Rinaldo Roberto de Jesus Guirro

To simulate light propagation in human skin irradiated with laser sources emitting at 660 nm, 830 nm, and 904 nm, using different beam diameters and divergences, in order to characterize the internal fluence rate distribution profiles within the tissue. Monte Carlo simulations were performed using the GPU-accelerated MCX platform. Optical properties (absorption and reduced scattering coefficients) were experimentally obtained from human skin samples and incorporated into a three-dimensional voxel-based model. Laser parameters, including output power, beam radius, and divergence, were experimentally characterized and used as input for simulations. The effects of wavelength, beam divergence, and source radius on axial and spatial fluence rate distribution were quantitatively evaluated under controlled power conditions. All wavelengths exhibited exponential attenuation with comparable depth-dependent behavior within the first millimeters of tissue. Beam radius significantly modulated surface peak fluence rate and central-axis magnitude at depth under constant total power. In contrast, real divergence values typical of commercial devices produced minimal changes in axial fluence under contact-mode conditions, whereas large theoretical divergence angles markedly reduced fluence retention and increased lateral spread. Among the investigated variables, beam radius exerted the strongest influence on subsurface fluence magnitude under constant power, whereas wavelengths within the therapeutic window (660–904 nm) showed comparable attenuation behavior in superficial tissue. Realistic divergence values typical of commercial devices minimally affected axial fluence under contact-mode conditions, while larger angular spreads significantly reduced central-axis fluence retention.

Background: Non‐invasive oximetry is crucial for the easy and continuous monitoring of blood oxygenation, from routine assessments to critical care in intensive care units (ICU). Studies indicate that pulse oximeter readings may be biased due to the high light absorption of melanin. Aim: This study aims to analyse the agreement among three different pulse oximeters and their concordance with arterial blood gas measurements in ICU patients and verify how accuracy varies with age and skin pigmentation. Study Design: We conducted a prospective cross‐sectional observational study with a population of intensive care patients. Blood oxygen saturation was measured simultaneously by pulse oximetry and arterial blood gas analysis. Skin pigmentation was objectively assessed at two anatomical sites using calibrated colorimeters and quantified by the individual typology angle (ITA°). Results: Among 100 ICU patients (SaO ₂ 85%–100%), two of the three oximeters exceeded the 3% accuracy root mean square (ARMS) 2013 FDA threshold, whereas one device remained within limits (2.91%). Agreement with arterial oxygen saturation was weak (CCC = 0.34–0.46) and lower SaO ₂ was associated with overestimation increase (0.31%–0.54% for every 1% SaO ₂ decrease). Multivariable models showed no evidence of association between ITA° and SpO ₂ error ( p > 0.05). In contrast, older age predicted greater overestimation ( β range = 0.05%–0.06% per year; 95% CI range = 0.02–0.09; all p ≤ 0.05). Conclusions: Although estimates suggested small pigmentation effects, analysis indicated these were indistinguishable from random error. In contrast, physiological factors such as lower SaO ₂ and older age were consistently associated with greater oximeter error. Substantial clinical variability limits detection of small biases, underscoring the need for improved calibration and validation using objective skin‐tone assessment. Relevance to Clinical Practice: In intensive care, where continuous monitoring is essential, pulse oximeter error was more strongly related to physiological factors, such as arterial oxygen saturation and age, than to skin tone. These findings support cautious interpretation of SpO ₂ values and appropriate device selection to ensure accurate assessment across diverse populations.

The physiological impact of neoadjuvant therapy on vascular and thermal responses in breast cancer patients remains poorly understood, despite its clinical relevance for predicting treatment outcomes and managing therapy-related side effects. Sensor-based monitoring technologies, such as thermography and Doppler ultrasound, provide non-invasive approaches to assess circulatory and thermal changes, potentially serving as predictive biomarkers of therapeutic efficacy. This study aimed to evaluate vascular impairment and correlate circulatory alterations with skin surface temperature in women undergoing neoadjuvant therapy for breast cancer. A total of 38 women were enrolled and distributed into two groups: patients receiving eight cycles of neoadjuvant chemotherapy and healthy controls. Thermographic imaging was employed to measure upper-limb surface temperature, while Doppler ultrasound assessed arterial and venous blood flow in the cubital fossa. Paired Student’s t-tests compared experimental moments (C1, C5, C8), with normality assessed from difference scores (Δ) and results expressed as mean differences with 95% CIs (p < 0.05, two-tailed). Associations between surface temperature and arterial blood flow were examined using simple linear regression (R², F-statistic, β, p-values). Analyses were performed in SPSS 20.0 (SPSS Inc., Chicago, IL, USA). Significant increases in surface temperature (p < 0.001) and blood flow velocity (p < 0.004) were observed in patients compared with controls prior to therapy, suggesting pre-existing vascular and thermal dysregulation. Neoadjuvant therapy significantly altered thermal and vascular dynamics, reinforcing the utility of sensor-based monitoring to capture subtle physiological responses during treatment.

