Mesh-to-raster based non-rigid registration of multi-modal images

Region of interest (ROI) alignment in medical images plays a crucial role in diagnostics, procedure planning, treatment, and follow-up. Frequently, a model is represented as triangulated mesh while the patient data is provided from CAT scanners as pixel or voxel data. Previously, we presented a 2D method for curve-to-pixel registration. This paper contributes (i) a general mesh-to-raster (M2R) framework to register ROIs in multi-modal images; (ii) a 3D surface-to-voxel application, and (iii) a comprehensive quantitative evaluation in 2D using ground truth provided by the simultaneous truth and performance level estimation (STAPLE) method. The registration is formulated as a minimization problem where the objective consists of a data term, which involves the signed distance function of the ROI from the reference image, and a higher order elastic regularizer for the deformation. The evaluation is based on quantitative light-induced fluoroscopy (QLF) and digital photography (DP) of decalcified teeth. STAPLE is computed on 150 image pairs from 32 subjects, each showing one corresponding tooth in both modalities. The ROI in each image is manually marked by three experts (900 curves in total). In the QLF-DP setting, our approach significantly outperforms the mutual information-based registration algorithm implemented with the Insight Segmentation and Registration Toolkit (ITK) and Elastix

OPTICAL GEOMETRY CALIBRATION METHOD FOR COMPUTED TOMOGRAPHY AND APPLICATIONS OF COMPACT MICROBEAM RADIATION THERAPY

Digital tomosynthesis is a type of limited angle tomography that allows for 3D information reconstructed from a set of X-ray projection images taken at various angles using an X-ray tube, a mechanical arm to rotate the tube, and a digital detector. Tomosynthesis reconstruction requires the knowledge of the precise location of the detector with respect to each X-ray source. Current clinical tomosynthesis methods use a physically coupled source and detector so the geometry is always known and is always the same. This makes it impractical for mobile or field operations. We demonstrated a free form tomosynthesis and free form computed tomography (CT) with a decoupled source and detector setup that uses a novel optical method for accurate and real-time geometry calibration. We accomplish this by using a camera to track the motion of the source relative to the detector. A checkerboard pattern is positioned on or next to the detector using an extension arm in such a way that the pattern will not move relative to the detector. A camera is mounted on the source in a way that the pattern is visible during imaging and will not move relative to the source. The image of the pattern captured by the camera is then used to determine the relative camera/pattern position and orientation by analyzing the pattern distortion. This allows for accurate, real time geometry calibration of the X-ray source relative to the detector. This method opens the doors for inexpensive upgrades to existing 2D imaging systems and an even more exciting application of a mobile, hand-held CT imaging system.Doctor of Philosoph

Issues in Contemporary Orthodontics

Issues in Contemporary Orthodontics is a contribution to the ongoing debate in orthodontics, a discipline of continuous evolution, drawing from new technology and collective experience, to better meet the needs of students, residents, and practitioners of orthodontics. The book provides a comprehensive view of the major issues in orthodontics that have featured in recent debates. Abroad variety of topics is covered, including the impact of malocclusion, risk management and treatment, and innovation in orthodontics

Characterisation of Implant Supported Soft Tissue Prostheses Produced with 3D Colour Printing Technology

The numbers of patients needing facial prostheses has increased in the last few decades due to improving cancer survival rates. The many limitations of the handmade prostheses together with rapid expansion of prototyping in all directions, particularly in producing human anatomically accurate parts, have raised the question of how to employ this technology for rapid manufacturing of facial soft tissue prostheses. The idea started to grow and the project was implemented based on CAD/CAM principles – additive manufacturing technology, by employing layered fabrication of facial prostheses from starch powder and a water based binder and infiltrated with a silicone polymer (SPIS). The project aimed to produce a facial prosthesis by using 3D colour printing, which would match the patient’s skin shade and have the desirable mechanical properties, through a relatively low cost process that would be accessible to the global patient community. This was achieved by providing a simple system for data capture, design and reproducible method of manufacture with a clinically acceptable material. The prosthesis produced has several advantages and few limitations when compared to existing products/prostheses made from silicone polymer (SP). The mechanical properties and durability were not as good as those of the SP made prosthesis but they were acceptable, although the ideal properties have yet to be identified. Colour reproduction and colour matching were more than acceptable, although the colour of the SPIS parts was less stable than the SP colour under natural and accelerated weathering conditions. However, it is acknowledged that neither of the two methods used represent the natural life use on patients and the deficiencies demonstrated in terms of mechanical properties and colour instability were partially inherent in the methodology used, as the project was still at the developmental stage and it was not possible to apply real life tests on patients. Moreover, deficiencies in mechanical and optical properties were probably caused by the starch present, which was used as a scaffold for the SP. Furthermore, a suitable retention system utilising existing components was designed and added to the prosthesis. This enabled the prosthesis to be retained by implants with no need for the addition of adhesive. This would also help to prolong the durability and life span of the prosthesis. The capability of the printer to produce skin shades was determined and it was found that all the skin colours measured fall within the range of the 3D colour printer and thereby the printer was able to produce all the colours required. Biocompatibility was also acceptable, with a very low rate of toxicity. However, no material is 100% safe and each material has a certain range of toxicity at certain concentrations. At this stage of the project, it can be confirmed that facial prostheses were successfully manufactured by using 3D colour printing to match the patient’s skin shade, using biocompatible materials and having the desirable mechanical properties. Furthermore, the technology used enabled prostheses to be produced in a shorter time frame and at a lower cost than conventional SP prostheses. They are also very lightweight, easier to use and possibly more comfortable for the patients. Moreover, this technology has the capability of producing multiple prostheses at the time of manufacture at reduced extra cost, whilst the data can be saved and can be utilised/modified for producing further copies in the future without having to going through all the steps involved with handmade prostheses. Based on the mechanical properties and colour measurements the prostheses will have a finite service life and the recommendation is that these prostheses will need replacing every 6 to 12 months, depending on how the patient handles and maintains the prostheses and whether the prosthesis is being used as an interim or definitive prosthesis. This was largely comparable to existing prostheses but without the time and cost implications for replacement. However, it is acknowledged that further investigations and clinical case studies are required to investigate the “real life” effect on the prostheses and to get feedback from the patients in order to make appropriate improvements to the mechanical properties and the durability of the prosthesis

