TOPAS-Tissue: A Framework for the Simulation of the Biological Response to Ionizing Radiation at the Multi-Cellular Level.

This work aims to develop and validate a framework for the multiscale simulation of the biological response to ionizing radiation in a population of cells forming a tissue. We present TOPAS-Tissue, a framework to allow coupling two Monte Carlo (MC) codes: TOPAS with the TOPAS-nBio extension, capable of handling the track-structure simulation and subsequent chemistry, and CompuCell3D, an agent-based model simulator for biological and environmental behavior of a population of cells. We verified the implementation by simulating the experimental conditions for a clonogenic survival assay of a 2-D PC-3 cell culture model (10 cells in 10,000 µm2) irradiated by MV X-rays at several absorbed dose values from 0-8 Gy. The simulation considered cell growth and division, irradiation, DSB induction, DNA repair, and cellular response. The survival was obtained by counting the number of colonies, defined as a surviving primary (or seeded) cell with progeny, at 2.7 simulated days after irradiation. DNA repair was simulated with an MC implementation of the two-lesion kinetic model and the cell response with a p53 protein-pulse model. The simulated survival curve followed the theoretical linear-quadratic response with dose. The fitted coefficients α = 0.280 ± 0.025/Gy and ß = 0.042 ± 0.006/Gy2 agreed with published experimental data within two standard deviations. TOPAS-Tissue extends previous works by simulating in an end-to-end way the effects of radiation in a cell population, from irradiation and DNA damage leading to the cell fate. In conclusion, TOPAS-Tissue offers an extensible all-in-one simulation framework that successfully couples Compucell3D and TOPAS for multiscale simulation of the biological response to radiation.

Microwave radiation and thermal effects on the bioenergetics of isolated mitochondria.

AIMS: This study proposes to investigate the effects of microwave radiation and its thermal effects, compared to thermal effects alone, on the bioenergetics of mitochondria isolated from mouse liver. METHODS: The main parameters investigated in this study are mitochondrial respiration (coupled states: S3 and S4; uncoupled state), using a high-resolution respirometer, and swelling, using a spectrophotometer. RESULTS: Mitochondria irradiated at 2.45 GHz microwave with doses 0.085, 0.113 and 0.141 kJ/g, presented a decrease in S3 and uncoupled state, but an increase in S4. Conversely, mitochondria thermally treated at 40, 44 and 50 °C presented an increasing in S3 and S4, while uncoupled state was unaltered. Mitochondrial swelling increases as a function of the dose or temperature, indicating membrane damages in both cases. CONCLUSION: Microwave radiation and thermal effect alone indicated different bioenergetics mitochondria response. These results imply that the effects due to microwave in medical treatment are not exclusively due to the increase in temperature, but a combination of electromagnetic and thermal effects.

Extending culture time to improve Mitotic Index for cytogenetic dosimetry.

PURPOSE: To analyze the effects of extending lymphocyte cultivation time on the Mitotic Index, frequency of first-division cells, and dose estimation after irradiating blood samples with different doses of radiation. MATERIALS AND METHODS: Blood samples from two healthy male volunteers were separately irradiated with three doses (3, 5, and 6 Gy) using a 60Co gamma source (average dose rate: 1.48 kGy.h-1) and cultivated in vitro for conventional (48 h) and extended (56, 68, and 72 h) amounts of time. Colcemid (0.01 µg.mL-1) was added at the beginning of the culture period. Cells were fixed, stained with fluorescence plus Giemsa (FPG), and analyzed under a light microscope. The effects of prolonged culture duration on the Mitotic Index (MI), frequency of first-division cells (M1 cells), and the First-Division Mitotic Index (FDMI) were investigated. The estimation of delivered doses was conducted using a conventional 48h-culture calibration curve. RESULTS: Overall, cells presented higher MI (up to 12-fold) with the extension of culture, while higher radiation doses led to lower MI values (up to 80% reduction at 48 h). Cells irradiated with higher doses (5 and 6 Gy) had the most significant increase (5- to 12-fold) of MI as the cultivation was prolonged. The frequency of M1 cells decreased with the prolongation of culture for all doses (up to 75% reduction), while irradiated cells presented higher frequencies of M1 cells than non-irradiated ones. FDMI increased for all irradiated cultures but most markedly in those irradiated with higher doses (up to 10-fold). The conventional 48h-culture calibration curve proved adequate for assessing the delivered dose based on dicentric frequency following a 72-hour culture. CONCLUSION: Compared to the conventional 48-hour protocol, extending the culture length to 72 hours significantly increased the Mitotic Index and the number of first-division metaphases of irradiated lymphocytes, providing slides with a better scorable metaphase density. Extending the culture time to 72 hours, combined with FPG staining to score exclusively first-division metaphases, improved the counting of dicentric chromosomes. The methodology presented and discussed in this study can be a powerful tool for dicentric-based biodosimetry, especially when exposure to high radiation doses is involved.

