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Healthcare research in the Physics Department

S. Department of Physics, University of Surrey, Guildford, GU2 7XH, UK. S J Doran, P Jenneson, P McDonald, E Morton, N Spyrou. Healthcare research in the Physics Department. Dr S J Doran Lecturer in Magnetic Resonance Imaging Department of Physics

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Healthcare research in the Physics Department

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  1. S Department of Physics, University of Surrey, Guildford, GU2 7XH, UK S J Doran, P Jenneson, P McDonald, E Morton, N Spyrou Healthcare research in the Physics Department Dr S J Doran Lecturer in Magnetic Resonance Imaging Department of Physics School of Electronics and Physical Sciences

  2. Structure of talk • Physics personnel with medical interests andhealthcare-related projects underway in Physics • Four brief case studies • MRI of the diffusion properties of tumours • Skin imaging • Radiation dosimetry • Characterisation of distortion in MRI

  3. Physics department “healthcare”personnel • Prof Tony CloughIon beam analysis (healthcare products) • Dr Simon DoranMagnetic Resonance ImagingRadiation dosimetrye-Health • Dr Walter GilboyRadiation dosimetry and protection • Dr Paul JennesonIon beam analysisX-ray CT micro-tomographyRadiation transport (Monte Carlo simulation) • Prof Peter McDonald Soft condensed matter PhysicsSkin imagingImaging of solvent ingress into dental resins • Dr Ed Morton (on secondment to Creative X-ray Ltd.)X-ray imagingNovel control systems for dose-reduction • Prof Nicholas SpyrouPositron Emission TomographyNuclear MedicineEpigastrographyTrace element detection in medicalconditions (e.g., Alzheimer’s)Ion beam analysis… and many more!

  4. Lancet 360, 307–308 (2002) MRI measurements of diffusion: (1) Cancer • Magnetic Resonance Imaging can be used to measure the speed of diffusion of water molecules. • The technique is widely applied in brain imaging, as there is a well-established link between altered diffusion values and stroke. • Extra-cranially, the technique has obvious potential, but this has been difficult to realise for a number of technical reasons.

  5. Diffusion coefficient / cm2 s-1 • The diffusion coefficient measured before treatment was correlated with the tumour response. % regression in tumour size after chemoradiation MRI measurements of diffusion: (1) Cancer • We developed novel MRI methodology to allow diffusion coefficients to be measured as part of a rectal tumour study. • Data acquisition is at the limit of what is technically possible with the current generation of scanners • With improved methodology, this could become a prognostic test. The Lancet 360, 307–308 (2002) A Dzik-Jurasz, C Domenig, S Doran et al.

  6. MRI measurements of diffusion: (2) Skin • Most Magnetic Resonance Imaging scanners are based round a magnet with a cylindrical geometry. • This is good for whole-body scans, but not for scanning thin samples. • Dr Glover and Prof McDonald put forward a novel magnet design, called GARField (Gradient At Right- Angles to Field). • Resolution of the new scanner is now of the order of tens of microns, rather than the few mm of a routine clinical scan. J Magn. Reson. 139, 90 P Glover, P Aptaker, J Bowler, E Ciampi, P McDonald

  7. Result after application of cream for 5 mins. 10 8 6 Intensity (a.u.) 4 “Dry” skin before cream applied (normal) 2 0 0 250 500 750 1000 Position (microns) MRI measurements of diffusion: (2) Skin • This type of imaging is very different from the sort of MR “pictures” we are used to seeing. • We can measure quantitatively the diffusion of compounds through the skin and follow them with time. P Glover, B Newling, P McDonald (UniS) M Dias, J Hadgraft (University of Cardiff)

  8. Target organ Organs to spare Treatment plan MRI-derived dose map Measurement of radiation dose in 3D • Modern radiotherapy treatments can be extremely complicated, in order to try and spare healthy tissue whilst killing the cancer. • Such treatments require extremely high spatial accuracy of delivery. • Hence, there is a pressing need to be able to measure the dose delivered. • Until recently, this has not been possible. Schematic prostate treatment Phys. Med. Biol. 43, 1113-1132 (1998) M Oldham et al.

  9. FXG spectral dose-response D(optical absorbance) / cm-1 • For a number of years, we have been investigating a novel method based on a gel that changes colour when irradiated from orange to purple. Wavelength / nm Measurement of radiation dose in 3D • Methods based on MRI have previously been used to measure the dose distribution in 3D. • However, these can be extremely slow (~ 6 hours for a 3-D scan). Phys. Med. Biol. (2001) S Doran, K Kleinkoerkamp, P Jenneson, E Morton, W Gilboy

  10. Unexposed gel Diffuser screen on which real shadow image forms Turntable controlled by acquisition computer via stepper motors • We have developed a new method of scanning the gels — 3-D opticalcomputed tomography (OCT). Exposed gel Scanning tank with matching medium CCD detector Lens  parallel beam • OCT is potentially two orders of magnitude cheaper than its MRI rival. Standard 50mm camera lens Cylindrical lens, pinhole and filter  pseudo point-source Hg lamp PC with frame-grabber card 10 Gy 57 mm 0 Gy Measurement of radiation dose in 3D • OCT is potentially two orders of magnitude faster than MRI. • Applications include brachytherapy, conformal radiotherapy and IMRT, radiation protection/ accident prevention. Phys. Med. Biol. (2001) S Doran, K Kleinkoerkamp, P Jenneson, E Morton, W Gilboy

  11. What would you say if you knew that MRI scans could turn this … … into this? Distortion in Magnetic Resonance Images • Would you rely on MRI data to plan your surgery or radiotherapy? S Doran (UniS), L Moore, S Reinsberg, M Leach (Institute of Cancer Research)

  12. By using a specially designed test object, we can work out how each pixel of the image is displaced. 10 • By analysing around 40,000 point-to-point correspondences between CT and MR images, we obtain 3-D distortion maps. x-distortion / mm -10 100 200 y / mm x / mm -100 -200 Distortion in Magnetic Resonance Images • We are researching how to correct MR images to make them reliable enough for surgery. S Doran (UniS), L Moore, S Reinsberg, M Leach (Institute of Cancer Research)

  13. Data from the test object is used in conjunction with patient image data in order to produce distortion corrected maps. • The eventual aim is to make it possible to eliminate the necessity for CT scans in the planning of some radiotherapy treatments.No radiation Less patient discomfort / inconvenience Saves NHS money Distortion in Magnetic Resonance Images S Doran (UniS), L Moore, S Reinsberg, M Leach (Institute of Cancer Research)

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