carriers for optical excitation, the responsivity increases, and after reaching the maximum point, the responsivity decreases because of the increase of carrier recombination. The responsivity increases with the increase in the diameter of Ag2Se quantum dots due to the quantum confinement effects, carrier escape, and tunneling effects and decreases after reaching the maximum point. Conclusion: Nowadays, increasing the quantum efficiency and optical responsivity of such biomedical optical sensors is a great challenge for medical device engineers. In general, maximizing the responsivity improves the performance, accuracy, and efficiency of the photodetectors, and this can be achieved by engineering the structure of the devices.

2Goals: Glioblastoma is one of the types of brain tumors with the highest degree of malignancy and high recurrence. Current treatment methods include surgery, radiation therapy, and chemotherapy, each of which has many side effects. Photodynamic therapy (PDT), a new method of inducing cell death based on the interaction of three photosensitive drug agents, light source and oxygen, is selective and minimally invasive and has fewer side effects than conventional methods. In this method, the combination of light-sensitive drug and laser beam through photochemical interactions causes the production of active toxic oxygen (cytotoxic) and free radicals that selectively cause cell death. The aim of this research is to investigate the effect of PDT on the survival of glioblastoma cell line (6C) using the photosensitizer ALA-5 in different concentrations. analysis method: First, 6C cells were cultured in DMEM medium. Then, the treatment of cancer cells by a low-power continuous diode laser at a wavelength of 635 nm with a power of 20 mW, at optical doses of 56.4 J/cm and 112.8 J/cm and different drug concentrations (25, 50, 75, 100 and μg 125/ml) has been checked by MTT test method. findings: The results show that in the PDT method of 6C cells with ALA-5 photosensitizer, there is a significant decrease in the number of cells in the photodynamic therapy group compared to the ALA-5 group without laser and the laser without ALA-5. The application of ALA-5 drug increases the production of the main light-sensitive substance PPIX and as a result increases cell death. Conclusion: Photodynamic treatment of 6C cancer cells with ALA-5 drug at a concentration of 75 μg/ml and an incubation time of 4 h along with diode laser radiation at a wavelength of 635 nm with a light dose of 112.8 2J/cm is optimal and the most effective in the death of cancer cells. It comes with in this case, the biological power of the cells decreases by 37%. The results show the sensitivity of malignant glioblastoma cancer cells to this treatment method

2Introduction: Dermoscopes are key in dermatology for magnifying skin lesion images, which is crucial for diagnosing diseases such as melanoma. Adding software that processes and analyzes these images significantly aids dermatologists. This article presents Optoskin version 1, software that provides a graphical interface to enhance dermoscopes, developed at Shahid Beheshti University's Optical Imaging Laboratory and supported by the Parto Ava Atlas Company. Method: This software is not only captures images of the skin but also processes them to analyze key features of skin lesions. By applying the ABCD algorithm, it measures symmetry, border irregularity, color, and diameter. After preprocessing the images and locating the lesion's edges, the software uses specialized algorithms to identify its visual characteristics. Findings: we assess this software's effectiveness using real-world data and information from datasets like HAM10000 and PH2. The software demonstrated a solid performance, with a detection accuracy of 67%, a sensitivity of 72%, and a specificity of 61%. Conclusion: Optoskin is designed to process and analyze dermatoscopic images. It automatically measures critical indices such as asymmetry, border irregularity, color, and diameter of lesions using the ABCD algorithm. The software also automatically classifies lesions as benign or malignant. When tested with real data and standard datasets, Optoskin has shown high effectiveness, with substantial accuracy, sensitivity, and specificity.

2Objectives: Removing part of the tooth and preparing the cavity for restoration using mechanical tools is often painful for the patient. A new approach being developed takes advantage of the precision laser machining capability. Laboratory and clinical studies have shown that 2CO lasers at wavelengths of 9.3 μm and 9.6 μm with a high absorption coefficient in hard tooth tissues and a pulse width in the range of 10 to 20 μs for efficient removal of enamel and dentin with minimum Environmental heat damage is suitable. The aim of this study is to estimate the hardness threshold of enamel and dentin hard tissues using CO2 laser micrometer pulses emitted at a wavelength of 9.3 μm with the help of laser-tissue interaction modeling. method: In this article, with a theoretical approach, based on the light-tissue interaction equations in the luminescence range, the depth and width of tooth dullness is estimated. Here, the changes in the degree of ablation with the change of the energy density of the 2CO laser pulse commonly used in dentistry are considered. To validate the model, the comparison of the modeling results with the experimental data of the articles using a pulsed 2CO laser at a wavelength of 9.3 μm with a change in energy density from about 2 J/cm 10 to 2 J/cm 100 was used, and the threshold dose of ablation predicted from Theory is compared with experimental values. Findings: The amount of tooth decay is strongly dependent on the laser beam fluence. At a constant energy density, the depth and size of dentin pit is greater than that of tooth enamel. According to the theoretical results, the energy density of the luminescence threshold at the wavelength of 9.3 μm is obtained for enamel at about 2.5 J/cm and for ivory at 2.4 J/cm. The values predicted for enamel and dentin by the model are in good agreement with the laboratory results. Conclusion: 2CO laser at a wavelength of 3.9 μm is widely accepted in dentistry for blunting the hard tissues of enamel and dentin. In order to choose the right laser energy for a specific dental application, it is necessary to know the blunting threshold energy. Laser-tissue interaction modeling, with the possibility of optimizing the laser parameters and predicting the response of materials under different conditions, is one of the methods that provides the ability of investigations that may be difficult, time-consuming or error-prone to achieve in the laboratory. By using the theoretical model based on the interaction of the laser pulse with the hard tissue of the tooth, it is possible to calculate the cutting threshold energy for tooth enamel and dentin with high accuracy, which is a good supplement for experimental studies.

2Objectives: Today, in order to reduce pain and stress during the removal of tooth decay, lasers have been proposed as a suitable alternative to dental burs. The purpose of this research is to investigate the effect of two characteristics of wavelength and the number of 2CO laser taps before and after spraying the cooling water spray on the decayed dentine tissue of human teeth, which was done with the help of optical microscope and scanning electron microscope (SEM). Materials and methods: The studied samples are a number of extracted human teeth in 0. 1% thymol solution, which were kept in water and room temperature until the last stage of the experiment to maintain tissue hydration. Since the irradiation was aimed at caries in the dental dentin area, the samples were cut along the length of the tooth and fixed in the orthodontic acrylic block for easy access and control. These samples were irradiated with the rays of a carbon dioxide laser (2CO) with a tap width of 200 ns at a repetition rate of 1 Hz, before and after spraying water spray. Finally, the effect of laser ablation on decayed tooth tissue at different wavelengths (9. 3, 9. 6, 10. 3 and 10. 6 μm) with a fluence of 7. 36 J/cm has been investigated with the help of SEM microscope. Findings: The decay was optimally removed and no irreversible thermal effects such as (carbonization, cracking, melting and recrystallization) were observed on the samples in the presence of water cooling. Conclusion: Based on the results obtained in this work, 2CO laser irradiation can effectively and optimally remove dental caries in the presence of water cooling. However, optimizing the parameters to achieve satisfactory results still requires more research