Dose-response and efficacy of 904 nm photobiomodulation on diabetic foot ulcers healing: a randomized controlled trial.

PURPOSE: This study aimed to examine the impact of a 904 nm photobiomodulation (PBM) on diabetic ulcers using varying dosages. METHODS: The study was a randomized, double-blind, placebo-controlled clinical trial that compared treatments using PBM (GaAs 904 nm 30w) with three different energy densities (4 J/cm2; 8 J/cm2; 10 J/cm2) in the healing process of non-infected diabetic foot ulcers. Eighty volunteers (48.75% female; 58.5 ± 11.1 years) were randomized into three intervention groups treated with PBM and one control group (PBM placebo). Volunteers performed up 20 interventions with PBM, either placebo or actual, in conjunction with conventional therapy, which involved dressing the wound with Helianthus annuus vegetable oil. The primary variable was the ulcer size reduction rate. RESULTS: GaAs 904 nm PBM yielded a clinically and significant ulcer size rate reduction of diabetic foot ulcers, independently of energy density range (p < 0.05). However, 10 J/cm² had 60% of completely healed ulcers and the highest proportion of patients reaching 50% of ulcer reduction rate after 5 weeks of treatment. In addition, only 10 J/cm² showed a significant difference between control group after a 10-week follow-up (p < 0.05). CONCLUSION: GaAs 904 nm PBM was effective in treating diabetic foot ulcers in this study and a dosage of 10 J/cm², after a 10-week follow-up, proved to be the most effective compared to the other groups. CLINICAL TRIAL REGISTRATION NUMBER: NCT04246814.

Side effects of different head and neck radiotherapy doses on wistar rat's behavior.

Radiotherapy (RT) is a common treatment for head and neck tumors. However, it causes several physical and behavioral side effects, and no study has assessed the emotional effects in rats. Therefore, the present study evaluated the influence of head and neck RT on the behavior and body weight gain in Wistar rats. Fifty-four male Wistar rats were allocated into six groups (n = 9) according to the irradiation dose, which was applied at the first day of the experiment: RT-7.5 (single dose of 7.5 Gy); RT-10 (single dose of 10 Gy); RT-15 (single dose of 15 Gy); RT-30 (single dose of 30 Gy); Control (without RT). The animals were irradiated in the region of the right face, and behavioral tests and weighing were performed on days one, seven, and 28. The open field and Y-maze tests were undertaken to analyze the animal's behavior. The dose of 30 Gy was lethal when applied to the head and neck region. The irradiated animals had less weight gain when compared to the control ones, but there was no statistical difference. In the open field and Y-maze tests, lower mobility of animals in the RT groups was observed both on day seven and at the end of the experiment (day 28) when compared to the control rats (p < 0.05). It was possible to conclude that the different doses of radiation induced depressive behavior in the animals, and that the weight gain tended to be lower in the irradiated groups, however, without statistical difference.

