| 1. |
- Asan, Noor Badariah, 1984-, et al.
(författare)
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Assessment of Blood Vessel Effect on Fat-Intrabody Communication Using Numerical and Ex-Vivo Models at 2.45 GHZ
- 2019
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Ingår i: IEEE Access. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2169-3536. ; 7, s. 89886-89900
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Tidskriftsartikel (refereegranskat)abstract
- The potential offered by the intra-body communication (IBC) over the past few years has resulted in a spike of interest for the topic, specifically for medical applications. Fat-IBC is subsequently a novel alternative technique that utilizes fat tissue as a communication channel. This work aimed to identify such transmission medium and its performance in varying blood-vessel systems at 2.45 GHz, particularly in the context of the IBC and medical applications. It incorporated three-dimensional (3D) electromagnetic simulations and laboratory investigations that implemented models of blood vessels of varying orientations, sizes, and positions. Such investigations were undertaken by using ex-vivo porcine tissues and three blood-vessel system configurations. These configurations represent extreme cases of real-life scenarios that sufficiently elucidated their principal influence on the transmission. The blood-vessel models consisted of ex-vivo muscle tissues and copper rods. The results showed that the blood vessels crossing the channel vertically contributed to 5.1 dB and 17.1 dB signal losses for muscle and copper rods, respectively, which is the worst-case scenario in the context of fat-channel with perturbance. In contrast, blood vessels aligned-longitudinally in the channel have less effect and yielded 4.5 dB and 4.2 dB signal losses for muscle and copper rods, respectively. Meanwhile, the blood vessels crossing the channel horizontally displayed 3.4 dB and 1.9 dB signal losses for muscle and copper rods, respectively, which were the smallest losses among the configurations. The laboratory investigations were in agreement with the simulations. Thus, this work substantiated the fat-IBC signal transmission variability in the context of varying blood vessel configurations.
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| 2. |
- Asan, Noor Badariah, et al.
(författare)
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Characterization of the Fat Channel for Intra-Body Communication at R-Band Frequencies
- 2018
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Ingår i: Sensors. - : MDPI. - 1424-8220. ; 18:9
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we investigate the use of fat tissue as a communication channel between in-body, implanted devices at R-band frequencies (1.7–2.6 GHz). The proposed fat channel is based on an anatomical model of the human body. We propose a novel probe that is optimized to efficiently radiate the R-band frequencies into the fat tissue. We use our probe to evaluate the path loss of the fat channel by studying the channel transmission coefficient over the R-band frequencies. We conduct extensive simulation studies and validate our results by experimentation on phantom and ex-vivo porcine tissue, with good agreement between simulations and experiments. We demonstrate a performance comparison between the fat channel and similar waveguide structures. Our characterization of the fat channel reveals propagation path loss of ∼0.7 dB and ∼1.9 dB per cm for phantom and ex-vivo porcine tissue, respectively. These results demonstrate that fat tissue can be used as a communication channel for high data rate intra-body networks.
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| 3. |
- Asan, Noor Badariah, 1984-, et al.
(författare)
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Effect of Thickness Inhomogeneity in Fat Tissue on In-Body Microwave Propagation
- 2018
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Ingår i: Proceedings of the 2018 IEEE/MTT-S International Microwave Biomedical Conference (IMBIOC). - Philadelphia, USA : IEEE. - 9781538659182 ; , s. 136-138
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Konferensbidrag (refereegranskat)abstract
- In recent studies, it has been found that fat tissue can be used as a microwave communication channel. In this article, the effect of thickness inhomogeneities in fat tissues on the performance of in-body microwave communication at 2.45 GHz is investigated using phantom models. We considered two models namely concave and convex geometrical fat distribution to account for the thickness inhomogeneities. The thickness of the fat tissue is varied from 5 mm to 45 mm and the Gap between the transmitter/receiver and the starting and ending of concavity/convexity is varied from 0 mm to 25 mm for a length of 100 mm to study the behavior in the microwave propagation. The phantoms of different geometries, concave and convex, are used in this work to validate the numerical studies. It was noticed that the convex model exhibited higher signal coupling by an amount of 1 dB (simulation) and 2 dB (measurement) compared to the concave model. From the study, it was observed that the signal transmission improves up to 30 mm thick fat and reaches a plateau when the thickness is increased further.
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| 4. |
- Asan, Noor Badariah, 1984-, et al.
