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1.
Med Phys ; 2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34387879

RESUMO

PURPOSE: In this work, an analytical model describing the noise in the retrieved three contrast channels, transmission, refraction, and ultra small-angle scattering, obtained with edge illumination X-ray phase-based imaging system is presented and compared to experimental data. METHODS: In EI, images acquired at different displacements of the presample mask (i.e., different illumination levels referred to as points on the "illumination curve"), followed by pixel-wise curve fitting, are exploited to quantitatively retrieve the three contrast channels. Therefore, the noise in the final image will depend on the error associated with the fitting process. We use a model based on the derivation of the standard error on fitted parameters, which relies on the calculation of the covariance matrix, to estimate the noise and the cross-channel correlation as a function of the position of the sampling points. In particular, we investigated the most common cases of 3 and 5 sampling points. In addition, simulations have been used to better understand the role of the integration time for each sampling point. Finally, the model is validated by comparison with the experimental data acquired with an edge illumination setup based on a tungsten rotating anode X-ray source and a photon counting detector. RESULTS: We found a good match between the predictions of the model and the experimental data. In particular, for the investigated cases, an arrangement of the sampling points leading to minimum noise and cross-channel correlation can be found. Simulations revealed that, given a fixed overall scanning time, its distribution into the smallest possible number of sampling points needed for phase retrieval leads to minimum noise thanks to higher statistics per point. CONCLUSIONS: This work presents an analytical model describing the noise in the various contrast channels retrieved in edge illumination as a function of the illumination curve sampling. In particular, an optimal sampling scheme leading to minimum noise has been determined for the case where 3 or 5 sampling points are used, which represent two of the most common acquisition schemes. In addition, the correlation between noise in the different channels and the role of the number of points and exposure time have been also investigated. In general, our results suggest a series of procedures that should be followed in order to optimize the experimental acquisitions.

2.
Molecules ; 26(16)2021 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-34443466

RESUMO

Bees and their products are useful bioindicators of anthropogenic activities and could overcome the deficiencies of air quality networks. Among the environmental contaminants, mercury (Hg) is a toxic metal that can accumulate in living organisms. The first aim of this study was to develop a simple analytical method to determine Hg in small mass samples of bees and beehive products by cold vapor atomic fluorescence spectrometry. The proposed method was optimized for about 0.02 g bee, pollen, propolis, and royal jelly, 0.05 g beeswax and honey, or 0.1 g honeydew with 0.5 mL HCl, 0.2 mL HNO3, and 0.1 mL H2O2 in a water bath (95 °C, 30 min); samples were made up to a final volume of 5 mL deionized water. The method limits sample manipulation and the reagent mixture volume used. Detection limits were lower than 3 µg kg-1 for a sample mass of 0.02 g, and recoveries and precision were within 20% of the expected value and less than 10%, respectively, for many matrices. The second aim of the present study was to evaluate the proposed method's performances on real samples collected in six areas of the Lazio region in Italy.


Assuntos
Abelhas/química , Monitoramento Biológico/métodos , Mercúrio/análise , Espectrometria de Fluorescência/métodos , Animais , Temperatura Baixa , Cucumis melo/química , Confiabilidade dos Dados , Poluição Ambiental/análise , Ácidos Graxos/análise , Mel/análise , Itália , Pólen/química , Própole/análise , Espectrofotometria Atômica/métodos , Ceras/análise
3.
Food Chem ; 360: 130027, 2021 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-34029926

RESUMO

The accurate determination of trace elements in vegetable edible oils is still an analytical challenge, owing to their low concentration levels and the complex matrix of the vegetable oils. The aim of this study was to develop a fast and simple analytical method to quantify 45 elements in small mass samples (0.5 g) of extra virgin olive oils by inductively coupled plasma mass spectrometry. To evaluate the best and fastest sample preparation procedure, ultrasonic extraction and wet digestion methods were compared using oil certified reference material with different reagent mixtures, reagent volumes, and times for sample extraction or digestion. The use of 5 mL reagent mixture F [10% (v/v) HNO3 and H2O2, 2:1 (v/v)] for sample digestion in a water bath (95 °C, 40 min) was found to produce satisfactory results in all cases as validated from sample recovery experiments over three different extra virgin olive oil samples.


