A highly phase-stable differential detector amplifier for magnetic induction tomography

Screening and Biosensor-Based Approaches for Lung Cancer Detection

Early diagnosis of lung cancer helps to reduce the cancer death rate significantly. Over the years, investigators worldwide have extensively investigated many screening modalities for lung cancer detection, including computerized tomography, chest X-ray, positron emission tomography, sputum cytology, magnetic resonance imaging and biopsy. However, these techniques are not suitable for patients with other pathologies. Developing a rapid and sensitive technique for early diagnosis of lung cancer is urgently needed. Biosensor-based techniques have been recently recommended as a rapid and cost-effective tool for early diagnosis of lung tumor markers. This paper reviews the recent development in screening and biosensor-based techniques for early lung cancer detection.

Electromagnetic induction holography imaging for stroke detection

This paper presents the application of the electromagnetic induction holography (EMIH) approach to imaging the electromagnetic activity of the brain, with a particular focus on stroke detection. An integral equation formulation is presented to describe the scattered magnetic field from the distribution of optically small dielectric and magnetic objects of arbitrary shapes adsorbed onto a planar electromagnetic substrate. A numerical computer model was developed in a MATLAB environment to validate the theory. Several realistic human head models were developed to investigate the detectability of strokes with the multi-channel EMIH system. Small strokes can be clearly identified with the correct location and size in the reconstructed head images. The simulation results demonstrated the feasibility of detecting and imaging small strokes using the approach.

Advancements in transmitters and sensors for biological tissue imaging in magnetic induction tomography

Magnetic Induction Tomography (MIT), which is also known as Electromagnetic Tomography (EMT) or Mutual Inductance Tomography, is among the imaging modalities of interest to many researchers around the world. This noninvasive modality applies an electromagnetic field and is sensitive to all three passive electromagnetic properties of a material that are conductivity, permittivity and permeability. MIT is categorized under the passive imaging family with an electrodeless technique through the use of excitation coils to induce an electromagnetic field in the material, which is then measured at the receiving side by sensors. The aim of this review is to discuss the challenges of the MIT technique and summarize the recent advancements in the transmitters and sensors, with a focus on applications in biological tissue imaging. It is hoped that this review will provide some valuable information on the MIT for those who have interest in this modality. The need of this knowledge may speed up the process of adopted of MIT as a medical imaging technology.

Hardware and software design for a National Instrument-based magnetic induction tomography system for prospective biomedical applications

Magnetic induction tomography (MIT) is a new and emerging type of tomography technique that is able to map the passive electromagnetic properties (in particular conductivity) of an object. Excitation coils are used to induce eddy currents in the medium, and the magnetic field produced by the induced eddy current is then sensed by the receiver coils. Because of its non-invasive and contactless feature, it becomes an attractive technique for many applications (especially in biomedical area) compared to traditional contact electrode-based electrical impedance tomography. Due to the low contrast in conductivity between biological tissues, an accurate and stable hardware system is necessary. Most MIT systems in the literature employ external signal generators, power amplifiers and highly stable down-conversion electronics to obtain a satisfactory phase measurement. However, this would increase design complexity substantially. In this paper, a National Instrument-based MIT system is developed at the University of Bath, aiming for biomedical applications. The system utilizes National Instrument products to accomplish all signal driving, switching and data acquisition tasks, which ease the system design whilst providing satisfactory performance. This paper presents a full-scaled medical MIT system, from the sensor and system hardware design, eddy current model verification to the image reconstruction software: the performance of this MIT instrumentation system is characterized in detail, including the system accuracy and system stability. The methods of solving eddy current problem are presented. The reconstructed images of detecting the presence of saline solutions are also included in this paper, which show the capability of national instrument products to be developed into a full-scaled biomedical MIT system, by demonstrating the practical experimental results.