• Title/Summary/Keyword: X-ray Micro-Imaging

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Simultaneous Measurement of Size and Velocity of Microbubbles inside Opaque Tube Using X-ray PTV Technique (X-ray PTV 기법을 이용한 불투명 튜브 내부의 미세기포의 크기 및 속도 동시 측정)

  • Kim, Seok;Lee, Sang-Joon
    • Journal of the Korean Society of Visualization
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    • v.4 no.2
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    • pp.69-75
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    • 2006
  • The microbubbles were used in various fields, such as turbulent control, drag reduction, material science and life science. The X-ray PTV using X-ray micro-imaging technique was employed to mea-sure the size and velocity of micro-bubbles moving in an opaque tube simultaneously. Micro-bubbles of $10{\sim}60{\mu}m$ diameter moving upward in an opaque tube (${\phi}$=2.7mm) were tested. Due to the different refractive indices of water and air, phase contrast X-ray images clearly show the exact size and shape of over-lapped microbubbles. In all of the working fluids tested (deionized water, tap water, 0.01 and 0.10M NaCl solutions), the measured terminal velocity of the microbubbles rising through the solution was proportional to the square of the bubble diameter. The rising velocity was increased with increasing mole concentration. The microbubble can be useful as contrast agent or tracer in life science and biology. The X-ray PTV technique should be able to extract useful information on the behavior of various bio/microscale fluid flows that are not amenable to analysis using conventional methods.

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Computer Simulation for X-ray Breast Elastography (X선 유방 탄성 영상을 위한 컴퓨터 모의 실험)

  • Kim, Hyo-Geun;Aowlad Hossain, A.B.M.;Lee, Soo-Yeol;Cho, Min-Hyoung
    • Journal of Biomedical Engineering Research
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    • v.32 no.2
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    • pp.158-164
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    • 2011
  • Breast cancer is the most frequently appearing cancer in women, these days. To reduce mortality of breast cancer, periodic check-up is strongly recommended. X-ray mammography is one of powerful diagnostic imaging systems to detect 50~100 um micro-calcification which is the early sign of breast cancer. Although x-ray mammography has very high spatial resolution, it is not easy yet to distinguish cancerous tissue from normal tissues in mammograms and new tissue characterizing methods are required. Recently ultrasound elastography technique has been developed, which uses the phenomenon that cancerous tissue is harder than normal tissues. However its spatial resolution is not enough to detect breast cancer. In order to develop a new elastography system with high resolution we are developing x-ray elasticity imaging technique. It uses the small differences of tissue positions with and without external breast compression and requires an algorithm to detect tissue displacement. In this paper, computer simulation is done for preliminary study of x-ray elasticity imaging. First, 3D x-ray breast phantom for modeling woman's breast is created and its elastic model for FEM (finite element method) is generated. After then, FEM experiment is performed under the compression of the breast phantom. Using the obtained displacement data, 3D x-ray phantom is deformed and the final mammogram under the compression is generated. The simulation result shows the feasibility of x-ray elasticity imaging. We think that this preliminary study is helpful for developing and verifying a new algorithm of x-ray elasticity imaging.

Zoom-in X-ray Micro Tomography System

  • Chun, In-Kon;Lee, Sang-Chul;Park, Jeong-Jin;Cho, Min-Hyoung;Lee, Soo-Yeol
    • Journal of Biomedical Engineering Research
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    • v.26 no.5
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    • pp.295-300
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    • 2005
  • We introduce an x-ray micro tomography system capable of high resolution imaging of a local region inside a small animal. By combining two kinds of projection data, one from a full field-of-view (FOV) scan of the whole body and the other from a limited FOV scan of the region of interest, we have obtained zoomed-in images of the region of interest without any contrast a nomalies. We have integrated a micro tomography system using a micro-focus x-ray source, a $1248\times1248$ flat-panel x-ray detector, and a precision scan mechanism. Using the cross-sectional images taken with the zoom-in micro tomography system, we measured trabecular thicknesses of femur bones in postmortem rats. To compensate the limited spatial resolution in the zoom-in micro tomography images, we used the fuzzy distance transform for the calculation of the trabecular thickness. To validate the trabecular thickness measurement with the zoom-in micro tomography images, we compared the measurement results with the ones obtained from the conventional micro tomography images of the extracted bone samples.

3D Inspection by Registration of CT and Dual X-ray Images

  • Kim, Youngjun;Kim, Wontae;Lee, Deukhee
    • Journal of International Society for Simulation Surgery
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    • v.3 no.1
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    • pp.16-21
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    • 2016
  • Computed tomography (CT) can completely digitize the interior and the exterior of nearly any object without any destruction. Generally, the resolution for industrial CT is below a few microns. The industrial CT scanning, however, has a limitation because it requires long measuring and processing time. Whereas, 2D X-ray imaging is fast. In this paper, we propose a novel concept of 3D non-destructive inspection technique using the advantages of both micro-CT and dual X-ray images. After registering the master object’s CT data and the sample objects’ dual X-ray images, 3D non-destructive inspection is possible by analyzing the matching results. Calculation for the registration is accelerated by parallel computing using graphics processing unit (GPU).

