This PDF file contains the front matter associated with SPIE Proceedings Volume 12826, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

Photobiomodulation therapy (PBMt) has been reported effective for the treatment of post-traumatic stress disorder (PTSD) at low cost in the clinical trial journals for years. PBMt is reported to increase the production of brain-derived neurotrophic factor (BDNF) which promotes the growth and survival of neurons. BDNF is thought to play a role in the regulation of mood, learning, and memory, and it is also thought to be involved in the treatment of PTSD. PBMt is also reported to reduce inflammation in the brain, which is regarded helpful for reducing the symptoms of the psychiatric disorders, including PTSD. In this paper, the PBMt treatment recipes and the results on the PTSDs from the clinical papers already published are analyzed and compared. The most frequently used treatment parameters such as irradiances, wavelengths, doses, and light pulsing frequencies are derived. The treatment recipes for PTSD patients are also suggested.

Photobiomodulation (PBM) dosimetry incorporates various irradiation parameters such as wavelength, beam area/spot size, power, fluence, irradiance, time, treatment duration, and optical properties of tissue. Among all those parameters, the optical properties, such as absorption coefficients (μ_a) and scattering (μ_s) of tissue, are the key components of determining PBM dosimetry. The absorption coefficient is primarily determined by the concentration and spectral characteristics of chromophores within the tissue. Consequently, wavelengths strongly absorbed by chromophores like hemoglobin or water may not penetrate deeply into tissue, making them inefficient for treating deeper targets. The scattering coefficient provides insight into the degree of light scattering due to interactions with tissue or inhomogeneities in the medium. In cases of high tissue scattering, a higher input dose may be necessary to ensure adequate energy density at the target site. We have studied the optical properties of pig jaws in seven different locations using contact probe developed at the University of Pennsylvania. The pig jaw is an excellent model for the human jaw since it has similar size and optical properties. Understanding the optical properties of the human jaw is the critical step for more precise and effective treatment of PBM in dental applications. This research aims to advance the understanding of the critical relationships between tissue optical properties absorption (μ_a) and scattering (μ_s), and the optimal dosimetry parameters for PBM, to enhance clinical outcomes. This highlights the importance of the PBM irradiation parameter variables and their influence on therapeutic efficacy.

Skin serves as a vital component for thermoregulation and acts as a barrier against external threats. Wounds compromise the integrity of the skin and can lead to serious pathologies. Therefore, effective treatment of skin wounds is imperative, particularly in cases of chronic wounds or in individuals with comorbidities. Fibroblast cells play a crucial role in wound healing and represent a model for in vitro studies on photobiomodulation (PBM). The use of blue LED light in PBM has been shown to be effective in wound management, although the exact mechanism of action is still unclear. Several studies have investigated this, identifying specific target molecules, including Cytochrome C oxidase. Mitochondria appear to be a key target for blue light irradiation. To investigate this further, primary cultures of human dermal fibroblasts were established and a blue LED light device (410 to 430nm, 1W optical emission power) was used. A single application administered three doses of blue light (4, 21, 41 J/cm²). Mitochondrial morphology was observed before and after irradiation using electron microscopy. Subsequent studies will aim to determine if changes in morphology correspond to alterations in function. Previous in vitro findings indicated enhanced cell viability, proliferation, and outward currents at the lower fluence (4 J/cm²). Conversely, the higher dose (41 J/cm²) reduced cell viability. Here, we present preliminary results on the impact of 4 J/cm² blue LED light on outward currents in fibroblasts. Our results highlight the PBM properties of short-wavelength blue LED light.

Photobiomodulation (PBM) is a non-ionizing, non-thermal, low-power laser, or LED light therapy with diverse clinical applications for pain management, wound healing, dermatology, oral health, neurorehabilitation, and oncology. The capability of PBM to promote cell proliferation and migration makes it a potential treatment alternative, especially for patients unresponsive to conventional methods. A key challenge of PBM is determining the optimal dosage parameters, which include wavelength, fluence, power, pulse structure, irradiance, time, and interval duration. Given the therapeutic goal of stimulating a biological response, delivering light to a predictable penetration depth is critical. This study aims to characterize PBM light transmission for the 661nm wavelength in 500mW and 1W power outputs across different soft tissue types relevant in the head and neck region. We developed a unique preclinical model using five non-fixed, intact porcine mandibles representative of the dental oral craniofacial complex to explore this concept of accurate penetration depth of the 661nm wavelength. We captured maximum light fluence measurements (mW/cm^2) at distances 2 to 14mm using an isotropic detector connected to a real-time dosimetry system. All experimental sites underwent digital imaging and histological processing for architectural investigation, followed by proprietary software analysis to correlate distance, density, tissue type, and max light fluence values. Preliminary findings indicate a general reduction in max fluence as the distance values increased. A notable finding was the significant increase in max fluence in sites composed of adipose tissue compared to muscle tissue, highlighting the impact of tissue architecture and tissue optical properties on PBM light delivery. These results emphasize the need for further optimization of PBM dosing protocols for maximal therapeutic benefits.

