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High-resolution computed microtomography for the characterization of a diffusion tensor imaging phantom

Kaczmarek Ł., Wejrzanowski T., Skibiński J., Maksimczuk M., Krzyżak A.

Acta Geophysica

2017

Vol. 65, no. 1

259--268

This paper addresses the issue of the quantitative characterization of the structure of the calibration model (phantom) for b-matrix spatial distribution diffusion tensor imaging (BSD-DTI) scanners. The aim of this study was to verify manufacturing assumptions of the structure of materials, since phantoms are used for BSD-DTI calibration directly after manufacturing. Visualization of the phantoms’ structure was achieved through optical microscopy and high-resolution computed microtomography (µCT). Using µCT images, a numerical model of the materials structure was developed for further quantitative analysis. 3D image characterization was performed to determine crucial structural parameters of the phantom: porosity, uniformity and distribution of equivalent diameter of capillary bundles. Additionally calculations of hypothetical flow streamlines were also performed based on the numerical model that was developed. The results obtained in this study can be used in the calibration of DTI-BST measurements. However, it was found that the structure of the phantom exhibits flaws and discrepancies from the assumed geometry which might affect BSD-DTI calibration.

Provenance study of Amerindian pottery figurines with Prompt Gamma Activation Analysis

Kasztovszky Z., Mackowiak de Antczak M., Antczak A., Millan B., Bermúdez J., Sajo-Bohus L.

Nukleonika

2004

Vol. 49, nr 3

107-113

A Prompt Gamma Activation Analysis (PGAA) facility has been in operation at the Budapest Neutron Centre (BNC) since 1996. Nonetheless that PGAA is a relatively new method, its applicability to archeological research has already been established by several studies. Archaeologists of the Simón Bolívar University initiated a research project aimed to perform a provenance study of pre-Hispanic pottery figurines. Forty samples were selected from two archaeological sites excavated in the Los Roques Archipelago. Almost five hundred figurines have been recovered altogether in four sites of the Archipelago. Amerindian groups from the adjacent Venezuela mainland were identified as island sites' occupants, between A.D. 1200 and the European contact period. Forty fragments of figurines were investigated by PGAA, the concentrations of major- and some trace components being determined. Among others, K2O, Cl and Cr were found to be the most significant indicators of the samples originated from the Lake Valencia Basin (mainland) and from Los Roques Islands. By relating the island figurines to their stylistical and chemical counterparts from the mainland we will provide chronological information on hundreds of mainland figurines.