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Research

At Ryerson University's Department of Physics, our research spans two broad areas: medical physics and complex systems. Our various labs explore both theoretical and applied topics in physics and medical physics. Most of our faculty members and researchers have research facilities at nearby hospitals and research institutes, and collaborate closely with clinicians and researchers. Many also work with industrial collaborators to translate clinically-focused research to market, with real-world impact on medicine.

Complex Systems

Cellular Biophysics

Colour represents calculated diffusion time on an endoplasmic reticulum structure extracted from live cell imaging

Life, emerging from the collective interaction of non-living components, is a pervasive example of a complex system. Although living systems are distinct from those that are not alive, life must follow physical rules. Our lab aims to understand the physical limits and mechanisms for processes within living cells. To do this, we take a theoretical approach, quantitatively describing the physics of cell biology with modeling, calculations, and simulations.

Life is fundamentally out of equilibrium and cells are characterized by many specialized subcellular compartments. Our research focuses on understanding how energy and geometric confinement drive intracellular signaling and the generation of spatial organization. The dynamic processes we explore include how cells decide which organelles to recycle, target proteins to their correct destinations, and recognize toxic conditions.

Researcher: Dr. Aidan Brown

Networks and Nonlinear Dynamics

Plot of how many cell phones are in a given area in the vicinity of Houston, Texas.

Complex systems typically combine complex structure (a network of interacting components) with complex dynamics (nonlinearity). Together, these properties can cause the system as a whole to behave in strange and unexpected ways that can't be anticipated by looking at the individual components. These "emergent behaviours" are at the heart of many negative outcomes in both the built and natural worlds, including large power blackouts, epidemics, and cascades of species extinctions in ecosystems.

Our research aims to understand the mechanisms behind emergent phenomena in a variety of different application areas. Our goal is to use this knowledge to control the dynamics of complex systems, preventing large-scale failures and guiding the system to better outcomes. Current application areas include how to eliminate invasive species in ecosystems, and how to design “smart”, self-healing infrastructure systems. 

Researcher: Dr. Sean P. Cornelius

Statistical Physics of Complex Systems

Illustration of flow of granular material, with forces highlighted

Our lab specializes in the statistical physics of complex systems. These systems are characterized by many degrees of freedom whose large-scale behaviour is often unexpected and dramatic.

We study specific systems, always with a view to developing generalized models to describe universal phenomena that are observable in many complex systems. We are currently exploring analytical techniques for topologically disordered systems, with particular focus on amorphous matter, syntactic structures, and reaction networks.

Researcher: Dr. Eric De Giuli  

Virophysics

Equations describing the infection status of cells and the concentration of virus over the course of a virus infection.

The Virophysics Lab applies the methods and approaches of physics to understand and solve problems, primarily in virology. We develop mathematical models, agent-based models, and other computer simulations to break-down and understand the dynamics of, and mechanisms behind, the spread of a virus infection within a cell culture (in vitro) or a host (in vivo). This enables us, for example, to quantify the mode of action and efficacy of antiviral drugs, or to pinpoint and quantify the phenotypic effect of virus mutations.

We are not an experimental group; the data we analyze come to us through our extensive network of experimental collaborators. The interdisciplinary nature of work in our lab and its wide applicability sometimes takes us beyond virology, into general biology and health sciences, but also astrophysics, and even ergonomics.

Researcher: Dr. Catherine Beauchemin

Medical Physics

Advanced Biomedical Ultrasound Imaging and Therapy (ABUITL)

 Top panel shows the LIPUS (low intensity pulsed ultrasound) experimental setup developed for GNP drug delivery and a typical result. Bottom panel show the LIPUS temperature map in the region of interest in tissue as used in the experiments.

The ABUITL lab is located at the Institute for Biomedical Engineering, Science & Technology (iBEST), external link in St. Michael’s Hospital’s Keenan Research Center. With a track record of research excellence and a 1,600 ft2 state-of-the-art research facility, the lab is one of Canada’s leading biomedical ultrasound research centers.

At ABUITL, we advance understanding in the basic science of ultrasound and the biophysical mechanisms governing its interactions with cells and tissues. We also engage in multidisciplinary R&D collaborations to develop both pre-clinical and clinical applications in therapeutic and diagnostic ultrasound. Some of our current research topics include: high-frequency quantitative ultrasound imaging; interaction of ultrasound with other energy modalities such as photoacoustics modality; high intensity focused ultrasound (HIFU) experiment, modeling and simulation; histotripsy and its applications, low intensity pulsed ultrasound (LIPUS); ultrasound-enhanced radiotherapy; ultrasound-mediated targeted drug delivery; and cannabinoid-based nanotechnology.

