Collimation-enhanced micro-radiography in real-time

Review of Scientific Instruments

Jeong

et al. 2004

We describe the general characteristics and the first result of a new synchrotron beamline at the Pohang Light Source in Korea. The beamline, operated by a Korean-Taiwanese-Swiss consortium, is dedicated to microimaging experiment in real time with coherent x rays. The performances of the first tests already reach excellent levels when compared to other similar facilities worldwide. The key feature is the use of unmonochromatized x rays to achieve very high lateral and time resolution.

Section: First Testsmentioning

confidence: 99%

International consortium on phase contrast imaging and radiology beamline at the Pohang Light Source

Baik

Review of Scientific Instruments

Jeong

et al. 2004

“…Basically, using a thicker attenuator allows only the higher energy portion of the SR to pass through the filter and so as to interact with the sample, thus acting as a high pass filter. Therefore, the use of different combinations of attenuators enabled the production of SR with higher average energy and reduced intensity 11. This imaging system is relatively simple and inexpensive compared to either an X-ray interferometry system or a diffractometry system 5,12-14.…”

Section: Methodsmentioning

confidence: 99%

Comparison of Unmonochromatized Synchrotron Radiation and Conventional X-rays in the Imaging of Mammographic Phantom and Human Breast Specimens: A Preliminary Result

Jung

et al. 2005

Yonsei Med J

Self Cite

A simple imaging setup based on the principle of coherence-based contrast X-ray imaging with unmonochromatized synchrotron radiation was used for studying mammographic phantom and human breast specimens. The use of unmonochromatized synchrotron radiation simplifies the instrumentation, decreases the cost and makes the procedure simpler and potentially more suitable for clinical applications. The imaging systems consisted of changeable silicon wafer attenuators, a tungsten slit system, a CdWO4 scintillator screen, a CCD (Charge Coupled Device) camera coupled to optical magnification lenses, and a personal computer. In preliminary studies, a spatial resolution test pattern and glass capillary filled with air bubbles were imaged to evaluate the resOolution characteristics and coherence-based contrast enhancement. Both the spatial resolution and image quality of the proposed system were compared with those of a conventional mammography system in order to establish the characteristic advantages of this approach. The images obtained with the proposed system showed a resolution of at least 25 µm on the test pattern with much better contrast, while the images of the capillary filled with air bubbles revealed coherence-based edge enhancement. This result shows that the coherence-based contrast imaging system, which emphasizes the refraction effect from the edge of materials of different refractive indexes, is applicable to imaging studies in fundamental medicine and biology, although further research works will be required before it can be used for clinical applications.

“…1. Depending on the total thickness of the silicon wafer filter, this imaging system uses an unmonochromatized SR beam of an average of 10 10 photons per second with energies of 6 to 30 keV, calculated using the given ring energy and the bending magnet field, as showed in Fig. 2.…”

Section: A Experimental Imaging System Setupmentioning

confidence: 99%

“…We used the unmonochromatized SR X-ray beam for acquiring projection data in real time and demonstrated high quality images with micrometer resolution and phase contrast at object boundaries based on the refractive index rather than on the absorption versus monochromatic SR X-ray imaging systems of previous studies [1] and [2], [9] and [10]. This study presents the results of unmonochromatized SR CT images for cancerous human breast tissue as a soft tissue representative, and mouse vertebras as a hard tissue representative.…”

Section: Introductionmentioning

confidence: 99%

Computed microtomography (/spl mu/CT) with unmonochromatized synchrotron X-rays for cancerous human breast tissue and mouse vertebra

Jung

Hong

et al. 2002

IEEE Trans. Nucl. Sci.

The use of X-ray computed microtomography (CT) has increased in biomedical research and industrial applications. The inherited high quality of synchrotron radiation (SR) X-rays including high flux, collimation, and coherence, has been used recently to produce radiographic images with high spatial resolution and contrast. A simple and stable imaging system using an unmonochromatized SR source based on the principle of phase contrast X-ray imaging consists of a charge-coupled device (CCD) detector coupled with an optical lens system at the Pohang Light Source (PLS) 5C1 beamline. The spatial resolution of the imaging system was determined using the modulation transfer function (MTF), which was measured by step-by step calculations obtained from sharp edge images. Projection image data were obtained at 250 steps over 180 degrees of rotation with an acquisition time, depending on the imaged object materials, of 30 to 150 ms per projection image. The tomographic images were reconstructed using a simple filtered backprojection algorithm to reconstruct two-dimensional (2-D) images using projection data which may include characteristics of beam collimation and phase contrast. Although the use of a monochromatic X-ray beam has previously demonstrated to provide high resolution and enhanced contrast, our approach uses an unmonochromatized SR X-ray beam and shows similar image capability, without the needs for sophisticated X-ray optics, in an exposure time which is significantly less, by two orders of magnitude, than that for the monochromatic SR system. The current PLS 5C1 SR imaging system can produce projection images at a spatial resolution of 8.3 m over a field of view of about 5 mm at an exposure time of 30 ms per projection image for 1.5 optical magnification. This study presents the results of SR CT images of cancerous human breast tissue containing microcalcifications, mouse lumbar vertebra, and mouse coccygeal vertebra. The unmonochromatized SR CT imaging system provides an effective means of evaluating microstructures, not only in biomedical specimens but also in inorganic samples.