Acute application of photobiomodulation does not bring important gains for the muscular performance and functionality of diabetic individuals.

Photobiomodulation therapy (PBMT) has been used to improve the physical performance of individuals with advanced age; however, there are no studies in the literature that support the application of light-emitting diode (LED) therapy for the muscular performance of individuals with diabetes mellitus who show a decline in functionality. The aim of the study was to analyze the acute effects of PBMT on strength and functional performance in type 2 diabetic individuals. Sixty-three volunteers were recruited and randomized into five groups: control (C), sham (S), red LED (R), infrared LED (IR), and red LED + infrared LED (R + IR). On the first day, the volunteers were evaluated using the time up and go (TUG), the 6-min walk test (6MWT), and isokinetic dynamometer of the ankle. In the following 3 days, groups R, IR, R + IR, and S returned for application of PBMT bilaterally, with 180 J of energy on each leg. On the fifth day, a reassessment was performed. There was no statistical difference between groups for the variables of the isokinetic dynamometer, TUG, and 6MWT. Analysis of the size of the clinical effect for the isokinetic variables showed that there was no pattern among the effects observed. There is a moderate effect in favor of R, IR, and R + IR in relation to C for the TUG and a moderate effect of R + IR in relation to C for the 6MWT. The PBMT applied for a short period does not bring important gains for the muscular performance and functionality of diabetic individuals.

Inverse heat transfer analysis in detecting tissue optical properties using laser.

A new methodology has been proposed to measure optical properties of homogeneous tissue where a laser beam is used to induce heat to a tissue. The induced heat increased the temperature inside the tissue, which is detected by a thermocouple. These readings are compared with that obtained from the solution of the finite element solution that used iterative values of optical properties in determining temperature distribution. The two temperature distributions are used to determine tissue optical properties using the Levenberg-Marquardt iteration. An accurate result is obtained in determining absorption coefficient and reduced scattering coefficient. The work is extended to obtain three parameters (i.e., absorption coefficient, scattering coefficient, and anisotropy). The only limitation is that the temperature readings have to be measured with a high-accuracy thermocouple (i.e., less than 0.4% of maximum-recorded temperature).

Exploiting Ballou's rule for better tissue classification.

Ultrasound tissue characterization based on the coefficient of nonlinearity, ßn = 1 + B/2A, has been demonstrated to produce added diagnostic value due to its large variation and sensitivity to tissue structure. However, the parameter has been observed to be significantly correlated to the speed of sound and density. These relationships are analyzed empirically as well as theoretically by developing a pressure-density relation based on a thermodynamic model and the Mie intermolecular potential. The results indicate that for many soft tissues, the coefficient of nonlinearity is largely determined by the isentropic compressibility, κs. Consequently, for tissue characterization, estimating the nonlinear response of the medium, given by ßp = ßnκs, appears to be beneficial due to correlated quantities.

Ultra-Wideband Temperature Dependent Dielectric Spectroscopy of Porcine Tissue and Blood in the Microwave Frequency Range.

The knowledge of frequency and temperature dependent dielectric properties of tissue is essential to develop ultra-wideband diagnostic technologies, such as a non-invasive temperature monitoring system during hyperthermia treatment. To this end, we characterized the dielectric properties of animal liver, muscle, fat and blood in the microwave frequency range from 0.5 GHz to 7 GHz and in the temperature range between 30 °C and 50 °C. The measured data were modeled to a two-pole Cole-Cole model and a second-order polynomial was introduced to fit the Cole-Cole parameters as a function of temperature. The parametric model provides access to the dielectric properties of tissue at any frequency and temperature in the specified range.

Photobiomodulation and different macrophages phenotypes during muscle tissue repair.

Macrophages play a very important role in the conduction of several regenerative processes mainly due to their plasticity and multiple functions. In the muscle repair process, while M1 macrophages regulate the inflammatory and proliferative phases, M2 (anti-inflammatory) macrophages direct the differentiation and remodelling phases, leading to tissue regeneration. The aim of this study was to evaluate the effect of red and near infrared (NIR) photobiomodulation (PBM) on macrophage phenotypes and correlate these findings with the repair process following acute muscle injury. Wistar rats were divided into 4 groups: control; muscle injury; muscle injury + red PBM; and muscle injury + NIR PBM. After 2, 4 and 7 days, the tibialis anterior muscle was processed for analysis. Macrophages phenotypic profile was evaluated by immunohistochemistry and correlated with the different stages of the skeletal muscle repair by the qualitative and quantitative morphological analysis as well as by the evaluation of IL-6, TNF-α and TGF-ß mRNA expression. Photobiomodulation at both wavelengths was able to decrease the number of CD68+ (M1) macrophages 2 days after muscle injury and increase the number of CD163+ (M2) macrophages 7 days after injury. However, only NIR treatment was able to increase the number of CD206+ M2 macrophages (Day 2) and TGF-ß mRNA expression (Day 2, 4 and 7), favouring the repair process more expressivelly. Treatment with PBM was able to modulate the inflammation phase, optimize the transition from the inflammatory to the regeneration phase (mainly with NIR light) and improve the final step of regeneration, enhancing tissue repair.

