94 results found
Jiang Z, Cudeiro-Blanco J, Ilbilgi Yildiz B, et al., 2024, An Ultrasound Array of Emitter-Receiver Stacks for Microbubble-Based Therapy., IEEE Trans Biomed Eng, Vol: 71, Pages: 467-476
Most therapeutic ultrasound devices place emitters and receivers in separate locations, so that the long therapeutic pulses (>1 ms) can be emitted while receivers monitor the procedure. However, with such placement, emitters and receivers are competing for the same space, producing a trade-off between emission efficiency and reception sensitivity. Taking advantage of recent studies demonstrating that short-pulse ultrasound can be used therapeutically, we aimed to develop a device that overcomes such trade-offs. The array was composed of emitter-receiver stacks, which enabled both emission and reception from the same location. Each element was made of a lead zirconate titanate (PZT)-polyvinylidene fluoride (PVDF) stack. The PZT (frequency: 500 kHz, diameter: 16 mm) was used for emission and the PVDF (thickness: 28 μm, diameter: 16 mm) for broadband reception. 32 elements were assembled in a 3D-printed dome-shaped frame (focal length: 150 mm; [Formula: see text]-number: 1) and was tested in free-field and through an ex-vivo human skull. In free-field, the array had a 4.5 × 4.5 × 32 mm focus and produced a peak-negative pressure (PNP) of 2.12 MPa at its geometric center. The electronic steering range was ±15 mm laterally and larger than ±15 mm axially. Through the skull, the array produced a PNP of 0.63 MPa. The PVDF elements were able to localize broadband microbubble emissions across the skull. We built the first multi-element array for short-pulse and microbubble-based therapeutic applications. Stacked arrays overcome traditional trade-offs between the transmission and reception quality and have the potential to create a step change in treatment safety and efficacy.
Diallo M, Eder C, Brasier D, et al., 2022, Electric-Field-Based Guidance for Percutaneous Catheter Vessel Crossing, SENSORS, Vol: 22
Jiang Z, Sujarittam K, Yildiz BI, et al., 2022, Passive cavitation detection with a needle hydrophone array, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol: 69, Pages: 233-240, ISSN: 0885-3010
Therapeutic ultrasound and microbubble technologies seek to drive systemically administered microbubbles into oscillations that safely manipulate tissue or release drugs. Such procedures often detect the unique acoustic emissions from microbubbles with the intention of using this feedback to control the microbubble activity. However, most sensor systems reported introduce distortions to the acoustic signal. Acoustic shockwaves, a key emission from microbubbles, are largely absent in reported recording, possibly due to the sensors being too large or too narrowband, or having strong phase distortions. Here, we built a sensor array that countered such limitations with small, broadband sensors and a low phase distorting material. We built 8 needle hydrophones with polyvinylidene fluoride (PVDF, diameter: 2 mm) then fit them into a 3D-printed scaffold in a two-layered, staggered arrangement. Using this array, we monitored microbubbles exposed to therapeutically-relevant ultrasound pulses (center frequency: 0.5 MHz, peak-rarefactional pressure: 130-597 kPa, pulse length: 4 cycles). Our tests revealed that the hydrophones were broadband with the best having a sensitivity of -224.8± 3.2 dB re 1 V/μPa from 1 to 15 MHz. The array was able to capture shockwaves generated by microbubbles. The signal-to-noise (SNR) ratio of the array was approximately 2 times higher than individual hydrophones. Also, the array could localize microbubbles (-3dB lateral resolution: 2.37 mm) and determine the cavitation threshold (between 161 kPa and 254 kPa). Thus, the array accurately monitored and localized microbubble activities, and may be an important technological step towards better feedback control methods and safer and more effective treatments.
