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phase-contrast imaging Simulation Based on a Micro-CT System

Chinese Journal of Biomedical Engineering(English Edition) 2016年第2期25卷 87-92页

作者： GUI Jian-bao ZOU Jing RONG Jun-yan HU Zhan-li ZHANG Qi-yang ZHENG Hai-rong XIA Dan Paul C.Lauterbur Research Center for Biomedical imaging Institute of Biomedical and Health EngineeringShenzhen Institutes of Advanced TechnologyChinese Academy of Sciences

Propagation-based phase-contrast imaging was simulated based on paraxial Fresnel-Kirchoff diffraction integral and spherical wave illumination. Under a developed micro-CT system parameters, the effects of focal-spot size and imaging geometry on phase-contrast imaging have been investigated using a 2-mm-thickness polystyrene edge phantom. An equivalent mono-energy was used to substitute the polychromatic spectrum of the micro-focus X-ray source. To consider effects of focal-spot size and detector resolution, the obtained phase-contrast image with an ideal point source was convolved with source intensity distribution and point spread function of detector. Simulations show reasonable influences of the two parameters which are in good agreement with experimental results.

关键词： micro-CT phase-contrast imaging X-ray micro-focus source simulation

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High spatial-resolution biological tissue imaging in the second near-infrared region via optical parametric amplification pumped by an ultrafast vortex pulse [Invited]

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Chinese Optics Letters 2022年第10期20卷 8-13页

作者：曾选科王聪颖蔡懿林庆钢陆小微林家和袁鑫明曹文华艾月霞徐世祥 Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province Shenzhen Key Laboratory of Micro-Nano Photonic Information TechnologyCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China College of Electronics and Information Engineering Shenzhen UniversityShenzhen 518060China

Applying an ultrafast vortex laser as the pump,optical parametric amplification can be used for spiral phase-contrast imaging with high gain,wide spatial bandwidth,and high imaging contrast.Our experiments show that this design has realized the 1064 nm spiral phase-contrast idler imaging of biological tissues(frog egg cells and onion epidermis)with a spatial resolution at several microns level and a superior imaging contrast to both the traditional bright-or dark-field imaging under a weak illumination of 7 nW/cm^(2).This work provides a powerful way for biological tissue imaging in the second near-infrared region.

关键词： optical parametric amplification ultrafast vortex laser pulse spatial resolution phase-contrast imaging

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phase imaging of irradiated foils at the OMEGA EP facility using phase-stepping X-ray Talbot–Lau deflectometry

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High Power Laser Science and Engineering 2023年第4期11卷 45-54页

作者： G.Pérez-Callejo V.Bouffetier L.Ceurvorst T.Goudal S.R.Klein D.Svyatskiy M.Holec P.Perez-Martin K.Falk A.Casner T.E.Weber G.Kagan M.P.Valdivia Departamento de Física Teórica Atómica yÓptica Universidad de ValladolidValladolidSpain Universitéde Bordeaux-CNRS-CEA Centre Lasers Intenses et Applications(CELIA)UMR 5107TalenceFrance European XFEL GmbH SchenefeldGermany Laboratory for Laser Energetics RochesterNew YorkUSA CEA-DAM DIFArpajonFrance University of Michigan Ann ArborMichiganUSA Los Alamos National Laboratory Los AlamosNew MexicoUSA Lawrence Livermore National Laboratory LivermoreCaliforniaUSA Helmholtz-Zentrum Dresden-Rossendorf DresdenGermany Technische Universität Dresden DresdenGermany Institute of Physics of the ASCR PragueCzech Republic CEA-CESTA CS 60001Le Barp CedexFrance Blackett Laboratory Imperial College LondonLondonUK Department of Astrophysics and Astronomy The Johns Hopkins UniversityBaltimoreMarylandUSA Center for Energy Research University of California San DiegoSan DiegoCaliforniaUSA

Diagnosing the evolution of laser-generated high energy density(HED)systems is fundamental to develop a correct understanding of the behavior of matter under extreme conditions.Talbot–Lau interferometry constitutes a promising tool,since it permits simultaneous single-shot X-ray radiography and phase-contrast imaging of dense plasmas.We present the results of an experiment at OMEGA EP that aims to probe the ablation front of a laser-irradiated foil using a Talbot–Lau X-ray interferometer.A polystyrene(CH)foil was irradiated by a laser of 133 J,1 ns and probed with 8 keV laser-produced backlighter radiation from Cu foils driven by a short-pulse laser(153 J,11 ps).The ablation front interferograms were processed in combination with a set of reference images obtained ex situ using phase-stepping.We managed to obtain attenuation and phase-shift images of a laser-irradiated foil for electron densities above 1022 cm−3.These results showcase the capabilities of Talbot–Lau X-ray diagnostic methods to diagnose HED laser-generated plasmas through high-resolution imaging.

关键词： deflectometry OMEGA EP phase-contrast imaging Talbot-Lau X-ray interferometry

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Application of synchrotron source based DEI method in guinea pig cochleae imaging

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Progress in Natural Science:Materials International 2007年第1期17卷 59-67页

作者： YIN Hongxia, LIU Bo, GAO Xin, GAO Xiulai and LUO Shuqian ( College of Biomedical Engineering, Capital University of Medical Sciences, Beijing 100069, China Department of Anatomy, Capital University of Medical Sciences, Beijing 100069, China) College of Biomedical Engineering Capital University of Medical Sciences Beijing 100069 China Department of Anatomy Capital University of Medical Sciences Beijing 100069 China

Hard X-ray diffraction enhanced imaging (DEI), which is based on a synchrotron source and monochromator-analyzer-crystal system, is an effective method for imaging X-ray phase shift. Utilizing an analyzer crystal with high angular sensitivity of micro-radian, DEI can measure the transmitted, refracted and scattered X-rays when projecting onto a sample. It dramatically improves the contrast and spatial resolution of the resultant images. At the topography station of Beijing Synchrotron Radiation Facilities (BSRF), we implemented DEI method in guinea pig cochleae imaging and acquired a series of DEI images. Based on these images, the apparent absorption and refraction images were calculated. The DEI images revealed the holistic spiral structures and inner details of guinea pig cochleae clearly, even including the structures at the cellular level, such as the static cilia of hairy cells and the limbus of Hansen cell. Due to the advantages of high contrast, high spatial resolution and distinct edge-enhanced effect, DEI method promises extensive applications in biology, medicine and clinic in the near future.

关键词： diffraction enhanced imaging hard X-ray imaging phase-contrast imaging cochlea micro-structure synchrotron source.

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