Assuntos
Espectrometria de Massas/métodos , Azeite de Oliva/química , Oligoelementos/análise , Calibragem , Peróxido de Hidrogênio , Padrões de Referência , Reprodutibilidade dos Testes , Sonicação
4.
Phys Med ; 84: 80-84, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33878654

RESUMO

Artifacts arising when differential phase images are integrated is a common problem to several X-ray phase-based experimental techniques. The combination of noise and insufficient sampling of the high-frequency differential phase signal leads to the formation of streak artifacts in the projections, translating into poor image quality in the tomography slices. In this work, we apply a non-iterative integration algorithm proven to reduce streak artifacts in planar (2D) images to a differential phase tomography scan. We report on how the reduction of streak artifacts in the projections improves the quality of the tomography slices, especially in the directions different from the reconstruction plane. Importantly, the method is compatible with large tomography datasets in terms of computation time.


Assuntos
Artefatos , Tomografia Computadorizada por Raios X , Algoritmos , Processamento de Imagem Assistida por Computador , Imagens de Fantasmas , Tomografia , Raios X
5.
Sci Rep ; 11(1): 3663, 2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33574584

RESUMO

Margins of wide local excisions in breast conserving surgery are tested through histology, which can delay results by days and lead to second operations. Detection of margin involvement intraoperatively would allow the removal of additional tissue during the same intervention. X-ray phase contrast imaging (XPCI) provides soft tissue sensitivity superior to conventional X-rays: we propose its use to detect margin involvement intraoperatively. We have developed a system that can perform phase-based computed tomography (CT) scans in minutes, used it to image 101 specimens approximately half of which contained neoplastic lesions, and compared results against those of a commercial system. Histological analysis was carried out on all specimens and used as the gold standard. XPCI-CT showed higher sensitivity (83%, 95% CI 69-92%) than conventional specimen imaging (32%, 95% CI 20-49%) for detection of lesions at margin, and comparable specificity (83%, 95% CI 70-92% vs 86%, 95% CI 73-93%). Within the limits of this study, in particular that specimens obtained from surplus tissue typically contain small lesions which makes detection more difficult for both methods, we believe it likely that the observed increase in sensitivity will lead to a comparable reduction in the number of re-operations.

7.
Med Phys ; 48(1): 376-386, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33107980

RESUMO

PURPOSE: In this work the performance of a compact multiresolution and multicontrast x-ray phase system based on edge illumination is investigated. It has been designed for small animal imaging and with a limited footprint for ease of deployment in laboratories. METHODS: The presented edge illumination system is based on a compact microfocus tungsten x-ray source combined with a flat panel detector. The source has a maximum output of 10 W when the minimum spot size of about 15 µm is used. The system has an overall length of 70 cm. A new double sample mask design, obtained by arranging both skipped and nonskipped configurations on the same structure, provides dual resolution capability. To test the system, we carried out computed tomography (CT) scans of a plastic phantom with different source settings using both single-image and multi-image acquisition schemes at different spatial resolutions. In addition, CT scans of an ex-vivo mouse specimen were acquired at the best identified working conditions to demonstrate the application of the presented system to small animal imaging. RESULTS: We found this system delivers good image quality, allowing for an efficient material separation and improving detail visibility in small animals thanks to the higher signal-to-noise ratio (SNR) of phase contrast with respect to conventional attenuation contrast. The system offers high versatility in terms of spatial resolution thanks to the double sample mask design integrated into a single scanner. The availability of both multi- and single-image acquisition schemes coupled with their dedicated retrieval algorithms, allows different working modes which can be selected based on user preference. Multi-image acquisition provides quantitative separation of the real and imaginary part of the refractive index, however, it requires a long scanning time. On the other hand, the single image approach delivers the best material separation and image quality at all the investigated source settings with a shorter scanning time but at the cost of quantitativeness. Finally, we also observed that the single image approach combined with a high-power x-ray source may result in a fast acquisition protocol compatible with in-vivo imaging.