Lui D, Popa S, Dickinson RJ, et al., 2021, Distal re-entry to treat lower limb chronic total occlusions using a novel electrically guided re-entry catheter, EJVES Vascular Forum, Vol: 51, Pages: 5-8, ISSN: 2666-688X
What this paper adds:With technological advances in endovascular devices, endovascular treatment of complex chronic total occlusions in the peripheral vasculature is becoming more feasible. Re-entering the true vessel lumen after subintimal crossing of heavily calcified lesions remains a limiting factor for successful treatment. The first in human use of an innovative electrically guided re-entry catheter, which has the potential for improving success in these challenging cases, is presented.
Jiang Z, Dickinson RJ, Hall TL, et al., 2021, A PZT-PVDF stacked transducer for short-pulse ultrasound therapy and monitoring, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol: 68, Pages: 2164-2171, ISSN: 0885-3010
Therapeutic ultrasound technologies using microbubbles require a feedback control system to perform the treatment in a safe and effective manner. Current feedback control technologies utilize the microbubble’s acoustic emissions to adjust the treatment acoustic parameters. Typical systems use two separated transducers: one for transmission and the other for reception. However, separating the transmitter and receiver leads to foci misalignment. This limitation could be resolved by arranging the transmitter and receiver in a stacked configuration. Taking advantage of an increasing number of short-pulse-based therapeutic methods, we have constructed a PZT-PVDF stacked transducer design that allows the transmission and reception of short-pulse ultrasound from the same location. Our design had a piston transmitter composed of a PZT disc (1 MHz, 12.7 mm in diameter), a backing layer, and two matching layers. A layer of Polyvinylidene fluoride (PVDF) (28 μm in thickness, 12.7 mm in diameter) was placed at the front surface of the transmitter for reception. Transmission and reception from the same location was demonstrated in pulse-echo experiments where PZT transmitted a pulse and both PZT and PVDF received the echo. The echo signal received by the PVDF was 0.43 μs shorter than the signal received by the PZT. Reception of broadband acoustic emissions using the PVDF was also demonstrated in experiments where microbubbles were exposed to ultrasound pulses. Thus, we have shown that our PZT-PVDF stack design has unique transmission and reception features that could be incorporated into a multi-element array design that improves focal superimposing, transmission efficiency, and reception sensitivity.
Zubair M, Dickinson R, 2021, Calculating the effect of ribs on the focus quality of a therapeutic spherical random phased array, Sensors, Vol: 21, ISSN: 1424-8220
The overlaying rib cage is a major hindrance in treating liver tumors with high intensity focused ultrasound (HIFU). The problems caused are overheating of the ribs due to its high ultrasonic absorption capability and degradation of the ultrasound intensity distribution in the target plane. In this work, a correction method based on binarized apodization and geometric ray tracing approach was employed to avoid heating the ribs. A detailed calculation of the intensity distribution in the focus plane was undertaken to quantify and avoid the effect on HIFU beam generated by a 1-MHz 256-element random phased array after the ultrasonic beam passes through the rib cage. Focusing through the ribs was simulated for 18 different idealized ribs-array configurations and 10 anatomically correct ribs-array configurations, to show the effect of width of the ribs, intercostal spacing and the relative position of ribs and array on the quality of focus, and to identify the positions that are more effective for HIFU applications in the presence of ribs. Acoustic simulations showed that for a single focus without beam steering and for the same total acoustic power, the peak intensity at the target varies from a minimum of 211 W/cm2 to a maximum of 293 W/cm2 for a nominal acoustic input power of 15 W, whereas the side lobe level varies from 0.07 Ipeak to 0.28 Ipeak and the separation between the main lobe and side lobes varies from 2.5 mm to 6.3 mm, depending on the relative positioning of the array and ribs and the beam alignment. An increase in the side lobe level was observed by increasing the distance between the array and the ribs. The parameters of focus splitting and the deterioration of focus quality caused by the ultrasonic propagation through the ribs were quantified in various possible different clinical scenarios. In addition to idealized rib topology, anatomical realistic ribs were used to determine the focus quality of the HIFU beam when the beam is steered both in axial