Propuesta metodológica para el uso del programa PCXMC 2.0 en modalidad rotacional / Methodological Proposal for the use of the program PCXMC 2.0 in Rotational Mode

RESUMEN Durante los procedimientos intervencionistas que utilizan fluoroscopia, se entrega a los pacientes diferentes niveles de dosis de radiación, que pueden tener un impacto a corto, mediano o largo plazo, así como en su severidad. Esto en función del tipo de radiación utilizada y de la sensibilidad a la radiación del tipo(s) de órgano(s) irradiado, es en este punto que se vuelve determinante conocer la dosis a órganos entregada durante los procedimientos con el fin de asegurar el bienestar de los pacientes, este procedimiento no se puede realizar directamente en los órganos del paciente, por lo que se utilizan programas especializado en cálculos dosimétricos. El software PCXMC 2.0 logra estimar la dosis efectiva a través del método determinístico Monte Carlo, a su vez, agregando la dosis equivalente y evaluación de riesgo para estudios dosimétricos, por lo cual, el objetivo del presente trabajo fue proponer una metodología estandarizada para la utilización del programa PCXMC en el cálculo de estas dos magnitudes

ABSTRACT During interventional procedures that utilize fluoroscopy, patients are exposed to varying levels of radiation doses, which can have short, medium, or long term impacts, as well as varying severities. This depends on the type of radiation used and the radiation sensitivity of the organ(s) being irradiated. At this point, it becomes crucial to determine the organ doses delivered during procedures in order to ensure patient well-being. Since direct measurements cannot be made on the patient's organs, specialized software is used for dosimetric calculations. PCXMC 2.0 software achieves the estimation of effective dose through the deterministic Monte Carlo method, while also incorporating equivalent dose and risk assessment for dosimetric studies. Therefore, the objective of this work was to propose a standardized methodology for the use of the PCXMC 2.0 sofware in the calculation of these two magnitudes.it is important to outline a working method for this software and provide instructions on its operation

Radiosensitivity of radiotherapy patients: The effect of individual DNA repair capacity.

Individual radiosensitivity is a critical problem in radiotherapy because of the treatment restrictions it imposes. We have tested whether induction/repair of genomic lesions correlates with the acute cutaneous effects of radiotherapy. Peripheral blood samples of 56 healthy volunteers and 18 patients with breast cancer were studied. DNA damage and DNA repair capacity were assessed in vitro (alkaline comet assay). Patients without skin reaction did not show significant differences from healthy individuals, with respect to either initial or radiation-induced DNA damage. Similar DNA repair kinetics, fitting a decreasing exponential response, were observed in both groups, and there were no significant differences in residual genotoxic damage. In contrast, patients exhibiting acute side effects showed significantly lower DNA repair ability and significantly more residual damage, compared to patients without radiotoxicity. This approach may help to identify patients who are at greater risk of radiotherapy side effects. However, many other factors, such as dosimetry, irradiated volume, and lifestyle should also be considered in the evaluation of individual radiosensitivity.

Practice and prospects for PET/CT guided interventions.

During the past 10 years, performing real-time molecular imaging with positron emission tomography (PET) in combination with computed tomography (CT) during interventional procedures has undergone rapid development. Keeping in mind the interest of the nuclear medicine readers, an update is provided of the current workflows using real-time PET/CT in percutaneous biopsies and tumor ablations. The clinical utility of PET/CT guided biopsies in cancer patients with lung, liver, lymphoma, and bone tumors are reviewed. Several technological developments, including the introduction of new PET tracers and robotic arms as well as opportunities provided through acquiring radioactive biopsy specimens are briefly reviewed.

Salvage radiation therapy in prostate cancer: relationship between rectal dose and long-term, self-reported rectal bleeding.

