Dr. Chao-Jen Lai Profile

Dr. Chao-Jen Lai

Engineer

SPIE Involvement:

Author

Publications (22)

Proceedings Article | 19 March 2014 Paper

A sinogram based technique for image correction and removal of metal clip artifacts in cone beam breast CT

T. Wang, Y. Shen, Y. Zhong, C.-J. Lai, J. Wang, C. Shaw

Proceedings Volume 9033, 90332S (2014) https://doi.org/10.1117/12.2043927

KEYWORDS: Metals, Breast, Image segmentation, 3D image processing, Image quality, Reconstruction algorithms, Computed tomography, 3D image reconstruction, X-rays, Image processing algorithms and systems

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Proceedings Article | 3 March 2012 Paper

Contrast-to-noise ratio improvement in volume-of-interest cone beam breast CT

Youtao Shen, Xinming Liu, Chao-Jen Lai, Yuncheng Zhong, Ying Yi, Zhicheng You, Tianpeng Wang, Chris Shaw

Proceedings Volume 8313, 83134X (2012) https://doi.org/10.1117/12.911932

KEYWORDS: Breast, Image quality, X-rays, Sensors, Composites, 3D image reconstruction, Collimation, Monte Carlo methods, X-ray computed tomography, 3D image processing

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Proceedings Article | 23 March 2010 Paper

Detection of simulated microcalcifications in digital mammography: effects of quantum and anatomic noises: preliminary study

Chao-Jen Lai, Xinming Liu, Zhicheng You, Youtao Shen, Yuncheng Zhong, Lingyun Chen, Tao Han, Shuaiping Ge, Ying Yi, William Geiser, David Flores, Gary Whitman, Wei Yang, Chris Shaw

Proceedings Volume 7622, 76224Y (2010) https://doi.org/10.1117/12.844426

KEYWORDS: Breast, Digital mammography, Signal to noise ratio, Mammography, LCDs, Visibility, X-rays, Target acquisition, Tissues, Image processing

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Proceedings Article | 23 March 2010 Paper

Demonstration of dual resolution cone beam CT technique with an a-Si/a-Se flat panel detector

Youtao Shen, Yuncheng Zhong, Lingyun Chen, Chao-Jen Lai, Xinming Liu, Tao Han, Ying Yi, Zhicheng You, Shuaiping Ge, Tianpeng Wang, Chris Shaw

Proceedings Volume 7622, 76223B (2010) https://doi.org/10.1117/12.844423

KEYWORDS: Image resolution, Breast, Sensors, Aluminum, X-ray computed tomography, Breast cancer, X-rays, Reconstruction algorithms, Image quality, Mammography

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Proceedings Article | 23 March 2010 Paper

Images registration and superimposition for dual resolution cone beam CT: a preliminary study

Zhicheng You, Youtao Shen, Yuncheng Zhong, Lingyun Chen, Tao Han, Shuaiping Ge, Ying Yi, Tianpeng Wang, Chao-Jen Lai, Xinming Liu, Chris Shaw

Proceedings Volume 7622, 762234 (2010) https://doi.org/10.1117/12.844450

KEYWORDS: Image resolution, Breast, Sensors, Image registration, Aluminum, Computed tomography, X-ray computed tomography, Reconstruction algorithms, Breast cancer, X-rays

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Proceedings Article | 14 March 2009 Paper

Calcification visibility study using combined high dose and low dose cone beam CT projections

Y, Zhong, C. Lai, L. Chen, T. Han, Y. Shen, X. Liu, T. Wang, S. Ge, Y. Yi, Z. You, C. Shaw

Proceedings Volume 7258, 72585U (2009) https://doi.org/10.1117/12.813780

KEYWORDS: Visibility, Breast, 3D image processing, X-ray computed tomography, Computed tomography, Reconstruction algorithms, Calcium, Gaussian filters, Physics, X-rays

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Proceedings Article | 11 March 2009 Paper

Visibility of microcalcifications in CCD-based cone beam CT: a preliminary study

Youtao Shen, Lingyun Chen, Shuaiping Ge, Ying Yi, Tao Han, Yuncheng Zhong, Chao-Jen Lai, Xinming Liu, Tianpeng Wang, Chris Shaw

Proceedings Volume 7258, 72580M (2009) https://doi.org/10.1117/12.813806

KEYWORDS: Visibility, Signal to noise ratio, Breast, Charge-coupled devices, Sensors, CCD cameras, CCD image sensors, Imaging systems, Computed tomography, Breast cancer

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Proceedings Article | 11 March 2009 Paper

Volume and tissue composition preserving deformation of breast CT images to simulate breast compression in mammographic imaging

Tao Han, Lingyun Chen, Chao-Jen Lai, Xinming Liu, Youtao Shen, Yuncheng Zhong, Shuaiping Ge, Ying Yi, Tianpeng Wang, Chris Shaw

Proceedings Volume 7258, 72580K (2009) https://doi.org/10.1117/12.813813

KEYWORDS: Breast, Image segmentation, Mammography, Tissues, Image compression, Imaging systems, 3D modeling, X-ray computed tomography, Computed tomography, X-rays

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Proceedings Article | 11 March 2009 Paper

Breast density measurement: 3D cone beam computed tomography (CBCT) images versus 2D digital mammograms

