Medical Physics Research Group

The Medical Physics Group WWW pages are at http://newton.ex.ac.uk/medphys/.

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The Medical Physics Group is part of the School of Physics at the University of Exeter and has three academic staff (Dr I R Summers, Dr S J Matcher and Dr M Clemence), one principal experimental officer (Mr R E Ellis), one technician, research fellows, research assistants and postgraduate students. Medical Physics research topics at Exeter (see below) are linked by a common expertise in instrumentation, data acquisition and signal processing, allowing easy interaction between all members of the group. Much of our work is carried out in association with local hospitals, other UK and international research groups and/or industrial collaborators.

Medical Physics is a rapidly expanding discipline which concerns the application of experimental and theoretical physics techniques to medical diagnosis and treatment. The subject initially grew out of the involvement of physicists in the use of ionising radiations in both diagnostic and therapeutic applications, but nowadays Medical Physics has expanded to embrace a very wide spectrum of physics, including optics, ultrasonics, magnetism and electronics, with applications in a wide range of medical and surgical procedures. One of the many attractions of research in Medical Physics is that it involves working in a multi-disciplinary environment. Experiments generally require measurements on groups of human subjects with inherent variability and it is often a demanding task to establish statistically valid results.

The School offers Honours Degree programmes in Physics with Medical Physics (MPhys) and Physics with Medical Applications (BSc); also an MSc programme in Medical Physics. Research students within the group are expected to attend lectures from these programmes and thus acquire a general background in Medical Physics in addition to the specialist knowledge required for a particular research topic. Within the group at Exeter presentations by research students at international conferences, national conferences and other meetings are strongly encouraged.

Primary Research Areas

Magnetic Resonance Imaging

The Group has been in the forefront of research into low-cost systems for imaging a particular part of the body. We now have three systems for imaging the hand, wrist, leg or head. Particular attention has been concentrated on high-resolution imaging and imaging of pathology associated with diabetes and arthritis, e.g. degeneration of cartilage in arthritic joints. We are currently attempting to quantify the effect of different imaging procedures on subjective image quality and expanding our studies of the fundamental parameters that affect the magnetic-resonance signal. This latter area is in its infancy and is potentially very important for the interpretation of images in terms of the underlying pathology. In diabetes research magnetic resonance imaging has demonstrated the exciting possibility that the formation of ulcers can be predicted in the foot and lower limb; this research is being pursued with clinicians and a pharmaceutical company.

Physics in Human Perception

Previous work on the transmission of speech via vibrators on the skin resulted in the TAM device which has proved to be one of the most successful of the commercially available tactile aids for the profoundly deaf. This research has now expanded into a range of projects on digital and analogue speech processing, optimisation of information transfer via the sense of touch, design of high-efficiency vibrators, characterisation of normal and impaired hearing, and visual presentation of speech-derived information. We are also investigating the use of arrays on the skin to produce 'virtual reality' touch sensations.

Clinical Measurements

Our recent investigations have shown that respiration during feeding is co-ordinated in a more complex manner than has previously been recognised. This is particularly significant because it is now possible to attribute the swallowing problems observed in some neurologically impaired patients and some premature infants to a failure of this co-ordination. We are currently investigating clinical use of the instrumentation we have developed to monitor the timecourse of swallowing and respiration.

Veterinary Physics

This pioneering work, in conjunction with a local veterinary surgeon, has concentrated on the horse. In studies of respiration during locomotion we are investigating the co-ordination of the respiratory cycle with the locomotive cycle and the relation between breathing difficulties and impaired performance. Nuclear-medicine techniques developed for humans are currently being used to study defects in the equine skeleton. Exeter is one of very few veterinary centres where the techniques for such measurements have been developed. Experimental Facilities

1. Three horizontal-bore superconducting magnets for magnetic resonance imaging (bores of 310, 310 and 560 mm)
2. Three magnetic-resonance imaging consoles
3. Radio-frequency spectrum analyser and other equipment to characterise magnetic resonance signals
4. Soundproof room for audio recording and for tests of auditory perception
5. A large number of PCs for data analysis and control of experiments, many fitted with dedicated hardware cards for data capture, signal processing, image display, etc.
6. Local network for exchange of image data, etc. throughout the group
7. Patient-handling facilities within the laboratory
8. Access to clinical facilities, patients and Hospital Physicists at local hospitals
9. Nuclear medicine facility (gamma camera, etc.) for veterinary measurements

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