A Parallel Reconstruction Scheme in Fluorescence Tomography Based on Contrast of Independent Inversed Absorption Properties

Based on an independent forward model in fluorescent tomography, a parallel reconstructed scheme for inhomogeneous mediums with unknown absorption property is proposed in this paper. The method considers the two diffusion equations as separately describing the propagation of excited light in tissues with and without fluorescent probes inside. Then the concentration of fluorophores is obtained directly through the difference between two estimations of absorption coefficient which can be parallel inversed. In this way, the multiparameter estimation problem in fluorescent tomography is transformed into two independent single-coefficient determined schemes of diffusion optical tomography (DOT). Any algorithms proved to be efficient and effective in DOT can be directly applied here. In this study the absorption property is estimated from the independent diffusion equations by a gradient-based optimization method with finite element method (FEM) solving the forward model. Simulation results of three representative occasions show that the reconstructed method can well estimate fluorescent property and tissue absorption distribution

A Wavelet-Based Multiresolution Reconstruction Method for Fluorescent Molecular Tomography

Image reconstruction of fluorescent molecular tomography (FMT) often involves repeatedly solving large-dimensional matrix equations, which are computationally expensive, especially for the case where there are large deviations in the optical properties between the target and the reference medium. In this paper, a wavelet-based multiresolution reconstruction approach is proposed for the FMT reconstruction in combination with a parallel forward computing strategy, in which both the forward and the inverse problems of FMT are solved in the wavelet domain. Simulation results demonstrate that the proposed approach can significantly speed up the reconstruction process and improve the image quality of FMT

Fast time-domain diffuse optical tomography for breast tissue characterization and imaging

Ph.DDOCTOR OF PHILOSOPH

Tomographic measurement of industrial parts at temperature below freezing point

je ultimátnym nástrojom umožňujúcim nedeštruktívnu analýzu objektov. Za normálnych okolností je objekt umiestnený na podstavec a teplota objektu je daná teplotou okolitého vzduchu. Existujú však prípady kedy je žiaduce skenovanie za nízkych prípadne vysokých teplôt za účelom odhalenia tepelnej stability objektu. Samotné riešenie je do veľkej miery podradené rozmerom samotného zariadenia a vzorky ako aj zvolenému spôsobu ohrevu a chladenia. Táto práca podáva prehľad už použitých spôsobov pre tomografiu za kontrolovanej teploty. Okrem toho sa v tejto práci nachádza aj návrh komory umožňujúcej dosiahnuť -40°C pri zachovaní vysokej transparentnosti pre Röntgenovo žiarenie. Ako dodatok vyplývajúci s dodatočných okolností je v tejto práci aj návrh komory umožňujúcej ohriať vzorku na 80°C . Všetky testy a merania prebiehali na prístroji GE phoenix v|tome|x L240.X-ray computed tomography presents and ultimate for non-destructive investigation of objects. Under normal circumstances is the object placed on stage and the temperature of the object is defined by ambient air. However there are also cases when observation at freezing or high temperatures is needed to reveal thermal stability of observed object. Naturally the size of used tomography equipment and the object just like form of cooling or heating are subjected to final design. This work provides a summary of used methods for temperature controlled tomography. Furthermore handles about design of cooling chamber capable to reach -40°C by preserving relative high X-ray transparency. As an addition that showed up as a response to additional requirements is here presented a heating chamber, in which the object can be maintained at 80°C . All test and scans were carried out on GE phoenix v|tome|x L240 industrial computed tomography scanner.

Roadmap on Label-Free Super-resolution Imaging

Label-free super-resolution (LFSR) imaging relies on light-scattering processes in nanoscale objects without a need for fluorescent (FL) staining required in super-resolved FL microscopy. The objectives of this Roadmap are to present a comprehensive vision of the developments, the state-of-the-art in this field, and to discuss the resolution boundaries and hurdles that need to be overcome to break the classical diffraction limit of the label-free imaging. The scope of this Roadmap spans from the advanced interference detection techniques, where the diffraction-limited lateral resolution is combined with unsurpassed axial and temporal resolution, to techniques with true lateral super-resolution capability that are based on understanding resolution as an information science problem, on using novel structured illumination, near-field scanning, and nonlinear optics approaches, and on designing superlenses based on nanoplasmonics, metamaterials, transformation optics, and microsphere-assisted approaches. To this end, this Roadmap brings under the same umbrella researchers from the physics and biomedical optics communities in which such studies have often been developing separately. The ultimate intent of this paper is to create a vision for the current and future developments of LFSR imaging based on its physical mechanisms and to create a great opening for the series of articles in this field.Peer reviewe

