Browsing by Author "Chien, Chia-Chi"

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Detecting small lung tumors in mouse models by refractive-index microradiology
(2011-08-01)
Chien, Chia-Chi
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Zhang, Guilin
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Hwu, Y.
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Liu, Ping
;
Yue, Weisheng
Refractive-index (phase-contrast) radiology was able to detect lung tumors less than 1 mm in live mice. Significant micromorphology differences were observed in the microradiographs between normal, inflamed, and lung cancer tissues. This was made possible by the high phase contrast and by the fast image taking that reduces the motion blur. The detection of cancer and inflammation areas by phase contrast microradiology and microtomography was validated by bioluminescence and histopathological analysis. The smallest tumor detected is less than 1 mm(3) with accuracy better than 1 x 10(-3) mm(3). This level of performance is currently suitable for animal studies, while further developments are required for clinical application.
Image Alignment for Tomography Reconstruction from Synchrotron X-Ray Microscopic Images
(2014-01-09)
Cheng, Chang-Chieh
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Chien, Chia-Chi
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Chen, Hsiang-Hsin
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Hwu, Yeukuang
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Ching, Yu-Tai
A synchrotron X-ray microscope is a powerful imaging apparatus for taking high-resolution and high-contrast X-ray images of nanoscale objects. A sufficient number of X-ray projection images from different angles is required for constructing 3D volume images of an object. Because a synchrotron light source is immobile, a rotational object holder is required for tomography. At a resolution of 10 nm per pixel, the vibration of the holder caused by rotating the object cannot be disregarded if tomographic images are to be reconstructed accurately. This paper presents a computer method to compensate for the vibration of the rotational holder by aligning neighboring X-ray images. This alignment process involves two steps. The first step is to match the "projected feature points" in the sequence of images. The matched projected feature points in the x-theta plane should form a set of sine-shaped loci. The second step is to fit the loci to a set of sine waves to compute the parameters required for alignment. The experimental results show that the proposed method outperforms two previously proposed methods, Xradia and SPIDER. The developed software system can be downloaded from the URL, http://www.cs.nctu.edu.tw/similar to chengchc/SCTA or http://goo.gl/s4AMx.
Reconfigurable liquid-core/liquid-cladding optical waveguides with dielectrophoresis-driven virtual microchannels on an electromicrofluidic platform
(2016)
Fan, Shih-Kang
;
Lee, Hsuan-Ping
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Chien, Chia-Chi
;
Lu, Yi-Wen
;
Chiu, Yi
An electrically reconfigurable liquid-core/liquid-cladding (L-2) optical waveguide with core liquid gamma-butyrolactone (GBL, n(core) = 1.4341, epsilon(core) = 39) and silicone oil (n(cladding) = 1.401, epsilon(cladding) = 2.5) as cladding liquid is accomplished using dielectrophoresis (DEP) that attracts and deforms the core liquid with the greater permittivity to occupy the region of strong electric field provided by Teflon-coated ITO electrodes between parallel glass plates. Instead of continuously flowing core and cladding liquids along a physical microchannel, the DEP-formed L-2 optical waveguide guides light in a stationary virtual microchannel that requires liquids of limited volume without constant supply and creates stable liquid/liquid interfaces for efficient light guidance in a simply fabricated microfluidic device. We designed and examined (1) stationary and (2) moving L-2 optical waveguides on the parallel-plate electromicrofluidic platform. In the stationary L-shaped waveguide, light was guided in a GBL virtual microchannel core for a total of 27.85 mm via a 90 degrees bend (radius 5 mm) before exiting from the light outlet of cross-sectional area 100 mu m x 100 mu m. For the stationary spiral waveguide, light was guided in a GBL core containing Rhodamine 6G (R6G, 1 mM) and through a series of 90 degrees bends with decreasing radii from 5 mm to 2.5 mm. With the stationary straight waveguide, the propagation loss was measured to be 2.09 dB cm(-1) in GBL with R6G (0.01 mM). The moving L-shaped waveguide was implemented on a versatile electromicrofluidic platform on which electrowetting and DEP were employed to generate a precise GBL droplet and form a waveguide core. On sequentially applying appropriate voltage to one of three parallel L-shaped driving electrodes, the GBL waveguide core was shifted; the guided light was switched at a speed of up to 0.929 mm s(-1) (switching period 70 ms, switching rate 14.3 Hz) when an adequate electric signal (173.1 V-RMS, 100 kHz) was applied.
Very small photoluminescent gold nanoparticles for multimodality biomedical imaging
(2013-05-01)
Lai, Sheng-Feng
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Chien, Chia-Chi
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Chen, Wen-Chang
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Chen, Hsiang-Hsin
;
Chen, Yi-Yun
An original synthesis method based on X-ray irradiation produced gold nanoparticles (AuNPs) with two important properties for biomedical research: intense visible photoluminescence and very high accumulation in cancer cells. The nanoparticles, coated with MUA (11-mercaptoundecanoid acid), are very small (1.4 nm diameter); the above two properties are not present for even slightly larger sizes. The small MUA-AuNPs are non-cytotoxic (except for very high concentrations) and do not interfere with cancer cell proliferation. Multimodality imaging using visible light fluorescence and X-ray microscopy is demonstrated by tracing the nanoparticle-loaded tumor cells. (C) 2012 Elsevier Inc. All rights reserved.