PURPOSE: To quantify the relationship between the rectal dose distribution and the prevalence of self-reported rectal bleeding among men treated with salvage radiotherapy (ST) delivered by three-dimensional conformal radiotherapy (3DCRT) for prostate cancer. To use this relationship to estimate the risk of rectal bleeding for a contemporary cohort of patients treated with volumetric modulated arc therapy (VMAT) ST. METHODS AND PATIENTS: Rectal bleeding of any grade was reported by 56 (22%) of 255 men in a PROM-survey at a median follow-up of 6.7 years after 3DCRT ST. Treatment plan data were extracted and dose-response relationships for the rectal volumes receiving at least 35 Gy (V35Gy) or 63 Gy (V63Gy) were calculated with logistic regression. These relationships were used to estimate the risk of rectal bleeding for a cohort of 253 patients treated with VMAT ST. RESULTS: In the dose-response analysis of patients in the 3DCRT ST cohort, both rectal V35Gy and V63Gy were statistically significant parameters in univariable analysis (p = 0.005 and 0.003, respectively). For the dose-response models using either rectal V35Gy or V63Gy, the average calculated risk of rectal bleeding was 14% among men treated with VMAT ST compared to a reported prevalence of 22% for men treated with 3DCRT ST. CONCLUSIONS: We identified dose-response relationships between the rectal dose distribution and the risk of self-reported rectal bleeding of any grade in a long-term perspective for men treated with 3DCRT ST. Furthermore, VMAT ST may have the potential to decrease the prevalence of late rectal bleeding.

ET-B receptors involvement in peripheral opioid analgesia induced by light-emitting diode photobiomodulation in male and female mice.

Currently, photobiomodulation therapy (PBMT) is gaining space in the scientific and clinical environment. To help elucidate the importance of irradiance, this study evaluated the effect of two different PBMT irradiances (3.5 and 90 mW/cm2), given a fixed wavelength of 630 nm and a dose of 2 J/cm2, on mechanical hyperalgesia following Complete Freund's Adjuvant (CFA) intraplantar (i.pl.) injection in mice. Additionally, we investigated the role of peripheral opioid and endothelin-B receptors (ETB-R), as well as sex differences in treatment outcome. Different groups of male or female mice were evaluated 6 and 96 h after CFA. Mechanical hyperalgesia was evaluated 30 min after treatments. Naloxone or Bq-788 administration, fifteen minutes before PBMT or Sarafotoxin S6c, helped determine the involvement of peripheral opioid and ETB-Rs on PBMT. Lastly, ETB-Rs skin immunocontent in both sexes was quantified after PBMT consecutive daily treatments. PBMT at an irradiance of 90 mW/cm2, was more effective than 3.5 mW/cm2. Bq-788 and naloxone administration prevented the effects of PBMT and SRTX S6c; however, PBMT did not influence peripheral ETB-Rs immunocontent. The results suggest that irradiance influences PMBT effect; and that activation of ETB-R play a role in peripheral PBMT opioid induced analgesia. Lastly, PMBT effects do not appear to be sex-dependent.

Monte Carlo simulation of the effect of magnetic fields on brachytherapy dose distributions in lung tissue material.

