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Jahan Tavakkoli, PhD

Undergraduate Program Director
Associate Professor

KHE-332C
Ryerson University
350 Victoria Street
Toronto, Ontario M5B 2K3
416-979-5000 x7535
jtavakkoli@ryerson.ca

Specialization

  • Biomedical Ultrasound (Therapeutic and Diagnostic)
  • Image-guided Ultrasound Surgery
  • Nonlinear Acoustic Modeling and Simulation
  • Ultrasound Signal and Image Processing
  • Medical Devices and Technologies

Research

Ultrasound is a unique modality that offers both diagnostic and therapeutic benefits in medicine and biology. Biomedical ultrasound is, therefore, an active area of research and development in various research centers in both academia and industry. My areas of research interest span a range of novel therapeutic and diagnostic applications of ultrasound in medicine and biology including:

  • Image-guided HIFU Surgery

    HIFU (high intensity focused ultrasound) is a novel energy-based modality that causes coagulative tissue necrosis in a well-delineated focal zone by rapidly elevating tissue temperature (to above 65°C) in a short exposure duration of a few milliseconds to a few seconds, while keeping the intervening tissue temperatures at physiologically safe levels. HIFU is well known for its ability to produce precisely defined and well-controlled thermal lesions deep inside tissue. Under proper imaging guidance and treatment monitoring, HIFU can effectively be used in a number of non- and/or minimally-invasive surgery procedures. I am mainly interested in applications of HIFU in oncology for non- and/or minimally-invasive treatment of malignant solid tumors, and in neurology and neurosurgery for irreversible and reversible neural tissue manipulations.

  • Nonlinear Acoustic Modeling and Simulation

    Interaction of ultrasound energy with biological tissue is a complicated phenomenon, which is governed by various physical and biophysical effects such as diffraction, attenuation, absorption, dispersion, scattering, reflection, refraction, etc. Moreover, in most therapeutic regimes a significant degree of nonlinearity exists in generation and propagation of ultrasound energy in tissue. I am interested in developing more accurate and more efficient numerical models and simulation tools for nonlinear propagation of ultrasound energy in biological tissue. Such models could significantly enhance our understanding of ultrasound bio-effects and also could help us in designing new applications and/or optimizing current applications of ultrasound in medicine and biology.

  • Imaging, Monitoring and Controlling of IFUS Therapy

    Intensive focused ultrasound (IFUS) is a promising non-invasive therapy modality that makes use of either thermal effects (HIFU) and/or mechanical effects (histotripsy) to induce controlled focalized lesions in deep-seated regions of interest in tissue. I have an active research program in my group to investigate novel acoustical and optical methods to detect HIFU/histotripsy lesions in tissue with the ultimate goal of developing robust imaging methods for real-time monitoring and control of IFUS therapies. To this end, novel ultrasound and photo-acoustic imaging methods are under investigation. My current projects in this area are:
    • Development of novel real-time ultrasound RF echo acquisition and signal processing methods to detect changes in tissue acousto-mechanical properties caused by IFUS exposure. Notable examples are: tissue attenuation coefficient estimation, tissue parameter of nonlinearity (B/A) estimation, elastography imaging, Nakagami imaging, and neural network RF processing methods.
    • Photo-acoustic detection and characterization of IFUS thermo-mechanical lesions. The purpose of this research is two-fold. Firstly, to investigate the capability of photo-acoustic imaging in detecting HIFU-induced thermal and/or histotripsy-induced mechanical lesions in tissue. Secondly, to understand the photo-acoustic response of tissue through determining the optical properties of treated versus normal tissues using optical spectroscopy methods.
    • Development of novel nonlinear ultrasound-based thermometry methods to estimate tissue temperature non-invasively during ultrasound therapy through estimation of tissue’s parameters of nonlinearity (B/A and C/A).

  • Ultrasound Signal and Image Processing

    Ultrasound signal/image processing toward information enhancement and/or noise reduction is an area of active research with significant interests in both academia and industry communities. SP/IP algorithms can be developed in various domains including: time, space, temporal frequency, spatial frequency, and/or mixed domains. I am interested in developing novel SP/IP methodologies especially in applications such as: IFUS treatment monitoring, ultrasound quantitative imaging, and ultrasound image de-noising.

Publications

Mohammadi M.M., Behnam H., Rangraz, P., Tavakkoli J. (2017) HIFU thermal lesion detection using entropy imaging of ultrasound radio frequency signal time series. Journal of Medical Ultrasound (accepted).

McCutcheon V., Park E., Liu E., Sobhebidari P., Tavakkoli J., Wen X.Y., Baker A.J. (2017) A novel model of traumatic brain injury in adult zebrafish demonstrates response to injury and treatment comparable with mammalian models. J. Neurotrauma, 34(7), DOI: 10.1089/neu.2016.4497.

Maraghechi B., Hasani M.H., Kolios M.C., Tavakkoli J. (2016) Temperature dependence of acoustic harmonics generated by nonlinear ultrasound wave propagation in water at various frequencies. J. Acoust. Soc. Am., 139(5), 2475-2481, DOI: http://dx.doi.org/10.1121/1.4946898.

