Giles Santyr

At A Glance

Dr. Giles Santyr is a medical biophysicist working with physicians and engineers to pioneer new techniques for imaging the lungs of children. Magnetic Resonance Imaging (MRI) is an attractive option but is challenging in the lung due to very low signal. Dr. Santyr’s lab is one of a handful in the world that is developing the use of MRI with hyperpolarized xenon-129 gas to allow the exploration of the pediatric lung, allowing for safer, earlier and more accurate diagnosis and long-term tracking of disease progression and treatment response. This research is expected to have a significant impact on the way physicians detect, diagnose and treat pediatric lung diseases such as cystic fibrosis, asthma and lung injury.

Short Bio

I pursued undergraduate studies in Physics at Queen’s University in Kingston and received my PhD in Medical Biophysics from the University of Toronto in 1990. I went on to work as a Research Associate and Assistant Scientist at the University of Wisconsin where I earned a National Cancer Institute FIRST award. Moving to Carleton University in Ottawa in 1995, I helped establish the Ottawa Medical Physics Institute and pioneered hyperpolarized xenon-129 for lung MRI in rodents. In 2004, I joined the Robarts Research Institute (RRI) where I held a CIHR Industry-Partnered Chair award for Respiratory Imaging as the Director of the Robarts GE 3T MRI Facility. The RRI team produced the first xenon-129 human lung images in Canada and the first carbon-13 lung images in the world. In 2013, I joined the Hospital for Sick Children as a Senior Scientist where I am focusing on MRI approaches to study the lungs of children and young adults. My current research current research involves hyperpolarized xenon-129 and proton MRI of anatomical and functional lung tissue and cellular biomarkers, specifically: airway and lung parenchymal morphology, ventilation, perfusion, gas exchange and inflammatory cell trafficking in lung diseases afflicting children and animal models of these diseases. This research currently involves collaborations with other scientists at SickKids, and the University of Toronto, including the Physiology & Experimental Medicine program, Critical Care Medicine, Respirology, Diagnostic Imaging and Medical Biophysics as well as industrial partnerships.

Research Synopsis

• As a member of the RRI team, my laboratory produced the first 129Xe human lung images in Canada and the first 13C lung images in the world. In the past 14 years, this research has led to over 50 publications and numerous presentations at national and international scientific meetings. My work on the fundamental physics, signal-to-noise ratio, relaxation processes and application of hyperpolarized 3He, 129Xe and 13C MRI is widely cited. Specifically, my pioneering studies of hyperpolarized MRI in rodent models of lung injury have established novel biomarkers of lung disease including regional ventilation, alveolar oxygen partial pressure, apparent diffusion coefficient and morphometry. These breakthroughs were featured in invited first-authored reviews of preclinical hyperpolarized gas MRI in Journal of Applied Physics (2009) as well as an invited talk and book chapter for the Royal Society of Chemistry (UK) in 2014.
• From 2003-2013, I helped establish the Clinical Imaging Research Laboratory (CIRL) at Robarts Research Institute (RRI). For this effort, I was awarded a CIHR Industry-Partnered Chair for Respiratory Imaging Research (2006-11). I also co-authored an invited review article on clinical lung imaging published in AJRCC (Impact factor: 11.04). This work has been important for the translation of my research to patient care. Of particular significance, I have senior-authored research on the application of hyperpolarized 129Xe MRI for early diagnosis of chronic obstructive pulmonary disease (Magn. Reson. Med. 70: 1699-1706, 2013) and lung injury (Magn. Reson. Med. 2015 July. DOI 10.1002/mrm.25825).
• As an extension of the above, I established a program for rodent pulmonary imaging at Robarts using hyperpolarized MRI and micro-CT. My lab was the first to show the earliest detection of lung injury (two weeks) due to radiotherapy, which will have a significant impact on the management of cancer patients. This has attracted CIHR, CINO, ORF and NSERC funding, individual contracts (Merck, GEHC), an invitation to provide a keynote address at the 2008 ISMRM Educational Program, and most recently an invited talk and review article (NMR in Biomedicine 27: 1515-1524, 2014) and two book chapter describing the application of hyperpolarized MRI tools to rodent models of radiation-induced lung injury.
• Since 2013, I have been appointed as a Senior Scientist at the Hospital for Sick Children and Professor of Medical Biophysics at the University of Toronto. My lab at SickKids was the first in Canada to image children with hyperpolarized Xe-129 MRI and the first in the world to compare Xe-129 MRI with lung clearance index in Cystic Fibrosis (CF) and asthma subjects. My lab utilises several research-dedicated facilities: (i) 129Xe hyperpolarized gas facility, (ii) two research-dedicated human MRI systems and (iii) one rodent MRI system. My research program is currently supported by a CIHR and NSERC. I have also recently obtained a Catalyst award from the SickKids CF Centre to support research to develop multiple-breath wash-out MRI to study pulmonary exacerbations in CF populations.