Tao Han, Chao-Jen Lai, Lingyun Chen, Xinming Liu, Youtao Shen, Yuncheng Zhong, Shuaiping Ge, Ying Yi, Tianpeng Wang, Wei Yang, Chris Shaw

Proceedings Volume 7258, 72580L (2009) https://doi.org/10.1117/12.813823

KEYWORDS: Breast, Image segmentation, Tissues, Mammography, 3D image processing, Computed tomography, Breast cancer, 3D metrology, Radiology, Sensors

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Proceedings Article | 19 March 2008 Paper

Comparison of the performances between anti-scatter grid and slot scanning technique for digital chest radiography: effect of anatomical background

Chao-Jen Lai, Chris Shaw, Xinming Liu, Lingyun Chen, Tao Han, Tianpeng Wang

Proceedings Volume 6913, 69134T (2008) https://doi.org/10.1117/12.771687

KEYWORDS: Radiography, Chest, X-rays, Seaborgium, X-ray imaging, Sensors, Signal attenuation, Chromium, Chest imaging, X-ray detectors

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Proceedings Article | 19 March 2008 Paper

Dose saving and scatter reduction in volume-of-interest (VOI) cone beam CT: work in progress

Chao-Jen Lai, Chris Shaw, Lingyun Chen, Xinming Liu, Tao Han, Tianpeng Wang

Proceedings Volume 6913, 69134V (2008) https://doi.org/10.1117/12.772807

KEYWORDS: Breast, Sensors, X-rays, Image quality, X-ray computed tomography, Optical filters, Lead, Image filtering, X-ray detectors, Mammography

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Proceedings Article | 18 March 2008 Paper

Simulation of mammograms and tomosynthesis imaging with cone beam breast CT images

Tao Han, Chris Shaw, Lingyun Chen, Chao-jen Lai, Xinming Liu, Tianpeng Wang

Proceedings Volume 6913, 691317 (2008) https://doi.org/10.1117/12.772944

KEYWORDS: Breast, X-ray computed tomography, Mammography, X-rays, Optical simulations, Tissues, Sensors, Computer simulations, X-ray imaging, Breast cancer

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Proceedings Article | 18 March 2008 Paper

Feasibility of dual-resolution cone beam breast CT: a simulation study

Lingyun Chen, Chris Shaw, Chao-Jen Lai, Tao Han, Xinming Liu, Tianpeng Wang

Proceedings Volume 6913, 69131E (2008) https://doi.org/10.1117/12.772288

KEYWORDS: Sensors, Breast, Image resolution, X-rays, X-ray computed tomography, Monte Carlo methods, X-ray detectors, Spatial resolution, Computed tomography, 3D image processing

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The feasibility of using the dual-resolution cone beam breast CT technique to obtain high-resolution images inside a selected volume-of-interest (VOI). The spatial resolution improvement, dose saving and scatter reduction with this technique are studied and demonstrated with simulations. With the dual-resolution cone beam CT technique, the breast is first scanned with a low resolution detector at a lower exposure level. A selected volume-of-interest (VOI) in the breast is then scanned with a small field, high-resolution detector at a higher exposure level. The two image sets are then combined together to reconstruct high-resolution 3-D images for the VOI. The spatial resolution that can be achieved was estimated by obtaining 3-D images of point objects and use them to compute the MTFs for evaluation as a function of the geometric magnification, detector blurring function and focal spot size. Monte Carlo simulation based on the Geant4 package was used to estimate the degree of dose saving and scatter reduction for a cylinder shaped breast phantom. The VOI images generated with the dual-resolution cone beam CT technique demonstrated the same visibility of micro-calcifications as those generated with the full-breast, high resolution image acquisition. It has been shown that the spatial resolution can be increased by factor of 1.2 with smaller focal spot size and larger magnification. With the exposure level outside the VOI reduced by a factor of 15, scatter components can be reduced by a factor of 5.5 or greater in and outside the VOI. Dose can be reduced by a factor of 5.5 inside the VOI and up to 20 outside the VOI. We have demonstrated that high spatial resolution inside the VOI may be achieved with a high-resolution detector (e.g. CCD/CsI), reduced focal spot size (0.3 mm), and optimized geometrical magnification (e.g.1.63). Exposure reduction outside the VOI has been shown to reduce the scatter components in the high-resolution projection image data for the VOI. This has also led to significantly lowered doses inside and outside the VOI.

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

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 | 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 | 20 April 2005 Paper

Analysis of confidence level scores from an ROC study: comparison of three mammographic systems for detection of simulated calcifications

Chao-Jen Lai, Chris Shaw, Gary Whitman, Wei Yang, Peter Dempsey

Proceedings Volume 5745, (2005) https://doi.org/10.1117/12.597212

KEYWORDS: Imaging systems, Mammography, CCD cameras, Control systems, Charge-coupled devices, Sensors, Digital mammography, X-rays, Breast, Tissues

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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

Dual-energy digital mammography for calcification imaging: improvement by post-image processing

S. Kappadath, Chris Shaw, Chao-Jen Lai, Xinming Liu, Gary Whitman, Wei Yang

Proceedings Volume 5745, (2005) https://doi.org/10.1117/12.596903

KEYWORDS: Image processing, Tissues, X-rays, Sensors, Digital mammography, Breast, Image filtering, X-ray imaging, Signal processing, Imaging systems

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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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