Advancements and Breakthroughs in Ultrasound Imaging

Ultrasonic imaging is a powerful diagnostic tool available to medical practitioners, engineers and researchers today. Due to the relative safety, and the non-invasive nature, ultrasonic imaging has become one of the most rapidly advancing technologies. These rapid advances are directly related to the parallel advancements in electronics, computing, and transducer technology together with sophisticated signal processing techniques. This book focuses on state of the art developments in ultrasonic imaging applications and underlying technologies presented by leading practitioners and researchers from many parts of the world

Ultrasound Imaging

This book provides an overview of ultrafast ultrasound imaging, 3D high-quality ultrasonic imaging, correction of phase aberrations in medical ultrasound images, etc. Several interesting medical and clinical applications areas are also discussed in the book, like the use of three dimensional ultrasound imaging in evaluation of Asherman's syndrome, the role of 3D ultrasound in assessment of endometrial receptivity and follicular vascularity to predict the quality oocyte, ultrasound imaging in vascular diseases and the fetal palate, clinical application of ultrasound molecular imaging, Doppler abdominal ultrasound in small animals and so on

Design of Fully-Integrated High-Resolution Radars in CMOS and BiCMOS Technologies

The RADAR, acronym that stands for RAdio Detection And ranging, is a device that uses electromagnetic waves to detect the presence and the distance of an illuminated target. The idea of such a system was presented in the early 1900s to determine the presence of ships. Later on, with the approach of World War II, the radar gained the interest of the army who decided to use it for defense purposes, in order to detect the presence, the distance and the speed of ships, planes and even tanks. Nowadays, the use of similar systems is extended outside the military area. Common applications span from weather surveillance to Earth composition mapping and from flight control to vehicle speed monitoring. Moreover, the introduction of new ultrawideband (UWB) technologies makes it possible to perform radar imaging which can be successfully used in the automotive or medical field. The existence of a plenty of known applications is the reason behind the choice of the topic of this thesis, which is the design of fully-integrated high-resolution radars. The first part of this work gives a brief introduction on high resolution radars and describes its working principle in a mathematical way. Then it gives a comparison between the existing radar types and motivates the choice of an integrated solution instead of a discrete one. The second part concerns the analysis and design of two CMOS high-resolution radar prototypes tailored for the early detection of the breast cancer. This part begins with an explanation of the motivations behind this project. Then it gives a thorough system analysis which indicates the best radar architecture in presence of impairments and dictates all the electrical system specifications. Afterwards, it describes in depth each block of the transceivers with particular emphasis on the local oscillator (LO) generation system which is the most critical block of the designs. Finally, the last section of this part presents the measurement results. In particular, it shows that the designed radar operates over 3 octaves from 2 to 16GHz, has a conversion gain of 36dB, a flicker-noise-corner of 30Hz and a dynamic range of 107dB. These characteristics turn into a resolution of 3mm inside the body, more than enough to detect even the smallest tumor. The third and last part of this thesis focuses on the analysis and design of some important building blocks for phased-array radars, including phase shifter (PHS), true time delay (TTD) and power combiner. This part begins with an exhaustive introduction on phased array systems followed by a detailed description of each proposed lumped-element block. The main features of each block is the very low insertion loss, the wideband characteristic and the low area consumption. Finally, the major effects of circuit parasitics are described followed by simulation and measurement results

Photoacoustic Microscopy and Computed Tomography: From Bench to Bedside

Photoacoustic imaging (PAI) of biological tissue has seen immense growth in the past decade, providing unprecedented spatial resolution and functional information at depths in the optical diffusive regime. PAI uniquely combines the advantages of optical excitation and those of acoustic detection. The hybrid imaging modality features high sensitivity to optical absorption and wide scalability of spatial resolution with the desired imaging depth. Here we first summarize the fundamental principles underpinning the technology, then highlight its practical implementation, and finally discuss recent advances toward clinical translation

1-D broadside-radiating leaky-wave antenna based on a numerically synthesized impedance surface

A newly-developed deterministic numerical technique for the automated design of metasurface antennas is applied here for the first time to the design of a 1-D printed Leaky-Wave Antenna (LWA) for broadside radiation. The surface impedance synthesis process does not require any a priori knowledge on the impedance pattern, and starts from a mask constraint on the desired far-field and practical bounds on the unit cell impedance values. The designed reactance surface for broadside radiation exhibits a non conventional patterning; this highlights the merit of using an automated design process for a design well known to be challenging for analytical methods. The antenna is physically implemented with an array of metal strips with varying gap widths and simulation results show very good agreement with the predicted performance

