Dr. Shu-Ju Tu Profile

Dr. Shu-Ju Tu

at Chang Gung Univ

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Publications (11)

Proceedings Article | 16 April 2012 Paper

Micro CT imaging assessment for spatial distribution of magnetic nanoparticles in an ex vivo thrombolysis model

Fu-Sheng Wang, Tsi-Chian Chao, Shu-Ju Tu

Proceedings Volume 8317, 83171V (2012) https://doi.org/10.1117/12.911123

KEYWORDS: Magnetism, Nanoparticles, X-ray computed tomography, Computed tomography, Blood, Wind energy, Tissues, Imaging systems, Animal model studies, Magnetic sensors

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Proceedings Article | 23 March 2010 Paper

Imaging properties of gold nanoparticles: CT number dependence study

Shu-Ju Tu, Hui-Ling Hsieh, Tsi-Chian Chao

Proceedings Volume 7622, 76222R (2010) https://doi.org/10.1117/12.843887

KEYWORDS: Computed tomography, Gold, Nanoparticles, Imaging systems, Signal attenuation, X-ray computed tomography, Molecular imaging, Animal model studies, Biomedical optics, Scanners

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Proceedings Article | 14 March 2009 Paper

Feasibility of using the micro CT imaging system as the conformal radiation therapy facility for small animals

Shu-Ju Tu, Hui-Ling Hsieh, Tsi-Chian Chao, Chung-Chi Lee

Proceedings Volume 7258, 72585T (2009) https://doi.org/10.1117/12.813598

KEYWORDS: X-ray computed tomography, Imaging systems, Tumors, Animal model studies, Radiotherapy, Monte Carlo methods, Molecular imaging, X-rays, Scanners, Photon transport

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In recent years, there has been an increasing number of integration for using the micro CT scanners, either home-built bench-top or commercially made, as the small animal radiation therapy irradiator in several research groups. In this paper, we study the x-ray beam physics such as the percentage depth dose distribution and their dose conformity characteristics using Monte Carlo simulation method for a series of photon energy levels often found in the current commercial micro CT imaging systems. Micro CT scanners have been one of the key imaging modalities in the current state-of-the-art molecular imaging techniques and their applications in various biomedical research areas have been increasing tremendously in recent years due to the ultra-high image quality. Tumor growth development and the corresponding therapeutic response in the small animal model study can be evaluated by a micro CT imaging system. In the most current advanced commercially available micro CT units, the nominal spatial resolution is typically at the scale of 10.0 μm or less. In current research trend, there have been an increasing number of investigations for the applications of x-ray units to organ-specific and whole-body radiation in dedicated small animal model study. In particular, scientists have identified that the integrated micro CT imagers can be commissioned as the dual-purpose unit for the high spatial resolution image acquisition and radiation delivery. As we all realized that small animal models are important and critical in several studies of experimental (or pre-clinical) radiation therapy research. In this paper, a Monte Carlo code (Penelope) was used to calculate the percentage depth dose distributions at different photon energy levels. Also the corresponding iso-dose contour curves were computed and plotted from the circular CT scanning geometry to study the desired dose conformity property. We note that the selected photon energy range that is included in this work is often included in the current commercial micro CT systems.

Proceedings Article | 18 March 2008 Paper

CT number variations in micro CT imaging systems

Shu-Ju Tu, Hui-Ling Hsieh, Tsi-Chian Chao

Proceedings Volume 6913, 691343 (2008) https://doi.org/10.1117/12.772160

KEYWORDS: X-ray computed tomography, Imaging systems, X-rays, Bone, X-ray imaging, Reconstruction algorithms, Image filtering, Image processing, X-ray detectors, Sensors

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Proceedings Article | 2 March 2006 Paper

Effects of scattered radiation and beam quality on low contrast performance in cone beam breast CT

M. Cem Altunbas, Chris Shaw, Lingyun Chen, Tianpeng Wang, Shuju Tu

Proceedings Volume 6142, 614236 (2006) https://doi.org/10.1117/12.655745

KEYWORDS: Radiation effects, Tissues, X-rays, Sensors, Breast, Signal detection, Ions, X-ray computed tomography, X-ray detectors, Signal attenuation

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Proceedings Article | 2 March 2006 Paper

Comparison of full-scan and half-scan for cone beam breast CT imaging

Lingyun Chen, Chris Shaw, Chao-jen Lai, Mustafa Altunbas, Tianpeng Wang, Shu-ju Tu, Xinming Liu

Proceedings Volume 6142, 61424M (2006) https://doi.org/10.1117/12.648670

KEYWORDS: Reconstruction algorithms, Breast, X-ray computed tomography, Image quality, Fluctuations and noise, Computed tomography, Sensors, Tissues, Mammography, Breast imaging

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Proceedings Article | 2 March 2006 Paper

Effects of radiation dose level on calcification visibility in cone beam breast CT: a preliminary study

Chao-Jen Lai, Chris Shaw, Mustafa Altunbas, Yang Meng, Lingyun Chen, Shu-Ju Tu, Tianpeng Wang, Xinming Liu, Wei Yang, Gary Whitman

