Why I Became a Scientist
We all pursue directions in life that give us the greatest satisfaction. My greatest satisfaction comes from combining physics and engineering principles with a love of developing new ideas and concepts to do things no-one has done before – and nowhere is this more rewarding than in the development of new ideas for medical imaging. Medical imaging in all its forms provides information on diseases and disease processes that have revolutionized medical practice over the past 30 years. Following studies in engineering physics (Queen’s), nuclear physics (McMaster) and medical physics (Toronto), I have been fortunate to work as a scientist at Robarts and the Lawson Health Research Institute to explore and develop ideas that are continuing to push the frontiers of medical imaging.
Paramount to achieving optimal benefits from the use of diagnostic imaging is ensuring the benefits of each procedure outweigh the risks. In diagnostic radiography this is achieved by providing the best diagnostic information while exposing patients to low acceptable exposures. Working with graduate students in the Department of Medical Biophysics and the Biomedical Engineering program, and building on a background of formal training in Engineering and Physics, Dr Cunningham's overall goal is the training of highly-skilled personnel in science and engineering through a research program at the Robarts Research Institute aimed at novel advances in a cross-disciplinary approach to the development of new detectors and applications in diagnostic radiography.
High-quality medical care requires the use of high-quality medical images. This can be achieved using low patient exposures only with the development and use of high-DQE (detective quantum efficiency) detectors. To achieve high-DQE detector designs, and building on an early contribution by Van Metter et al., Dr. Cunningham's group is responsible for developing much of what is called “cascaded-systems theory” - a set of design principles to incorporate advanced concepts of signal and noise in the development of new detectors for digital radiography and CT. These principles are now widely used by scientists and design engineers in both academic and commercial laboratories around the world. It is also necessary to ensure detectors are validated and maintained to ensure high DQE standards. Working with CIHR proof-of-principle funding, Dr. Cunningham's group developed an instrument to make DQE evaluations accessible to a wide base of scientists, engineers and hospital end users. In partnership with the Robarts Research Institute, the Lawson Research Institute and The University of Western Ontario, they subsequently patented this technology and founded a start-up company to manufacture and sell a commercial instrument that is now used by major manufacturers and leading hospitals in Canada, USA, Europe and Asia for use in research, manufacturing, and quality assurance. Their goal is to make DQE testing sufficiently simple, accurate, fast and robust that it will be widely adopted in QA programs by end users to ensure patients receive the benefits of high-quality imaging with the very lowest possible radiation exposures.
A second theme in their program is the development of composition imaging which is critical in many disease processes. For example, plaque composition is linked to thrombosis risk and the vulnerable atherosclerotic plaque, while metabolic bone diseases, such as osteoporosis and osteoarthritis, are directly linked to tissue distributions of hydroxyapatite and collagen. They are exploiting the unique ability of using x-ray diffraction in tissues for the development of a novel molecular imaging technique that maps tissue composition at the atomic level using computed tomography. Their new approach is currently being evaluated in the first clinical trial in the world that identifies the mineral composition at the core of kidney stones in order to direct personalized recurrence-prevention strategies and correlate stone composition with patient outcomes.
How must the design of x-ray detectors used for digital radiography be changed to produce better images with less radiation?
Improved image quality affects all diseases and diagnoses benefiting from medical radiography. Reduced x-ray exposures reduce the risk of radiation-induced effects such as cancer.
How can we exploit the unique diffraction characteristics of many tissue types to identify composition and help disease diagnoses and treatment?
Composition of tissue plays an important role in many diseases, such as atherscloerosis, metabolic bone diseases including osteoporosis and osteoarthritis, and in the treatment of urinary calculi.