Magnetotherapy: The quest for tendon regeneration.

Tendons are mechanosensitive tissues that connect and transmit the forces generated by muscles to bones by allowing the conversion of mechanical input into biochemical signals. These physical forces perform the fundamental work of preserving tendon homeostasis assuring body movements. However, overloading causes tissue injuries, which leads us to the field of tendon regeneration. Recently published reviews have broadly shown the use of biomaterials and different strategies to attain tendon regeneration. In this review, our focus is the use of magnetic fields as an alternative therapy, which has demonstrated clinical relevance in tendon medicine because of their ability to modulate cell fate. Yet the underlying cellular and molecular mechanisms still need to be elucidated. While providing a brief outlook about specific signalling pathways and intracellular messengers as framework in play by tendon cells, application of magnetic fields as a subcategory of physical forces is explored, opening up a compelling avenue to enhance tendon regeneration. We outline here useful insights on the effects of magnetic fields both at in vitro and in vivo levels, particularly on the expression of tendon genes and inflammatory cytokines, ultimately involved in tendon regeneration. Subsequently, the potential of using magnetically responsive biomaterials in tendon tissue engineering is highlighted and future directions in magnetotherapy are discussed.

Anti-tumor responses to hypofractionated radiation in mice grafted with triple negative breast cancer is associated with decorin induction in peritumoral muscles.

Triple negative breast cancer (TNBC) is the most lethal one for all types of breast cancer. Though radiotherapy is an efficient treatment, long-term survival rate of TNBC patients is still suboptimal. Hyprofractionated radiotherapy, an improved radiotherapy, has made an inspiring result in clinic. However, the mechanism underlying TNBC treated with hyprofractionated radiotherapy is not clear. Decorin (DCN) is a small poteoglycan of matrix which has an inhibitory effect on the breast cancer and is secreted by muscle under certain conditions. In this study, we demonstrated that peritumoral muscles secrete more DCN at higher dose irradiation than that at conventional irradiation dose in TNBC tumor-bearing mice. Thus, it indicates that DCN secreted from peritumoral muscle may be one of the reasons why hyprofractionated radiotherapy could inhibit the growth of TNBC more effectively. Moreover, we also indicated that the up-regulated DCN attenuated lung metastasis of TNBC. In conclusion, we demonstrated that hypofractionated radiation promotes the secretion of DCN in peritumoral muscle, thus enhancing the inhibitory effect on TNBC, which might help to optimize the strategy of radiotherapy for TNBC patients in the future.

Photobiomodulation therapy for the improvement of muscular performance and reduction of muscular fatigue associated with exercise in healthy people: a systematic review and meta-analysis.

Researches have been performed to investigate the effects of phototherapy on improving performance and reduction of muscular fatigue. However, a great variability in the light parameters and protocols of the trials are a concern to establish the efficacy of this therapy to be used in sports or clinic. The aim of this study is to investigate the effectiveness, moment of application of phototherapy within an exercise protocol, and which are the parameters optimally effective for the improvement of muscular performance and the reduction of muscular fatigue in healthy people. Systematic searches of PubMed, PEDro, Cochrane Library, EMBASE, and Web of Science databases were conducted for randomized clinical trials to March 2017. Analyses of risk of bias and quality of evidence of the included trials were performed, and authors were contacted to obtain any missing or unclear information. We included 39 trials (861 participants). Data were reported descriptively through tables, and 28 trials were included in meta-analysis comparing outcomes to placebo. Meta-analysis was performed for the variables: time until reach exhaustion, number of repetitions, isometric peak torque, and blood lactate levels showing a very low to moderate quality of evidence and some effect in favor to phototherapy. Further investigation is required due the lack of methodological quality, small sample size, great variability of exercise protocols, and phototherapy parameters. In general, positive results were found using both low-level laser therapy and light-emitting diode therapy or combination of both in a wavelength range from 655 to 950 nm. Most of positive results were observed with an energy dose range from 20 to 60 J for small muscular groups and 60 to 300 J for large muscular groups and maximal power output of 200 mW per diode.