Proceedings Volume 6142, 614233 (2006) https://doi.org/10.1117/12.656471

KEYWORDS: Breast, Mammography, X-rays, Radiation effects, Sensors, Imaging systems, Tissues, Breast cancer, X-ray imaging, Breast imaging

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Proceedings Article | 2 March 2006 Paper

Comparison of two detector systems for cone beam CT small animal imaging: a preliminary study

Yang Meng, Chris Shaw, Xinming Liu, Mustafa Altunbas, Tianpeng Wang, Lingyun Chen, Shu-Ju Tu, S. Cheeenu Kappadath, Chao-Jen Lai

Proceedings Volume 6142, 614245 (2006) https://doi.org/10.1117/12.656690

KEYWORDS: Imaging systems, Charge-coupled devices, X-ray computed tomography, Sensors, X-rays, X-ray detectors, Preclinical imaging, CCD image sensors, CCD cameras, X-ray imaging

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Proceedings Article | 20 April 2005 Paper

Cone-beam CT breast imaging with a flat panel detector: a simulation study

Lingyun Chen, Chris Shaw, Shu-Ju Tu, Mustafa Altunbas, Tianpeng Wang, Chao-Jen Lai, Xinming Liu, S. Kappadath

Proceedings Volume 5745, (2005) https://doi.org/10.1117/12.597065

KEYWORDS: Breast, Sensors, Tissues, X-ray computed tomography, X-ray detectors, X-rays, Breast imaging, Imaging systems, Image filtering, X-ray imaging

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This paper investigates the feasibility of using a flat panel based cone-beam computer tomography (CT) system for 3-D breast imaging with computer simulation and imaging experiments. In our simulation study, 3-D phantoms were analytically modeled to simulate a breast loosely compressed into cylindrical shape with embedded soft tissue masses and calcifications. Attenuation coefficients were estimated to represent various types of breast tissue, soft tissue masses and calcifications to generate realistic image signal and contrast. Projection images were computed to incorporate x-ray attenuation, geometric magnification, x-ray detection, detector blurring, image pixelization and digitization. Based on the two-views mammography comparable dose level on the central axis of the phantom (also the rotation axis), x-ray kVp/filtration, transmittance through the phantom, detected quantum efficiency (DQE), exposure level, and imaging geometry, the photon fluence was estimated and used to estimate the phantom noise level on a pixel-by-pixel basis. This estimated noise level was then used with the random number generator to produce and add a fluctuation component to the noiseless transmitted image signal. The noise carrying projection images were then convolved with a Gaussian-like kernel, computed from measured 1-D line spread function (LSF) to simulated detector blurring. Additional 2-D Gaussian-like kernel is designed to suppress the noise fluctuation that inherently originates from projection images so that the reconstructed image detectability of low contrast masses phantom can be improved. Image reconstruction was performed using the Feldkamp algorithm. All simulations were performed on a 24 PC (2.4 GHz Dual-Xeon CPU) cluster with MPI parallel programming. With 600 mrads mean glandular dose (MGD) at the phantom center, soft tissue masses as small as 1 mm in diameter can be detected in a 10 cm diameter 50% glandular 50% adipose or fatter breast tissue, and 2 mm or larger masses are visible in a 100% glandular 0% adipose breast tissue. We also found that the 0.15 mm calcification can be detected for 100μm detector while only 0.2 μm or above are visible for 200 μm detector. Our simulation study has shown that the cone-beam CT breast imaging can provide reasonable good quality and detectability at a dose level similar to that of two views\mammography. For imaging experiments, a stationary x-ray source and detector, a step motor driven rotating phantom system was constructed to demonstrate cone beam breast CT image. A breast specimen from mastectomy and animal tissue embedded with calcifications were imaged. The resulting images show that 355-425 μm calcifications were visible in images obtained at 77 kVp with a voxel size of 316 μm and a center dose of 600 mrads. 300-315 μm calcifications were visible in images obtained at 60 kVp with a voxel size of 158 μm and a center dose of 3.6 rads.

Proceedings Article | 20 April 2005 Paper

Simulation of cone beam computed tomography chest imaging with parallel computing: nodule detectability versus dose

Shu-Ju Tu, Chris Shaw, Lingyun Chen

Proceedings Volume 5745, (2005) https://doi.org/10.1117/12.596995

KEYWORDS: Sensors, Photons, Computer simulations, X-rays, Imaging systems, X-ray computed tomography, X-ray detectors, Visualization, Optical simulations, Image processing

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Proceedings Article | 6 May 2004 Paper

Slot scanning versus antiscatter grid in digital mammography: comparison of low-contrast performance using contrast-detail measurement

Chao-Jen Lai, Chris Shaw, William Geiser, Srinivas Kappadath, Xinming Liu, TianPeng Wang, Shu-Ju Tu, Mustafa Altunbas

Proceedings Volume 5368, (2004) https://doi.org/10.1117/12.535986

KEYWORDS: Digital mammography, Imaging systems, X-rays, Image quality, Sensors, Mammography, Image processing, Charge-coupled devices, X-ray imaging, Manufacturing

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Showing 5 of 11 publications

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