Zubair M, Dickinson RJ, 2021, 3D synthetic aperture imaging with a therapeutic spherical random phased array for transcostal applications, PHYSICS IN MEDICINE AND BIOLOGY, Vol: 66, ISSN: 0031-9155
Zubair M, Dickinson RJ, 2019, SIMULATION OF A MODIFIED MULTIELEMENT RANDOM PHASED ARRAY FOR IMAGE GUIDANCE AND THERAPY, 16th IEEE International Symposium on Biomedical Imaging (ISBI), Publisher: IEEE, Pages: 1137-1140, ISSN: 1945-7928
Zubair M, Harput S, Dickinson RJ, 2018, 3D Ultrasound Image Guidance and Therapy through the Rib Cage with a Therapeutic Random Phased Array, IEEE International Ultrasonics Symposium (IUS), Publisher: IEEE, ISSN: 1948-5719
Diallo M, Popa S, Dickinson R, 2018, Orthogonal electric field-based catheter alignment, BioMedEng18
Heymans SV, Martindale CF, Suler A, et al., 2017, Simultaneous Ultrasound Therapy and Monitoring of Microbubble-Seeded Acoustic Cavitation Using a Single-Element Transducer, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, Vol: 64, Pages: 1234-1244, ISSN: 0885-3010
Ultrasound-driven microbubble (MB) activity is used in therapeutic applications such as blood clot dissolution and targeted drug delivery. The safety and performance of these technologies are linked to the type and distribution of MB activities produced within the targeted area, but controlling and monitoring these activities in vivo and in real time has proven to be difficult. As therapeutic pulses are often milliseconds long, MB monitoring currently requires a separate transducer used in a passive reception mode. Here, we present a simple, inexpensive, integrated setup, in which a focused single-element transducer can perform ultrasound therapy and monitoring simultaneously. MBs were made to flow through a vesselmimicking tube, placed within the transducer's focus, and were sonicated with therapeutic pulses (peak rarefactional pressure: 75-827 kPa, pulse lengths: 200 μs and 20 ms). The MB-seeded acoustic emissions were captured using the same transducer. The received signals were separated from the therapeutic signal with a hybrid coupler and a high-pass filter. We discriminated the MB-generated cavitation signal from the primary acoustic field and characterized MB behavior in real time. The simplicity and versatility of our circuit could make existing single-element therapeutic transducers also act as cavitation detectors, allowing the production of compact therapeutic systems with real time monitoring capabilities.
Moghal MEU, Goburdhun AR, Morrell M, et al., 2017, A Novel Smartphone Based Auto-Titrating Oxygen System Reduces Intermittent Hypoxia During Activities Of Daily Living In Patients On Long-Term Oxygen Therapy, International Conference of the American-Thoracic-Society (ATS), Publisher: AMER THORACIC SOC, ISSN: 1073-449X
Cvijovic M, Hoefer T, Acimovic J, et al., 2016, Strategies for structuring interdisciplinary education in Systems Biology: an European perspective, npj Systems Biology and Applications, Vol: 2, ISSN: 2056-7189
Systems Biology is an approach to biology and medicine that has the potential to lead to a better understanding of how biological properties emerge from the interaction of genes, proteins, molecules, cells and organisms. The approach aims at elucidating how these interactions govern biological function by employing experimental data, mathematical models and computational simulations. As Systems Biology is inherently multidisciplinary, education within this field meets numerous hurdles including departmental barriers, availability of all required expertise locally, appropriate teaching material and example curricula. As university education at the Bachelor’s level is traditionally built upon disciplinary degrees, we believe that the most effective way to implement education in Systems Biology would be at the Master’s