LED photobiomodulation therapy (PBMT) is widely recognized for its beneficial effects in several clinical conditions; however, its potential in modulating vascular function is not yet fully established. This study aimed to evaluate the application of PBMT by LED (light-emittion diode) using a combined red and near-infrared light spectrum, with a focus on improving the vascular function of the radial artery in vitro. A total of 40 radial artery segments were studied and divided into Four groups of 10 segments, including the control (C), red (R), infrared (IR), and combined red + infrared (R + IR). Prior to light irradiation at wavelengths of 650 nm and 940 nm, vascular function in these segments was pharmacologically inhibited using L-NAME. The drugs phenylephrine, acetylcholine, and sodium nitroprusside were used to determine if irradiation could restore the inhibited vascular functions. Superoxide anion levels, an important reactive oxygen specie (ROS), were measured using a chemiluminescence assay with lucigenin. The bioavailability of nitric oxide was evaluated using a Griess Reagent Kit assay. The vascular inflammation was determined by the Intercellular Adhesion Molecule 1 (ICAM-1) expression. The results indicate that combined PBMT improved vascular function compared to PBMT with isolated light spectra, promoting greater vascular relaxation by increasing nitric oxide by increasing nitric oxide bioavailability and decreasing the superoxide anion production. Additionally, the combined light spectrum and the red spectrum decreased the ICAM-1 expression. Combined spectrum LED photobiomodulation therapy improves vascular function by promoting vasodilation, reducing reactive oxygen species (ROS) production, and attenuating inflammatory responses.

Introduction The association of photobiomodulation (PBM) and antibiotics has been little investigated for bacterial control. Objectives This study aimed to verify possible changes in the antibiotic sensitivity profile in ATCC-type bacteria and bacteria collected from burned patients after irradiation with 465 and 630 nm LED at 30, 40 and 50 J/cm². Methods The species Staphylococcus aureus (ATCC^®BAA-977), Pseudomonas aeruginosa (ATCC 27853), and Staphylococcus aureus and Pseudomonas aeruginosa from burned patients were used as proof of concept. A qualitative method was adopted to verify the antibiotic sensitivity profile. To quantify oxidative stress, assessments were performed using Malondialdehyde (MDA) and antioxidant action using glutathione (GSH). Data were analyzed by Shapiro-Wilk and ANOVA single-factor tests, with Tukey post-hoc (p < 0.05). Results Differences between the irradiated groups were found, however, without statistical significance or representing a change in the sensitivity profile of the bacteria investigated. The highest production of oxidative stress was at 465 nm (30 J/cm²), and no glutathione production was detected. Conclusion LED irradiation was found to be safe for application to bacterial colonies, as it did not modify their antibiotic susceptibility profile, despite inducing oxidative stress.

Introduction: Recent evidence suggests that the combination of exercise and photobiomodulation therapy (PBMT) enhances muscle performance, including improvements in strength, hypertrophy, and fatigue resistance. As muscle tissue changes after training, a dose progression over time may show additional effects. However, there needs to be more clarity regarding the optimal physical parameters for enhancing muscle performance. Thus, the aim was to evaluate the impact of strength training combined with PBMT at fixed or progressive doses on strength performance, metabolic activity, and clinical outcomes in healthy individuals. Methods: This was a double-blind, randomized clinical trial. Fifty-six male participants were randomly allocated into four groups: Sham, minimal dose (60 J), maximal dose (300 J), and incremental dose (60–300 J). Baseline assessments included body composition analysis and isokinetic dynamometry (peak torque and total work of the quadriceps femoris and hamstring muscles), followed by ten sessions of strength training combined with PBMT applied before each exercise session, which consisted of three sets of stiff and squats. PBMT irradiation was applied to the quadriceps and hamstrings. Training loads and psychophysiological responses were monitored throughout the intervention. Participants were reassessed at the end of the training period and followed up for a total duration of seven days. Results: No significant differences were observed between the groups in isokinetic strength parameters (P>0.05), although small to moderate effect sizes favored the Incremental and Maximal Dose groups. Similar patterns were found for psychophysiological responses and training loads across the groups. Conclusion: In the context of this research model, PBMT combined with strength training did not yield superior outcomes in muscle strength, psychophysiological, or metabolic parameters compared to the different dosing strategies evaluated.

