Development of micro-computed tomography for human fetal post-mortem imaging

Perinatal autopsy is an essential way of assessing the cause of fetal loss during pregnancy. However, parents are reluctant to consent to an invasive autopsy. Modern imaging techniques can offer a non-invasive solution, but most current clinical techniques are unable to offer adequate image resolution for early gestation miscarriages, typically below 20weeks gestation or 300g body weight. This thesis describes evaluating micro-CT imaging for this purpose, culminating in developing a pragmatic clinical protocol. Within this thesis, five aspects are evaluated: 1. Scan preparation. The optimal concentration and immersion time for I2KI was established, with a formula to predict the immersion time required for full iodination. 2. Imaging parameters. Optimal micro-CT imaging parameters were investigated, comparing the signal-to-noise (SNR) and relative contrast-to-noise ratio (rCNR) across different settings. 3. Patient factors. The effect of demographics/external factors on image quality was evaluated. Maceration was identified as having the greatest detriment to image quality, yet high image quality was attained in the majority of scans. Fetal weight and number of projections were also noted to be positive predictors. 4. Image SNR / rCNR. Assessments were tested across whole fetus organ volumes with imaging parameters defined as 110kV, 200µA, 250ms, 2frames-per-projection, enabling a single anatomical area to be optimally imaged within a clinically relevant timeframe, <30minutes. 5. Parental experience. A pilot study consisting of parents who have experienced a miscarriage was also undertaken. Response to the technique was overwhelmingly positive, with key potential benefits being increased choice and uptake of autopsy investigations with multiple mental health benefits. Finally, the future direction of this work within the clinical setting is presented. The clinical impact of the research is to be able to offer parents a more acceptable non-invasive imaging investigation following miscarriage

Contributions of precision engineering to the revision of the SI

All measurements performed in science and industry are based on the International System of Units, the SI. It has been proposed to revise the SI following an approach which was implemented for the redefinition of the unit of length, the metre, namely to define the SI units by fixing the numerical values of so-called defining constants, including c, h, e, k and NA. We will discuss the reasoning behind the revision, which will likely be put into force in 2018. Precision engineering was crucial to achieve the required small measurement uncertainties and agreement of measurement results for the defining constants

Co-Nanomet: Co-ordination of Nanometrology in Europe

Nanometrology is a subfield of metrology, concerned with the science of measurement at the nanoscale level. Today’s global economy depends on reliable measurements and tests, which are trusted and accepted internationally. It must provide the ability to measure in three dimensions with atomic resolution over large areas. For industrial application this must also be achieved at a suitable speed/throughput. Measurements in the nanometre range should be traceable back to internationally accepted units of measurement (e.g. of length, angle, quantity of matter, and force). This requires common, validated measurement methods, calibrated scientific instrumentation as well as qualified reference samples. In some areas, even a common vocabulary needs to be defined. A traceability chain for the required measurements in the nm range has been established in only a few special cases. A common strategy for European nanometrology has been defined, as captured herein, such that future nanometrology development in Europe may build out from our many current strengths. In this way, European nanotechnology will be supported to reach its full and most exciting potential. As a strategic guidance, this document contains a vision for European nanometrology 2020; future goals and research needs, building out from an evaluation of the status of science and technology in 2010. It incorporates concepts for the acceleration of European nanometrology, in support of the effective commercial exploitation of emerging nanotechnologies. The field of nanotechnology covers a breadth of disciplines, each of which has specific and varying metrological needs. To this end, a set of four core technology fields or priority themes (Engineered Nanoparticles, Nanobiotechnology, Thin Films and Structured Surfaces and Modelling & Simulation) are the focus of this review. Each represents an area within which rapid scientific development during the last decade has seen corresponding growth in or towards commercial exploitation routes. This document was compiled under the European Commission Framework Programme 7 project, Co-Nanomet. It has drawn together input from industry, research institutes, (national) metrology institutes, regulatory and standardisation bodies across Europe. Through the common work of the partners and all those interested parties who have contributed, it represents a significant collaborative European effort in this important field. In the next decade, nanotechnology can be expected to approach maturity, as a major enabling technological discipline with widespread application. This document provides a guide to the many bodies across Europe in their activities or responsibilities in the field of nanotechnology and related measurement requirements. It will support the commercial exploitation of nanotechnology, as it transitions through this next exciting decade

Thermophysical Phenomena in Metal Additive Manufacturing by Selective Laser Melting: Fundamentals, Modeling, Simulation and Experimentation

Among the many additive manufacturing (AM) processes for metallic materials, selective laser melting (SLM) is arguably the most versatile in terms of its potential to realize complex geometries along with tailored microstructure. However, the complexity of the SLM process, and the need for predictive relation of powder and process parameters to the part properties, demands further development of computational and experimental methods. This review addresses the fundamental physical phenomena of SLM, with a special emphasis on the associated thermal behavior. Simulation and experimental methods are discussed according to three primary categories. First, macroscopic approaches aim to answer questions at the component level and consider for example the determination of residual stresses or dimensional distortion effects prevalent in SLM. Second, mesoscopic approaches focus on the detection of defects such as excessive surface roughness, residual porosity or inclusions that occur at the mesoscopic length scale of individual powder particles. Third, microscopic approaches investigate the metallurgical microstructure evolution resulting from the high temperature gradients and extreme heating and cooling rates induced by the SLM process. Consideration of physical phenomena on all of these three length scales is mandatory to establish the understanding needed to realize high part quality in many applications, and to fully exploit the potential of SLM and related metal AM processes

The measurement of rough surface topography using coherence scanning interferometry

This guide describes good practice for the measurement and characterisation of rough surface topography using coherence scanning interferometry (commonly referred to as vertical scanning white light interferometry). It is aimed at users of coherence scanning interferometry for the optical measurement of surface texture within production and research environments. The general guidelines described herein can be applied to the measurement of rough surfaces exhibiting different types of surface topography. For the purpose of this guide, the definition of a rough surface is one that has features with heights ranging from approximately 10 nm to less than 100 µ

Measurements, Models, Systems and Design

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