Researcher: Dr. Jahangir (Jahan) Tavakkoli

Biomedical Optics and Ultrasound Laboratory (BOUL)

BOUL is part of the Institute for Biomedical Engineering, Science and Technology (iBEST), external link, located in the Keenan Research Centre at St. Michael’s Hospital. Our lab works primarily on photoacoustics (PA), advanced ultrasound imaging, optical coherence tomography, and biomicroscopy. We study a wide array of biomedical problems from the cellular level through to whole organs. We actively collaborate with clinicians, academic researchers and industrial partners to develop novel medical imaging techniques.

Clinical trials using methods developed in our lab are ongoing at Odette Cancer Centre at Sunnybrook Hospital to monitor cell death, and in the planning stages at St. Michael’s Hospital for applying PA imaging to visualize fibrotic scarring in donor kidneys. Our work with Canadian Blood Services and Broad Institute of Harvard and MIT used image flow cytometry and machine learning to assess and potentially predict the quality of stored red blood. With Case Western Reserve University, we are optimizing the use of micro and nanobubbles as theranostic agents for localized delivery of nanoparticles and chemotherapeutics.

Researcher: Dr. Michael Kolios

Computational Biomedical Physics Laboratory

Illustrated image of S-GNR4 field.

The Computational Biomedical Physics Laboratory focuses on computation modeling in the detection and treatment of cancer. With our access to power computational tools, our graduate students have the opportunity to develop and use very sophisticated models in these areas. We conduct computational investigations coupled with complementary experiments on a wide range of highly innovative techniques, including:

  • Treatment planning of laser and magnetic thermal therapy
  • Ultrasound and photoacoustic imaging
  • Photoacoustic monitoring and control thermal therapy
  • Enhancement of radiation and chemotherapy using nano-particles

Researcher: Dr. J. Carl Kumaradas

Magnetic Resonance Imaging and Near Infrared Spectroscopy

Experimental design - TAVI measurements

Our lab researches the simultaneous application of two techniques for functional brain imaging: continuous wave broadband near infrared spectroscopy (NIRS) and functional magnetic resonance imaging (fMRI).

NIRS is a promising technology that measures hemodynamic signals from the brain, similar to those of fMRI. However, as both techniques have their own limitations, their combined application can help to better understand the blood-oxygen-level-dependent (BOLD) effect in normal and diseased brains. We are currently working to merge the physiological information from NIRS with MRI signals to enhance the diagnostic power of imaging for cerebrovascular reactivity conditions, such as steno-occlusive disorders.

Researcher: Dr. Vladislav Toronov

Photonics Group

The Phototronics Group research facilities include the dry Photonics Lab (PL) on Ryerson campus, and the Biomedical Optics Lab (BOL) in St. Michael’s Hospital at the Institute of Biomedical Engineering, Science and Technologies (iBEST). We combine electronics and light to create biomedical physics tools including medical lasers, advanced spectroscopy and imaging (both therapeutic and surgical), and diagnostic applications.

We frequently collaborate with clinical partners in developing original, optoelectronic technologies to solve concrete, current problems in healthcare. As our research targets eventual commercialization, graduate students have the chance to work on individual projects that typically result in a patent, IP disclosure and/or peer-reviewed publications. Our research strategy is supported by the Ryerson’s Lab2Market initiative and Zones’ infrastructure for technology incubation.

Researcher: Dr. Alexandre (Sasha) Douplik

Quantitative Image Analysis in Medicine

Left Panel.  VIDA Diagnostics Inc. software (Coralville, IA, USA) enables segmentation of lung structures, such as the airways of the lung shown here in pink, and three dimensional (3D) reconstructions of the airway tree. Right Panel.  Quantitative analysis of the lungs includes parenchymal measurements of emphysematous tissue destruction (highlighted in red), airway measurements that are derived from the 3D airway tree (pathway to a particular airway segment ie. RB1 is highlighted in green), vessel measurements, as well as disease probability map measurements that classify voxels in the lung as normal, emphysema and functional small airway disease (fSAD).

The Quantitive Image Analysis Lab, external link uses medical imaging tools, such as computed tomography (CT) and magnetic resonance imaging (MRI), and advanced image processing techniques, such as machine learning, to develop new methods for extracting quantitative information to better understand lung disease

Our techniques are now uncovering new information that conventional clinical tools still cannot access — such as the location and severity of underlying disease in the lung. More specifically, we use quantitative methods to characterize the spatial and temporal dynamics of lung disease — how disease initiates and how it progresses over time. Our research is very interdisciplinary, involving active collaborations with imaging physicists, biomedical engineers, computer scientists and medical specialists in hospitals, academia and industry.