(författare)
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Effects of Blood Vessels on Fat Channel Microwave Communication
- 2018
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Ingår i: 2018 IEEE Conference on Antenna Measurements & Applications (CAMA). - : IEEE. - 9781538657959
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Konferensbidrag (refereegranskat)abstract
- This study aims to investigate the reliability of intra-body microwave propagation through the fat tissue in presence of blood vessels. Here, we consider three types of blood vessels with different sizes. We investigate the impact of the number of blood vessels and their alignment on the transmission of microwave signals through the fat channel. In our study, we employ two probes that act as a transmitter and a receiver. The probes are designed to operate at the Industrial, Scientific, and Medical radio band (2.45 GHz). For a channel length of 100 mm, our results indicate that the presence of the blood vessels may increase the channel path loss by similar to 1.5 dB and similar to 4.5 dB when the vessels are aligned and orthogonally aligned with the fat channel, respectively.
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| 5. |
- Asan, Noor Badariah, 1984-, et al.
(författare)
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Impact of Blood Vessels on Data Packet Transmission Through the Fat Channel
- 2018
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Ingår i: 2018 IEEE INTERNATIONAL RF AND MICROWAVE CONFERENCE (RFM 2018). - : IEEE conference proceedings. - 9781538667200 - 9781538667194 - 9781538667217 ; , s. 196-198
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Konferensbidrag (refereegranskat)abstract
- The reliability of intra-body wireless communication systems is very important in medical applications to ensure the data transmission between implanted devices. In this paper, we present newly developed measurements to investigate the effect of blood vessels on the data packet reception through the fat tissue. We use an IEEE 802.15.4-based WBAN prototype to measure the packet reception rate (PRR) through a tissue-equivalent phantom model. The blood vessels are modelled using copper rods. We measure the PRR at the frequency 2.45 GHz for several power levels. The results revealed that the presence of blood vessels aligned with the fat channel has tiny influence on the PRR when measured over the range -25 dBm to 0 dBm power level and for different blood vessels positions. Our investigations show 97% successful PRR through a 10 cm length fat channel in presence of the blood vessels.
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| 6. |
- Asan, Noor Badariah, 1984-, et al.
(författare)
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Reliability of the fat tissue channel for intra-body microwave communication
- 2017
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Ingår i: 2017 IEEE Conference on Antenna Measurements & Applications (CAMA). - : IEEE. - 9781509050284 ; , s. 310-313
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Konferensbidrag (refereegranskat)abstract
- Recently, the human fat tissue has been proposed as a microwave channel for intra-body sensor applications. In this work, we assess how disturbances can prevent reliable microwave propagation through the fat channel. Perturbants of different sizes are considered. The simulation and experimental results show that efficient communication through the fat channel is possible even in the presence of perturbants such as embedded muscle layers and blood vessels. We show that the communication channel is not affected by perturbants that are smaller than 15 mm cube.
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| 7. |
- Lee, D, et al.
(författare)
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A preliminary study on monitoring the progression of osteoporosis using UWB radar technique in distal femur model
- 2016
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 52:8, s. 589-590
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Tidskriftsartikel (refereegranskat)abstract
- In this Letter, the preliminary study on the progression of osteoporosis using ultra wide band radar technique suggesting two different cases, (1) For various bone thickness and (2) For different effective permittivity is presented. To monitor the progression of osteoporosis, resistively loaded dipole antenna was designed and used as a sensor. For use in targets representing intermediate stages of progression, methanol, ethanol, water, and wood were used for emulating effective dielectric constant of bone in real situation. Measurement results show consistent decrease in the enveloped difference voltage in the two cases which correlate to the loss of bone mineral density. In the future, these results will be useful for people with osteoporosis to predict fractures in advance.
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| 8. |
- Mathur, Parul, et al.
(författare)
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An Efficient Method for Computing the Interaction of Open Ended Circular Waveguide with a Layered Media
- 2018
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Ingår i: Progress In Electromagnetics Research Letters. - : E M W PUBLISHING. - 1937-6480. ; 76, s. 55-61
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a new method for studying the near-field electromagnetic interaction between a dielectric filled open ended circular waveguide (OECW) and a layered dielectric structure. The proposed model is based on plane wave spectrum theory using a novel and computationally efficient two step integration method. The first integral, involving multiple singularities in the integration path, is efficiently solved using a deformed elliptical integration path which encircles the singularities of the integral. The infinite domain tail integral involving the slowly converging integrand is further solved using an efficient trigonometric transformation. The proposed OECW based method is capable of determining the unknown material properties of any layered dielectric medium, and hence finds application in nondestructive evaluation of materials.
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| 9. |
- Mohd Shah, Syaiful Redzwan, 1984-, et al.
