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- 2017
- spectral reconstruction
- interference
- polarization
- transform
- imaging spectrometer
- Optoelectronic Information Science and Engineering
- BITTT
- Zhejiang University
- Guilin University of Aerospace Technology
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Dose reconstruction from PET images in carbon ion therapy: a deconvolution approach
摘要： Dose and range verification have become important tools to bring carbon ion therapy to a higher level of confidence in clinical applications. Positron emission tomography is among the most commonly used approaches for this purpose and relies on the creation of positron emitting nuclei in nuclear interactions of the primary ions with tissue. Predictions of these positron emitter distributions are usually obtained from time-consuming Monte Carlo simulations or measurements from previous treatment fractions, and their comparison to the current, measured image allows for treatment verification. Still, a direct comparison of planned and delivered dose would be highly desirable, since the dose is the quantity of interest in radiation therapy and its confirmation improves quality assurance in carbon ion therapy. In this work, we present a deconvolution approach to predict dose distributions from PET images in carbon ion therapy. Under the assumption that the one-dimensional PET distribution is described by a convolution of the depth dose distribution and a filter kernel, an evolutionary algorithm is introduced to perform the reverse step and predict the depth dose distribution from a measured PET distribution. Filter kernels are obtained from either a library or are created for any given situation on-the-fly, using predictions of the β+-decay and depth dose distributions, and the very same evolutionary algorithm. The applicability of this approach is demonstrated for monoenergetic and polyenergetic carbon ion irradiation of homogeneous and heterogeneous solid phantoms as well as a patient computed tomography image, using Monte Carlo simulated distributions and measured in-beam PET data. Carbon ion ranges are predicted within less than 0.5 mm and 1 mm deviation for simulated and measured distributions, respectively.
关键词： evolutionary algorithm,PET imaging,range verification,carbon ion therapy,dose reconstruction
更新于2025-09-04 15:30:14
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Multi-Core DSP Based Parallel Architecture for FMCW SAR Real-Time Imaging
摘要： This paper presents an e?cient parallel processing architecture using multi-core Digital Signal Processor (DSP) to improve the capability of real-time imaging for Frequency Modulated Continuous Wave Synthetic Aperture Radar (FMCW SAR). With the application of the proposed processing architecture, the imaging algorithm is modularized, and each module is e?ciently realized by the proposed processing architecture. In each module, the data processing of di?erent cores is executed in parallel, also the data transmission and data processing of each core are synchronously carried out, so that the processing time for SAR imaging is reduced signi?cantly. Speci?cally, the time of corner turning operation, which is very time-consuming, is ignored under computationally intensive case. The proposed parallel architecture is applied to a compact Ku-band FMCW SAR prototype to achieve real-time imageries with 34 cm × 51 cm (range × azimuth) resolution.
关键词： real-time imaging,FMCW SAR,Parallel processing,multi-core DSP
更新于2025-09-04 15:30:14
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Breaking the Energy-Symmetry-Based Propagation Growth Blockade in Magneto-Optical Rotation
摘要： The magneto-optical polarization rotation effect has myriad applications in many research areas spanning the scientific spectrum, including space and interstellar research, nanotechnology, material science, biomedical imaging, and subatomic particle research. In the nonlinear magneto-optical rotation (NMOR) effect, the angle of rotation of a linearly polarized optical field in a magnetized medium is dependent upon its intensity. However, typical NMOR signals of conventional single-beam Λ-scheme atomic magnetometers are peculiarly small, requiring sophisticated magnetic shielding and high-frequency phase-sensitive detection. Here, we show the presence of an energy-symmetry-based propagation growth blockade that undermines the NMOR effect in conventional single-beam Λ-scheme atomic magnetometers. We further demonstrate, both experimentally and theoretically, an inelastic wave-mixing technique that breaks this NMOR blockade, resulting in more-than-2-orders-of-magnitude enhancement of the NMOR signal power amplitude that cannot be achieved with conventional single-beam Λ-scheme atomic magnetometers. This technique, demonstrated here with substantially reduced light intensities at near-room temperatures, may lead to many applications, especially in the field of biomagnetism and high-resolution low-field magnetic imaging.