Defining the hypoxic target volume based on positron emission tomography for image guided radiotherapy - the influence of the choice of the reference region and conversion function.

BACKGROUND: Hypoxia imaged by positron emission tomography (PET) is a potential target for optimization in radiotherapy. However, the implementation of this approach with respect to the conversion of intensities in the images into oxygenation and radiosensitivity maps is not straightforward. This study investigated the feasibility of applying two conversion approaches previously derived for 18F-labeled fluoromisonidazole (18F-FMISO)-PET images for the hypoxia tracer 18F-flortanidazole (18F-HX4). MATERIAL AND METHODS: Ten non-small-cell lung cancer patients imaged with 18F-HX4 before the start of radiotherapy were considered in this study. PET image uptake was normalized to a well-oxygenated reference region and subsequently linear and non-linear conversions were used to determine tissue oxygenations maps. These were subsequently used to delineate hypoxic volumes based partial oxygen pressure (pO2) thresholds. The results were compared to hypoxic volumes segmented using a tissue-to-background ratio of 1.4 for 18F-HX4 uptake. RESULTS: While the linear conversion function was not found to result in realistic oxygenation maps, the non-linear function resulted in reasonably sized sub-volumes in good agreement with uptake-based segmented volumes for a limited range of pO2 thresholds. However, the pO2 values corresponding to this range were significantly higher than what is normally considered as hypoxia. The similarity in size, shape, and relative location between uptake-based sub-volumes and volumes based on the conversion to pO2 suggests that the relationship between uptake and pO2 is similar for 18F-FMISO and 18F-HX4, but that the model parameters need to be adjusted for the latter. CONCLUSIONS: A non-linear conversion function between uptake and oxygen partial pressure for 18F-FMISO-PET could be applied to 18F-HX4 images to delineate hypoxic sub-volumes of similar size, shape, and relative location as based directly on the uptake. In order to apply the model for e.g., dose-painting, new parameters need to be derived for the accurate calculation of dose-modifying factors for this tracer.

Evaluation of DNA damage induced by gamma radiation in gill and muscle tissues of Cyprinus carpio and their relative sensitivity.

The effect of radiation on the aquatic environment is of major concern in recent years. Limited data is available on the genotoxicity of gamma radiation on different tissues of aquatic organisms. Hence, the present investigation was carried out to study the DNA damage induced by gamma radiation in the gill and muscle tissues and their relative sensitivity using the comet assay in the freshwater teleost fish, common carp (Cyprinus carpio). The comet assay was optimized and validated in common carp using cyclophosphamide (CP), a reference genotoxic agent. The fish were exposed (acute) to various doses of gamma radiation (2, 4, 6, 8 and 10Gy) and samplings (gill and muscle tissue) were done at regular intervals (24, 48 and 72h) to assess the DNA damage. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA for all doses of gamma radiation in both tissues. We also observed a dose-related increase and a time-dependent decrease of DNA damage. In comparison, DNA damage showed different sensitivity among the tissues at different doses. This shows that a particular dose may have different effects on different tissues which could be due to physiological factors of the particular tissue. Our study also suggests that the gills and muscle of fish are sensitive and reliable tissues for evaluating the genotoxic effects of reference and environmental agents, using the comet assay.

The effects of ultrasound and alternating current on the laser penetration in the tissue.

The visible (VIS) and near-infrared (NIR) lasers are now widely used in therapeutic and other medical applications. Some of these applications require to deliver the laser energy deep toward the desired tissue target or organ. The aim of this in vitro study is to investigate practically whether the modulation of laser energy by employing the therapeutic ultrasound or electrical energies can increase the penetration depth of the laser light inside the tissue. Such modulation was implemented in this study by coupling the (c.w.) diode and Nd:YAG laser energies with the ultrasound or AC current simultaneously as they pass through preprepared ex vivo bovine muscular tissue strips. Two wavelengths of diode lasers were used, 637 and 808 nm beside the 1064-nm Nd:YAG laser. The results showed a noticeable decrease of these laser attenuation factors as they pass through the tissue strips in the presence of the ultrasound or AC energies. By using this coupling modulation, the capability of increasing the laser penetration depths inside the tissue was confirmed without having to increase their applied power.

Thermal and elastic response of subcutaneous tissue with different fibrous septa architectures to RF heating: numerical study.