Assuntos
Iluminação , Tomografia Computadorizada por Raios X , Animais , Camundongos , Imagens de Fantasmas , Radiografia , Raios X
8.
Front Neurosci ; 14: 584161, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33240038

RESUMO

We report a qualitative study on central nervous system (CNS) damage that demonstrates the ability of X-ray phase contrast tomography (XPCT) to confirm data obtained with standard 2D methodology and permits the description of additional features that are not detected with 2D or other 3D techniques. In contrast to magnetic resonance or computed tomography, XPCT makes possible the high-resolution 3D imaging of soft tissues classically considered "invisible" to X-rays without the use of additional contrast agents, or without the need for intense processing of the tissue required by 2D techniques. Most importantly for studies of CNS diseases, XPCT enables a concomitant multi-scale 3D biomedical imaging of neuronal and vascular networks ranging from cells through to the CNS as a whole. In the last years, we have used XPCT to investigate neurodegenerative diseases, such as Alzheimer's disease (AD) and multiple sclerosis (MS), to shed light on brain damage and extend the observations obtained with standard techniques. Here, we show the cutting-edge ability of XPCT to highlight in 3D, concomitantly, vascular occlusions and damages, close associations between plaques and damaged vessels, as well as dramatic changes induced at neuropathological level by treatment in AD mice. We corroborate data on the well-known blood-brain barrier dysfunction in the animal model of MS, experimental autoimmune encephalomyelitis, and further show its extent throughout the CNS axis and at the level of the single vessel/capillary.

9.
Molecules ; 25(18)2020 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-32957599

RESUMO

Bee health and beehive products' quality are compromised by complex interactions between multiple stressors, among which toxic elements play an important role. The aim of this study is to optimize and validate sensible and reliable analytical methods for biomonitoring studies and the quality control of beehive products. Four digestion procedures, including two systems (microwave oven and water bath) and different mixture reagents, were evaluated for the determination of the total content of 40 elements in bees and five beehive products (beeswax, honey, pollen, propolis and royal jelly) by using inductively coupled plasma mass and optical emission spectrometry. Method validation was performed by measuring a standard reference material and the recoveries for each selected matrix. The water bath-assisted digestion of bees and beehive products is proposed as a fast alternative to microwave-assisted digestion for all elements in biomonitoring studies. The present study highlights the possible drawbacks that may be encountered during the elemental analysis of these biological matrices and aims to be a valuable aid for the analytical chemist. Total elemental concentrations, determined in commercially available beehive products, are presented.


Assuntos
Metais/análise , Oligoelementos/análise , Animais , Abelhas , Ácidos Graxos/química , Mel , Espectrometria de Massas , Micro-Ondas , Pólen/química , Própole/química , Espectrometria de Fluorescência , Temperatura , Ceras/química
10.
J Synchrotron Radiat ; 27(Pt 5): 1347-1357, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32876610

RESUMO

Recent trends in hard X-ray micro-computed tomography (microCT) aim at increasing both spatial and temporal resolutions. These challenges require intense photon beams. Filtered synchrotron radiation beams, also referred to as `pink beams', which are emitted by wigglers or bending magnets, meet this need, owing to their broad energy range. In this work, the new microCT station installed at the biomedical beamline ID17 of the European Synchrotron is described and an overview of the preliminary results obtained for different biomedical-imaging applications is given. This new instrument expands the capabilities of the beamline towards sub-micrometre voxel size scale and simultaneous multi-resolution imaging. The current setup allows the acquisition of tomographic datasets more than one order of magnitude faster than with a monochromatic beam configuration.


Assuntos
Microtomografia por Raio-X/instrumentação , Animais , Desenho de Equipamento , Europa (Continente) , Humanos , Imageamento Tridimensional , Técnicas In Vitro , Pulmão/diagnóstico por imagem , Camundongos , Imagens de Fantasmas , Medula Espinal/diagnóstico por imagem , Síncrotrons
11.
Environ Res ; 191: 110209, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32937173

RESUMO

Air pollution is recognized as the world's largest environmental health risk. In this work we evaluated in vivo the effects of three relevant components of atmospheric dusts (brake dust, wood pellet ash and Saharan dust) employing the animal model Caenorhabditis elegans. Main endpoints of C. elegans such as life span, brood size and oxidative stress were addressed by exposing the nematodes to different dust concentrations. Brake dust and pellet ash affected the life span and increased significantly the oxidative stress of exposed nematodes, while Saharan dust showed no effects. Water soluble and insoluble fractions of these dusts were used to investigate the impact of the single fraction on C. elegans. The two fractions of brake dust and pellet ash exerted different effects on C. elegans endpoints in terms of life span and oxidative stress response. These fractions acted in different ways on the worm susceptibility to infection of two human pathogens (Staphylococcus aureus and Pseudomonas aeruginosa) affecting the sek-1 gene expression. In conclusion, our study showed that C. elegans is a valuable tool to investigate in vivo possible effects of atmospheric dusts.