(författare)
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Microwave-Sensor-Based Clinical Measurements for Monitoring Post-Craniotomy Bone Development in Pediatric Craniosynostosis Patients
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Tidskriftsartikel (refereegranskat)abstract
- The bone density analysis system is a new method to analyze the amount of bone healed in cranial vault defects. Craniotomy creates such defects to treat pediatric patients with craniosynostosis. This method uses the variations in the resonance of a microwave sensor attached to the area under test in the patient. Data were collected from infants treated for craniosynostosis through craniotomy surgery in clinical trials. The data, which consist of resonance parameters (frequency, amplitude, and Q-factor) is collected using a microwave-based biomedical sensor. This sensor could detect changes in the resonance as changes in the permittivity of the various tissues at the ISM band. By observing differences between a reference and target defect points, bone healing over time could be accessed. In this paper, we analyze the validity of a proposed Computational Simulation Technology (CST) based numerical model for the sensor and extend the clinical data analysis from previous works with our bone density analysis system. The validity of the model is analyzed by comparing its outcomes to available measurements from numerical simulations, phantoms mimicking living tissues and clinical trial. In the data analysis, a hypothesis is formulated and tested regarding the healing over time. By deriving a set of parameters for each collected dataset in the clinical trials, a distinct pattern was found which shows visible changes such as edema and tissue thickening over the course of the healing process with this technique. Moreover, we manage to distinguish significant differences between the reference and defect points after the craniosynostosis surgery.
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| 10. |
- Perez, Mauricio D., et al.
(författare)
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Head-compliant microstrip split ring resonator for non-invasive healing monitoring after craniosynostosis-based surgery
- 2020
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Ingår i: HEALTHCARE TECHNOLOGY LETTERS. - : INST ENGINEERING TECHNOLOGY-IET. - 2053-3713. ; 7:1, s. 29-34
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Tidskriftsartikel (refereegranskat)abstract
- A soft and highly directive, proximity-coupled split-ring resonator fabricated with a liquid alloy, copper and polydimethylsiloxane (PDMS) is presented. The same was designed for sensing osteogenesis of calvarial bone. As dielectric properties of bone grafts in ossifying calvarial defects should change during the osteogenesis process, devices like this could monitor the gradual transformation of the defect into bone by differentiating changes in the dielectric properties as shifts in the resonance frequency. Computational Software Technology (CST) Microwave Studio (R)-based simulation results on computational head models were in good agreement with laboratory results on head phantom models, which also included the comparison with an in-vivo measurement on the human head. A discussion based on an inductive reasoning regarding dynamics' considerations is provided as well. Since the skin elasticity of newborn children is high, stretching and crumpling could be significant. In addition, due to typical head curvatures in newborn children, bending should not be a significant issue, and can provide higher energy focus in the defect area and improve conformability. The present concept could support the development of soft, cheap and portable follow-up monitoring systems to use in outpatient hospital and home care settings for post-operative monitoring of bone healing after reconstructive surgical procedures.
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| 11. |
- Perez, Mauricio D., et al.
(författare)
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Microwave Sensors for New Approach in Monitoring Hip Fracture Healing
- 2017
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Ingår i: 2017 11th European Conference On Antennas And Propagation (EUCAP). - : IEEE. - 9788890701870 ; , s. 1838-1842
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Konferensbidrag (refereegranskat)abstract
- Cyber-Physical System (CPS) applications in lower-extremity bony-fracture rehabilitation systems require real-time biophysical data. Emerging and interesting solutions are microwave approaches that provide good contrast between hard and soft tissues and between local anomalies inside tissues. Preliminarily some contacting non-invasive planar methods have been investigated in their feasibility of detecting human tissues variations with promising results. In this work we introduce two new microwave planar sensors for a new approach of hip fracture healing follow-up tool. They are designed for improved resolution and penetration at frequencies between 1 to 3 GHz in detecting variations in bone, muscle or fat tissues that are expected during a rehabilitation process. The resonant devices are optimized using Frequency Domain Reflectometry and CST (R) environment and validated using clinical trials with volunteers. The new approach is validated using clinical trials with volunteers and patients. These outcomes further emphasize the feasibility of devising systems for fracture rehabilitation.
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| 12. |
- Perez, Mauricio D., et al.
(författare)
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New Approach for Clinical Data Analysis of Microwave Sensor Based Bone Healing Monitoring System in Craniosynostosis Treated Pediatric Patients
- 2018
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Ingår i: 2018 IEEE Conference On Antenna Measurements & Applications (CAMA). - : IEEE. - 9781538657959
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Konferensbidrag (refereegranskat)abstract
- In the BDAS project one of the goals is to provide a solution to the monitoring bone healing issue complementing current techniques. Data have been collected in clinical trials from infants treated for Craniosynostosis by a craniotomy surgery. The data are collected with a biomedical sensor based in microwave technology. This sensor could be able to sense changes in the composition of the different tissues in the upper-hemisphere of the head by noticing a difference in the propagation of the microwaves, as the bone injury from the craniotomy heals over time. In this thesis, we analyse the clinical data in BDAS project incorporating new approaches with respect to previous analysis methods. These new approaches could give new insight into the proposed solution, but more analysis need to be done.
