Optical imaging for breast cancer prescreening

Breast cancer prescreening is carried out prior to the gold standard screening using X-ray mammography and/or ultrasound. Prescreening is typically carried out using clinical breast examination (CBE) or self-breast examinations (SBEs). Since CBE and SBE have high false-positive rates, there is a need for a low-cost, noninvasive, non-radiative, and portable imaging modality that can be used as a prescreening tool to complement CBE/SBE. This review focuses on the various hand-held optical imaging devices that have been developed and applied toward early-stage breast cancer detection or as a prescreening tool via phantom, in vivo, and breast cancer imaging studies. Apart from the various optical devices developed by different research groups, a wide-field fiber-free near-infrared optical scanner has been developed for transillumination-based breast imaging in our Optical Imaging Laboratory. Preliminary in vivo studies on normal breast tissues, with absorption-contrasted targets placed in the intramammary fold, detected targets as deep as 8.8 cm. Future work involves in vivo imaging studies on breast cancer subjects and comparison with the gold standard X-ray mammography approach

Volumetrically scanning the structure of stray-fields above grain-oriented electrical-steel using a variably angled TMR sensor

Abstract—a new versatile scanning hardware based on a Micromagnetics® STJ-020 MgO-based tunnelling magneto-resistance (TMR) sensor has been developed to volumetrically scan the thin boundary layer above a given sample. An (x,y) planar scan of the surface of a 7.5 mm × 7.5 mm sample of grain-oriented (3% Si) electrical steel is presented. Stray fields normal to the surface between -116 and 272 A/m are measured. At 10 μm/pixel domain and micro-domain structures are seen. At 5 μm/pixel the micro-domain structures resolve into clear Lancet domains. The domain images presented have greater qualitative similarity with Kerr effect observations than with Bitter technique results. An (x,z) vertical scan along a 2.35 mm transect reveals the perpendicular extent of the stray fields, with the normal components shown to emanate from the domain bodies and extend approximately 40 - 100 μm from the sample surface. With the aim of investigating how the stray fields close back onto the surface, the (x,z) transect is repeated with the sensor at 5, 10, 15 and 20 degrees from the vertical. For the first time, the stray fields from surface domains viewed by other techniques in only a planar (x,y) projection have been

MEMS Technology for Biomedical Imaging Applications

Biomedical imaging is the key technique and process to create informative images of the human body or other organic structures for clinical purposes or medical science. Micro-electro-mechanical systems (MEMS) technology has demonstrated enormous potential in biomedical imaging applications due to its outstanding advantages of, for instance, miniaturization, high speed, higher resolution, and convenience of batch fabrication. There are many advancements and breakthroughs developing in the academic community, and there are a few challenges raised accordingly upon the designs, structures, fabrication, integration, and applications of MEMS for all kinds of biomedical imaging. This Special Issue aims to collate and showcase research papers, short commutations, perspectives, and insightful review articles from esteemed colleagues that demonstrate: (1) original works on the topic of MEMS components or devices based on various kinds of mechanisms for biomedical imaging; and (2) new developments and potentials of applying MEMS technology of any kind in biomedical imaging. The objective of this special session is to provide insightful information regarding the technological advancements for the researchers in the community

Local liquid velocity measurement of trickle bed reactor using digitial industrial X-ray radiography

Trickle Bed Reactors (TBRs) are fixed beds of particles in which both liquid and gas flow concurrently downward. They are widely used to produce not only fuels but also lubrication products. The measurement and the knowledge of local liquid velocities (VLL) in TBRs is less which is essential for advancing the understanding of its hydrodynamics and for validation computational fluid dynamics (CFD). Therefore, this work focused on developing a new, non-invasive, statistically reliable technique that can be used to measure local liquid velocity (VLL) in two-dimensions (2-D). This is performed by combining Digital Industrial X-ray Radiography (DIR) and Particle Tracking Velocimetry (PTV) techniques. This work also make possible the development of three-dimensional (3-D) VLL measurements that can be taken in TBRs. Measurements taken through both the combined and the novel technique, once validated, were found to be comparable to another technique (a two-point fiber optical probe) currently being developed at Missouri University of Science and Technology. The results from this study indicate that, for a gas-liquid-solid type bed, the measured VLL can have a maximum range that is between 35 and 51 times that of its superficial liquid velocity (VSL). Without the existence of gas, the measured VLL can have a maximum range that is between 4 and 4.7 times that of its VSL. At a higher VSL, the particle tracer was greatly distributed and became carried away by a high liquid flow rate. Neither the variance nor the range of measured VLL varied for any of the replications, confirming the reproducibility of the experimental measurements used, regardless of the VSL. The liquid\u27s movement inside the pore was consistent with findings from previous studies that used various techniques --Abstract, page iii

