Biomedical Imaging and Instrumentation
Oxford Brookes has a long involvement with the development of biomedical instrumentation and imaging techniques. The group at Oxford Brookes is one of the most productive and long standing groups working on Electrical Impedance Tomography (EIT) worldwide and has made a number of important contributions to the theoretical and practical aspects of this problem. The reconstruction techniques and the Electrical Impedance Tomographs developed were tested in clinical trials in the Churchill and John Radcliffe Hospitals in Oxford. Novel current-mode design techniques are applied not only to EIT, but also to other areas of medical instrumentation such as a new design for Electrical Impedance Cardiography (EIG) and integrated circuit pH sensors based on Ion Sensitive Field Effect Transistors (ISFET) technology. Closely related is also the research on Functional Electrical Stimulation (FES), a means of producing contractions in muscles, paralysed due to central nervous system lesions, by means of electrical stimulation, with important practical applications as FES rowing and the 'bladder button'.
Electrical Impedance Tomography (EIT)
EIT is a technology developed to image the electrical conductivity distribution of a conductive medium. It is of interest because of its low cost and also because the electrical conductivity gives direct information about the internal composition of the conductive medium. The technique works by performing simultaneous measurements of direct or alternating electric currents and voltages on the boundary of an object. These are the data used by an image reconstruction algorithm to determine the electrical conductivity distribution within the object. EIT is an imaging tool with important applications in medicine (detection of pulmonary emboli, monitoring of apnoea, monitoring of heart functional blood flood and breast cancer detection).
Medical instrumentation for personalised healthcare
The research area of biomedical electronic engineering is diverse and rapidly expanding. The scope spans personalised healthcare to improved systems in intensive care. There are many benefits to be unlocked and harnessed to produce products and equipment that can affect many people and industries. It is also seen as the next frontier in electronic engineering, generating much interest from many research groups worldwide.
Analogue signal processing has a major part to play in the development of biomedical sensors. The key reason behind this is due to the low power requirements of today’s medical instrumentation with wearable and implantable systems being needed for continuous monitoring. Digital systems whilst always inherently more accurate are less desirable due to their higher power consumption, greater circuit complexity, and sufficient accuracy can be obtained with elegant novel analogue circuit design.
Current work is in the following areas:
- Instrumentation Amplifier (IA) Design with high common mode rejection ratio for Electrocardiogram (ECG), electroencephalogram (EEG) and electromyogram (EMG) and
- Ion Sensitive Field Effect Transistor (ISFET) sensor design for pH sensing device, for buffer index/capacity measurement. Also the system is capable of providing both pH and 'real-time' buffer capacity measurement.
- Design and assess novel high output impedance circuit topologies (10MΩ at 1MHz) suitable for medical applications.
Non-contacting infra-red (IR) thermometer
This research project is related to the design of a novel self-calibrating non-contacting infra-red (IR) thermometer primarily intended for use in food industry applications where existing systems are unable to match either the accuracy or the speed at which measurements can be. The device will be produced by Calex Limited. The project was awarded an Industrial Fellowship by the Royal Commission for the Exhibition of 1851 for this research work.