The aim of this work was to use TOPAS Monte Carlo simulations to model the effect of magnetic fields on dose distributions in brachytherapy lung treatments, under ideal and clinical conditions. Idealistic studies were modeled consisting of either a monoenergetic electron source of 432 keV, or a polyenergetic electron source using the spectrum of secondary electrons produced by 192Ir gamma-ray irradiation. The electron source was positioned in the center of a homogeneous, lung tissue phantom (ρ = 0.26 g/cm3). Conversely, the clinical study was simulated using the VariSource VS2000 192Ir source in a patient with a lung tumor. Three contoured volumes were considered: the tumor, the planning tumor volume (PTV), and the lung. In all studies, dose distributions were calculated in the presence or absence of a constant magnetic field of 3T. Also, TG-43 parameters were calculated for the VariSource and compared with published data from EGS-brachy (EGSnrc) and PENELOPE. The magnetic field affected the dose distributions in the idealistic studies. For the monoenergetic and poly-energetic studies, the radial distance of the 10% iso-dose line was reduced in the presence of the magnetic field by 64.9% and 24.6%, respectively. For the clinical study, the magnetic field caused differences of 10% on average in the patient dose distributions. Nevertheless, differences in dose-volume histograms were below 2%. Finally, for TG-43 parameters, the dose-rate constant from TOPAS differed by 0.09% ± 0.33% and 0.18% ± 0.33% with respect to EGS-brachy and PENELOPE, respectively. The geometry and anisotropy functions differed within 1.2% ± 1.1%, and within 0.0% ± 0.3%, respectively. The Lorentz forces inside a 3T magnetic resonance machine during 192Ir brachytherapy treatment of the lung are not large enough to affect the tumor dose distributions significantly, as expected. Nevertheless, large local differences were found in the lung tissue. Applications of this effect are therefore limited by the fact that meaningful differences appeared only in regions containing air, which is not abundant inside the human.

Melanopsin mediates UVA-dependent modulation of proliferation, pigmentation, apoptosis, and molecular clock in normal and malignant melanocytes.

Cutaneous melanocytes and melanoma cells express several opsins, of which melanopsin (OPN4) detects temperature and UVA radiation. To evaluate the interaction between OPN4 and UVA radiation, normal and malignant Opn4WT and Opn4KO melanocytes were exposed to three daily low doses (total 13.2 kJ/m2) of UVA radiation. UVA radiation led to a reduction of proliferation in both Opn4WT cell lines; however, only in melanoma cells this effect was associated with increased cell death by apoptosis. Daily UVA stimuli induced persistent pigment darkening (PPD) in both Opn4WT cell lines. Upon Opn4 knockout, all UVA-induced effects were lost in three independent clones of Opn4KO melanocytes and melanoma cells. Per1 bioluminescence was reduced after 1st and 2nd UVA radiations in Opn4WT cells. In Opn4KO melanocytes and melanoma cells, an acute increase of Per1 expression was seen immediately after each stimulus. We also found that OPN4 expression is downregulated in human melanoma compared to normal skin, and it decreases with disease progression. Interestingly, metastatic melanomas with low expression of OPN4 present increased expression of BMAL1 and longer overall survival. Collectively, our findings reinforce the functionality of the photosensitive system of melanocytes that may subsidize advancements in the understanding of skin related diseases, including cancer.

Single and repeated low-dose UVB radiation exposures affect the visual system.

The visual system is an important biological indicator of effects induced by ultraviolet (UV) radiation. However, research has extensively investigated the effects of high-dose UV radiation in a single exposure, thus, the differential of this work was to investigate the effects of UVB radiation in low doses in single and repeated exposure. Therefore, we investigated the effects of repeated exposure to environmental UVB doses (0.09 J/cm2) on the retina and optic lobes of the crab Neohelice granulata. We evaluated the reactive oxygen species (ROS) concentration, antioxidant capacity against peroxyl radicals (ACAP) levels, catalase (CAT) and glutathione S-transferase (GST) activities and lipoperoxidation (LPO) levels and performed histological analysis. The crabs were exposed to UVB radiation for 1 or 60 days, while the control group was exposed to visible light. In the retina region, increases in ROS concentration and CAT and GST activities after the single exposure were observed. After 60 days of exposure, we observed an increase in ACAP levels. In the optic lobes, we observed an increase in GST activity and a decrease in LPO levels after the single exposure. However, we observed an increase in ROS concentration after 60 days of exposure. Moreover, after 60 days of exposure, infiltrating hemocytes in the retina and disorganization in neuron cell bodies of the external medulla were observed. In this sense, single and repeated exposure to low doses of UVB radiation induced changes in oxidative status and inflammatory process in the visual system of the crab Neohelice granulata.