Assuntos
Poluentes Atmosféricos , Poluentes Ambientais , África do Norte , Poluentes Atmosféricos/toxicidade , Animais , Caenorhabditis elegans , Poeira , Humanos
12.
Artigo em Inglês | MEDLINE | ID: mdl-32784783

RESUMO

In this study, we have evaluated the efficiency of a chemical fractionation procedure for the characterization of both the water-soluble and the insoluble fraction of the main elemental components of particulate matter (PM) deposited on urban leaves. The proposed analytical approach is based on the chemical analysis of leaf washing solutions and membrane filters used for their filtration. The ionic concentration of leaf washing solutions was compared with their electrical conductivity, making it a valuable proxy for the quantification of the water-soluble and ionic fraction of leaf deposited PM. The chemical composition of both the water-soluble and the insoluble fraction of PM, resulting from this fractionation procedure, was compared with results obtained by scanning electron microscopy coupled with energy-dispersed X-Rays spectroscopy (SEM/EDX) and processed through chemometrics. Results obtained proved that the proposed approach is able to provide an estimation of total leaf deposited PM and it is highly reliable for the evaluation of the emission impact of different PM sources, being able to increase the selectivity of PM elemental components as specific source tracers; consequently providing useful information also for the assessment of human health risks.


Assuntos
Fracionamento Químico/métodos , Monitoramento Ambiental/métodos , Material Particulado/análise , Folhas de Planta/química , Poluentes Atmosféricos/análise , Humanos , Tamanho da Partícula
13.
Environ Pollut ; 266(Pt 3): 115271, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32814272

RESUMO

The ability of particulate matter (PM) to induce oxidative stress is frequently estimated by acellular oxidative potential (OP) assays, such as ascorbic acid (AA) and 1,4-dithiothreitol (DTT), used as proxy of reactive oxygen species (ROS) generation in biological systems, and particle-bound ROS measurement, such as 2',7'-dichlorodihydrofluorescein (DCFH) assay. In this study, we evaluated the spatial and size distribution of OP results obtained by three OP assays (OPAA, OPDCFH and OPDTT), to qualitative identify the relative relevance of single source contributions in building up OP values and to map the PM potential to induce oxidative stress in living organisms. To this aim, AA, DCFH and DTT assays were applied to size-segregated PM samples, collected by low-pressure cascade impactors, and to PM10 samples collected at 23 different sampling sites (about 1 km between each other) in Terni, an urban and industrial hot-spot of Central Italy, by using recently developed high spatial resolution samplers of PM, which worked in parallel during three monitoring periods (February, April and December 2017). The sampling sites were chosen for representing the main spatially disaggregated sources of PM (vehicular traffic, rail network, domestic heating, power plant for waste treatment, steel plant) present in the study area. The obtained results clearly showed a very different sensitivity of the three assays toward each local PM source. OPAA was particularly sensitive toward coarse particles released from the railway, OPDCFH was sensible to fine particles released from the steel plant and domestic biomass heating, and OPDTT was quite selectively sensitive toward the fine fraction of PM released by industrial and biomass burning sources.


Assuntos
Poluentes Atmosféricos/análise , Material Particulado/análise , Monitoramento Ambiental , Itália , Oxirredução , Estresse Oxidativo , Tamanho da Partícula
14.
Sci Rep ; 10(1): 11233, 2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32641715

RESUMO

Visualization and characterization of [Formula: see text]-amyloid deposits is a fundamental task in pre-clinical study of Alzheimer's disease (AD) to assess its evolution and monitor the efficiency of new therapeutic strategies. While the cerebellum is one of the brain areas most underestimated in the context of AD, renewed interest in cerebellar lesions has recently arisen as they may link to motor and cognitive alterations. Thus, we quantitatively investigated three-dimensional plaque morphology in the cerebellum in APP/PS1 transgenic mouse, as a model of AD. In order to obtain a complete high-resolution three-dimensional view of the investigated tissue, we exploited synchrotron X-ray phase contrast tomography (XPCT), providing virtual slices with histology-matching resolution. We found the formation of plaques elongated in shape, and with a specific orientation in space depending on the investigated region of the cerebellar cortex. Remarkably, a similar shape is observed in human cerebellum from demented patients. Our findings demonstrate the capability of XPCT in volumetric quantification, supporting the current knowledge about plaque morphology in the cerebellum and the fundamental role of the surrounding tissue in driving their evolution. A good correlation with the human neuropathology is also reported.


