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Population-based X-ray gastric cancer screening in Hiroshima prefecture, Japan
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作者 Nhu Thi Hanh Vu Yuji Urabe +2 位作者 Duc Trong Quach Shiro Oka Toru Hiyama 《World Journal of Clinical Oncology》 2024年第2期271-281,共11页
BACKGROUND X-ray gastric cancer(GC)screening has been shown to decrease mortality.Population-based X-ray GC screening has been performed in Hiroshima Prefe-cture,Japan,since 1983 but time trends and the efficacy of th... BACKGROUND X-ray gastric cancer(GC)screening has been shown to decrease mortality.Population-based X-ray GC screening has been performed in Hiroshima Prefe-cture,Japan,since 1983 but time trends and the efficacy of the method over 39 years have not been assessed.METHODS This was a population-based retrospective study.The data were derived from aggregated data of the Hiroshima Regional Health Medical Promotion Organization,including the number and rate of participants and those requiring esophagogastroduodenoscopies(EGDs),the number and rate of participants diagnosed as having GC,and the positive predictive value of the abnormal findings detected by X-ray and confirmed by EGDs.The number and rate of esophageal cancers were also collected.Further,the cost of detecting one GC was evaluated.RESULTS The number of participants has decreased during the last four decades,from 39925 in 1983 to 12923 in 2021.The rate of those requiring EGDs decreased significantly in recent years(P<0.001).The number of participants diagnosed as having GC has also declined,from 76 to 10 cases.However,the rate of cases diagnosed as GC among the participants remained around 0.1%.The positive predictive value increased significantly in recent years except during 1983-1991.The number and rate of accidentally detected esophageal cancers have risen recently,from 0%in 2008 to 0.02%in 2021,one-fifth of the diagnosis rate of GC.One GC diagnosis costs approximately 4200000 Japanese Yen(30000 United States Dollars)for the X-ray screenings and EGDs.CONCLUSION X-ray GC screening in Hiroshima has been efficient,but one challenge is the cost.Esophageal cancers may also need to be considered because they have gradually increased in recent years. 展开更多
关键词 POPULATION Retrospective studies x-ray Gastric cancer screenING
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Ultra-stable CsPbBr3 Perovskite Nanosheets for X-Ray Imaging Screen 被引量:6
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作者 Liangling Wang Kaifang Fu +3 位作者 Ruijia Sun Huqiang Lian Xun Hu Yuhai Zhang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2019年第3期263-270,共8页
Wet chemistry methods,including hot-injection and precipitation methods,have emerged as major synthetic routes for high-quality perovskite nanocrystals in backlit display and scintillation applications.However,low che... Wet chemistry methods,including hot-injection and precipitation methods,have emerged as major synthetic routes for high-quality perovskite nanocrystals in backlit display and scintillation applications.However,low chemical yield hinders their upscale production for practical use.Meanwhile,the labile nature of halide-based perovskite poses a major challenge for long-term storage of perovskite nanocrystals.Herein,we report a green synthesis at room temperature for gram-scale production of CsPbBr3 nanosheets with minimum use of solvent,saving over 95% of the solvent for the unity mass nanocrystal production.The perovskite colloid exhibits record stability upon long-term storage for up to 8 months,preserving a photoluminescence quantum yield of 63% in solid state.Importantly,the colloidal nanosheets show self-assembly behavior upon slow solidification,generating a crack-free thin film in a large area.The uniform film was then demonstrated as an efficient scintillation screen for X-ray imaging.Our findings bring a scalable tool for synthesis of high-quality perovskite nanocrystals,which may inspire the industrial optoelectronic application of large-area perovskite film. 展开更多
关键词 CsPbBr3 PEROVSKITE NANOSHEETS SELF-ASSEMBLY x-ray imaging screen
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A new method of detecting interferogram in differential phase-contrast imaging system based on special structured x-ray scintillator screen 被引量:6
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作者 刘鑫 郭金川 牛憨笨 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第7期193-197,共5页