BACKGROUND AND OBJECTIVE: Radiofrequency currents are commonly used in dermatology to treat cutaneous and subcutaneous tissues by heating. The subcutaneous morphology of tissue consists of a fine, collagenous and fibrous septa network enveloping clusters of adipocyte cells. The architecture of this network, namely density and orientation of septa, varies among patients and, furthermore, it correlates with cellulite grading. In this work we study the effect of two clinically relevant fibrous septa architectures on the thermal and elastic response of subcutaneous tissue to the same RF treatment; in particular, we evaluate the thermal damage and thermal stress induced to an intermediate- and a high-density fibrous septa network architecture that correspond to clinical morphologies of 2.5 and 0 cellulite grading, respectively. STUDY DESIGN/MATERIALS AND METHODS: We used the finite element method to assess the electric, thermal and elastic response of a two-dimensional model of skin, subcutaneous tissue and muscle subjected to a relatively long, constant, low-power RF treatment. The subcutaneous tissue is constituted by an interconnected architecture of fibrous septa and fat lobules obtained by processing micro-MRI sagittal images of hypodermis. As comparison criteria for the RF treatment of the two septa architectures, we calculated the accumulated thermal damage that corresponds to 63% loss in cell viability. RESULTS: Electric currents preferentially circulated through the fibrous septa in the subcutaneous tissue. However, the intensity of the electric field was higher within the fat because it is a poor electric conductor. The power absorption in the fibrous septa relative to that in the fat varied with septum orientation: it was higher in septa with vertical orientation and lower in septa with horizontal orientation. Overall, maximum values of electric field intensity, power absorption and temperature were similar for both fibrous septa architectures. However, the high-density septa architecture (cellulite grade 0) had a more uniform and broader spatial distribution of power absorption, resulting in a larger cross-sectional area of thermal damage (≈1.5 times more). Volumetric strains (expansion and contraction) were small and similar for both network architectures. During the first seconds of RF exposure, the fibrous septa were subjected to thermal expansion regardless of orientation. In the long term, the fibrous septa contracted due to the thermal expansion of fat. Skin and muscle were subjected to significantly higher Von Mises stresses (measure of yield) or distortion energy than the subcutaneous tissue. CONCLUSION: The distribution of electric currents within subcutaneous tissues depends on tissue morphology. The electric field is more intense in septum oriented along the skin to muscle (top to bottom) direction, creating lines or planes of preferential heating. It follows that the more septum available for preferential heating, the larger the extent of volumetric RF-heating and thermal damage to the subcutaneous tissue. Thermal load alone, imposed by long-exposure to heating up to 50 °C, results in small volumetric expansion and contraction in the subcutaneous tissue. The subcutaneous tissue is significantly less prone to non-reversible deformation by a thermal load than the skin and muscle.

Thermal effects of 2450 MHz microwave exposure near a titanium alloy plate implanted in rabbit limbs.

This study aimed to examine the safety profile of microwave therapy on limbs with metal implants. New Zealand white rabbits were implanted with titanium alloy internal fixation plates. Femurs were exposed to 20, 40, 60, or 80 W of microwave radiation for 30 min (microwave applicator at 2450 MHz), and temperatures of the implants and muscles adjacent to implants were recorded. To evaluate thermal damage, nerves were electrodiagnostically assessed immediately after radiation, and histologic studies performed on nerve and muscle sections. As expected, implant temperature was highest in the exposure field. Temperatures of limbs with titanium alloy implants increased significantly at 60 and 80 W, with a significant decline in the nerve conduction velocity and acute thermal injuries in nerves and muscles adjacent to implants. However, temperature remained unchanged and no adverse effects were observed in nerves and muscles at 20 and 40 W. These findings are inconsistent with the current notion that surgical metal implants in the treatment field are contraindications for microwave therapy. Hence, we believe that a lower dose of continuous wave microwave irradiation is safe for limbs with titanium alloy implants.

Phototherapy with combination of super-pulsed laser and light-emitting diodes is beneficial in improvement of muscular performance (strength and muscular endurance), dyspnea, and fatigue sensation in patients with chronic obstructive pulmonary disease.