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| 13. |
- Rangaiah, Pramod K. B., et al.
(författare)
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Design of constant width branch line directional coupler for the microwave sensing application
- 2020
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Ingår i: 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008 - 9781728137124
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the design of directional branch-line coupler using constant width multiple sections of series and open microstrip line stubs. This device is operating at the center frequency of 2.45 GHz. The designed coupler is having good performance for the frequency band 2-3 GHz. The proposed design is compared with a typical branch line coupler and shows the improved performance. The design is simulated and fabricated on the Fibreglass-resin laminate (FR4) substrate of height 1.5 mm. The results of simulated and experimented circuits are discussed and analyzed. The circuit is measured using Combination Analyzer N9918A Field Fox Handheld Microwave Analyzer. The proposed topology is easy to design and fabricate with a planar microstrip line technology. The designed coupler shows the good results at 2.45GHz i.e. S 11 = -61.26 dB, S 21 = -45 dB, S 31 = -2dB and S 41 = -4.5dB. The main target of this work is to design a coupler to differentiate between transmitted and reflected signals in the split ring resonator (SRR) sensor for Bone Density Measurement Analysis (BDAS) system.
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| 14. |
- Redzwan Mohd Shah, Syaiful, et al.
(författare)
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Improved Sensor for Non-invasive Assessment of Burn Injury Depth Using Microwave Reflectometry
- 2019
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Ingår i: 2019 13th European Conference on Antennas and Propagation (EuCAP). - 9788890701887
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Konferensbidrag (refereegranskat)abstract
- The European project “Senseburn” aims to develop a non-invasive diagnostic instrument for assessing the depth and propagation of human burns in the clinical scenario. This article introduces an improved flexible microwave split-ring resonator-based sensor, as a new development in this project. The excitation system and the fabrication process are the major improvements with respect to its precedent microwave sensor, both based in polydimethylsiloxane (PDMS) and copper. Both improvements are introduced together with the design of the sensor and of the experimental setup. Human tissue emulating phantoms are designed, fabricated, validated, and employed to emulate different burn depths and to validate the conceptual functionality of the proposed sensor. The Keysight dielectric probe 85070E is employed for the phantom validation. The analysis suggests that the sensor could estimate the burn depth. Future works will be carried out with ex vivo human tissues.
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| 15. |
- Redzwan, Syaiful, et al.
(författare)
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Analysis of Thickness Variation in Biological Tissues using Microwave Sensors for Health Monitoring Applications
- 2019
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Ingår i: IEEE Access. - 2169-3536. ; 7, s. 156033-156043
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Tidskriftsartikel (refereegranskat)abstract
- Microwave sensing technique is a possible and attractive alternative modality to standard Xrays,magnetic resonance imaging, and computed tomography methods for medical diagnostic applications.This technique is beneficial since it uses non-ionizing radiation and that can be potentially used for themicrowave healthcare system. The main purpose of this paper is to present a microwave sensing techniqueto analyze the variations in biological tissue thickness, considering the effect of physiological and biologicalproperties on microwave signals. With this goal, we have developed a two-port non-invasive sensor systemcomposed of two split ring resonators (SRRs) operating at an Industrial, Scientific, and Medical frequencyband of 2.45 GHz. The system is verified using the amplitude and phase of the transmitted signal in ex-vivomodels, representing different tissue thicknesses. Clinical applications such as the diagnosis of muscularatrophy can be benefitted from this study.
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| 16. |
- Redzwan, Syaiful, et al.
(författare)
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Initial in-vitro trial for intra-cranial pressure monitoring using subdermal proximity-coupled split-ring resonator
- 2018
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Ingår i: IMBioc 2018 - 2018 IEEE/MTT-S International Microwave Biomedical Conference. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538659182 ; , s. 73-75
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Konferensbidrag (refereegranskat)abstract
- Intra cranial pressure (ICP) monitoring is used in treating severe traumatic brain injury (TBI) patients. All current clinical available measurement methods are invasive presenting considerable social costs. This paper presents a preliminary investigation of the feasibility of ICP monitoring using an innovative microwave-based non-invasive approach. A phantom mimicking the dielectric characteristics of human tissues of the upper part of the head at low microwave frequencies is employed together to a proof-of-concept prototype based on the proposed approach consisting in a readout system and a sub-dermally implanted passive device, both based in split ring resonator techniques. This study shows the potential of our approach to detect two opposite pressure variation stages inside the skull. The employed phantom model needs to be improved to support finer variations in the pressure and better phantom parts, principally for the skull mimic and the loss tangent of all mimics.