An x-ray scintillator screen with a special structure, functioning as detector and analyser grating, was proposed for collecting the interferogram of differential phase contrast imaging without absorption grating and ... An x-ray scintillator screen with a special structure, functioning as detector and analyser grating, was proposed for collecting the interferogram of differential phase contrast imaging without absorption grating and difficulty of fabrication by a state of the art technique. On the basis of phase grating diffraction, a detecting model of the scintillator screen was built for analysing the phase and absorption information of objects. According to the analysis, a new method of phase retrievals based on two-images and the optimal structure of screen were presented. 展开更多
关键词 differential phase contrast x-ray scintillator screen phase retrieval
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Screening and early diagnosis of osteoporosis through X-ray and ultrasound based techniques 被引量:5
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作者 Paola Pisani Maria Daniela Renna +5 位作者 Francesco Conversano Ernesto Casciaro Maurizio Muratore Eugenio Quarta Marco Di Paola Sergio Casciaro 《World Journal of Radiology》 CAS 2013年第11期398-410,共13页
Effective prevention and management of osteoporosis would require suitable methods for population screenings and early diagnosis. Current clinicallyavailable diagnostic methods are mainly based on the use of either X-... Effective prevention and management of osteoporosis would require suitable methods for population screenings and early diagnosis. Current clinicallyavailable diagnostic methods are mainly based on the use of either X-rays or ultrasound(US). All X-ray based methods provide a measure of bone mineral density(BMD), but it has been demonstrated that other structural aspects of the bone are important in determining fracture risk, such as mechanical features and elastic properties, which cannot be assessed using densitometric techniques. Among the most commonly used techniques, dual X-ray absorptiometry(DXA) is considered the current 'gold standard' for osteoporosis diagnosis and fracture risk prediction. Unfortunately, as other X-ray based techniques, DXA has specific limitations(e.g., use of ionizing radiation, large size of the equipment, high costs, limited availability) that hinder its application for population screenings and primary care diagnosis. This has resulted in an increasing interest in developing reliable pre-screening tools for osteoporosis such as quantitative ultrasound(QUS) scanners, which do not involve ionizing radiation exposure and represent a cheaper solution exploiting portable and widely available devices. Furthermore, the usefulness of QUS techniques in fracture risk prediction has been proven and, with the last developments, they are also becoming a more and more reliable approach for assessing bone quality. However, the US assessment of osteoporosis is currently used only as a pre-screening tool, requiring a subsequent diagnosis confirmation by means of a DXA evaluation. Here we illustrate the state of art in the early diagnosis of this 'silent disease' and show up recent advances for its prevention and improved management through early diagnosis. 展开更多
关键词 Diagnosis of OSTEOPOROSIS screenING TECHNIQUES x-ray BASED methods Quantitative ULTRASOUND Peripheral sites Bone mineral density
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Current issues and future perspectives of gastric cancer screening 被引量:48
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作者 Chisato Hamashima 《World Journal of Gastroenterology》 SCIE CAS 2014年第38期13767-13774,共8页
Gastric cancer remains the second leading cause of cancer death worldwide. About half of the incidence of gastric cancer is observed in East Asian countries, which show a higher mortality than other countries. The eff... Gastric cancer remains the second leading cause of cancer death worldwide. About half of the incidence of gastric cancer is observed in East Asian countries, which show a higher mortality than other countries. The effectiveness of 3 new gastric cancer screening techniques, namely, upper gastrointestinal endoscopy, serological testing, and &#x0201c;screen and treat&#x0201d; method were extensively reviewed. Moreover, the phases of development for cancer screening were analyzed on