Centre for Medical Science &Technology Optical Developments in Medical Engineering

1. Centre for Medical Science &Technology Optical Developments in Medical Engineering Prof. P.J. Bryanston-Cross Presentation of research interests Belfast 2001 4:30pm, Friday 14th September

2. A series of Optical & Medical Engineering innovations have been developed through the interaction between Engineering, Computer and Medical Sciences. In particular there are areas of exchange between medical instrumentation and aerospace science, which promise to create new types of intelligent optical diagnostic technology. .

3. Synthetic Intelligence • Synthetic intelligence is gaining use in optical diagnostics. • low cost processing power • allowing for highly sophisticated signal processing software • hardware programmed into embedded systems • Example: solving highly complex image connectivity problems.

4. Application of Fuzzy Logic in Fluid Dynamics Raw PIV particle Image Processed Velocity Map of the Flow

5. Opera Singer Holographic Interferometry The movement in the face has been contoured using holographic interferometry. The fringe spacing represents a movement of 30 m and was created by two pulses from a ruby laser.

6. Miniature Instrumentation Optical system: Developed for delivering a high power ‘Q’ switched laser beam into a gas turbine engine at MIT to visualise airflows. The probe exit beam diameter was 4 mm delivering a 200 mJ laser pulse in 10 ns. Similar construction has been developed for application to surgery.

7. Medical Applications Fundus Camera Technology Tonometer Diabetes probe Vitrectomy

8. Fundus Camera The resolution must be a minimum of 10 line pairs/mm. The colour contrast must be calibrated. The colour balance must be compared to a stored standard. The pixel integrity/optical cleanliness of the system must be checked, on both the camera and the monitors used. The camera test should be carried out under the same conditions weekly. A flat resolution test chart can be used to evaluate the camera

9. Active Non-Contacting Diabetes Probe • 1 Year of research and the subject of a DTI Smart Award. • Design and implementation of a low cost, on-line, non-contact, spectral testing device to be used as a Diabetes Probe.

10. Diagnostic sensors for testing for diabetes

11. Colour intensity plot: spectral variation through the lens Normal eye illuminated with blue light fluorescent green glow: glucose retention Laboratory demonstration system

12. Optical Tonometer • Active Non-Contacting Glaucoma Probe (AGP) • 3 years of research, laboratory prototype tested on human subjects • Design and implementation of an active Non-Contacting Glaucoma Probe which has the potential to be used as a low cost, on-line testing device. • The objective is to provide a low cost probe which could be used by mobile medics, small practices and surgeons in the third world, eliminating in some cases the need for contact methods of testing methods

13. Non-invasive, non-contact, intelligent tonometer for the detection of glaucoma Warwick has recently been exploring the early detection of glaucoma. In this case the objective is to measure the intra-ocular pressure. This can be achieved using acoustic resonance.

14. Laser Eye Surgery Instrumentation Test and prototyping a series of probes for application to ophthalmic surgery. Criteria: external diameter < 0.8mm preferably disposable debris suction optical fibre illumination cutting capability Further research: spectral analysis and proximity detection while retaining a disposable fibre optic construction.

15. New Laser Cutting Tools for Vitrectomy Suitability of IR (Infra Red) laser wavelengths has been investigated. FTIR spectral plot shows 6.1 and 6.45 m to be particularly suited to soft tissue ablation. FELIX Free Electron Laser facility in the Netherlands is being used to characterise the thermal, mechanical and molecular dynamics of the ablation process in swine vitreous.

16. A high resolution low cost Loupe system • 1 year Smart Award, 2 years research as part of an EU grant. • The loupe is for use in the third world as a low cost operating stereoscopic system. • It uses low cost plastic aspheric lenses. The lens system has been designed with a magnification of 3 at an object distance of 300 mm. Its optical resolution is 20 lines/mm • It has been designed to be viewed by the eye, which requires the exit pupil of the lens to be focused at infinity. • The operation of the lens is to minimise spherical and chromatic aberrations. This is achieved by a complex surface curvature and a specially designed spectral spatial filter.