Innovative Concepts for the Electronic Interface of Massively Parallel MRI Phased Imaging Arrays

In Magnetic Resonance Imaging (MRI), the concept of parallel imaging shows significant enhancements in boosting the signal-to-noise ratio, reducing the imaging time, and enlarging the imaging field of view. However, this concept necessitates increased size, cost, and complexity of the MR system. This thesis introduces an innovative solution for the electronics of the MRI system that allows parallel imaging with massive number of channels while avoiding, at the same time, the associated drawback

Measurement of the magnetic field of an RF-encoding birdcage-coil design for magnetic resonance imaging

Magnetic Resonance Imaging (MRI) is a non-invasive imaging technique used in radiology to investigate the anatomy and physiology of the body in both health and disease. MRI currently depends on the use of magnetic field gradient coils to visualize tissue. However, there is an alternate method, which can only use RF to encode the image. The idea behind RF encoding is that it uses spatial phase variation in the RF transmission to encode spatial information in the MRI signal instead of using gradient magnetic fields. This alternate method of encoding with RF, without magnetic field gradients, allows for a much simpler hardware configuration for the MRI device. Therefore, it could become possible to design a cheaper and lighter portable MRI. In this study, a measurement device was designed and constructed for a DC model of an RF encoding birdcage coil design. When the appropriate currents were applied onto the legs of the coil, a magnetic field was generated as quantified by the Biot-Savart law. Herein we presumed that the wires are infinitely long. These currents were calculated according to the RF phase encoding method, aimed to produce a linear varying phase mapping along with one axis. By using the constructed measurement device, the experimental phase profile could be obtained. It was found that a linear spatial phase variation occurs along the axis, with the RF birdcage-coil setup. By comparing the theoretical phase map with the experimental, the difference was quantified. Then, we could reach the conclusion that the proposed RF coil design works as predicted by theory

Advanced Image Acquisition, Processing Techniques and Applications

"Advanced Image Acquisition, Processing Techniques and Applications" is the first book of a series that provides image processing principles and practical software implementation on a broad range of applications. The book integrates material from leading researchers on Applied Digital Image Acquisition and Processing. An important feature of the book is its emphasis on software tools and scientific computing in order to enhance results and arrive at problem solution

Volumetrically scanning the structure of stray-fields above grain-oriented electrical-steel using a variably angled TMR sensor

Abstract—a new versatile scanning hardware based on a Micromagnetics® STJ-020 MgO-based tunnelling magneto-resistance (TMR) sensor has been developed to volumetrically scan the thin boundary layer above a given sample. An (x,y) planar scan of the surface of a 7.5 mm × 7.5 mm sample of grain-oriented (3% Si) electrical steel is presented. Stray fields normal to the surface between -116 and 272 A/m are measured. At 10 μm/pixel domain and micro-domain structures are seen. At 5 μm/pixel the micro-domain structures resolve into clear Lancet domains. The domain images presented have greater qualitative similarity with Kerr effect observations than with Bitter technique results. An (x,z) vertical scan along a 2.35 mm transect reveals the perpendicular extent of the stray fields, with the normal components shown to emanate from the domain bodies and extend approximately 40 - 100 μm from the sample surface. With the aim of investigating how the stray fields close back onto the surface, the (x,z) transect is repeated with the sensor at 5, 10, 15 and 20 degrees from the vertical. For the first time, the stray fields from surface domains viewed by other techniques in only a planar (x,y) projection have been