Recent Publications

• Doganay O., K. Thind, T. Wade, A. Ouriadov and G. Santyr
  Transmit-Only/Receive-Only Radiofrequency Coil Configuration for Hyperpolarized ¹²⁹Xe Imaging of Rodent Lung, Concepts in MR Part B 45B(3): 115-124 (2015).

• Doganay O., T. Wade, E. Hegarty, R.F. Schulte, C.A. McKenzie and G.E. Santyr
  Hyperpolarized ¹²⁹Xe MRI of the Lung using Spiral IDEAL, Magn. Reson. Med. 2015 Aug 29. DOI: 10.1002/mrm.25911

• Ouriadov A., M. Fox, E. Hegarty, G. Parraga, E. Wong and G. Santyr
  Early Stage Radiation-Induced Lung Injury Detected with Hyperpolarized ¹²⁹Xe Morphometry: Proof-of-concept Demonstration in a Rat Model, Magn. Reson. Med. 2015 July. DOI 10.1002/mrm.25825.

• Ouriadov A., A. Farag, M. Kirby, D.G. McCormack, G. Parraga and G.E. Santyr
  Pulmonary Hyperpolarized ¹²⁹Xe Morphometry for Mapping Xenon Gas Concentrations and Alveolar Oxygen Partial Pressure:  Proof-of-concept Demonstration in Healthy and COPD Subjects, Magn. Reson. Med.  2014 Dec. DOI 10.1002/mrm.25550.

• Santyr G., M. Fox, K. Thind, E. Hegarty, A. Ouriadov, M. Jensen, T. Scholl, J. VanDyk and E. Wong, Anatomical, Functional and Metabolic MRI of Lung Injury using Hyperpolarized Nuclei, NMR in Biomedicine 27(12): 1515-1524 (2014).

• Kirby M, A. Ouriadov, S. Svenningsen, A. Owrangi, A. Wheatley, R. Etemad-Rezai, G.E. Santyr, D.G. McCormack, G. Parraga, Hyperpolarized ³He and ¹²⁹Xe MRI Apparent Diffusion Coefficients: Physiological Relevance in Older Never- and Ex-smokers, Physiological Reports 2(7): 1-15 (2014).

• Fox M., A. Ouriadov, K. Thind, E. Wong, A. Hope and G.E. Santyr
  Detection of Radiation-Induced Lung Injury in Rats Using Dynamic Hyperpolarized ¹²⁹Xe Magnetic Resonance Spectroscopy, Medical Physics 41(7): 072302 (2014).

• Thind K., M.D. Jensen, E. Hegarty, A.P. Chen, H. Lim, P. Martinez, J. VanDyk, E. Wong, T. Scholl and G.E. Santyr
  Mapping Metabolic Changes Associated with Early Radiation Induced Lung Injury post Conformal Radiotherapy using Hyperpolarized ¹³C-pyruvate Magnetic Resonance Spectroscopic Imaging, Radiotherapy and Oncology 110(2):  317-322 (2014).