SARS-CoV-2 is a pandemic that claimed millions of lives, and to date, there has been no identifiable cure for SARS-CoV- 2. LLLT is a thriving technology used to treat different kinds of conditions that require stimulation of healing, relief of pain and inflammation, and repair of function. LLLT has been used to treat wounds, sports injuries, chronic pain, dermatitis, and hair loss. Although LLLT can treat some medical conditions, it has been observed that it can cause an increase in blood antioxidants and heat shock protein expression. There are many kinds of stress caused by laser irradiation, and how a cell reacts to them depends on the kind and severity of the insult. The aim of this study is to investigate the effect of LLLT on SARS-CoV-2-infected HEK293/ACE2 cells. In this study, biological assays, including MTT assay, cell viability live/dead, green/deep red assay, and reactive oxygen species (ROS) detection assay, were used to determine the effects of laser irradiation on SARS-CoV-2 infected and uninfected HEK293/ACE2. HEK29/ACE2 cells were infected with SARS-CoV-2 and 48 hours post-infection they were subject to laser irradiation. After 24 hours post-irradiation, biological assays were performed. Both infected non-irradiated and irradiated cells displayed signs of cell stress and produced ROS. There were more dead cells observed in infected HEK293/ACE2 cells, while more viable cells were seen in the uninfected irradiated HEK293/ACE2 cells. LLLT can be used to explore the therapeutic qualities of laser light in SARS-CoV-2 research. LLLT can be used to explore the therapeutic effects of laser light in SARS-CoV-2 research.

Transcranial Photobiomodulation (tPBM) offers significant potential for cognitive enhancement and therapy. A critical gap remains in our understanding of the differential impacts of pulsed versus continuous tPBM on human electroencephalogram (EEG) patterns. Treatment planners do not have objective metrics to ascertain optimal dosage parameters which hampers the development of effective closed-loop neuromodulation systems. This study focuses on key EEG markers: interhemispheric coherence and frequency entrainment. Concurrent tPBM and EEG recordings were conducted on healthy participants in single sessions with continuous, pulsed and modular protocols. Putative indicators of effective tPBM protocols in healthy participants are hypothesized to be significant post-intervention increases in relative alpha frequency power and coherence normalization. The study quantifies changes from baseline to demonstrate tPBM dosimetry effects. We anticipate that our study will elucidate the distinct effects of pulsed versus continuous tPBM protocols, with an expected interhemispheric coherence normalization and frequency entrainment.

The physical emissions from cold atmospheric plasma (CAP) devices have been shown to be efficacious in killing U87-MG glioblastoma multiform cells in vitro. While reduction of cell viability has been previously demonstrated, the biological mechanisms involved remain a mystery. To address this, the present study investigates the bioeffects of CAP discharge tube (DT) treatment on U87-MG glioblastoma multiform cells in vitro, considering separation distance, treatment duration, multiple treatments, and incubation time post treatment. Assessment of apoptotic progression, membrane permeability, intracellular reactive oxygen species (ROS) concentration, and mitochondrial membrane potential by flow cytometry demonstrates that DT treatment causes oxidative stress and apoptotic progression in U87-MG cells. Cumulative treatment with multiple short duration treatments is also shown to increase efficacy of DT treatment compared to single long duration treatment. Cell viability and intracellular ROS concentration observed 2, 6, 24, 48, and 72 hours post DT treatment demonstrate pronounced effects of DT treatment lasting multiple days, improving upon our current understanding of this novel treatment modality.

Low-level laser therapy (LLLT) is a method of exposing cells or tissue to low levels of red and near-infrared light that has a high success rate for the treatment of various ailments. LLLT has been used to treat various diseases, including wounds, spinal cord injuries, and symptoms of viral conditions like blisters caused by the Herpes Simplex Virus. The aims of the study are to investigate the effect of laser irradiation on SARS-CoV-2 infected cells and on uninfected cells using a scanning electron microscope (SEM) and transmission electron microscopy (TEM) as analysis tools. SEM was used to determine the morphological differences caused by laser irradiation on SARS-CoV-2 infected HEK293/ACE2 cells as well as non-irradiated SARS-CoV-2 infected ones. In addition, the results obtained were compared to irradiated and non-irradiated uninfected cells. To further evaluate the effect of irradiation and SARS-CoV-2, the transmission electron microscope (TEM) was used to investigate the changes in the interior of the aforementioned cells. In preparation for SEM and TEM, HEK293/ACE2 cells were infected with SARS-CoV-2 and irradiated with a 640nm laser at different fluences. Following irradiation, the cells were then fixed and mounted. The data obtained using different magnifications in SEM, revealed differences in the occurrence of surface projections and shape of SARS-CoV-2 infected and uninfected cells, and in TEM they display clear difference in the interior structure of both SARS-CoV-2 infected and uninfected HEK29/ACE2 cells irradiated.

Photobiomodulation (PBM) involves the use of red and near-infrared (NIR) light between 600 and 1,100 (nm) as a therapeutic modality. PBM’s non-invasive, non-thermal, non-ionizing characteristics are useful for applications in medicine, including dentistry, dermatology, neurology, physical therapy, sports medicine, and ophthalmology. The light source in PBM typically includes a low-power laser or LED, with the choice of wavelength dependent on the target tissue and therapeutic objectives. Superficial layers absorb red light (600 to 700nm) and NIR light (780 to 1,100nm) has the ability for deeper penetration. While wavelength is a key parameter in PBM, other factors significantly influence therapeutic efficacy. The understanding of these variables is critical in achieving desired outcomes. PBM devices often utilize a Gaussian light source, notable for its highest intensity at the center, tapering off towards the edges. This characteristic allows for precise, targeted treatment and uniform dose distribution, which is crucial for clinical efficacy. This study aims to assess the light distribution and fluence rate distribution of a 660nm FDA-approved PBM device. This novel modeling platform will measure the light distribution in a heterogenous medium (air) via an isotropic detector at standardized distances of 0 to 14mm. We will employ both linear and non-linear wavelength fitting algorithms to assess light absorption (μ_a), scattering (μ_s’), and effective attenuation (μeff) to determine the final output of mW/cm^2. Statistical analysis will scrutinize the mean and standard deviation from the resulting profile, thereby providing valuable insight for future research and the clinical application of this Gaussian light source.