This investigation attempts to elucidate power density's interplay with observed outcomes subsequent to a training regimen. Forty-two participants were stratified into three groups (Sham, Cluster, LED-Blanket), with irradiated groups receiving 300 J of energy under distinct parameters. Photobiomodulation irradiation was applied to the quadriceps and hamstrings before each of the ten prescribed training sessions, which consisted of three sets of stiff and squats. Participants underwent assessment during sessions, encompassing blood lactate measurements and psychophysiological scales (Numerical Rating Pain Scale for Pain and Rate of Perceived Effort). Additionally, pre-intervention, post-intervention, and follow-up evaluations on an isokinetic dynamometer measured peak torque. Two-way repeated measures ANOVA for intra- and inter-group comparisons. No significant inter-group differences or group-time interactions were discerned in lactate concentration or psychophysiological indices. Solely, a difference surfaced in the peak torque of the dominant limb during knee flexion, manifesting across pre-, post, and follow-up intervals (p = 0.003 and p < 0.001) with an effect size of n² = 0.080. Within the outlined methodological framework, photobiomodulation was ineffective in eliciting performance enhancements, with divergent parameters evincing equivocal efficacy.

Objective This study investigated the efficacy of cognitive functional therapy (CFT) versus a sham procedure for pain intensity and disability for patients with non-specific chronic low back pain (CLBP). Methods This is a randomised sham-controlled trial conducted in a primary care public health service. A total of 152 participants were randomly assigned to the CFT group (n=76) and the sham group (n=76). The CFT group received six 1 hour individualised sessions; the sham procedure group received six individual sessions of neutral talking+detuned photobiomodulation (low-level laser therapy) equipment. Both groups received an education booklet with information on strategies for CLBP self-management. Primary outcomes were pain intensity and disability at 6 weeks. Participants were assessed preintervention, postintervention (at 6 weeks), and 3 and 6 months after randomisation. Results We obtained primary outcome data from 97.4% (n=74) of participants in the CFT group and 98.7% (n=75) from the sham group. The CFT group showed greater effects in pain intensity (mean difference (MD)=−1.8; 95% CI −2.5 to −1.1) and disability (MD=−9.9; 95% CI −13.2 to −6.5) postintervention compared with the sham group. The effect remained at the 3-month and 6-month follow-ups. Conclusions CFT showed sustained clinical efficacy compared with a sham procedure for treating pain intensity and disability in patients with CLBP. Trial registration number This trial was registered in ClinicalTrials.gov, NCT04518891 and was previously published https://pubmed.ncbi.nlm.nih.gov/35788240/.

This study aimed to investigate the influence of photobiomodulation therapy (PBMT) in hypoxia (HYP) and normoxia (NOR) on time to exhaustion and the energetic contribution of treadmill running in amateur athletes. Eleven male participants, aged between 18 and 29 years, were submitted to an incremental test to determine the iV̇O₂max, and subsequently on separated days, to the PBMT application (irradiation = 720 s; wavelength = 850 nm), followed by four efforts to exhaustion, in treadmill running, under different conditions [NOR + placebo (PLA); NOR + PBMT; HYP + PLA; HYP + PBMT], in random order, to access energy contribution and maximal accumulated oxygen deficit alternative (MAOD_ALT). Time to exhaustion and absolute aerobic contribution were lower in HYP than NOR, for both PLA and PBMT conditions (p < 0.05). In the percentage energy contribution of each metabolism during exhaustion effort, aerobic participation was lower, while MAOD_ALT was higher in HYP than NOR, only in the PLA situation; alactic anaerobic participation was higher in HYP than NOR in the PBMT application situation (p = 0.002). The PBMT does not promote additional benefits over time to exhaustion in NOR and HYP conditions, however PBMT during exhaustive efforts in HYP results in an increase in anaerobiosis.