HIGH-SPEED ENDOSCOPIC OPTICAL COHERENCE TOMOGRAPHY AND ITS APPLICATIONS

Optical coherence tomography (OCT) is a real-time high-resolution imaging technology providing cross-sectional images of biological structures at a resolution of <1 to 20 µm and a penetration depth of 1 to 3 mm in most highly scattering tissues. OCT is in general non-invasive and can perform real-time ‘optical biopsy’ with a resolution approaching standard low magnification histopathology but without tissue removal. Conventional OCT requires a bulky imaging probe, which limits most of the in vivo applications to ophthalmology and dermatology. The development of miniature OCT imaging probe has greatly expanded the scope of the applications (e.g., cardiology, gastroenterology, etc.). Recent technical advances in OCT has extended the imaging speed from a few kHz to a few hundreds kHz, enabling in vivo three-dimensional (3D) imaging. This dissertation describes the development of a high-speed endoscopic OCT imaging system. The system employs the Fourier domain mode locking laser technology at a wavelength range of 1300 nm to reach an axial resolution of 9.7 µm and an A-scan rate of 220 kHz. A Mach-Zehnder interferometer setup is used to achieve shot-noise limited detection. A generic OCT software platform is developed for data acquisition, processing, display, storage, and 3D visualization. Miniature OCT imaging probes are designed and fabricated for in vivo 3D OCT imaging. The utility of the high-speed endoscopic OCT system is demonstrated for clinical and basic researches in pulmonology and gastroenterology. In addition, an ultrahigh-resolution endoscopic OCT system is developed at a wavelength range of 800 nm to reach an axial resolution of 3.0 µm and an A-scan rate of up to 20 kHz. Furthermore, a novel type of OCT contrast agents, scattering dominant gold nanocages, is developed with the aid of a cross-reference OCT imaging method. Finally, a multimodal endoscopic imaging system combines 1300 nm en face OCT and 1550 nm two photon fluorescence is developed. Compared with most of other imaging modalities, high-speed endoscopic OCT has unmatched advantages including high spatial resolution, imaging speed, and non-invasiveness / minimal invasiveness. The results in this dissertation suggest that high-speed endoscopic OCT may has a great impact on healthcare as well as basic research

Nondestructive Testing Methods and New Applications

Nondestructive testing enables scientists and engineers to evaluate the integrity of their structures and the properties of their materials or components non-intrusively, and in some instances in real-time fashion. Applying the Nondestructive techniques and modalities offers valuable savings and guarantees the quality of engineered systems and products. This technology can be employed through different modalities that include contact methods such as ultrasonic, eddy current, magnetic particles, and liquid penetrant, in addition to contact-less methods such as in thermography, radiography, and shearography. This book seeks to introduce some of the Nondestructive testing methods from its theoretical fundamentals to its specific applications. Additionally, the text contains several novel implementations of such techniques in different fields, including the assessment of civil structures (concrete) to its application in medicine

X-Ray imaging applied to the characterization of polymer foam's cellular structure and its evolution

Las espumas poliméricas son materiales celulares que poseen una fase sólida continua y otra gaseosa bien discontinua (celda cerrada) o continua (celda abierta). Habitualmente estas estructuras se describen mediante parámetros macroscópicos como la densidad relativa y otros microscópicos como el tamaño de celda o la densidad de celdas. Además, estos materiales poseen características peculiares como anisotropía, orientación de los poros y tortuosidad que les proporcionan propiedades físicas singulares. Convencionalmente el estudio de las espumas poliméricas se realiza mediante el análisis de la estructura celular final obtenida. Ello se debe principalmente a que es complicado detener el proceso de expansión una vez se ha iniciado. Debido a esto los estadios intermedios durante los procesos de espumado no son accesibles, es decir, no se obtiene información acerca de los mecanismos que generan la estructura final. Estos mecanismos físico-químicos fundamentales que gobiernan la generación y evolución de la estructura celular durante el espumado son la nucleación y el crecimiento. Por el contrario, existen otros mecanismos que son responsables de la degeneración de la estructura celular son el drenaje, la coalescencia y el coarsening. Los inconvenientes que existen para abordar el estudio de estos mecanismos durante el proceso de espumado, junto con las peculiaridades de estos sistemas hacen que las técnicas de imagen mediante rayos X sean una herramienta extraordinaria para el estudio in-situ de la evolución de la estructura celular y los mecanismos de espumado. Además, de manera complementaria, la imagen mediante rayos X permite la obtención de tomogramas para el estudio de la estructura celular en el estado final. Incluso es posible llegar más lejos gracias a los últimos desarrollos en tomografía rápida. Esta técnica es capaz de estudiar en 3D la evolución de la estructura celular en el tiempo. Uno de los requisitos esenciales para el estudio de las espumas poliméricas mediante la imagen con rayos X y que condiciona su aplicabilidad es la correcta selección de los componentes y el diseño del equipo de imagen. Esto se debe principalmente a características intrínsecas a las espumas poliméricas: baja absorción de los rayos X, espesores reducidos, estructura de celdas en el rango micrométrico, rápida evolución durante su fabricación y otras peculiaridades morfológicas de su estructura.Departamento de Física de la Materia Condensada, Cristalografía y Minerealogí

Synthesis of positron emitter-labelled amino acids: Application to the investigation of metabolic preferences and vulnerabilities in a mouse prostate cancer model.

152 p.El carcinoma de próstata es una de las principales causas de muerte en todo el mundo. Por ello, su estudio en modelos animales que mimeticen la enfermedad en humanos se convierte en un tema de interés científico. El objetivo de esta tesis es investigar los marcadores moleculares relacionados con la enfermedad. Con este fin, se eligieron los aminoácidos radiomarcados, para ser utilizados como sondas PET (Positron Emission Tomography) en un modelo animal de cáncer de próstata. Se han desarrollado estrategias sintéticas para la preparación de L- y D-[metil-11C]alanina y L-[13N]alanina, basadas en la catálisis por transferencia de fase y la biocatálisis, respectivamente. Se ha llevado a acabo su estudio de imagen PET, que mostró diferente biodistribución in vivo y una elevada acumulación en las próstatas de los animales inyectados con D-[metil-11C]alanina. Asimismo, se ha abierto una nueva ruta biosintética para la producción de L-[13N]glutamina, cuyo refinamiento hará posible su uso en estudios de imagen