Journal of X-Ray Science and Technology - Volume 13, issue 3

Authors: Ninomiya, Toshio

Article Type: Research Article

Abstract: The capability of synchrotron radiation (SR) is demonstrated by its new applications in the field of criminal investigation. X-ray fluorescence spectrometry with SR provides very high signal-to-noise ratios and showed concentration profiles of trace elements in forensic samples such as illegal drugs and automobile coating chips. The profiles are so unique as to be called "chemical fingerprints" and have become valuable information to investigative authorities. Also, x-ray refraction contrast imaging technique reveals specific …structures of materials that can be never observed by optical examination. Such new techniques with SR are making an innovation in police investigations. Show more

Keywords: Fluorescent x-ray analysis, x-ray refraction contrast, drugs, fingerprints, car coating, cloths

Citation: Journal of X-Ray Science and Technology, vol. 13, no. 3, pp. 109-116, 2005

Authors: Lin, Pan | Zheng, ChongXun | Yang, Yong | Zhang, Feng | Yan, XiangGuo

Article Type: Research Article

Abstract: Level set methods are useful tools for medical image segmentation. In this paper, a novel image segmentation technique was developed that combines region statistical information with the level set method. The classical level set methods depend mainly on local edge-based image features to guide the convergence of the contour. This makes the method sensitive to noise and the initial estimate. The method has two features. The first is that it uses obtain region-based information by a …mixture model. The second feature is that we combine region statistical information with curvature-based regularization penalizing the length of curve. The method is useful for a large variety of segmentation problems. We present some preliminary experimental results using synthetic images and, magnetic resonance (MR), ultrasound (US), computed tomography (CT) images to demonstrate our methods. The experimental results show that by incorporating region statistical information into the level set framework, an accurate and robust segmentation can be achieved. Show more

Keywords: Level set method, region statistical information, mixture model, and Image segmentation

Citation: Journal of X-Ray Science and Technology, vol. 13, no. 3, pp. 117-127, 2005

Authors: Liu, Yingjie | Su, Yixiong | Yao, Jianquan | Wang, Ruikang K.

Article Type: Research Article

Abstract: Recent progress in photoacoustic imaging has shown its potential in biomedical imaging of biological tissues in vivo because it can offer the imaging contrast comparable to the optical techniques and the imaging resolution similar to the ultrasonic techniques. However, its imaging depth and contrast have a dependence on the optical properties of surrounding medium that has not yet investigated. Therefore, the understanding of how the tissue optical properties affect the performance of photoacoustic imaging would be …important. In this paper, we investigate the influence of absorption and scattering coefficients of surrounding tissue on the measured acoustic signal generated from the photoacoustic source of interest. In the experiments, tissue phantoms were constructed with a range of optical properties. We used the intralipid solution to control the scattering property, and the methylene blue to control the absorption property of the phantom. The results show that the absorption and scattering coefficient of surrounding medium is one of major factors that affect the photoacoustic imaging depth and contrast. Show more

Keywords: Photoacoustic imaging, absorption, scattering, light attenuation

Citation: Journal of X-Ray Science and Technology, vol. 13, no. 3, pp. 129-136, 2005

Authors: Gea, S.L.R. | Decraemer, W.F. | Dirckx, J.J.J.

Article Type: Research Article

Abstract: Computed microtomography (μCT) is an imaging technique that produces virtual slices of an object, based on a set of x-ray images taken while the object is stepwise rotated. The stack of slices is calculated with a backprojection algorithm, it demands that the entire object remains within the x-ray beam for all observed angles. During region-of-interest (ROI) tomography however, one zooms in on a small part of the object. As a consequence the above condition is no …longer fulfilled; the input data become incomplete and reconstructed slices are corrupted. In this study we show that, if we are not interested in grayscale values but only in geometrical information, conventional backprojection algorithms still perform well for ROI tomography. We demonstrate this with ROI scans performed on several phantom objects and we show ROI images of the gerbil hearing organ. We found that the resolution could considerably be improved and small details, not visible in a conventional full object scan, can be revealed by a ROI scan. One can use the benefits of ROI-μCT in situations where physical constrains are such that large parts of the object exceed the field of view (FOV), or where a very high magnification is required. Show more

Keywords: Microtomography, region of interest, temporal bone, middle ear

Citation: Journal of X-Ray Science and Technology, vol. 13, no. 3, pp. 137-147, 2005

Authors: Jiang, Jingying | Wang, Ruikang K.

Article Type: Research Article

Abstract: Currently, there is an increasing interest in tissue optical clearing by the use of hyperosmotic agents due to its consequence in increasing light penetration into tissue. This has shown a great potential in enhancing the capabilities of non-invasive light-based diagnostic and imaging techniques. In this study, we introduce the oleic acid, a mono-unsaturated fatty acid, as an enhancer and investigate how its different molarities exert its effect on optical clearing of skin tissue in vitro. Experimental …results from near infrared spectroscopy and mass loss measurement showed that OA01PG40, i.e. 0.1 M oleic acid in 40% propylene glycol, obtained the best clearing effect. Meanwhile, it is noticed that the molarity of oleic acid in propylene glycol is important when used in optical clearing of skin tissue in vitro. Show more

Keywords: Tissue optical clearing, hyperosmotic agent, oleic acid, propylene glycol, refractive index matching, dehydration

Citation: Journal of X-Ray Science and Technology, vol. 13, no. 3, pp. 149-159, 2005