The Age-Dependence of Microwave Dielectric Parameters of Biological Tissues

Ibrani, Mimoza; Ahma, Luan; Hamiti, Enver

doi:10.5772/51400

Cited by 14 publications

(17 citation statements)

References 17 publications

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“…Apart from the electrode placement, all impedance measurements were carried out identically to those for the gelatine phantoms. These trends are due to the water content that is evaporated (or absorbed) over time making the phantom drier [45]. The contact impedance response results obtained from the electrical model (discussed in more detail in Section V-E) were found to fit well with the experimental measurements of the gelatine phantoms.…”

Section: Ex Vivo Porcine Skin Fittingmentioning

confidence: 57%

Electrical properties, accuracy, and multi-day performance of gelatine phantoms for electrophysiology

Owda

Casson

2020

Preprint

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Gelatine based phantoms for electrophysiology are becoming widely used as they allow the controlled validation of new electrode and new instrumentation designs. The phantoms mimic the electrical properties of the human body and allow a pre-recorded electrophysiology signal to be played-out, giving a known signal for the novel electrode or instrumentation to collect. Such controlled testing is not possible with on-person experiments where the signal to be recorded is intrinsically unknown. However, despite the rising interest in gelatine based phantoms there is relatively little public information about their electrical properties and accuracy, how these vary with phantom formulation, and across both time and frequency. This paper investigates ten different phantom configurations, characterising the impedance path through the phantom and comparing this impedance path to both previously reported electrical models of Ag/AgCl electrodes placed on skin and to a model made from ex vivo porcine skin. This article shows how the electrical properties of the phantoms can be tuned using different concentrations of gelatine and of sodium chloride (NaCl) added to the mixture, and how these properties vary over the course of seven days for a.c. frequencies in the range 20-1000 Hz. The results demonstrate that gelatine phantoms can accurately mimic the frequency response properties of the body-electrode system to allow for the controlled testing of new electrode and instrumentation designs.

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Section: Ex Vivo Porcine Skin Fittingmentioning

confidence: 57%

Electrical properties, accuracy, and multi-day performance of gelatine phantoms for electrophysiology

Owda

Casson

2020

Preprint

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“…The measurements also reveal that biological tissue is responding similarly to the application of heat treatment as the mean emissivity values increase after each application of heat treatment for all samples as summarized in Table 2. However, the mean emissivity values for the burn-damaged skin are different from sample to sample and this is due to the resistivity and the conductivity of the skin, as that varies from animal to animal [46,47,48]. The measurements presented in Figure 9 confirm that radiometry can distinguish between different burn depths as it provides different mean emissivity values after each application of localized heat treatment.…”

Section: Resultsmentioning

confidence: 79%

“…The measurements in Figure 9 indicate that the mean emissivity values for the four samples before the application of heat treatments are in the range of 0.52–0.55. It is reasonable to find differences in the mean emissivity value of the skin as the samples were taken from different animals in which each animal has a different skin thickness and different dielectric properties [46,47]. The measurements also reveal that biological tissue is responding similarly to the application of heat treatment as the mean emissivity values increase after each application of heat treatment for all samples as summarized in Table 2.…”

Section: Resultsmentioning

confidence: 99%

Assessment of Bandaged Burn Wounds Using Porcine Skin and Millimetric Radiometry

Owda

Salmon

Shylo

et al. 2019

Sensors

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This paper describes the experimental setup and measurements of the emissivity of porcine skin samples over the band of 80–100 GHz. Measurements were conducted on samples with and without dressing materials and before and after the application of localized heat treatments. Experimental measurements indicate that the differences in the mean emissivity values between unburned skin and burned damaged skin was up to ~0.28, with an experimental measurement uncertainty of ±0.005. Measured differences in the mean emissivity values between unburned and burn damaged skin increases with the depth of the burn, indicating a possible non-contact technique for assessing the degree of a burn. The mean emissivity of the dressed burned skin was found to be slightly higher than the undressed burned skin, typically ~0.01 to ~0.02 higher. This indicates that the signature of the burn caused by the application of localized heat treatments is observable through dressing materials. These findings reveal that radiometry, as a non-contact method, is capable of distinguishing between normal and burn-damaged skin under dressing materials without their often-painful removal. This indicates the potential of using millimeter wave (MMW) radiometry as a new type of medical diagnostic to monitor burn wounds.

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“…Figure 4 depicts the measured permittivity values of the human skin within the frequency range of 0.3-3.3 GHz, which was also considered as the reference. It is worth noting that the low-conductive materials have interesting properties, due to the lower absorption, and thus, the better penetration depth within the complex EM propagation medium [29,30].…”

Section: Composite Materials Development and Characterizationmentioning

confidence: 99%

Hybrid Development of a Compact Antenna Based on a Novel Skin-Matched Ceramic Composite for Body Fat Measurement

et al. 2020

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This work presents the thorough hybrid (numerical and experimental) development of a miniaturized microwave antenna, to be better matched to the permittivity of the human skin. This would allow the abdominal fat to be measured more accurately, based on the employed reflection methods with minimal mismatches. This objective was achieved by designing the pyramidal horn antenna that was modeled based on the proposed and manufactured ceramic composite material. Moreover, by using the developed composite of barium titanate and titanium oxide, the ratio of the two could be precisely adjusted, so that the permittivity was a reasonable match to that of the skin. This step was validated by the open-ended probe method. This framework can be instrumental in a range of microwave biomedical applications, which aim to realize the body-centric systems.

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The Age-Dependence of Microwave Dielectric Parameters of Biological Tissues

Cited by 14 publications

References 17 publications

Electrical properties, accuracy, and multi-day performance of gelatine phantoms for electrophysiology

Electrical properties, accuracy, and multi-day performance of gelatine phantoms for electrophysiology

Assessment of Bandaged Burn Wounds Using Porcine Skin and Millimetric Radiometry

Hybrid Development of a Compact Antenna Based on a Novel Skin-Matched Ceramic Composite for Body Fat Measurement

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