- 1978 BSc Engineering Physics, Queen’s University
- 1981 MSc Physics, McMaster University
- 1986 PhD Medical Biophsyics, University of Toronto
- F.C.C.P.M. Fellow, Canadian College of Physicists in Medicine
- 2011 Annual Award for Academic Excellence, Awarded for Excellence in Research, Department of Medical Imaging, Western University
- 2009 Radiological Society of North America Trainee Award (with student Saul Friedman)
- 2008 Lawson Innovation Prize
- 2007 Best Paper, World Congress of Endourology (with G. Wignall)
- 2006 COMP Young Investigators Award Runner-up (with student S. Friedman)
- 2005 Elected to Fellow by the American Association of Physicists in Medicine
- 2003 Sylvia Fedoruk Prize (best paper of the year)
- 2003 Sylvia Fedoruk Prize Runner-up (best paper of the year)
- 2002 AAPM Young Investigators Award (with student D. Batchelar)
- 1999 COMP Young Investigators Award (with student D. Batchelar)
- 1998 Team Award of Excellence
- 1998 Sylvia Fedoruk Prize Runner-up (best paper of the year)
- 1997 Sylvia Sorkin Greenfield Award (best paper of the year)
- 1995 Sylvia Fedoruk Prize Runner-up (best paper of the year)
- 1995 SPIE Michael B. Merickel Award
- 1995 COMP Young Investigators Award Runner-up (with student M. Westmore)
Tanguay J, Yun S, Kim HK, Cunningham IA. Detective quantum efficiency of photon-counting x-ray detectors. Medical Physics. 42(1): 491-509 (2015).
Joe O, Kim HK, Han JC, Youn H, Park J, Kim S, Kim S, Lee HK, Cunningham IA. Extraction of detector-material parameters from x-ray-induced signals in screen-printed mercuric iodide photoconductors for mammography: preliminary results. Physics in Medicine and Biology. (Submitted 2015).
Jang SY, Kim HK, Youn H, Han JC, Jeon H, Kim SS, Cunningham IA. Empirical investigation of the signal and noise characteristics in cone-beam microtomography with flat-panel detectors. Physics in Medicine and Biology. (Submitted 2015).
Han JC, Kim HK, Kim DW, Yun S, Youn H, Kam S, Tanguay J, Cunningham IA. Single-shot dual-energy x-ray imaging with a flat-panel sandwich detector for preclinical imaging. Current Applied Physics. 14(12): 1734-1742 (2014).
Nykamp S, Cunningham IA. Dual-energy computed tomography for kidney stone composition. Radiology. (Submitted 2014).
Yun S, Kim HK, Jeon H, Tanguay J, Cunningham IA. Theoretical characterization of imaging performance of screen-printed mercuric iodide photoconductors for mammography. Journal of Instrumentation. 9: C05043 (2014).
Yun S, Kim HK, Youn H, Tanguay J, Cunningham IA. Analytic model of energy-absorption response functions in compound X-ray detector materials. IEEE Transactions on Medical Imaging. 32(10): 1819-1828 (2013).</p
Owrangi AM, Etemad-Rezai R, McCormack DG, Cunningham IA, Parraga G. Computed tomography density histogram analysis to evaluate pulmonary emphysema in ex-smokers. Academic Radiology. 20(5): 537-545 (2013).
Yun S, Tanguay J, Kim HK, Cunningham IA. Cascaded-systems analyses and the detective quantum efficiency of single-Z x-ray detectors including photoelectric, coherent and incoherent interactions. Medical Physics. 40(4): 041916 (2013).
Tanguay J, Yun S, Kim HK, Cunningham IA. The detective quantum efficiency of photon-counting x-ray detectors using cascaded-systems analyses. Medical Physics. 40(4): 041913 (2013).
Friedman SN, Nguyen N, Nelson AJ, Granton PV, Macdonald DB, Hibbert R, Holdsworth DW, Cunningham IA. Computed tomography (CT) bone segmentation of an ancient Egyptian mummy: A comparison of automated and semi-automated threshold and dual-energy techniques. Journal of Computer Assisted Tomography. 36(5): 616-622 (2012).
Kim HK, Lim CH, Tanguay J, Yun S, Cunningham IA. Spectral analysis of fundamental signal and noise performances in photoconductors for mammography. Medical Physics. 39(5): 2478-2490 (2012).
Tanguay J, Kim HK, Cunningham IA. A theoretical comparison of x-ray angiographic image quality using energy-dependent and conventional subtraction methods. Medical Physics. 39(1): 132-142 (2012).