关键词： atomic magnetometers,wave-mixing,magneto-optical rotation,biomagnetism,nonlinear magneto-optical rotation,magnetic imaging
更新于2025-09-04 15:30:14
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Folic acid-nanoscale gadolinium-porphyrin metal-organic frameworks: fluorescence and magnetic resonance dual-modality imaging and photodynamic therapy in hepatocellular carcinoma
摘要： Background: Hepatocellular carcinoma (HCC) is the most common primary liver cancer and severely threatens human health. Since the prognosis of advanced HCC remains poor, there is an urgent need to develop new therapeutic approaches. Porphyrin metal-organic frameworks are a class of porous organic-inorganic hybrid functional materials with good biocompatibility. Methods: Gadolinium-porphyrin metal-organic frameworks were used as a skeleton for folic acid (FA) conjugation to synthesize a novel type of nanoparticle, denoted as folic acid-nanoscale gadolinium-porphyrin metal-organic frameworks (FA-NPMOFs). The FA-NPMOFs were characterized using transmission electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric-differential thermal analysis. The biotoxicity and imaging capability of the FA-NPMOFs were determined using HepG2 cells and embryonic and larval zebrafish. The delivery and photodynamic therapeutic effect of FA-NPMOFs were explored in transgenic zebrafish with doxycycline-induced HCC. Results: FA-NPMOFs were spherical in structure with good dispersion and water solubility. They showed low biotoxicity, emitted bright red fluorescence, and exhibited an excellent magnetic resonance imaging capability, both in vitro and in vivo. Meanwhile, the FA-NPMOFs exhibited a strong affinity for folate receptor (FR)-expressing cells and were delivered to the tumor site in a targeted manner. Moreover, HCC tumor cells were eliminated following laser irradiation. Conclusion: FA-NPMOFs can be used for dual-modality imaging and photodynamic therapy in HCC and show promise for use as a carrier in new therapies for HCC and other FR-positive tumors.
关键词： nanoscale gadolinium-porphyrin metal-organic frameworks,folic acid,hepatocellular carcinoma,photodynamic therapy,dual-modality imaging
更新于2025-09-04 15:30:14
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[IEEE 2018 International Conference on Electrical Engineering (ICEE) - Lahore, Pakistan (2018.2.15-2018.2.16)] 2018 International Conference on Electrical Engineering (ICEE) - Active Pixel Digital Sun Sensor for Satellites
摘要： Satellites use sun sensors as a reliable source of attitude determination during sunlit conditions while in orbit around the earth. This work elucidates the design and development of high precision and wide field of view digital sun sensor for space applications. Sun sensor employs active pixel image sensor along with processing techniques of feature extraction and image correlation. Software algorithm exploits the distinctive features of Active Pixel imaging Sensor (APS), in comparison to CCD based image sensor, for computationally efficient algorithm design. Sunlight falling on the sun sensor produces an image of the sun on image sensor. Software algorithm processes this image for noise removal, feature extraction, centroid analysis and sun vector calculations. Digital sun sensor, presented here, achieves 0.018 pixels (3σ) centroid accuracy with 120°×120° field of view.
关键词： Sun Sensor,Image Correlation,Image Processing,Feature Extraction,Active Pixel imaging Sensor
更新于2025-09-04 15:30:14
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NONPARAMETRIC ROTATIONAL MOTION COMPENSATION TECHNIQUE FOR HIGH-RESOLUTION ISAR IMAGING VIA GOLDEN SECTION SEARCH
摘要： A novel rotational motion compensation algorithm for high-resolution inverse synthetic aperture radar (ISAR) imaging based on golden section search (GSS) method is presented. This paper focuses on the migration through cross-range resolution cells (MTCRRC) compensation, which requires rotation angle and center as priori information. The method performs in a nonparametric way and uses entropy criterion to estimate rotation angle and rotation center, which are used for rotational motion compensation. Experimental results show that the rotational motion in ISAR imaging can be e?ectively compensated. Moreover, the proposed method is robust and computationally more e?cient compared to the parametric methods.
关键词： entropy criterion,nonparametric method,rotational motion compensation,golden section search,ISAR imaging
更新于2025-09-04 15:30:14
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FOCUSING TRANSLATIONAL VARIANT BISTATIC FORWARD-LOOKING SAR DATA BASED ON TWO-DIMENSIONAL NON-UNIFORM FFT
摘要： Forward-looking imaging has extensive potential applications, such as self-navigation and self-landing. By choosing proper geometry, bistatic synthetic aperture radar (BiSAR) can break through the limitations of monostatic SAR on forward-looking imaging and provide possibility of the forward-looking imaging. In this special bistatic configuration, two problems involving large range cell migration (RCM) and large range-azimuth coupling are introduced by the forward-looking beam, which make it difficult to use traditional data focusing algorithms. To address these problems, a novel Omega-K algorithm based on two-dimensional non-uniform FFT (2-D NUFFT) for translational variant (TV) bistatic forward-looking SAR (BFSAR) imaging is proposed in this paper. In this study, we derive an accurate spectrum expression based on two-dimensional principle of stationary phase (2-D POSP). 2-D NUFFT is utilized to eliminate the range-variant term, which can make full use of the data and improve the computational efficiency as well. The experimental results, presented herein, demonstrate the effectiveness and advantages of the proposed algorithm.
