A5018401704- Ultrasound and Hyperthermia Applications
- Ultrasonics and Acoustic Wave Propagation
- Ultrasound and Cavitation Phenomena
- Ultrasound Imaging and Elastography
- Photoacoustic and Ultrasonic Imaging
- Microwave Imaging and Scattering Analysis
- Acoustic Wave Phenomena Research
- Smart Materials for Construction
- Liver physiology and pathology
- Fluid Dynamics and Mixing
- Electromagnetic Simulation and Numerical Methods
- Hepatocellular Carcinoma Treatment and Prognosis
- Geophysical Methods and Applications
- Organ Transplantation Techniques and Outcomes
- Numerical methods in engineering
- Underwater Acoustics Research
- Flow Measurement and Analysis
- Electromagnetic Scattering and Analysis
- Osteoarthritis Treatment and Mechanisms
- Bone Tissue Engineering Materials
- Advanced Fiber Optic Sensors
- Non-Destructive Testing Techniques
- Cancer Research and Treatments
- Seismic Waves and Analysis
- Orthopaedic implants and arthroplasty
University College London
2014-2023
University of Cambridge
2021
Faculty (United Kingdom)
2021
Torrington Hospital
2009-2012
The London College
2010-2011
Institute of Cancer Research
2010
Imperial College London
2006
Ultrasonic Technologies (United States)
1998
UCL Australia
1986-1987
A problem with tissue engineering scaffolds is maintaining seeded cell viability and function due to limitations of oxygen nutrient transfer. An approach maintain suitable concentrations throughout the scaffold would be controllably incorporate microchannelling within these scaffolds. This study investigated incorporation unidirectionally aligned soluble phosphate based glass fibers (PGF) into dense collagen PGF are degradable, their degradation can controlled through chemistry dimensions....
A novel design for continuous flow sonocrystallization of adipic acid in a capillary device is presented and investigated experimentally numerically. The effect supersaturation ultrasound power studied. To elucidate the relationship between crystallization cavitation, sonochemiluminescence sonoemulsification experiments are performed, numerical investigation wave propagation aqueous solution used to predict probability cavitation. Crystal size distribution at different operating conditions...
A theoretical model for the dynamics of a bubble in an elastic blood vessel is applied to study numerically effect confinement on free oscillations bubble. The wall deformations are described using lumped-parameter membrane-type model, which coupled Navier-Stokes equations fluid motion inside vessel. It shown that finite-length characterized by spectrum frequencies, with distinguishable high-frequency and low-frequency modes. frequency mode increases modulus and, thin-wall vessel, can be...
A pseudospectral model of linear elastic wave propagation is described based on the first order stress-velocity equations elastodynamics. k-space adjustments to spectral gradient calculations are derived from dyadic Green’s function solution second-order equation and used (a) ensure exact for homogeneous timesteps arbitrarily large size, (b) also allows larger time steps without loss accuracy in heterogeneous media. The formulation wavefield be split easily into compressional shear parts....
Continuous-flow crystallization of adipic acid in a millichannel chip equipped with piezoelectric element is presented and investigated experimentally numerically. A single, straight channel (cross section: 2 mm × 5 mm, length: 76 mm) made glass, which ultrasonically transparent, was designed fabricated. The allows studying the effect different ultrasound frequencies kHz to MHz range. Ultrasound applied burst mode reduce heating; this allowed operating at higher levels input power. To...
Neuro-stimulation has wide ranging clinical and research potential but this is currently limited either by low resolution, penetration or highly invasive procedures. It been reported in previous studies that ultrasound able to elicit a neuro-stimulatory effect at higher resolution than other non-invasive approaches both the underlying mechanism makes possible practical details of how it can be implemented are still poorly understood. The current study identified main issues need resolved...
The authors have demonstrated three-dimensional trapping of ultrasound contrast agent microbubbles using a circularly scanning optical tweezers to confine the microbubble in time-averaged potential. They measured maximum transverse drag force that may be applied trapped before it escapes and found this decreases significantly at small trap radii. explain terms relative volumes anticipate feature will important experiments involving insonation optically microbubbles.
A forward model, which predicts the scattering by human ribs of a multi-element high-intensity focused ultrasound transducer, was used to investigate efficacy range focusing approaches described in literature. This model is based on boundary element method and Gélat et al (2011 Phys. Med. Biol. 56 5553–81; 2012 57 8471–97). The has since been improved features complex surface impedance condition at ribs. inverse problem through implemented six transducer array-rib topologies five methods...
The majority of the existing models describing behavior microbubble ultrasound contrast agents consider single, isolated microbubbles suspended in infinite media. a population is predicted by summing results for single and ignoring multiple scattering effects. aim this investigation to determine significance populations establish whether an alternative approach required. In first part work, linear are derived identify approximately conditions under which may be expected. A nonlinear model...
High intensity focused ultrasound (HIFU) enables highly localized, non-invasive tissue ablation and its efficacy has been demonstrated in the treatment of a range cancers, including those kidney, prostate breast. HIFU offers ability to treat deep-seated tumours locally, potentially bears fewer side effects than more invasive modalities such as resection, chemotherapy ionizing radiation. There remains however number significant challenges which currently hinder widespread clinical...
Boiling histotripsy is a High Intensity Focused Ultrasound (HIFU) technique which uses number of short pulses with high acoustic pressures at the HIFU focus to induce mechanical tissue fractionation. In boiling histotripsy, two different types cavitation contribute towards destruction: vapour bubble and clouds. An understanding mechanisms underpinning these phenomena their dynamics therefore paramount predicting controlling overall size lesion produced for given exposure condition. A studies...
This paper interrogates the intersections between bubble dynamics and classical nucleation theory (CNT) towards constructing a model that describes intermediary events extrema of cavitation boiling. We employ Zeldovich's hydrodynamic approach to obtain description nuclei grow simultaneously via excitation by acoustic field vapour transport. By quantifying relative dominance both mechanisms, it is then possible discern extent which viscosity, inertia, surface tension transport shape growth...
The efficacy of high-intensity focused ultrasound (HIFU) for the treatment a range different cancers, including those liver, prostate and breast, has been demonstrated. As non-invasive therapy, HIFU offers considerable advantages over techniques such as chemotherapy surgical resection in terms reduced risk harmful side effects. Despite this, there are number significant challenges which currently hinder its widespread clinical application. One these is need to transmit sufficient energy...
A phenomenological implementation of Classical Nucleation Theory (CNT) is employed to investigate the connection between high intensity focused ultrasound (HIFU) pressure and temperature fields with energetic requirements bubble nucleation. As a case study, boiling histotripsy in tissue-mimicking phantoms modelled. The physics key components CNT HIFU conditions such as derivation nucleation thresholds approximations regarding surface tension liquid are reviewed discussed. Simulations show...