17. Surgical Loupe

18. Cumulative Effect of Technological Advances If the innovations discussed are applied, then: Cameras provide a visual history and library for surgeons and a map for operations where vision is restricted. Intelligent cameras will assist in aiding the pre-diagnostics. Images of the eye placed into a 3-D drawing model would allow the surgeon to evaluate the complexity of the operation. Self-illuminating probes make surgery simpler and easier; they also free the surgeon, in that he no longer needs to control the position of the light source. Active probes make training in surgery safer and can provide direct feedback, e.g. power delivery during laser ablation. Disposable surgical instrumentation and non-contact diagnostics considerably lower risk of infection. Intelligent non-contacting low cost intelligent diagnostics make the early detection of potentially sight threatening diseases possible.

19. The probes are still at an early research stage; but with the falling costs of computer technology and innovations in optical design and laser technology, the prospect of lower cost, synthetically intelligent, accurate optical diagnostics are starting to emerge.

20. Industrial Applications Tomographic array Spectral probe Small Engine

21. Tomographic measurement of heat release • Part of a 3 year Faraday Intersect project with Rolls-Royce, CORUS and DERA as the industrial partners. • The Aim here is to find a SME partner interested to develop the approach as a testing instrument for Rolls Royce. • The probe is constructed from a ring of fibre optics which record the light emitted from the within the combustor. A tomographic reconstruction is used to capture the emitted light and a 40 fibre optics placed in a ring around the combustor. The objective of the work is to measure the heat release from the combustor to a spatial resolution of 10mm and a temporal resolution of 600Hz.

22. Tomographic array: Modified Burner Array Result Colour Intensity photograph Thermocouple Result

23. Fibres

24. Tomographic array

25. Spectral Measurements in a Gas Turbine Engine • A spectrometer on a chip has been fibre optic linked to a diagnostic probe. The probe has been used in the fuel injector within the combustion chamber of a gas turbine engine. Tests have been made at RAe Farnborough to show how a engine can be run at a minimal running condition with switching off the engine. • This work is part of the INTErSECT faraday Centre project: The Application of Data Fusion to a Multi Sensored Intelligent Engine. • Its industrial partners are: Rolls-Royce, CORUS and DERA. • The project represents 2 years of research work in the area.

26. Spectroscopic Measurements on a DERA Reverse Flow Combustor

27. Fuel Injector INLET Fibreoptic Primary Holes Combustor Wall OUTLET Spectroscopic Measurements on a DERA Reverse Flow Combustor Optical Access Through Injector

28. Spectroscopic Measurements on a DERA Reverse Flow Combustor Three-way Beam Splitter 25m UV Fibre Optic 25m VIS-IR Fibre Optic Twin Channel Spectrometer Combustor Rig

29. Spectroscopic Measurements on a DERA Reverse Flow Combustor 430nm CH 470nmCHO 590nm H2O 394nm S2 308nm OH 516nm C2 559nm C2

30. The Small Engine project • The operating pressure and temperature of a I.C. engine is very similar to those of a gas turbine engine. As a result of this a small low cost test bed engine has been develop on which a series of novel instruments are in the process of development. In particular the engine is optically instrumented and has heat transfer gauges mounted on its head and piston. It is possible to also investigate the fundamental aspects of, for example direct injection. • This work is part of the INTErSECT faraday Centre project: The Application of Data Fusion to a Multi Sensored Intelligent Engine. • It represents 2 years of research.

31. Heat Transfer • Thin film, constant current, Platinum resistance, thermometers. • 90 kHz response • Measure Heat Flux (Not capacity)

32. Heat Transfer - Results • Fired (note noise) • Wall temp increases • Interpretation

33. Electrode Fibreoptic Coupling GRIN lens Plano-concave lens Spark tip Quartz Protection Window Firing Probe • Spectroscopy • Conveys light to Spectrometer • 3mm lenses • Overall optics diameter 4mm

34. Emission Spectra. TDC. Emission Spectra. 15 ATDC. Intensity (counts) Intensity (counts) Wavelength (nm) Wavelength (nm) Spectral Results