Researcher: Dr. Miranda Kirby

Treatment Optimization for Radiation Therapy and Image Reconstruction

Our lab researches radiation treatment for tumours, with particular focus on Intensity Modulated Radiation Therapy (IMRT). Our goal is to develop fast, reliable optimization algorithms that are crucial for effective radiation treatment planning and implementing future interactive, adaptive treatment techniques. We introduced a new Fast Inverse Dose Optimization (FIDO) method that directly solves the inverse problem while avoiding negative beamlet intensities. We’re now developing a full fledged, 3-D planning system that includes scattering effects, dose-volume constraints, and gantry angle optimization and biological effects.

We also explore Intensity Modulated Arc Therapy (IMAT) optimization. We produced a new method to calculate analytic pre-optimized intensities and are now developing a very fast, full optimization including all constraints mentioned above. We’re also working to solve the inverse image reconstruction problem in Computed Tomography (CT) through the application of FIDO, and novel alternatives to avoid nasty imaging artifacts introduced by Fourier transforms.

Researcher: Dr. Pedro Goldman

Ultrasound-Mediated Imaging

Fig 1. Experiment images using (a) Delay and Sum (DAS) and (b) Decorrelating Compounding with Time Gain Compensation (DC-TGC)

The Ultrasound Mediated Imaging Lab research focuses on ultrasound image reconstruction for medical and industry applications. Our research interests include the development of novel algorithms to improve the quality of ultrasound images. This can be seen in the accompanying images (to the left). The bottom image is the result of the standard ultrasound imaging techniques, whereas the top image displays the increased image clarity using one of the reconstruction methods developed by our lab.

We also work on extracting quantitative information from ultrasound images — such as the speed of sound, attenuation coefficient, and backscattering coefficient. Lastly, we develop methods to reduce the cost and complexity of ultrasound imaging systems, especially for 3D and large-array systems.

Researcher: Dr. Yuan Xu

Ultrasound and Microbubble Mediated Therapeutic Applications

This research area specializes in combining the use of ultrasound and microbubbles to treat disease. More specifically, we merge these technologies with a view to achieving several aims:

  • Improve the local delivery of medicinal drugs, with special focus on the mediating targeted delivery of chemotherapy
  • Enhance the therapeutic efficacy of radiotherapy by stimulating the sensitivity of tumours to ionzing radiation
  • Explore the acoustic behaviour of microbubbles as contrast agents in medical imaging

We are currently collaborating with researchers at Sunnybrook Health Sciences Centre to extend investigation of these effects in animal tumour models.

Researcher: Dr. Raffi Karshafian

X-Ray Imaging Lab

Over 400 million x-ray imaging procedures are performed each year in North America alone. In our lab, we investigate novel x-ray imaging techniques and technologies with the goal of discovering those that will improve the quality of x-ray images and/or enable new, advanced x-ray imaging applications. We are currently investigating spectroscopic x-ray imaging of cardiovascular disease, breast cancer and lung cancer, in addition to dual-energy x-ray approaches for functional imaging of respiratory disease.

Our research focuses primarily on understanding and quantifying relationships between the fundamental physics of x-ray imaging and the quality of x-ray images, with specific interest in the aforementioned applications. To this end, we develop and implement advanced theoretical, modelling and experimental methodologies for quantifying objectively the quality of medical x-ray images. We welcome trainees with strong backgrounds in physics and mathematics, as well as new collaborations in academia, hospitals and industry.

Researcher: Dr. Jesse Tanguay

X-ray Fluorescence Laboratory for Trace Element Detection in Human and Biological Samples

The research in this laboratory primarily focuses on the development of new X-ray fluorescence (XRF) based diagnosing tools and biomedical devices for measuring metals (ex vivo and in vivo) accumulated in living human subjects or human tissues. We built the world’s first in vivo systems for painless, non-invasive, low dose measurement of bone strontium, and we have capability to measure other elements such as lanthanum, gadolinium, lead and tungsten.

Our laboratory houses one of the few bench-top, low-power total reflection X-ray fluorescence (TXRF) spectrometers in Canada. With it, we are developing new methods for the in situ low-level quantification of nanoparticles such as gold, our current research focus. Ex-vivo TXRF measurements provide multi-elemental analysis, which could help diagnose or monitor medical conditions or environmental exposure to many other trace and toxic elements. We also conduct destructive and non-destructive analyses of any other sample at detection limits of ppm and ppb levels.

Researcher: Dr. Ana Pejović-Milić