level, as it offers a more flexible framework. Our team of experts and active performers of Systems Biology education suggest here (i) a definition of the skills that students should acquire within a Master’s programme in Systems Biology, (ii) a possible basic educational curriculum with flexibility to adjust to different application areas and local research strengths, (iii) a description of possible career paths for students who undergo such an education, (iv) conditions that should improve the recruitment of students to such programmes and (v) mechanisms for collaboration and excellence spreading among education professionals. With the growing interest of industry in applying Systems Biology approaches in their fields, a concerted action between academia and industry is needed to build this expertise. Here we present a reflection of the European situation and expertise, where most of the challenges we discuss are universal, anticipating that our suggestions will be useful internationally. We believe that one of the overriding goals of any Systems Biology education should be a student’s ability to phrase and communicate research
Omer H, Dickinson RJ, Awan SA, 2015, Phased array coil for implementing parallel MRI in intravascular imaging: A feasibility study, Concepts in Magnetic Resonance Part A, Vol: 43, Pages: 267-276, ISSN: 1552-5023
The use of intravascular MRI imaging of vessels will provide high qualityimages for improved diagnosis and treatment. An intravascular MR receive coil provideshigh SNR because of proximity to the tissue but respiratory and cardiovascular motionmay affect the quality of acquired images. Parallel MRI provides a framework to reducethe scan time using multiple coils. This article presents a novel design of a Phased ArrayMR receive coil for intravascular imaging which can implement Parallel MRI. Cartesianand Radial GRAPPA are used as the main reconstruction algorithms. We demonstratethat Moving Segment Radial GRAPPA provides good image reconstruction with minimumartifacts when data is under-sampled by a factor of 16.
Moghal M, Goburdhun R, Hopkinson N, et al., 2015, An auto-titrating intelligent oxygen therapy (iO<sub>2</sub>T) system in COPD patients: A randomised cross-over trial, Publisher: EUROPEAN RESPIRATORY SOC JOURNALS LTD, ISSN: 0903-1936
Omer H, Qureshi M, Dickinson RJ, 2015, Regularization-based SENSE reconstruction and choice of regularization parameter, CONCEPTS IN MAGNETIC RESONANCE PART A, Vol: 44, Pages: 67-73, ISSN: 1546-6086
Synthetic Biology - A Primer (Revised Edition) presents an updated overview of the field of synthetic biology and the foundational concepts on which it is built. This revised edition includes new literature references, working and updated URL links, plus some new figures and text where progress in the field has been made. The book introduces readers to fundamental concepts in molecular biology and engineering and then explores the two major themes for synthetic biology, namely ‘bottom-up’ and ‘top-down’ engineering approaches. ‘Top-down’ engineering uses a conceptual framework of systematic design and engineering principles focused around the Design-Build-Test cycle and mathematical modelling. The ‘bottom-up’ approach involves the design and building of synthetic protocells using basic chemical and biochemical building blocks from scratch exploring the fundamental basis of living systems. Examples of cutting-edge applications designed using synthetic biology principles are presented, including: the production of novel, microbial synthesis of pharmaceuticals and fine chemicals the design and implementation of biosensors to detect infections and environmental waste. The book also describes the Internationally Genetically Engineered Machine (iGEM) competition, which brings together students and young researchers from around the world to carry out summer projects in synthetic biology. Finally, the primer includes a chapter on the ethical, legal and societal issues surrounding synthetic biology, illustrating the integration of social sciences into synthetic biology research. Final year undergraduates, postgraduates and established researchers interested in learning about the interdisciplinary field of synthetic biology will benefit from this up-to-date primer on synthetic biology.
