Jahan Tavakkoli, PhD
- Biomedical Ultrasound (Therapeutic and Diagnostic)
- Image-guided Ultrasound Surgery
- Nonlinear Acoustic Modeling and Simulation
- Ultrasound Signal and Image Processing
- Medical Devices and Technologies
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.