Advanced Materials for Oral Application

This book consists of one editorial, 12 original research articles and two review papers from scientists across the world, with expertise in materials for dental application. The main subjects covered are: biomaterials and techniques for oral tissue engineering and regeneration; biomaterials for surgical reconstruction; CAD/CAM technologies and dedicated materials; novel restorative and endodontic materials and instruments

Multilayer microcapsules for delivery, control and triggered release of bioactive compounds

PhDDeveloping of targeted drug delivery systems is currently a very important topic, which can be easily judged by a great number of papers published every year. Materials science proposes, among others, microcapsules as one of the possible solutions to the problem. Known for more than a decade by know, microcapsules, their properties, methods of encapsulation, release, control where under thorough investigation by several scientific groups in the world. Despite the fact that many factors were already studied, application of this system to drug delivery provides an enormous amount of work yet to be done, lying across several areas of science – biology, chemistry, physics, medicine. To be used as a technique of targeted delivery, not only the microcapsules should meet many constraints on their physical and chemical properties, but also the means of their control and release triggering irradiation should be applicable and harmless to living body. This means, that there's a lot more to do than to encapsulate the substances of interest and make sure they stay inside the capsules. This is why this research was devoted to investigation of stability of cargo encapsulated to layer-by-layer microcapsules constructed on silica and CaCO3 microparticles using various shell constructions with synthetic and biodegradable polyelectrolytes, nanoparticles, DNA, enzyme and other materials, methods of microcapsules control by magnetic field, which can be used for navigation of the carriers in-vivo to the place of interest and methods of release of encapsulated substances from the microcapsules, that are friendly to living body. The thesis starts with introduction and a literature review to help reader to get a better understanding on the structures discussed in this work and what have already been done in the area. These are followed by a short description of main materials and methods used to conduct this research. Three following chapters of experimental section describe the research itself. Chapter 4 shows feasibility of triggered IR-laser and high-frequency ultrasound release, including intracellular release. Reporting application of cargo using pH-sensitve dye is shown. Ultrasoundtriggered release at parameters, close to that currently used in medical applications, is shown to achieve up to 60% efficiency of previously reported highpower 20 kHz ultrasonic irradiation. Feasibility of laser-induced triggered release using microcapsules functionalized photo-sensitive dyes was also shown. In Chapter 5 retention of activity of DNA and enzyme molecules upon encapsulation was demonstrated. Activity of encapsulated substances was shown to be lower, than of free ones, but the accessibility and kinetics of reactions can be controlled by adjusting the construction of microcapsules. In Chapter 6 feasibility of control of cells impregnated with microcapsules functionalized with magnetite nanoparticles was shown at distances of up to 10 mm using usual constant magnets

Maintaining the Integrity Over Wear Time of a Hydrocolloid-based Ostomy Adhesive Whilst Maintaining Skin Barrier Function