Phototherapy is an electrophysical intervention being considered for the retardation of peripheral muscular fatigue usually observed in chronic obstructive pulmonary disease (COPD). The objective of this study was to evaluate the acute effects of combination of super-pulsed laser and light-emitting diodes phototherapy on isokinetic performance in patients with COPD. Thirteen patients performed muscular endurance tests in an isokinetic dynamometer. The maximum voluntary isometric contraction (MVIC), peak torque (PT), and total work (TW) of the non-dominant lower limb were measured in two visits. The application of phototherapy or placebo (PL) was conducted randomly in six locations of femoral quadriceps muscle by using a cluster of 12 diodes (4 of 905 nm super-pulsed lasers, 0.3125 mW each; 4 of 875 nm LEDs, 17.5 mW each; and 4 of 640 nm LEDs, 15 mW each, manufactured by Multi Radiance Medical™). We found statistically significant increases for PT (174.7 ± 35.7 N · m vs. 155.8 ± 23.3 N · m, p = 0.003) and TW after application of phototherapy when compared to placebo (778.0 ± 221.1 J vs. 696.3 ± 146.8 J, p = 0.005). Significant differences were also found for MVIC (104.8 ± 26.0 N · m vs. 87.2 ± 24.0 N · m, p = 0.000), sensation of dyspnea (1 [0-4] vs. 3 [0-6], p = 0.003), and fatigue in the lower limbs (2 [0-5] vs. 5 [0.5-9], p = 0.002) in favor of phototherapy. We conclude that the combination of super-pulsed lasers and LEDs administered to the femoral quadriceps muscle of patients with COPD increased the PT by 20.2% and the TW by 12%. Phototherapy with a combination of super-pulsed lasers and LEDs prior to exercise also led to decreased sensation of dyspnea and fatigue in the lower limbs in patients with COPD.

Characterisation of tissue shrinkage during microwave thermal ablation.

PURPOSE: The aim of this study was to characterise changes in tissue volume during image-guided microwave ablation in order to arrive at a more precise determination of the true ablation zone. MATERIALS AND METHODS: The effect of power (20-80 W) and time (1-10 min) on microwave-induced tissue contraction was experimentally evaluated in various-sized cubes of ex vivo liver (10-40 mm ± 2 mm) and muscle (20 and 40 mm ± 2 mm) embedded in agar phantoms (N = 119). Post-ablation linear and volumetric dimensions of the tissue cubes were measured and compared with pre-ablation dimensions. Subsequently, the process of tissue contraction was investigated dynamically during the ablation procedure through real-time X-ray CT scanning. RESULTS: Overall, substantial shrinkage of 52-74% of initial tissue volume was noted. The shrinkage was non-uniform over time and space, with observed asymmetry favouring the radial (23-43 % range) over the longitudinal (21-29%) direction. Algorithmic relationships for the shrinkage as a function of time were demonstrated. Furthermore, the smallest cubes showed more substantial and faster contraction (28-40% after 1 min), with more considerable volumetric shrinkage (>10%) in muscle than in liver tissue. Additionally, CT imaging demonstrated initial expansion of the tissue volume, lasting in some cases up to 3 min during the microwave ablation procedure, prior to the contraction phenomenon. CONCLUSIONS: In addition to an asymmetric substantial shrinkage of the ablated tissue volume, an initial expansion phenomenon occurs during MW ablation. Thus, complex modifications of the tissue close to a radiating antenna will likely need to be taken into account for future methods of real-time ablation monitoring.

Bremsstrahlung dose of 165Dy in radiosynovectomy.

There has been an increased interest in 165Dy radiossynovectomy, which emits relatively high-energy (> 1 MeV) beta rays. The production of in vivo bremsstrachlung radiation hazards warrants evaluation. The bremsstrahlung component of the decay scheme of 165Dy has been traditionally ignored in internal dosimetry calculations. We have estimated the bremsstrahlung dose of 165Dy distributed in muscle and bone to body by various internal organs (adrenals, brain, breasts, gallbladder wall, LLI wall, small intestine, stomach, ULI wall, heart wall, kidneys, liver, lungs, muscle, ovaries, pancreas, red marrow, bone surfaces, skin, spleen, testes, thymus, thyroid, urine bladder wall, uterus, fetus, placenta, and total body) during radiosynovictomy. In the present study, muscle and bone are considered to be source organs. These estimated values show that the bremsstrahlung radiation absorbed dose contribution from an organ to itself is very small compared to that originating from the beta source. However, contribution to other organs is not always negligible, especially when large amounts of 165Dy may be involved, such as in therapy applications. Hence the component of the total dose due to bremsstrahlung dose should be considered in radiosynovictomy or other therapy applications.

Effect of fibrous septa in radiofrequency heating of cutaneous and subcutaneous tissues: computational study.