Can photobiomodulation therapy (PBMT) control blood glucose levels and alter muscle glycogen synthesis?

Photobiomodulation therapy (PBMT) has many effects on the energy metabolism of musculoskeletal tissue, such as increased glycogen and adenosine triphosphate synthesis. In addition, these effects may be due to a systemic blood glucose control. Twenty-four Wistar rats were randomly and equally allocated into four groups: sham, PBMT 10 J/cm2, PBMT 30 J/cm2 and PBMT 60 J/cm2. The animals were fasting for 6 h for blood glucose evaluations during pre-irradiation period, 1 h, 3 h and 6 h after PBMT. Muscle glycogen synthesis was measured 24 h after PBMT. This PBMT used a cluster of 69 LEDs (light-emitting diodes) with 35 red (630 ± 10 nm) and 34 infrared (850 ± 20 nm); 114 mW/cm2 for 90s (10 J/cm2), 270 s (30 J/cm2), 540 s (60 J/cm2) applied on large muscle areas (back and hind legs) of the animals. The 10 J/cm2 group showed lower blood glucose levels and glucose variability over 6 h (5.92 mg/dL) compared to the sham (13.03 mg/dL), 30 J/cm2 (7.77 mg/dL) and 60 J/cm2 (9.07 mg/dL) groups. The PBMT groups had the greatest increase in muscle glycogen (10 J/cm2 > 60 J/cm2 > 30 J/cm2 > sham), characterizing a triphasic dose-response of PBMT. There was a strong negative correlation between blood glucose variability over 6 h and muscle glycogen concentration for 10 J/cm2 group (r = -0.94; p < .001) followed by 30 J/cm2 group (r = -0.84; p < .001) and 60 J/cm2 group(r = -0.73; p < .006). These results suggest that PBMT can play a very important role in the control of blood glucose levels, and its possible mechanism of action is the induction of greater muscle glycogen synthesis independently of physical exercise.

Photosynthetic characterization of flavodoxin-expressing tobacco plants reveals a high light acclimation-like phenotype.

Flavodoxins are electron carrier flavoproteins present in bacteria and photosynthetic microorganisms which duplicate the functional properties of iron-sulphur containing ferredoxins and replace them under adverse environmental situations that lead to ferredoxin decline. When expressed in plant chloroplasts, flavodoxin complemented ferredoxin deficiency and improved tolerance to multiple sources of biotic, abiotic and xenobiotic stress. Analysis of flavodoxin-expressing plants grown under normal conditions, in which the two carriers are present, revealed phenotypic effects unrelated to ferredoxin replacement. Flavodoxin thus provided a tool to alter the chloroplast redox poise in a customized way and to investigate its consequences on plant physiology and development. We describe herein the effects exerted by the flavoprotein on the function of the photosynthetic machinery. Pigment analysis revealed significant increases in chlorophyll a, carotenoids and chlorophyll a/b ratio in flavodoxin-expressing tobacco lines. Results suggest smaller antenna size in these plants, supported by lower relative contents of light-harvesting complex proteins. Chlorophyll a fluorescence and P700 spectroscopy measurements indicated that transgenic plants displayed higher quantum yields for both photosystems, a more oxidized plastoquinone pool under steady-state conditions and faster plastoquinone dark oxidation after a pulse of saturating light. Many of these effects resemble the phenotypes exhibited by leaves adapted to high irradiation, a most common environmental hardship faced by plants growing in the field. The results suggest that flavodoxin-expressing plants would be better prepared to cope with this adverse situation, and concur with earlier observations reporting that hundreds of stress-responsive genes were induced in the absence of stress in these lines.

Combination of organic acids and low-dose gamma irradiation as antimicrobial treatment to inactivate Shiga toxin-producing Escherichia coli inoculated in beef trimmings: Lack of benefits in relation to single treatments.