关键词： range-azimuth coupling,Omega-K algorithm,bistatic synthetic aperture radar,forward-looking imaging,2-D NUFFT,range cell migration
更新于2025-09-04 15:30:14
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NOISE REMOVAL TECHNIQUE IN NEAR-FIELD MILLIMETER-WAVE CYLINDRICAL SCANNING IMAGING SYSTEM
摘要： The accuracy of scattering measurements in near-?eld millimeter-wave cylindrical scanning imaging system is often degraded by the contamination from additive noise and clutter. Thus, e?cient noise and clutter removal technique is necessary to achieve accuracy improvement. This paper proposes an independent component analysis denoising algorithm, which relies on the assumption of statistical independence of the sources, where high order statistical properties are used. In the algorithm, the virtual noise components are incorporated into the independent component analysis model, which expands original one-dimensional observation to virtual multi-dimensional observations. The computationally e?cient sources estimation technique is presented, based on the joint diagonalization of fourth order cumulant matrix. The high speed millimeter-wave near-?eld cylinder scanning imaging system is set up to verify the denoising results in the range pro?les, three-dimensional scatter intensity and two-dimensional projection images. Compared with three di?erent noise models, the results indicate that the denoising algorithm shows both feasibility and validity in the near-?eld millimeter-wave cylindrical scanning imaging system.
关键词： millimeter-wave,cylindrical scanning imaging system,independent component analysis,denoising algorithm
更新于2025-09-04 15:30:14
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Concurrent pituitary and adrenocortical lesions on computed tomography imaging in dogs with spontaneous hypercortisolism
摘要： Background: Spontaneous hypercortisolism or Cushing's syndrome in dogs is either pituitary or adrenal dependent, but concurrent pituitary and adrenal hypercortisolism also has been reported. Objective: To determine how often concurrent pituitary and adrenal lesions are present in dogs with spontaneous hypercortisolism. Animals: Two hundred one client-owned dogs with spontaneous hypercortisolism. Methods: Retrospective study. Pre- and post-contrast computed tomography (CT) scans of the pituitary and adrenal glands were performed in dogs with confirmed hypercortisolism. Results: In dogs with dexamethasone-suppressible hypercortisolism (122/201), 78 dogs (64%) had an enlarged pituitary gland (median pituitary height/brain area [P/B], 0.43 × 10?2 mm?1; range, 0.32-1.21 × 10?2 mm?1). Two of these 78 dogs had concurrent adrenal lesions. In the remaining dogs (44/122; 36%), the pituitary gland was not enlarged. In the dexamethasone-resistant group (79/201), the pituitary gland was enlarged in 47 dogs (59%; median P/B, 0.57 × 10?2; range, 0.32-1.50 × 10?2 mm?1). Eight of these 47 dogs (17%) had concurrent adrenal lesions. In the remaining 32 dexamethasone-resistant dogs (41%), the pituitary gland was not enlarged. Among them, 27 dogs had adrenal lesions and suppressed ACTH concentrations consistent with adrenal-dependent hypercortisolism and 5 dogs were diagnosed with pituitary-dependent hypercortisolism. Conclusions and Clinical Importance: Concurrent pituitary and adrenal lesions were present in 5% of all dogs with hypercortisolism and in 10% of the dexamethasone-resistant dogs. Diagnostic imaging of both pituitary and adrenal glands should be included in the diagnostic evaluation of every dog with spontaneous hypercortisolism to obtain information needed for estimation of prognosis and choosing the optimal treatment.
关键词： CT scan,diagnostic imaging,Cushing's,ACTH
更新于2025-09-04 15:30:14
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SPAD-Based LiDAR Sensor in 0.35 μm Automotive CMOS with Variable Background Light Rejection
摘要： We present a SPAD-based LiDAR sensor fabricated in an automotive certified 0.35 μm CMOS process. Since reliable sensor operation in high ambient light environment is a crucial factor in automotive applications, four SPADs are implemented in each pixel to suppress ambient light by the detection of photon coincidences. By pixel individual adjustment of the coincidence parameters to the present ambient light condition, an almost constant measurement performance is achieved for a wide range of different target reflectance and ambient illumination levels. This technique allows the acquisition of high dynamic range scenes in a single laser shot. For measurement and demonstration purpose a LiDAR camera with the developed sensor has been built.
关键词： time-of-flight (TOF),background rejection,single-photon avalanche diode (SPAD),range imaging,light detection and ranging (LiDAR),photon coincidence
更新于2025-09-04 15:30:14