In this extensive body of work, a thorough exploration delves into hydrocolloid based adhesives, with a focus on addressing challenges faced by stoma patients, particularly the susceptibility of ostomy adhesives to breakdown upon exposure to liquids. Stoma patients, compelled to wear pouching systems continuously, encounter issues like the compromise of skin barrier integrity, leading to medical adhesive-related skin injuries. The primary objective of this thesis is to reinforce the structural integrity of ostomy adhesives while preserving the skin barrier during pouching system use, an aspect often overlooked in current literature due to the hydrophilic nature of hydrocolloid based adhesives. The study introduces novel aims, examining the potential link between handedness and the preferred direction of adhesive removal, and its impact on peristomal skin complications as well as a novel skin capacitive imagery stitching technique. Another goal involves developing hierarchical structures on adhesive surfaces to enhance integrity, initial tack, and minimize skin contact for optimal skin health. The introduction provides a detailed breakdown of hydrocolloid-based ostomy adhesives, stoma anatomy, and the purpose of pouching systems. A comprehensive literature review, utilizing the PICO approach, encompasses stoma anatomy, physiology, indications for stoma surgery, and methods for assessing skin health. The review explores various methodologies to improve the durability of hydrocolloid-based adhesives, incorporating hydrodynamics, crosslinking, and layering systems. The potential influence of handedness on adhesive removal techniques is examined, considering its impact on peristomal skin complications. Results reveal the consistent performance of Welland Medical Ltd.'s hydrocolloid based adhesive but highlight the need for improved integrity over wear time. Strategies include modifying sodium-carboxymethylcellulose degree of substitution and increasing pectin degree of esterification, resulting in enhanced fluid handling capabilities and reduced susceptibility to degradation. Residual testing indicates that residual particles on the skin can impair the barrier function, remedied by a silicone-based adhesive remover. Surveys show that a patient's dominant hand and following the skin's natural langer lines during adhesive removal may minimize skin trauma. The results also show that structured surface profiles on hydrocolloid-based adhesive surfaces impact the skin's functional barrier recovery time. The research goal of this project and its objectives have been reached, the approaches have been explained clearly and implementations have been assessed using experimental findings. This project's findings contribute to advancements in ostomy care by enhancing adhesive performance, understanding patient behaviour, and improving the overall user experience. It also facilitates the efficient detachment of the adhesive from the skin surface

STATIONARY DIGITAL TOMOSYNTHESIS: IMPLEMENTATION, CHARACTERIZATION, AND IMAGE PROCESSING TECHNIQUES

The use of carbon nanotube cathodes for x-ray generation was pioneered and perfected by our team in the Applied Nanotechnology Laboratory at the University of North Carolina at Chapel Hill. Over the past decade, carbon nanotube (CNT) field emission x-ray source technology has matured and translated into multiple pre-clinical and clinical devices. One of the most prominent implementations of CNT x-ray technology is a limited angle tomography method called tomosynthesis, which is rapidly emerging in clinical radiography. The purpose of this project is two-fold, to develop and characterize to the latest iteration, stationary intraoral tomosynthesis, and develop a low-dose, effective scatter reduction technique for breast and chest tomosynthesis. The first portion of this project was to develop and evaluate a new quasi-3D imaging modality for dental imaging. My work consists of experiments which dictated the design parameters and subsequent system evaluation of the dedicated s-IOT clinical prototype system currently installed in the UNC Department of Oral and Maxillofacial Radiology clinic in the School of Dentistry. Experiments were performed in our lab to determine optimal source array geometry and system configuration. The system was fabricated by our commercial partner then housed in our research lab where I performed initial characterization and assisted with software development. After installation in the SOD, I performed additional system characterization, including source output validation, dosimetry, and quantification of resolution. The system components and software were refined through a rapid feedback loop with the engineers involved. Four pre-clinical imaging studies have been performed in collaboration with several dentists using phantoms, extracted teeth, and cadaveric dentition. I have generated an operating manual and trained four dental radiologists in the use of the s-IOT device. The system has now been vetted and is ready for patient use. The second portion of this project consists of hardware development and implementation of an image processing technique for scatter correction. The primary sampling scatter correction (PSSC) is a beam pass technique to measure the primary transmission through the patient and calculate the scatter profile for subtraction. Though developed for breast and chest tomosynthesis, utilization in mammography and chest radiography are also demonstrated in this project. This dissertation is composed of five chapters. Chapters one and two provide the basics of x-ray generation and a brief history of the evolution of carbon nanotube x-ray source technology in our lab at UNC. Chapter three focuses on stationary intraoral tomosynthesis. The first section provides background information on dental radiology and project motivation. Sections 3.2 and 3.3 detail my work in benchtop feasibility and optimization studies, as well as characterization and evaluation of the clinical prototype. Chapter four introduces scatter in imaging, providing motivation for my work on primary sampling scatter correction (PSSC) image processing method, detailed in chapter five.Doctor of Philosoph

Optical Methods in Sensing and Imaging for Medical and Biological Applications

The recent advances in optical sources and detectors have opened up new opportunities for sensing and imaging techniques which can be successfully used in biomedical and healthcare applications. This book, entitled ‘Optical Methods in Sensing and Imaging for Medical and Biological Applications’, focuses on various aspects of the research and development related to these areas. The book will be a valuable source of information presenting the recent advances in optical methods and novel techniques, as well as their applications in the fields of biomedicine and healthcare, to anyone interested in this subject

Ceramic Materials

This is the first book of a series of forthcoming publications on this field by this publisher. The reader can enjoy both a classical printed version on demand for a small charge, as well as the online version free for download. Your citation decides about the acceptance, distribution, and impact of this piece of knowledge. Please enjoy reading and may this book help promote the progress in ceramic development for better life on earth