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Dual-energy material decomposition (DEMD) is a well-established theoretical x-ray technique that uses low- and high-kilovoltage radiographs to separate soft tissue and bone in radiography and compu...

In the last few years, textile electrodes have become an interesting topic for physiological monitoring, steadily developing to be applied in innovative wearable sensing systems. The structure of textile electrodes can be fabricated by weaving, knitting, or embroidering conductive yarn and is now commercially available. The upgraded textile electrode is used in biosignal sensing and was designed in the form of a jacquard woven structure to measure the ECG. In the case of knit fabric, which has piezo‐resistive properties, the textile electrodes were developed by using the fabric’s flexible strain gauges in a bio‐monitoring system. However, the piezo‐resistive sensing fabrics have some shortcomings such as low dynamic range, poor repeatability, and performance deterioration after washing or repeated folding. Woven fabric, which is cloth woven in the warp and weft directions, has less strain properties and can be constructed more uniformly than knit fabric. Therefore, due to their more consistent woven struc...

We developed an automated digital gamma-imaging system for nondestructive testing of welded structures in steel pipes. The imaging system consists of a 750-μm-thick CdTe (cadmium telluride) photoconductor coupled to a commercially available complementary metal-oxide semiconductor readout array having a 100 μm x 100 μm pixel size and a 5.4 mm x 151.0 mm active area, a collimated 75 Se (selenium) gamma source having an activity of ∼ 78.7 Ci and a physical dimension or 3.0 mm in diameter and 3.0 mm in height, and a beam limiter 1.0 mm in width and 2.6 mm in height to restrict field size. All the components were assembled with a track-typed trailer mounted around a steel pipe and moved by using a microstepping motor at a fixed speed of 5.0 mm/s. We obtained useful gamma images of some test specimens such as a duplex wire phantom and American Society for Testing and Materials batches from the imaging system and evaluated the image quality in terms of the modulation transfer function, the noise power spectrum, and the detective quantum efficiency.

We have developed a prototyped digital panoramic tomography (DPT) system which mainly consists of a slit-collimated X-ray generator of a 0.4-mm focal spot and a 3.5-mmAl filtration, a linear-array typed CMOS imaging sensor of a 48 × 48 μm2 pixel size and a 128 (in the scan direction) × 3072 (in the vertical direction) pixel format, a series of microstep motors for the precise movement of the imaging system, and the designed motion control and pixel readout sequences required to make a specific plane of interest (POI) to be focused. With the several test phantoms we designed, we, for the first time, succeeded in obtaining useful DPT images by moving the X-ray generator and the CMOS imaging sensor along a continuously sliding rotation center during a continuous X-ray exposure. We demonstrated that the prototyped DPT system can be applicable to any shaped POI to be focused, provided that adequate motion control and pixel readout sequences are designed. We expect the system to be useful for our future imaging...

Jungwon Precision Ind. Co., Ltd. has recently developed precise carbon-interspaced antiscatter grids by adopting the sawing process in order to employ them to digital radiographic (DR) systems. Twelve grid samples of strip densities ranging from 40 to 85 lines/cm at a fixed grid ratio of 5:1 and of grid ratios from 5:1 to 10:1 at a fixed strip density of 80 lines/cm were prepared and their physical characteristics were examined under a well-controlled test condition with the IEC standard fixture, in terms of the transmission of primary radiation, the transmission of scattered radiation, the transmission of total radiation, the contrast improvement factor, and the Bucky factor. We expect that these experimental results will be useful for the selection of antiscatter grids in the applications of DR imaging as well as for the improvement of grid design.

As a continuation of our digital radiographic sensor R&D, we have developed a digital gamma imaging system based upon the cadmium-telluride (CdTe) photoconductor for the applications of industrial gamma-imaging. The imaging system consists of a commercially-available CMOS pixel array of a 100 × 100 μm2 pixel size and a 5.4 × 151.0 mm2 active area, coupled with a 750-μm-thick CdTe photoconductor, and a collimated selenium (75Se) radioisotope of an about 2.3 × 1012 Bq activity and a physical size of 3.0 mm in diameter. In this study, we, for the first time, succeeded in obtaining useful gamma images of several test phantoms with the 75Se radioisotope from the imaging system and evaluated its imaging performance in terms of the line spread function (LSF), the modulation transfer function (MTF), the noise power spectrum (NPS), and the detective quantum efficiency (DQE). For comparison, we also tested its X-ray imaging performance with a microfocus X-ray tube of an about 5 μm focal spot size at an operation co...

In this study, by using the MATLAB® 7.0 program, we investigated the fundamental principle of digital X-ray tomosynthesis (DTS) and, furthermore, the influence of tomographic parameters associated with the acquisition and reconstruction processes for the isocenter motion, including the tomographic angle (θ) and the angle increment between each projection (Δθ) on the reconstructed images. A proper compensation for the ununiform magnification for the isocenter motion was made in the tomographic algorithm to remove the geometrical distortion in the acquired projections. A simple tomographic algorithm, the so-called the modified shift-and-add (MSAA), was also studied in order to reduce effectively the blurring artifact that occurs typically in the conventional reconstruction algorithm of SAA. We expect that the simulation results we obtained in this study will be useful for the optimal design of a digital X-ray tomosynthesis system for our ongoing application of nondestruction testings.