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Comparison of Four Forward Models for Breast Imaging in ultrasound computed tomography

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Chinese Journal of Electronics 2019年第4期28卷 805-816页

作者： LI Ruijing CHEN Houjin PENG Yahui LI Jupeng School of Electronic and Information Engineering Beijing Jiaotong University

ultrasound computed tomography(USCT) is considered to have great potential for breast cancer screening. Compared with ray-based methods,Waveform inversion(WI) methods obtain high spatial resolution images because they consider higher-order diffraction effects. For the WI method, considering more properties of the medium in a forward model can estimate more accurate images. However, longer reconstruction time is required. Therefore, to reduce the reconstruction time, three hypotheses are set in this work to develop the medium under different conditions. We compare the reconstructed images using the four forward models to analyze the effects of the various considered medium properties, which include the sound speed, density of the medium, acoustic absorption and dispersion. To reduce the difficulty of hardware manufacturing, a square border ultrasonic transducer array is adopted in the USCT data acquisition system. Penalized leastsquares optimization problems are constructed to obtain numerical solutions of the sound speed and bulk modulus distributions. The reconstruction of the bulk modulus makes the reconstructed sound speed images more accurate. Computer simulations are conducted to compare reconstructed images using the four forward models under different noise conditions. A numerical breast phantom is used to evaluate the performance. The results suggest that for breast imaging, the forward model(which only considers the heterogeneous sound speed) is a compromise option between image accuracy and computational time.

关键词： Sound speed Breast cancer Image reconstruction ultrasound computed tomography Waveform inversion

Numerical Study of Square Border Ultrasonic Transducer Element Arrays for Breast Imaging in ultrasound computed tomography with Waveform Inversion Method

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Chinese Journal of Electronics 2019年第5期28卷 1000-1007页

作者： LI Ruijing CHEN Houjin PENG Yahui LI Jupeng School of Electronic and Information Engineering Beijing Jiaotong University

ultrasound computed tomography(USCT) is a promising approach for early breast cancer screening. Existing studies that estimate breast images using Waveform inversion(WI) methods utilize a Circular ultrasonic transducer element array(CUTA) to collect the measurement data. However, very accurate transducer element positioning and directivity are required for signal calibration in the hardware system of these studies,thereby causing difficulties in hardware *** purpose of this study is to estimate high-resolution USCT images using a WI method with a Square border ultrasonic transducer element array(SUTA), which reduces the difficulty of hardware manufacturing and creates accurate correspondence between the continuous and discrete forms of the transducer element ***, in this study, an SUTA is adopted to collect the measurement data of breast imaging using the WI method. A penalized least-squares optimization problem is constructed to obtain the numerical solution of a sound speed distribution. Computer simulations are conducted to compare images reconstructed from the measurement data that are collected using an SUTA and a *** performance is evaluated using a numerical breast phantom. Results suggest that the biases of the images reconstructed are less than 1% with the evenly distributed SUTA and 1% with the CUTA, under a noise condition.

关键词： Square border Breast cancer Image reconstruction ultrasound computed tomography Waveform inversion

Sitting or Standing Data Acquisition Based Breast ultrasound computed tomography

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Chinese Journal of Electronics 2021年第5期30卷 909-917页

作者： LI Ruijing CHEN Houjin PENG Yahui LI Jupeng LI Yanfeng School of Electronic and Information Engineering Beijing Jiaotong University

ultrasound computed tomography(UCT)is a promising approach for early breast cancer ***, current studies which use prone posture to collect breast ultrasonic data cause four problems, a long non-data-acquisition time, inconvenient, possible chances for cross infection, and a large area occupied by *** purpose of this study is to estimate a complete breast UCT image by using sitting or standing data acquisition, which can obtains a more rapid, convenient and sanitary examination process, and a less space occupied by equipment. Therefore, this study proposes a sitting or standing data acquisition based breast UCT method, which is a more practical data acquisition method for breast UCT. This study places a uniform soft sleeve on the outside of the breast so that it would not be deformed significantly due to the change of body posture. Because the soft sleeve is an influencing factor from outside for breast imaging, this study discusses the considerations for selecting that. Computer simulations are conducted to prove the effectiveness of the proposed method. Results suggest that, by using a soft sleeve whose sound speed is between 1450 m/s and 1550 m/s, the proposed method is effective; the biases of the reconstructed images are less than 1% under the 5% noise condition.

关键词： Sonic and ultrasonic radiation (medical uses) Optical, image and video signal processing Sonic and ultrasonic radiation (biomedical imaging/measurement) X-ray techniques: radiography and computed tomography (biomedical imaging/measurement) Sonic and ultrasonic applications Computer vision and image processing techniques X-rays and particle beams (medical uses) Patient diagnostic methods and instrumentation Biology and medical computing Data acquisition ultrasound computed tomography Image reconstruction Sound speed Breast cancer Full waveform inversion

Enhancement of photoacoustic tomography in the tissue with speed-of-sound variance using ultrasound computed tomography

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Chinese Physics B 2015年第11期24卷 63-69页

作者：程任翔陶超刘晓峻 Key Laboratory of Modern Acoustics of Ministry of Education Department of Physics Nanjing University

The speed-of-sound variance will decrease the imaging quality of photoacoustic tomography in acoustically inhomo- geneous tissue. In this study, ultrasound computed tomography is combined with photoacoustic tomography to enhance the photoacoustic tomography in this situation. The speed-of-sound information is recovered by ultrasound computed to- mography. Then, an improved delay-and-sum method is used to reconstruct the image from the photoacoustic signals. The simulation results validate that the proposed method can obtain a better photoacoustic tomography than the conventional method when the speed-of-sound variance is increased. In addition, the influences of the speed-of-sound variance and the fan-angle on the image quality are quantitatively explored to optimize the image scheme. The proposed method has a good performance even when the speed-of-sound variance reaches 14.2%. Furthermore, an optimized fan angle is revealed, which can keep the good image quality with a low cost of hardware. This study has a potential value in extending the biomedical application of photoacoustic tomography.

关键词： photoacoustic tomography speed of sound ultrasound computed tomography

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Combating acoustic heterogeneity in photoacoustic computed tomography:A review

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Journal of Innovative Optical Health Sciences 2020年第3期3卷 32-47页

作者： Tong Wang Wen Liu Chao Tian Department of Optics and Optical Engineering University of Science and Technology of China Hefei Anhui 230026 P.R.China Department of Precision Machinery and Precision Instrumentation University of Science and Technology of China Hefei Anhui 230026P.R.China Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes University of Science and Technology of China Hefei Anhui 230026P.R.China

Based on the energy conversion of light into sound,photoacoustic computed tomography(PACT)is an emerging biomedical imaging modality and has unique applications in a range of biomedical *** PACT,image formation relies on a process called acoustic inversion from received photoacoustic *** most PACT systems perform this inversion with a basic assumption that biological tissues are acoustically homogeneous,the community gradually rea-lizes that the intrinsic acoustic heterogeneity of tissues could pose distortions and artifacts to finally formed *** paper surveys the most recent research progress on acoustic het-erogeneity correction in *** major strategies are reviewed in detail,including half-time or partial-time reconstruction,autofocus reconstruction by optimizing sound speed maps,joint reconstruction of optical absorption and sound speed maps,and ultrasound computed tomog-raphy(USCT)enhanced *** correction of acoustic heterogeneity helps improve the imaging performance of PACT.

关键词： Photoacoustic computed tomography image reconstruction acoustic heterogeneity ultrasound computed tomography speed of sound