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| 17. |
- Redzwan, Syaiful, et al.
(författare)
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Split-Ring Resonator Sensor Penetration Depth Assessment Using In Vivo Microwave Reflectivity and Ultrasound Measurements for Lower Extremity Trauma Rehabilitation
- 2018
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Ingår i: Sensors. - : MDPI. - 1424-8220. ; 18:2
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Tidskriftsartikel (refereegranskat)abstract
- In recent research, microwave sensors have been used to follow up the recovery of lower extremity trauma patients. This is done mainly by monitoring the changes of dielectric properties of lower limb tissues such as skin, fat, muscle, and bone. As part of the characterization of the microwave sensor, it is crucial to assess the signal penetration in in vivo tissues. This work presents a new approach for investigating the penetration depth of planar microwave sensors based on the Split-Ring Resonator in the in vivo context of the femoral area. This approach is based on the optimization of a 3D simulation model using the platform of CST Microwave Studio and consisting of a sensor of the considered type and a multilayered material representing the femoral area. The geometry of the layered material is built based on information from ultrasound images and includes mainly the thicknesses of skin, fat, and muscle tissues. The optimization target is the measured S-11 parameters at the sensor connector and the fitting parameters are the permittivity of each layer of the material. Four positions in the femoral area (two at distal and two at thigh) in four volunteers are considered for the in vivo study. The penetration depths are finally calculated with the help of the electric field distribution in simulations of the optimized model for each one of the 16 considered positions. The numerical results show that positions at the thigh contribute the highest penetration values of up to 17.5 mm. This finding has a high significance in planning in vitro penetration depth measurements and other tests that are going to be performed in the future.
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| 18. |
- Rydberg, Anders, et al.
(författare)
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Theranostic Instrument based on the Combination of Low and High Frequency EM-bio interaction for Bone Defects Analysis and Healing
- 2018
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Ingår i: 2018 EMF-MED 1st World Conference On Biomedical Applications Of Electromagnetic Fields (EMF-MED 2018). - : IEEE. - 9789532900798
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Konferensbidrag (refereegranskat)abstract
- Bone defects due to different diseases and trauma represent a significant health problem. For the follow up on the healing process a sensor which measures the bone mineral density has been developed in the firm of a sensitive split-ring microwave resonator. However, it is not only important to follow up of the healing process but also to find ways of improving the healing, where one way exploited here is to use an externally applied low frequency magnetic field to increase the cell proliferation in the fractured hones. This combines high frequency (microwave) technique with the low frequency (magnetic field) creating a theranostic instrument for clinical and hotneca re applications.
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| 19. |
- Velander, Jacob, et al.
(författare)
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A Four-Layer Phantom for Testing In-Vitro Microwave-Based Sensing Approach in Intra-Cranial Pressure Monitoring
- 2018
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Ingår i: Proceedings Of The 2018 IEEE/MTT-S International Microwave Biomedical Conference (IMBioC). - : IEEE. - 9781538659182 ; , s. 49-51
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Konferensbidrag (refereegranskat)abstract
- Multi-layer phantoms in proofs of concept, designs and validations of both microwave-based biomedical sensing and imaging system are becoming popular means to facilitate in-vitro experiments. In addition, they can contribute significantly to reduce animal use in scientific experimentation. In this paper, we design and fabricate a four-layer phantom composed of skin, skull, cerebrospinal fluid and brain mimic tissues to work between 2 and 3 GHz. In addition, the phantom incorporates a mechanism to produce pressure variation between the cerebrospinal fluid and the brain mimic tissues. This phantom is used in an in-vitro experiment to test and validate a new approach which could sense intra-cranial pressure variations through a microwave-based reflection method. The similarity of the phantom's tissues with human tissues from the viewpoint of the microwave response is analyzed in comparison with data from Italian Institute of Applied Physics in Florence. We found good agreement for the dielectric constant (Rel. Err. < 13 % for 68% of significance) in skin, cerebrospinal fluid and brain mimic tissues. For the skin, we got also good agreement for the loss tangent (Rel. Err. < 11 % for 68% of significance). The skull mimic phantom was stiff enough, but even presenting considerable errors, it was still good enough for the experiment. In addition, the capability of the phantom to operate at different pressures is discussed.
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