Beam scanning by liquid-crystal biasing in a modified SIW structure

A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium

Annu Rev Biomed Eng

Photoacoustic imaging (PAI) of biological tissue has seen immense growth in the past decade, providing unprecedented spatial resolution and functional information at depths in the optical diffusive regime. PAI uniquely combines the advantages of optical excitation and those of acoustic detection. The hybrid imaging modality features high sensitivity to optical absorption and wide scalability of spatial resolution with the desired imaging depth. Here we first summarize the fundamental principles underpinning the technology, then highlight its practical implementation, and finally discuss recent advances toward clinical translation.DP1 EB016986/DP/NCCDPHP CDC HHS/United StatesDP1 EB016986/EB/NIBIB NIH HHS/United StatesR01 CA134539/CA/NCI NIH HHS/United StatesR01 CA134539/CA/NCI NIH HHS/United StatesR01 CA157277/CA/NCI NIH HHS/United StatesR01 CA157277/CA/NCI NIH HHS/United StatesR01 CA159959/CA/NCI NIH HHS/United StatesR01 CA159959/CA/NCI NIH HHS/United StatesR01 EB008085/EB/NIBIB NIH HHS/United StatesR01 EB008085/EB/NIBIB NIH HHS/United StatesR01 EB016963/EB/NIBIB NIH HHS/United StatesR01 EB016963/EB/NIBIB NIH HHS/United StatesU54 CA136398/CA/NCI NIH HHS/United StatesU54 CA136398/CA/NCI NIH HHS/United States2014-08-11T00:00:00Z24905877PMC410289

A BCB Diaphragm Based Adhesive Wafer Bonded CMUT Probe for Biomedical Application

This dissertation presents the design methodology, fabrication procedure, and key experimental characterization results of a linear array of capacitive micromachined ultrasonic transducers (CMUT) for possible ophthalmic anterior segment imaging application. The design methodology involves analytical, 3-D electromechanical finite element analysis, and Verasonics Vantage 128 ultrasonic research platform based diagnostic imaging simulations to develop a technique that minimizes electrical charging and center frequency drift while improving the transduction efficiency. In the design, Bisbenzocyclobutene (BCB), a low K polymer from Dow Chemical Company, has been innovatively used for the first time to fabricate the structural layer of the CMUT diaphragm, realize the interelectrode dielectric spacer, and to act as a low temperature adhesive bonding agent. Additionally, the top CMUT electrode has been placed at the bottom of the diaphragm to affect higher capacitance change that increases sensitivity and provides additional decoupling of the electrical charging effects. Several arrays with element count ranging from 8 to 128 elements and a center frequency range of 5 MHz to 40 MHz have been designed and fabricated. Due to an unforeseen adhesion issue during wirebonding, a 32 channel 40 MHz CMUT array has been packaged manually to validate the fabrication process and CMUT operation. Extensive SEM inspections of the CMUT cross-sections show good agreement with the design specifications. Static and dynamic measurements using a Polytec laser Doppler vibrometer, impedance measurement using an Agilent vector network analyzer, and LCR measurement results are in excellent agreement with analytical and FEA analysis using IntelliSuite. The frequency analysis exhibits high electromechanical coupling coefficient of 0.66 at a low bias voltage of 20 V and high uniformity. A successful measurement of the lower drift of the center frequency 0.32% and higher coupling coefficient verifies the hypothesis that the excellent electrical, structural, and processing characteristics of BCB is a viable option to mitigate the dielectric charging and improve the transduction efficiency of CMUTs

Imaging Sensors and Applications

In past decades, various sensor technologies have been used in all areas of our lives, thus improving our quality of life. In particular, imaging sensors have been widely applied in the development of various imaging approaches such as optical imaging, ultrasound imaging, X-ray imaging, and nuclear imaging, and contributed to achieve high sensitivity, miniaturization, and real-time imaging. These advanced image sensing technologies play an important role not only in the medical field but also in the industrial field. This Special Issue covers broad topics on imaging sensors and applications. The scope range of imaging sensors can be extended to novel imaging sensors and diverse imaging systems, including hardware and software advancements. Additionally, biomedical and nondestructive sensing applications are welcome