Yun H, Kim HK, Kang DG, Kim S, Park J, Marchal J, Tanguay J, Cunningham IA. X-ray interaction-induced signal and noise performances of edge-on silicon microstrip detectors for digital mammography. Journal of Instrumentation. 6: C11004 (2011).
Youn H, Han JC, Cho MK, Jang SY, Kim HK, Tanguay J, Cunningham IA. Numerical generation of digital mammograms considering imaging characteristics of an imager. Nuclear Instruments and Methods in Physics Research A. 652(1): 810-814 (2011).
Yun S, Lim CH, Kim HK, Tanguay J, Cunningham IA. Finding the best photoconductor for digital mammography detectors. Nuclear Instruments and Methods in Physics Research A. 652(1): 629-633 (2011).
Lim CH, Yun S, Han JC, Kim HK, Farrier MG, Achterkirchen TG, McDonald M, Cunningham IA. Characterization of imaging performance of a large-area CMOS active-pixel detector for low-energy x-ray imaging. Nuclear Instruments and Methods in Physics Research A. 652(1): 500-503 (2011).
Yun S, Kim HK, Youn H, Joe O, Kim S, Park J, Kang DG, Sung YH, Marchal J, Tanguay J, Cunningham IA. Detective quantum efficiency of a silicon microstrip photon-counting detector having edge-on geometry under mammography imaging condition. Journal of Instrumentation. 6: C12006 (2011).
Tanguay J, Kim HK, Cunningham IA. The role of x-ray Swank factor in energy-resolving photon-counting imaging. Medical Physics. 37(12): 6205-6211 (2010).
Friedman SN, Cunningham IA. A spatio-temporal detective quantum efficiency and its application to fluoroscopic systems. Medical Physics. 37(11): 6061-6069 (2010).
Yun SM, Lim CH, Kim HK, Graeve T, Cunningham IA. Signal and noise characteristics induced by unattenuated x rays from a scintillator in indirect-conversion CMOS photodiode array detectors. IEEE Transactions on Nuclear Science. 56(3): 1121-1128 (2009).</p
Friedman SN, Cunningham IA. A small-signal approach to temporal modulation transfer functions with exposure-rate dependence and its application to fluoroscopic detective quantum efficiency. Medical Physics. 36(8): 3775-3785 (2009).
Beath SR, Cunningham IA. Pseudomonoenergetic x-ray diffraction measurements using balanced filters for coherent-scatter computed tomography. Medical Physics. 36(5): 1839-1847 (2009).</p
Wignall GR, Cunningham IA, Denstedt JD. (2009). Coherent scatter computed tomography for structural and compositional stone analysis: a prospective comparison with infrared spectroscopy. Journal of Endourology / Endourological Society. 23(3): 351-357 (2009).
Kim HA, Cunningham IA, Yin Z, Cho G. On the development of digital radiology detectors. International Journal of Precision Engineering and Manufacturing. 9(4): 86-100 (2008).
Friedman SN, Cunningham IA. Normalization of the modulation transfer function: the open-field approach. Medical Physics. 35(10): 4443-4449 (2008).
Hajdok G, Battista JJ, Cunningham IA. Fundamental x-ray interaction limits in diagnostic imaging detectors: spatial resolution. Medical Physics. 35(7): 3194-3204 (2008).
Hajdok G, Battista JJ, Cunningham IA. Fundamental x-ray interaction limits in diagnostic imaging detectors: frequency-dependent Swank noise. Medical Physics. 35(7): 3180-3193 (2008).
Friedman SN, Cunningham IA. A moving slanted-edge method to measure the temporal modulation transfer function of fluoroscopic systems. Medical Physics. 35(6): 2473-2484 (2008).
Akbarpour R, Friedman SN, Siewerdsen JH, Neary JD. Cunningham IA. Signal and noise transfer in spatiotemporal quantum-based imaging systems. Virtual Journal for Biomedical Optics, http://vjbo.osa.org/virtual_issuecfm (2008).
Imaging Research Laboratories
Robarts Research Institute
1151 Richmond St. N.
London, Ontario, Canada N6A 5B7