Luboz V, Kyaw-Tun J, Sen S, et al., 2014, Real-time stent and balloon simulation for stenosis treatment, VISUAL COMPUTER, Vol: 30, Pages: 341-349, ISSN: 0178-2789
Dickinson RJ, Kitney RI, 2014, Information driven care pathways and procedures, IFMBE Proceedings, Vol: 41, Pages: 1322-1325, ISSN: 1680-0737
The paper addresses the issue of the implementation of care pathways in electronic form. Within the National Health Service (NHS) of England, Care Pathways are becoming increasingly important. These are typically provided by the Department of Health. The Pathways provided are in the form of paper-based schema. They either have to be implemented via paper forms or, as presented here, in electronic form. In addition, care pathways must be seen in the context of the TModel of health care which comprises the care continuum and the biological continuum. The two care pathways which had been chosen as exemplars are myocardial infarction and stroke. However, the objective of the paper is not to discuss the specific care pathways in detail, but, rather, to describe technology which has been developed for their electronic implementation. The result of this implementation is that all the data and information acquired from the implementation of the care pathway is stored in a single clinical information system (CIS), which has incorporated in it the SQL database. Another important element of the system which has been developed is the ability to display data and information in terms of two dashboards (i.e. single screens which show the most important information). The two dashboards display clinical information (the point of care dashboard) and management information (the management dashboard). © Springer International Publishing Switzerland 2014.
Mizandari M, Pai M, Xi F, et al., 2013, Percutaneous Intraductal Radiofrequency Ablation is a Safe Treatment for Malignant Biliary Obstruction: Feasibility and Early Results, CardioVascular and Interventional Radiology, ISSN: 0174-1551
Kelay T, Kesavan S, Collins RE, et al., 2013, Techniques to aid the implementation of novel clinical information systems: A systematic review, INTERNATIONAL JOURNAL OF SURGERY, Vol: 11, Pages: 783-791, ISSN: 1743-9191
Dijemeni ED, Dickinson R, 2013, Portable Mobile Real Time Oxygen Monitoring Auto-Ventilation System, 4th IEEE International Conference on E-Health and Bioengineering (EHB), Publisher: IEEE, ISSN: 2575-5137
Putra NK, Dickinson RJ, Siggers JH, 2013, Image Processing as the Validation Method of Droplet Dispersion Modeling Process, 3rd International Conference on Instrumentation, Communications, Information Technology, and Biomedical Engineering (ICICI-BME), Publisher: IEEE, Pages: 242-245, ISSN: 2158-0456
Awan SA, Mcginley JVM, Dickinson RJ, et al., 2012, Design and development of a planar B0-coil for patient respiratory motion correction in magnetic resonance imaging, CONCEPTS IN MAGNETIC RESONANCE PART B-MAGNETIC RESONANCE ENGINEERING, Vol: 41B, Pages: 130-138, ISSN: 1552-5031
Yang X, Han R, Guo Y, et al., 2012, Modelling and performance analysis of clinical pathways using the stochastic process algebra PEPA, Bmc Bioinformatics, Vol: 13, ISSN: 1471-2105
Kitney RI, 2012, Synthetic Biology - A Primer, Publisher: Imperial College Press London
Kallis Y, Phillips N, Steel A, et al., 2012, Radiofrequency Ablation for Biliary Metal Stent Occlusion: Evolution of a Novel Endoscopic Technique and Proof of Concept, Digestive Disease Week (DDW), Publisher: MOSBY-ELSEVIER, Pages: 377-378, ISSN: 0016-5107
Omer H, Dickinson R, 2011, Regularization in Parallel MR Image Reconstruction, CONCEPTS IN MAGNETIC RESONANCE PART A, Vol: 38A, Pages: 52-60, ISSN: 1546-6086
Simonds AK, Hanak A, Chatwin M, et al., 2010, Evaluation of droplet dispersion during non-invasive ventilation, oxygen therapy, nebuliser treatment and chest physiotherapy in clinical practice: implications for management of pandemic influenza and other airborne infections, HEALTH TECHNOLOGY ASSESSMENT, Vol: 14, Pages: 131-+, ISSN: 1366-5278
Omer H, Dickinson R, 2010, A Graphical Generalized Implementation of SENSE Reconstruction Using Matlab, CONCEPTS IN MAGNETIC RESONANCE PART A, Vol: 36A, Pages: 178-186, ISSN: 1546-6086
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