Modeling Human Head at Microwave Frequencies Using Optimized Debye Models and FDTD Method

Ireland, David; Abbosh, Amin

doi:10.1109/tap.2013.2242037

Cited by 79 publications

(61 citation statements)

References 13 publications

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“…Another less accurate but computationally faster model to calculate complex dielectric permittivity of materials as a function of frequency is known as N-term Debye model. The N-term Debye model was optimized by Ireland and Abbosh [19], to 2-term Debye model to calculate the dielectric properties specifically for head tissues in the microwave frequency band (0.1 to 5 GHz). Extending Debye's work model Mustafa, et al [21], modeled human head tissues using 4-term Debye.…”

Section: Fig 1: Layout Of An Emit-based Head Imaging Systemmentioning

confidence: 99%

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An Investigation Into Electromagnetic Based Impedance Tomography Using Realistic Human Head Model

Munawar

Mustansar

Nadeem

et al. 2016

Int J Pharm Pharm Sci

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College of Electrical and Mechanical Engineering, National University of Sciences and Technology, Islamabad, Pakistan Email: awaismunawar.phd06@rcms.nust.edu.pkThe objective of this research is to investigate the feasibility of Electromagnetic based Impedance Tomography (EMIT) for brain stroke detection, localization and classification. Electromagnetic based Impedance Tomography employing microwave imaging technique is an emerging brain stroke diagnostic modality. It relies on the significant contrast between dielectric properties of the normal and abnormal brain tissues. To study the interaction between micro-wave signals and head tissues, the simulations are performed using a geometrically simple 3-D ellipsoid head model with emulated stroke. Finite Element numerical technique is adopted to find the solution of Maxwell's equations to measure the transmitted and backscattered signals in forward problem. Contrast Source Inversion technique is proposed to solve the inverse scattering problem and reconstruct brain images based on calculated dielectric profiles. Detailed analysis is performed to determine the safety limits of transmitted signals to minimize ionizing effects while ensuring maximum penetration. The simulations verify the inhomogeneous and frequency-dispersive behavior of brain tissue's dielectric properties. The solution of the forward problem demonstrates the microwave signals scattering by the multilayer structure of the head model, duly validated by analytical results. The scattering phenomena can be fully capitalized by image reconstruction algorithm to obtain brain images and detect stroke presence. The initial results obtained in this research and prior work indicates that EMIT-based head imaging system has a potential for rapid stroke detection, classification, and continuous brain monitoring and offers a comparatively cost-effective solution.

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Section: Fig 1: Layout Of An Emit-based Head Imaging Systemmentioning

confidence: 99%

“…The model has been effectively utilized in several studies conducted by different researchers [7,[17][18][19][20][21].…”

mentioning

confidence: 99%

An Investigation Into Electromagnetic Based Impedance Tomography Using Realistic Human Head Model

Munawar

Mustansar

Nadeem

et al. 2016

Int J Pharm Pharm Sci

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“…Most of the reported head imaging systems utilize frequencies between 0.5-4 GHz in narrowband or wideband manner, as a compromise between the image resolution and signal penetration [14,15,[38][39][40][41][42][43]. The size of the antenna is the major design concern at these low frequencies, especially when wideband is demanded.…”

Section: Existing Microwave-based Head Imaging Systemsmentioning

confidence: 99%

“…Depending on the number of antennas used in the system, wideband radar imaging method can be utilized in three different approaches: mono static, bi-static and multi-static. Various numerical simulations of the head imaging systems are found using 2D head slices [41] as well as 3D simple head model [42,44]. Although for microwave imaging, the properties of human tissues are fixed, in UWB scenario, the dispersive properties of the head has to be considered for realistic assumption.…”

Section: Wideband Microwave Imagingmentioning

confidence: 99%

“…However, they need electrically long conductors or strips along the way of the electromagnetic radiation, making them inappropriate for the compact microwave imaging applications [85]. Moreover, the profile of both types of antennas becomes really large and impractical to use in microwave systems that operate at low-microwave bands [41,86].…”