Assuntos
Doença de Alzheimer/diagnóstico , Córtex Cerebelar/patologia , Imageamento Tridimensional , Placa Amiloide/diagnóstico , Idoso de 80 Anos ou mais , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Precursor de Proteína beta-Amiloide/genética , Animais , Córtex Cerebelar/diagnóstico por imagem , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Placa Amiloide/genética , Placa Amiloide/patologia , Presenilina-1/genética , Radiografia , Síncrotrons , Tomografia Computadorizada por Raios X/instrumentação , Tomografia Computadorizada por Raios X/métodos
15.
Sci Total Environ ; 742: 140590, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-32629268

RESUMO

The ability of transplanted lichen Evernia (E.) prunastri (L.) to act as a high spatial biomonitoring tool for 14 polybrominated diphenyl ethers (PBDEs) was evaluated at 23 monitoring sites in a very polluted area in central Italy. The selected area is characterized by the presence of numerous emission sources, such as waste-to-energy plant, steel plant, vehicular traffic, and domestic heating. Transplanted E. prunastri proved to be a useful tool to biomonitor PBDEs, due to its ability to bioaccumulate individual congeners in varying concentrations in relation to the strength of the emission sources present over the territory. PBDEs levels widely ranged from 132 to 24,237 ng kg-1 dry weight, according to the sources of emission located around the monitoring sites. The highest concentrations were detected at the sites close to the municipal solid waste incinerator, steel plant, and high busy roads, confirming their important role as PBDEs emissions sources.


Assuntos
Éteres Difenil Halogenados/análise , Líquens , China , Monitoramento Ambiental , Itália , Resíduos Sólidos
16.
Biomed Opt Express ; 11(4): 2235-2253, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32341880

RESUMO

A crucial issue in the development of therapies to treat pathologies of the central nervous system is represented by the availability of non-invasive methods to study the three-dimensional morphology of spinal cord, with a resolution able to characterize its complex vascular and neuronal organization. X-ray phase contrast micro-tomography enables a high-quality, 3D visualization of both the vascular and neuronal network simultaneously without the need of contrast agents, destructive sample preparations or sectioning. Until now, high resolution investigations of the post-mortem spinal cord in murine models have mostly been performed in spinal cords removed from the spinal canal. We present here post-mortem phase contrast micro-tomography images reconstructed using advanced computational tools to obtain high-resolution and high-contrast 3D images of the fixed spinal cord without removing the bones and preserving the richness of micro-details available when measuring exposed spinal cords. We believe that it represents a significant step toward the in-vivo application.

17.
Artigo em Inglês | MEDLINE | ID: mdl-32183479

RESUMO

Small-scale or artisanal mining, using gold-mercury amalgamation to extract gold from ore, is a significant source of exposure for the workers and nearby populations. Few studies on hair mercury (Hg) have been conducted in Africa despite the fact that Africa has several gold deposits. No studies have been conducted in Eritrea that is one of the emerging gold producing countries in Africa. The aim of the study was to assess the Hg concentration in hair samples (n = 120) of a population living in Asmara, capital of Eritrea, and to evaluate the influence of some factors on the Hg levels in hair. Information on age, height, weight, occupation, smoking and fish consumption of participants were collected via questionnaire. Hair Hg concentration was significantly higher among women compared to men (p < 0.001) and among women preparing spicy products in Medeber market compared to those who did other jobs (p = 0.010). These results highlight the need for routine biomonitoring surveys and for health promotion campaigns devoted to local decision makers and workers.