• Fox. M., A. Ouriadov and G.E. Santyr, Comparison of Hyperpolarized ³He and ¹²⁹Xe MR Imaging for Measurement of Absolute Ventilated Lung Volume in Rats, revised for Magn. Reson. Med. 71: 1130-1136 (2013).

• Ouriadov A., A. Farag, M. Kirby, D.G. McCormack, G. Parraga and G.E. Santyr, Lung Morphometry using Hyperpolarized ¹²⁹Xe Apparent Diffusion Coefficient Anisotropy in Chronic Obstructive Pulmonary Disease, Magn. Reson. Med. 70: 1699-1706 (2013).

• Thind K., L. Friesen-Waldner, A. Chen, A. Ouriadov, T. Scholl, M. Fox, E. Wong, J. VanDyk, R. Hill, A. Hope and G.E. Santyr, Detection of Radiation-Induced Lung Injury using Hyperpolarized ¹³C Magnetic Resonance Spectroscopy and Imaging, Magn. Reson. Med. 70: 601-609 (2013).

• Kirby M., S. Svenningsen, N. Kanhere, A. Owrangi, A. Wheatley, H.O. Coxon, G.E. Santyr, N.A.M. Paterson, D.G. McCormack and G. Parraga, Pulmonary Ventilation Visualized using Hyperpolarized Helium-3 and Xenon-129 Magnetic Resonance Imaging: Differences in COPD and Relationship to Emphysema, J. Appl. Physiol. 114:707-715 (2013).

• Boudreau M., X. Xu and G. E. Santyr, Measurement of ¹²⁹Xe Apparent Diffusion Coefficient Anisotropy in an Elastase-instilled Rat Model of Emphysema, Magn. Reson. Med. 69: 211-220 (2013).

• Fox M., I. Welch, D. Hobson and G. E. Santyr, A Novel Intubation Technique for Non-Invasive Longitudinal Studies of Rat Lungs using hyperpolarized ³He MRI, Laboratory Animal 46, 311-317 (2012).

• Kirby M., A. Owrangi, S. Svenningsen, A. Wheatley, A. Farag, A. Ouriadov, G.E. Santyr, D.G. McCormack and G. Parraga, Hyperpolarized ³He and ¹²⁹Xe MRI in Healthy Volunteers and Patients with Chronic Obstructive Pulmonary Disease, Radiology 265, 600-610 (2012).

• Shukla Y., D.M. McCormack, N. Patterson, A. Wheatley, A. Farag, G.E. Santyr and G. Parraga, Hyperpolarized ¹²⁹Xe MRI: Tolerability in Healthy Volunteers and Subjects with Pulmonary Disease, Academic Radiology 19, 941-951 (2012).

• Couch M., A.V. Ouriadov and G. E. Santyr, Regional Ventilation Mapping of the Rat Lung using Hyperpolarized ¹²⁹Xe Magnetic Resonance Imaging, Magn. Reson. Med. 68: 1623-1631 (2012).

• Xu X., M. Boudreau, A. Ouriadov and G.E. Santyr, Mapping of ³He Apparent Diffusion Coefficient Anisotropy at Sub-millisecond Diffusion Times in an Elastase-instilled Rat Model of Emphysema, Magn. Reson. Med. 67: 1146-1153 (2012).

• Mathew L., M. Kirby, D. Farquahar, C. Licskai, G. Santyr, R. Etemad-Rezai, G. Parraga and D.G. McCormack, Hyperpolarized  ³He Magnetic Resonance Imaging of Bronchoscopic Airway Bypass in Chronic Obstructive Pulmonary Disease Can Resp J 19: 41-43 (2012).

Graduate Students

Faiyza Alam
Jordan Fliss,
Yonni Friedlander
Yeyoung Janny Kim
Andras Lindenmaier
Samal Munidasa