Worthington A., Peng P., Rod K., Bril V., Tavakkoli J. (2016) Image-guided high intensity focused ultrasound (HIFU) system for large animal nerve ablation studies. IEEE J. Translational Eng. in Health and Medicine, Vol. PP, Issue 99, Article # 20002, DOI: 10.1109/JTEHM.2016.2581811.

Tavakkoli J., Karshafian R., Kolios M.C. (2016) Advanced biomedical ultrasound imaging and therapy laboratory. Canadian Acoustics, Vol. 44, No. 2, 50-51.

Shaswary E., Xu Y., Tavakkoli J. (2016) Performance study of a new time-delay estimation algorithm in ultrasonic echo signals and ultrasound elastography. Ultrasonics, 69:11-18, DOI: 10.1016/j.ultras.2016.03.002.

Mobasheri S., Behnam H., Rangraz P., Tavakkoli J. (2016) RF ultrasound time series signal analysis to evaluate HIFU lesion formation status in tissue. J. Med. Signals Sens., 6:91-98.

Rizvi B., Da Silva E., Slatkovska L., Cheung A.M., Tavakkoli J., Pejović‐Milić A. (2016). Technical Note: Bone mineral density measurements of strontium‐rich trabecular bone‐mimicking phantoms using quantitative ultrasound. Medical Physics, 43(11), 5817-5825.

Maraghechi B., Kolios M.C., Tavakkoli J. (2015) Temperature dependence of acoustic harmonics generated by nonlinear ultrasound beam propagation in ex vivo tissue and tissue-mimicking phantoms. Int. J. Hyperthermia, 31:6, 666-673, DOI: 10.3109/02656736.2015.1052856.

Haji Hasani M., Gharibzadeh S., Farjami Y., Tavakkoli J. (2015) Investigating the effect of thermal stress on nerve action potential using the soliton model. Ultrasound Med. Biol., 41(6), 1668-1680, DOI: http://dx.doi.org/10.1016/j.ultrasmedbio.2014.07.007.

Shaswary E., Tavakkoli J., Xu Y. (2015) A new algorithm for time-delay estimation in ultrasonic echo signals. IEEE Trans. Ultrason., Ferroelect., Freq. Contr. , Vol. 62, No. 1, 236-241 (editor-selected article).

Rangraz P., Behnam H., Sobhe Bidari P., Tavakkoli J. (2014) Real time monitoring of high-intensity focused ultrasound thermal therapy using the manifold learning method. Ultrasound Med. Biol., 40(12), 2841-2850, DOI: 10.1016/j.ultrasmedbio.2014.07.021.

Alhamami M., Kolios M.C., Tavakkoli J. (2014) Photoacoustic detection and optical spectroscopy of high-intensity focused ultrasound-induced thermal lesions in biologic tissue. Medical Physics, 41(5), 053502, DOI: 10.1118/1.4871621.

Rangraz P., Behnam H., Sobhe Bidari P., Shakhssalim N., Tavakkoli J. (2014) Dynamic changes in the acousto-mechanical and statistical parameters of tissue during high intensity focused ultrasound (HIFU) treatment. Biomedical Engineering: Applications, Basis and Communications, Vol. 26, No. 1, 1450009, DOI: 10.4015/S1016237214500094.

Rahimian S., Tavakkoli J. (2013) Estimating dynamic changes of tissue attenuation coefficient during high intensity focused ultrasound treatment. Journal of Therapeutic Ultrasound, 1:14, DOI: 10.1186/10.1186/2050-5736-1-14.

Hasani M.H., Gharibzadeh S., Farjami Y., Tavakkoli J. (2013) Unmitigated numerical solution to the diffraction term in the parabolic nonlinear ultrasound wave equation. J. Acoust. Soc. Am., 134: 1775-1790.

Rangraz P., Behnam H., Tavakkoli J. (2013) Nakagami imaging for detecting thermal lesions induced by high intensity focused ultrasound in tissue. Proceedings of the Institution of Mechanical Engineers, Part H: J. of Engineering in Medicine, 228(1), 19-26, DOI: 10.1177/0954411913511777.

Rangraz P., Behnam H., Shakhssalim N., Tavakkoli J. (2012) A feed-forward neural network algorithm to detect thermal lesions induced by high intensity focused ultrasound in tissue. J. Med. Signals Sens., 2(4):192-202.

Bhadane S., Karshafian R., Tavakkoli J., Microbubble-enhanced HIFU therapy: effect of exposure parameters on thermal lesion volume and temperature. In AIP Conference Proceedings, edited by Stephen Meairs, vol. 1503, no. 1, pp. 65-70, AIP, 2012, DOI: http://dx.doi.org/10.1063/1.4769919.

Tavakkoli J., Sanghvi N.T. (2011) Ultrasound-guided HIFU and Thermal Ablation. In: Frenkel V., ed. "Therapeutic Ultrasound: Mechanisms to Applications", Chapter 6, 137-161, Nova Science Publishers, Hauppauge, NY, January 2011.

Tavakkoli J., Mashouf S. (2011) Nonlinear acoustic beam propagation modeling in dissipative media. Canadian Acoustics, 39:19-25.

Weidman J., Ginsberg H.G., Tavakkoli J. (2011) The combined effects of low intensity pulsed ultrasound and heat on bone cell mineralization. Canadian Acoustics, 39:37-43 (best student paper award).