Visualization of Water-uptake Process in Excised Roots of Arabidopsis using Synchrotron X-ray Imaging Technique (가속기 X선 영상기법을 이용한 애기장대 뿌리털의 물 흡수과정 가시화)

  • Hwang, Bae-Geun;Kim, Hae-Koo;Lee, Sang-Joon
    • Journal of the Korean Society of Visualization
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    • v.8 no.4
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    • pp.48-53
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    • 2010
  • Water-uptake through roots, is an essential process of the water flow in plants. Its visualization is very useful for understanding sap flow dynamics at whole plant level. In this study, the tips of Arabidopsis' root hairs were excised and exposed to repeated dehydration and rehydration processes. The water-refilling through individual xylem vessels was visualized using the synchrotron X-ray micro-imaging technique. The high temporal resolution ($2\;{\mu}m$) and beam intensity of the X-ray source allowed to acquisition of consecutive X-ray images of the water-refilling process up to 10 frames/sec. Various flow patterns were observed and the ascending speed of the water-air interfaces was analyzed. The relation between the water-rising height and ascending speed was also analyzed. The present results would provide better alternative for investigating sap flows in roots.

Synchrotron Radiation Imaging of Breast Tissue Using a Phase-contrast Hard X-ray Microscope (경 엑스선 위상차 현미경을 이용한 유방 조직의 방사광 영상)

  • Jeong, Young-Ju;Bong, Jin-Gu;Park, Sung-Hwan
    • Progress in Medical Physics
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    • v.22 no.3
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    • pp.117-123
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    • 2011
  • Synchrotron radiation (SR) imaging enables us to observe internal structures of biologic samples without staining. In this study, we obtained X-ray microscopic images of human breast tissues with 11.1 KeV hard X-ray microscope of the Pohang light source and used zone plates and phase-contrast technique to get high resolution X-ray images. Hard X-ray microscopic images of fibrocystic change and breast cancer tissues with a spatial resolution of 60 nm were obtained and from these images, we could observe the micro-structures of human breast tissue. Also we analyzed and compared these images, which revealed distinct features of each condition. In conclusion, SR imaging with phase-contrast hard X-ray microscope for medical application, especially in breast disease can give some useful information for clinical research.

Development of X-ray PIV System Using a Medical X-ray Tube (임상용 X-선관을 이용한 X-ray PIV시스템의 개발)

  • Yim, Dae-Hyun;Kim, Guk-Bae;Kim, Do-Il;Lee, Hyong-Koo;Lee, Sang-Joon
    • 유체기계공업학회:학술대회논문집
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    • 2006.08a
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    • pp.403-406
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    • 2006
  • A new medical X-ray PIV technique was developed using a conventional medical X-ray tube. To acquire images of micro-scale particles, the X-ray PIV system consists of an x-ray CCD camera with high spatial resolution, and a X-ray tube with small a focal spot. A new X-ray exposure control device was developed using a rotating disc shutter to make double pulses which are essential for PIV application. Synchronization methodology was also developed to apply the PIV technique to a conventional medical X-ray tube. In order to check the performance and usefulness of the developed X-ray PIV technique, it was applied to a glycerin flow in an opaque silicon tube. Tungsten particles which have high X-ray absorption coefficient were used as tracer particles. Through this preliminary test, the spatial resolution was found to be higher than ultrafast MRI techniques, and the temporal resolution was higher than conventional X-ray PIV techniques. By improving its performance further and developing more suitable tracers, this medical X-ray PIV technique will have strong potential in the fields of medical imaging or nondestructive inspection as well as diagnosis of practical thermo-fluid flows.

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Advanced Flow Visualization Techniques for Diagnosing Microscale Biofluid Flows (미세 생체유동 해석을 위한 첨단 유동가시화기법)

  • Lee, Sang-Joon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.1
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    • pp.1-8
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    • 2009
  • Recently microscale biofluid flows have been receiving large attention in various research areas. However, most conventional imaging techniques are unsatisfactory due to difficulties encountered in the visualization of microscale biological flows. Recent advances in optics and digital image processing techniques have made it possible to develop several advanced micro-PIV/PTV techniques. They can be used to get quantitative velocity field information of various biofluid flows from visualized images of tracer particles. In this paper, as new advanced micro-PIV techniques suitable for biofluid flow analysis, the basic principle and typical applications of the time-resolved micro-PIV and X-ray micro-PIV methods are explained. As a 3D velocity field measurement technique for measuring microscale flows, holographic micro-PTV method is introduced. These advanced PIV/PTV techniques can be used to reveal the basic physics of various microscale biological flows and will play an important role in visualizing veiled biofluid flow phenomena, for which conventional methods have many difficulties to analyze.

Experimental research on blood sucking phenomena of a female mosquito (암모기 흡혈과정에 대한 실험적 연구)

  • Kim, Bo-Heum;Lee, Jung-Yeop;Lee, Sang-Joon
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1475-1478
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    • 2008
  • We have investigated the blood sucking phenomena of a female mosquito. The main objective of this study is to understand the mosquito's blood sucking mechanism and eventually to develop a bio-mimic technology that can be used to resolve the problem encountered in the transport of infinitesimal biological fluids in various bio-chips and microchips. At first, the consecutive velocity fields of blood-sucking flow in a proboscis were measured using a micro-particle image velocimetry (PIV) system employed with a high-speed camera. The velocity signals of the blood-sucking flow in the proboscis represent a periodic pulsatile flow pattern and spectral analysis on the velocity waveform shows a clear peak at 6.1 Hz.

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