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Dr Matthew Guy

Dr Guy is a consultant medical physicist who leads the imaging physics team at UHS.


Training and education

  • MPhys (master of physics) - University of Southampton
  • PhD - University of London (Institute of Cancer Research)
  • SRCS


Dr Guy leads the imaging physics team at University Hospital Southampton. He has extensive experience across both diagnostic and therapeutic applications of nuclear medicine, including PET and CT scans. He has also been involved in the development of dual-energy CT imaging techniques. He's the Trust’s medical physics expert (MPE) for nuclear medicine.

Dr Guy is involved in the delivery of both practitioner and scientist training programmes and takes a lead role in workforce development planning. He has lectured on a range of BSc, MSc and MEng courses, covering molecular imaging and therapy, diagnostic imaging and radiation protection. He's co-supervised numerous medical physics and medical imaging projects at MSc level and co-supervised and assessed PhD students at a variety of universities.

Key achievements

Whilst working at the Institute of Cancer Research at the University of London, Dr Guy developed one of the first patient-specific dose planning systems for molecular radiotherapy (MRT). He also worked extensively on improving the quantification of high count-rate SPECT imaging.

Dr Guy has been involved in both IPEM (Institute of Physics and Engineering in Medicine) and BIR (British Institute of Radiology) working parties on nuclear medicine, and is currently co-chair of the Internal Dosimetry User Group (IDUG). The group's aim is to deliver practical help to clinical and scientific staff undertaking MRT.


Dr Guy's current research interests include optimising patient-specific dosimetry for molecular radiotherapy, including providing quantitative imaging input data and utilising modern CT technology in a wider range of applications, for example at extreme low dose imaging and dual energy modes. Dosimetry is the calculation of how much radiation a patient has received during treatment.

Other research interests include understanding and correcting respiratory motion during SPECT and PET/CT imaging, the application of adaptive image filtering and automated shape analysis in neurological imaging. Dr Guy is a member of the Southampton Respiratory Imaging Group (SRIG).


  • D.R. McGowan, M.J. Guy, The Time to Demand Dosimetry for Molecular Radiotherapy?, Brit J Radiology, 88(1047), 2015
  • B. Rojas, C. Hooker, D.R. McGowan, M.J. Guy, Five years of Molecular Radiotherapy (MRT) Growth in the UK: Survey results from 2007 to 2012, Nucl Med Commun, 36(8): 761-765, 2015
  • W.T. Walker, A. Young, M. Bennett, M. Guy, M. Carroll, J. Fleming, J. Conway, J.S. Lucas, Pulmonary radioaerosol mucociliary clearance in primary ciliary dyskinesia, Eur Resp J, 2(5): 2014-2017, 2014

  • M.J. Guy, Quantification of Nuclear Medicine Images for Dosimetry Estimation, Chapter in An Introduction to Radionuclide Dosimetry (IPEM Report 104), 2011
  • A. A. Abd. Rahni, E. Lewis, M.J. Guy, B. Goswami, K. Wells, A Particle Filter Approach for Respiratory Motion Estimation in Nuclear Medicine Imaging, IEEE TNS, 58(5): 2276-2285, 2011
  • M.J. Guy, Fourier block noise reduction: an adaptive filter for reducing Poisson noise in scintigraphic images, Nucl Med Commun, vol. 29(3): 291-297, 2008
  • P. Papavasileiou, G.D. Flux, M.J. Guy, M.A. Flower, A novel four-dimensional image registration method for radionuclide therapy dosimetry, Phys Med Biol, vol. 49, pp. 5373-5391, 2004
  • F.M. Buffa, G.D. Flux, M.J. Guy, et al, A model-based method for the prediction of whole-body absorbed dose and bone marrow toxicity for 186Re-HEDP treatment of skeletal metastases from prostate cancer, Eur J Nucl Med Mol Imaging, vol.30, pp.1114-1124, 2003
  • M.J. Guy, et al, RMDP: A Dedicated Package For 131-I SPECT Quantification, Registration & Patient-Specific Dosimetry, Cancer Biother Radiopharm, vol 18(1), 61-69, 2003
  • M.J. Guy, et al, DETECT – Dual Energy Transmission Estimation CT – for improved attenuation correction in SPECT and PET, IEEE Trans Nucl Sci, vol. 45(3), pp. 1261-1267, 1998