The aim of this study was to assess the efficacy of lactic acid (LA), caprylic acid (CA), high- (HDI) and low- (LDI) dose gamma irradiation and LDI combined with LA or CA on the inactivation of a pool of Shiga toxin-producing Escherichia coli (STEC) strains inoculated on beef trimmings. The three most efficacious treatments were selected to study their effect on meat quality parameters and sensory attributes. The inoculum included five native STEC serogroups (O26, O103, O111, O145 and O157). The treatments applied were 0.5% LA, 0.04% CA, 0.5 kGy LDI, 2 kGy HDI, LDI+LA and LDI+CA. Beef trimmings were divided into two groups; one was inoculated with high (7 log CFU/g) and the other with low (1 log CFU/g) level of inoculum. Efficacy was assessed by estimating log reduction and reduction of stx- and eae-positive samples after enrichment, respectively. Results showed that treatments with organic acids alone were not effective in reducing STEC populations. For high inoculum samples, the most effective treatment was HDI followed by LDI+LA and LDI alone or combined with CA. For low inoculum samples, the most effective treatment was HDI followed by LDI alone or combined with organic acids. Concerning meat quality parameters and sensory attributes, irradiation treatments (LDI and HDI) caused minimal changes, while LDI+LA modified them significantly compared with the control. Therefore, based on our results, no benefits were observed after combining organic acids with gamma irradiation.

Biphasic Dose/Response of Photobiomodulation Therapy on Culture of Human Fibroblasts.

Objective: The objective of this study was to evaluate the effects of application of different fluences and energies of laser in the 24-, 48-, and 72-h periods in fibroblasts originating from human skin (HFF-1). Methods: The cell used as a template for cell proliferation was HFF-1. For the photobiomodulation (PBM) application, a 660 nm laser with a power of 40 mW and energies of 0.84, 1.40, 5.88, and 6.72 J was used. Five experimental groups were studied: one control group (CG) with simulated PBM and four groups that received PBM in different doses. The changes observed after laser irradiation were evaluated by cell viability (trypan blue) and proliferation [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)] tests. Intergroup comparisons were performed using two-way analysis of variance and the Tukey post hoc test (software GraphPad Prism 7.0). Results: In the trypan blue test, the total number of cells was significantly different between the irradiated groups and the CG at all times studied. The total number of cells increased in laser group (LG)1 (0.84 J) and LG2 (1.40 J) and decreased in LG4 (6.72 J). The mitochondrial activity increased significantly in LG1 and LG2 at 48 and 72 h and decreased in LG3 (5.88 J) and LG4 (6.72 J) compared with CG. Conclusions: The results indicate that the lower doses (0.45 and 0.75 J/cm2) of PBM induce the highest mitochondrial activity and cellular viability.

Systematic Review of Photobiomodulation Therapy (PBMT) on the Experimental Calcaneal Tendon Injury in Rats.

This systematic review analyzed the light parameters and the effects of photobiomodulation therapy (PBMT) through low-level laser therapy (LLLT) and/or LED (light-emitting diode) on tendon repair of rats submitted to calcaneal injury. This study was conducted in accordance with the guidelines of the Preferred Reporting Items for Meta-Analysis, and PubMed and MEDLINE databases were accessed to search eligible studies published in English. The search terms were as follows: "Achilles tendon" or "Calcaneal tendon" or "tendon injuries" or "soft tissue injuries" and "tendinopathy" or "tendinitis" and "low-level light therapy" or "low-level laser therapy" or "low intensity power therapy" or "light-emitting diode" or photobiomodulation." The SYRCLE (SYstematic Review Center for Laboratory animal Experimentation) risks of bias was used to assess the risk of bias for selected studies. A total of 225 studies were found based on the descriptors used, and only 33 studies were eligible. Light parameters identified per point of irradiation were approximately 60 mW (continuous mode at infrared spectra), 2 W cm-2 , 2 J and 45 J cm-2 . Light parameters at red spectra, continuous versus pulsed mode, and PBMT combined or compared with other therapies such as ultrasound, and studies using unhealthy rats (ovariectomized and/or diabetic models) were also identified and grouped according to these similarities. The main effects found were decreased inflammatory markers and signs of inflammatory process. PBMT (laser/LED) has positive effects in reducing the inflammatory and time for tissue repair in animal models of tendon injury and/or tendinitis using parameters identified.