Section: Systems and Literature Reviewmentioning

confidence: 99%

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Wideband microwave imaging system for brain injury diagnosis

Mobashsher¹

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Brain injury is a major cause of disability and mortality worldwide. This medical emergency occurs when the brain is damaged as a result of various traumatic and non-traumatic incidences including accidents, strokes, drug abuses, tumours, infections and various diseases. As the devastating disorder of brain injury deteriorates rapidly, fast diagnosis and management is critically important for the treatment and recovery of the affected patient. Therefore, on-the-spot accurate detection by means of head imaging is the governing factor of the timely medication to ensure complete recovery of the injured patient. Although some existing imaging technologies, like CT and MRI, are capable for brain injury diagnosis, they are time-consuming, expensive, bulky and mostly stationary. Thus they cannot be carried by first response paramedic teams for the diagnosis purpose or be used for monitoring the patient to observe concurrent brain injury over periods of time without moving the patient. A compact and mobile technology that can be applied to monitor the patient continuously in real time, either at the bedside or in emergency room, would be a significant advantage comparing to the existing imaging techniques. This thesis aims to develop wideband microwave imaging systems for brain injury diagnosis and in doing so makes seven main contributions to the field of microwave imaging systems.As the efficacy of the microwave imaging systems relies on the sensing antennas, emphasize is given in the developments of compact, wideband antennas with directional radiation patterns for low microwave frequencies, which is the first contribution of this thesis. Three-dimensional (3D) antennas are proposed relying on multiple folding and slot-loading techniques. Nevertheless, a novel generalized miniaturization technique is proposed for compact antennas. The antennas are found to be efficient in both near-and far-fields for both frequency-and time-domain characterizations.The second contribution is the development of artificial human head phantom with realistic heterogeneous tissue distributions and actual wideband frequency-dispersive dielectric properties.The phantom is fabricated from artificial tissue emulating materials which are contained and structured by using 3D printed structures and castes. This realistic 3D human head phantom significantly improves the reliability of the experimental validation process of wideband microwave imaging compared to the reported validations with existing simple and stylized head phantoms.The contribution third contribution is the performance comparison of directional and omni-directional antennas for wideband microwave head imaging systems. A novel near-field time-domain characterization technique is proposed that enables the comparative analysis of antennas for nearfield applications. Application of this technique demonstrates that for microwave imaging systems directional antennas are more effective than omni-directional antennas. In terms of imaging performance, it is observed that directio...

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Dielectric properties of dog brain tissue measured in vitro across the 0.3–3 GHz band

Mohammed

Bialkowski

Abbosh

et al. 2016

Bioelectromagnetics

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Dielectric properties of dead Greyhound female dogs' brain tissues at different ages were measured at room temperature across the frequency range of 0.3-3 GHz. Measurements were made on excised tissues, in vitro in the laboratory, to carry out dielectric tests on sample tissues. Each dataset for a brain tissue was parametrized using the Cole-Cole expression, and the relevant Cole-Cole parameters for four tissue types are provided. A comparison was made with the database available in literature for other animals and human brain tissue. Results of two types of tissues (white matter and skull) showed systematic variation in dielectric properties as a function of animal age, whereas no significant change related to age was noticed for other tissues. Results provide critical information regarding dielectric properties of animal tissues for a realistic animal head model that can be used to verify the validity and reliability of a microwave head scanner for animals prior to testing on live animals. Bioelectromagnetics. 37:549-556, 2016. © 2016 Wiley Periodicals, Inc.

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Modeling Human Head at Microwave Frequencies Using Optimized Debye Models and FDTD Method

Cited by 79 publications

References 13 publications

An Investigation Into Electromagnetic Based Impedance Tomography Using Realistic Human Head Model

An Investigation Into Electromagnetic Based Impedance Tomography Using Realistic Human Head Model

Wideband microwave imaging system for brain injury diagnosis

Dielectric properties of dog brain tissue measured in vitro across the 0.3–3 GHz band

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