BACKGROUND AND OBJECTIVES: Radiofrequency (RF) energy exposure is a popular non-invasive method for generating heat within cutaneous and subcutaneous tissues. Subcutaneous fat consists of fine collagen fibrous septa meshed with clusters of adipocytes having distinct structural, electrical and thermal properties that affect the distribution and deposition of RF energy. The objectives of this work are to (i) determine the electric and thermal effects of the fibrous septa in the RF heating; (ii) investigate the RF heating of individual fat lobules enclosed by fibrous septa; and, (iii) discuss the clinical implications. METHODS AND RESULTS: We used the finite element method to model the two-dimensional, time-dependent, electro-thermal response of a three-layer tissue (skin, subcutaneous fat, and muscle). We considered two different configurations of subcutaneous fat tissue: a homogenous layer of fat only and a honeycomb-like layer of fat with septa. Architecture of the fibrous septa was anatomically accurate, constructed from sagittal images from human micro-MRI. For a large electrode applied to the skin surface, results show that the absorbed electric power density is greater in some septa than in the surrounding fat lobules, favoring the flux of electric current density. Fibers aligned parallel to the electric field have higher electric flux and, consequently, absorb more power. Heat transfer from the septa occurs over time during and after RF energy delivery. There is a greater temperature rise in fat with fibrous septa. CONCLUSIONS: The presence of septa affects the local distribution of the static electric field, facilitates the flux of electric current and enhances the bulk electric power absorption of the subcutaneous fat layer. Fibrous septa aligned with the local electric field have higher absorbed power density than septa oriented perpendicular to the electric field. Individual fat lobules gain heat instantly by local power absorption and, eventually, by diffusion from the surrounding septa.

DNA repair gene expression in biological tissues exposed to low-intensity infrared laser.

Special properties of laser light have led to its usefulness in many applications in therapy. Excitation of endogenous chromophores in biotissues and generation of free radicals could be involved in its biological effects. DNA lesions induced by free radicals are repaired by base excision repair pathway. In this work, we evaluated the expression of APE1 and OGG1 genes related to repair of DNA lesions induced by free radicals. Skin and muscle tissues of Wistar rats were exposed to low-intensity infrared laser at different fluences and frequencies. After laser exposition of 1 and 24 h, tissue samples were withdrawn for total RNA extraction, cDNA synthesis, and evaluation of APE1 and OGG1 gene expression by quantitative polymerase chain reaction. Data obtained show that laser radiation alters the expression of APE1 and OGG1 mRNA differently in skin and muscle tissues of Wistar rats depending of the fluence, frequency, and time after exposure. Our study suggests that low-intensity infrared laser affects expression of genes involved in repair of DNA lesions by base excision repair pathway.

Dielectric properties of muscle and liver from 500 MHz-40 GHz.

Dielectric properties are the most important parameters determining energy deposition when biological tissues are exposed to radio frequency and microwave fields. Energy absorption is determined by the specific absorption rate (SAR). SAR distributions can be computed accurately only if the complex relative permittivity of the target tissue is known to a sufficiently high accuracy, and currently there is a lack of data on the dielectric properties of biological tissues at high frequencies. In this study, tissue dielectric properties are measured using an open-ended coaxial probe technique from 500 MHz up to 40 GHz. We present dielectric data for ex vivo bovine and porcine muscle and liver tissues at 37 °C. One-pole Cole-Cole model is used to fit the measured data as a function of frequency and the dispersion parameters are presented. This data is supported by an accurate study on reference liquids such as methanol and ethanediol.

SAR measurement due to mobile phone exposure in a simulated biological media.

The specific absorption rate (SAR) measurements are carried out for compliance testing of personal 3G Mobile phone. The accuracy of this experimental setup has been checked by comparing the SAR in 10 gm of simulated tissue and an arbitrary shaped box. This has been carried out using a 3G mobile Phone at 1718.5 MHz, in a medium simulating brain and muscle phantom. The SAR measurement system consists of a stepper motor to move a monopole E-field probe in two dimensions inside an arbitrary shaped box. The phantom is filled with appropriate frequency-specific fluids with measured electrical properties (dielectric constant and conductivity). That is close to the average for gray and white matters of the brain at the frequencies of interest (1718.5 MHz). Induced fields are measured using a specially designed monopole probe in its close vicinity. The probe is immersed in the phantom material. The measured data for induced fields are used to compute SAR values at various locations with respect to the mobile phone location. It is concluded that these SAR values are position dependent and well below the safety criteria prescribed for human exposure.