Assuntos
Mercúrio/análise , Adolescente , Adulto , África , Animais , Monitoramento Biológico , Exposição Ambiental/análise , Monitoramento Ambiental , Feminino , Ouro , Humanos , Masculino , Pessoa de Meia-Idade , Mineração , Adulto Jovem
18.
J Synchrotron Radiat ; 27(Pt 4): 1042-1048, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33566014

RESUMO

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting motor neurons. Pre-clinical studies drive the development of animal models that well mimic ALS disorder and enable both the dissection of disease processes and an early assessment of therapy efficacy. A comprehensive knowledge of neuronal and vascular lesions in the brain and spinal cord is an essential factor to understand the development of the disease. Spatial resolution and bidimensional imaging are important drawbacks limiting current neuroimaging tools, while neuropathology relies on protocols that may alter tissue chemistry and structure. In contrast, recent ex vivo studies in mice demonstrated that X-ray phase-contrast tomography enables study of the 3D distribution of both vasculature and neuronal networks, without sample sectioning or use of staining. Here we present our findings on ex vivo SOD1G93A ALS mice spinal cord at a micrometric scale. An unprecedented direct quantification of neuro-vascular alterations at different stages of the disease is shown.


Assuntos
Esclerose Amiotrófica Lateral/diagnóstico por imagem , Medula Espinal/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Animais , Modelos Animais de Doenças , Imageamento Tridimensional , Camundongos , Camundongos Transgênicos , Sensibilidade e Especificidade , Razão Sinal-Ruído
19.
Materials (Basel) ; 12(24)2019 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-31861202

RESUMO

The aim of this work was to study the potential of food waste materials (banana peel, potato peel, apple peel, lemon peel, coffee waste, decaf coffee waste, grape waste, and carob peel) as low-cost adsorbents for the removal of aliphatic and aromatic volatile organic compounds (VOCs) from wastewater. The ability of examined food waste materials to adsorb VOCs from synthetic multi-component standard solutions was evaluated and the examined food waste materials showed high removal efficiency. Performances of coffee waste, grape waste, and lemon peel were detailed by using Trichloroethylene and p-Xylene in mono-component standard solutions. The adsorption capacity of the three selected food wastes was determined by using linear Langmuir and Freundlich isotherm models. Two errors functions, average percentage error (APE) and the chi-square test (χ2), were used for isotherm optimization prediction. Freundlich isotherm well described the adsorption of VOCs on the considered materials. According to the obtained results, a multilayer, physical, and cooperative adsorption process was hypothesized, particularly evident when the VOCs' concentrations are high. This was confirmed by the high adsorption efficiency percentages (E% > 80%) of VOCs from a real polluted matrix (urban solid waste leachate), containing high concentrations of total organic content.

20.
Phys Med Biol ; 64(23): 235005, 2019 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-31569079

RESUMO

A significant number of patients receiving breast-conserving surgery (BCS) for invasive carcinoma and ductal carcinoma in situ (DCIS) may need reoperation following tumor-positive margins from final histopathology tests. All current intraoperative margin assessment modalities have specific limitations. As a first step towards the development of a compact system for intraoperative specimen imaging based on edge illumination x-ray phase contrast, we prove that the system's dimensions can be reduced without affecting imaging performance. We analysed the variation in noise and contrast to noise ratio (CNR) with decreasing system length using the edge illumination x-ray phase contrast imaging setup. Two-(planar) and three-(computed tomography (CT)) dimensional imaging acquisitions of custom phantoms and a breast tissue specimen were made. Dedicated phase retrieval algorithms were used to separate refraction and absorption signals. A 'single-shot' retrieval method was also used, to retrieve thickness map images, due to its simple acquisition procedure and reduced acquisition times. Experimental results were compared to numerical simulations where appropriate. The relative contribution of dark noise signal in integrating detectors is significant for low photon count statistics acquisitions. Under constant exposure factors and magnification, a more compact system provides an increase in CNR. Superior CNR results were obtained for refraction and thickness map images when compared to absorption images. Results indicate that the 'single-shot' acquisition method is preferable for a compact CT intraoperative specimen scanner; it allows for shorter acquisition times and its combination of the absorption and refraction signals ultimately leads to a higher contrast. The first CT images of a breast specimen acquired with the compact system provided promising results when compared to those of the longer length system.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos , Imagens de Fantasmas , Tomografia Computadorizada por Raios X , Algoritmos , Neoplasias da Mama/cirurgia , Feminino , Humanos , Período Intraoperatório , Margens de Excisão , Mastectomia Segmentar/métodos , Radiografia , Reoperação , Razão Sinal-Ruído , Raios X
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