Lesiones oculares y radiación ionizante / Eye injuries and ionising radiation

El número y la complejidad de los procedimientos de diagnóstico e intervencionismo cardiovascular han incrementado de manera significativa, hecho que genera mayor exposición a dosis bajas de radiación ionizante debido a la radiación dispersa por el paciente. El cristalino es una de las estructuras más sensibles a la radiación y las cataratas son la enfermedad ocular más estudiada y frecuente en el personal de la salud ocupacionalmente expuesto a dosis bajas de radiación. La formación de cataratas es un proceso multifactorial y la exposición a la radiación ionizante se ha asociado a opacidades subcapsulares posteriores, que es la forma más común de lesión, seguida por las cataratas corticales. Existen varios estudios que han evaluado los efectos de la exposición ocupacional por radiación ionizante en el cristalino en cardiólogos intervencionistas, comparándolos con controles no expuestos. Concluyen que hay mayor prevalencia de opacidades subcapsulares posteriores en el personal expuesto a radiación ionizante, especialmente en los cardiólogos intervencionistas (por trabajar muy cerca del generador de rayos X), las cuales están relacionadas con la duración de la práctica del intervencionismo cardíaco y disminuyen con el uso regular de los lentes plomados. Lo llamativo de muchos estudios es el bajo uso por parte de los cardiólogos intervencionistas de los elementos de protección radiológica, especialmente gafas y mampara plomada, las cuales han demostrado efectividad en la reducción de la radiación ionizante recibida por el personal de la sala de cateterismo cardiaco.

As the number and complexity of diagnostic and cardiovascular intervention procedures has increased significantly, this has led to a greater exposure to low doses of ionising radiation due to the radiation dispersal by the patient. The crystalline lens is one of the structures most sensitive to radiation, and cataracts are the most studied eye disease, and are common in health staff occupationally exposed to low radiation doses. The formation of cataracts is a process involving many factors, and exposure to ionising radiation has been associated with posterior sub-capsular opacities, the most common form of the injury, followed by cortical cataracts. There are several studies that have evaluated the effects of occupational exposure due to ionising radiation in the crystalline lens in interventionist cardiologists, and comparing them with non-exposed controls. They conclude that there is a higher prevalence of posterior sub-capsular opacities in personnel exposed to ionising radiation, especially in interventionist cardiologists (due to working very near the X-ray generator). These are associated with the duration of the practice of cardiac interventions, and decrease with the regular use of leaded glasses. The low use of radiation protection wear by interventionist cardiologists is highlighted in many studies, especially glasses and a leaded screen, which have shown to be effective in the reduction in the ionising radiation by the staff in the cardiac catheterisation room.

Light Sources and Dosimetry Techniques for Photodynamic Therapy.

Effective treatment delivery in photodynamic therapy (PDT) requires coordination of the light source, the photosensitizer, and the delivery device appropriate to the target tissue. Lasers, light-emitting diodes (LEDs), and lamps are the main types of light sources utilized for PDT applications. The choice of light source depends on the target location, photosensitizer used, and light dose to be delivered. Geometry of minimally accessible areas also plays a role in deciding light applicator type. Typically, optical fiber-based devices are used to deliver the treatment light close to the target. The optical properties of tissue also affect the distribution of the treatment light. Treatment light undergoes scattering and absorption in tissue. Most tissue will scatter light, but highly pigmented areas will absorb light, especially at short wavelengths. This review will summarize the basic physics of light sources, and describe methods for determining the dose delivered to the patient.