the basis of the biomarker development road map. Several observational studies have reported the effectiveness of endoscopic screening in reducing mortality from gastric cancer. On the other hand, serologic testing has mainly been used for targeting the high-risk group for gastric cancer. To date, the effectiveness of new techniques for gastric cancer screening has remained limited. However, endoscopic screening is presently in the last trial phase of development before their introduction to population-based screening. To effectively introduce new techniques for gastric cancer screening in a community, incidence and mortality reduction from gastric cancer must be initially and thoroughly evaluated by conducting reliable studies. In addition to effectiveness evaluation, the balance of benefits and harms must be carefully assessed before introducing these new techniques for population-based screening. 展开更多
关键词 Gastric cancer screening MORTALITY Upper gastrointestinal endoscopy Upper gastrointestinal x-ray Serum pepsinogen test Helicobacter pylori antibody
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Comparing upper gastrointestinal X-ray and endoscopy for gastric cancer diagnosis in Korea 被引量:6
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作者 Hoo-Yeon Lee Eun-Cheol Park +2 位作者 Jae Kwan Jun Kui Son Choi Myung-Il Hahm 《World Journal of Gastroenterology》 SCIE CAS CSCD 2010年第2期245-250,共6页
AIM:To compare the cost and accuracy of upper gastrointestinal(GI)X-ray and upper endoscopy for diagnosis of gastric cancer using data from the 2002-2004 Korean National Cancer Screening Program(NCSP). METHODS:The stu... AIM:To compare the cost and accuracy of upper gastrointestinal(GI)X-ray and upper endoscopy for diagnosis of gastric cancer using data from the 2002-2004 Korean National Cancer Screening Program(NCSP). METHODS:The study population included 1 503 646 participants in the 2002-2004 stomach cancer screening program who underwent upper GI X-ray or endoscopy.The accuracy of screening was defined as the probability of detecting gastric cancer.We calculated the probability by merging data from the NCSP and the Korea Central Cancer Registry.We estimated the direct costs of the medical examination and the tests for up- per GI X-ray,upper endoscopy,and biopsy. RESULTS:The probability of detecting gastric cancervia upper endoscopy was 2.9-fold higher than via upper GI X-ray.The unit costs of screening using upper GI X-ray and upper endoscopy were$32.67 and$34.89, respectively.In 2008,the estimated cost of identifying one case of gastric cancer was$53094.64 using upper GI X-ray and$16 900.43 using upper endoscopy.The cost to detect one case of gastric cancer was the same for upper GI X-ray and upper endoscopy at a cost ratio of 1:3.7. CONCLUSION:Upper endoscopy is slightly more costly to perform,but the cost to detect one case of gastric cancer is lower. 展开更多
关键词 Gastric cancer Mass screening ENDOSCOPY Early diagnosis x-ray diagnosis
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BL19U2:Small-angle X-ray scattering beamline for biological macromolecules in solution at SSRF 被引量:5
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作者 Yi-Wen Li Guang-Feng Liu +4 位作者 Hong-Jin Wu Ping Zhou Chun-Xia Hong Na Li Feng-Gang Bian 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2020年第12期32-40,共9页
The BL19U2 at the Shanghai Synchrotron Radiation Facility is a small-angle X-ray scattering beamline dedicated to structural studies pertaining to biological macromolecules in solution.The beamline has been officially... The BL19U2 at the Shanghai Synchrotron Radiation Facility is a small-angle X-ray scattering beamline dedicated to structural studies pertaining to biological macromolecules in solution.The beamline has been officially opened to users in March 2015,and since then,a series of technological innovations has been developed to optimize beamline performance,thereby significantly improving the data collection efficiency and broadening the application scope of biological small-angle X-ray scattering.BL19U2 is ideal for the high-throughput screening of weakly scattered proteins,protein assemblies,nucleic acids,inorganic nanomaterials,and organic drug molecules.This paper describes the design and overview of the BL19U2 beamline.Versatile sample environments at the experimental station and some recent scientific highlights are presented. 展开更多
关键词 Shanghai synchrotron radiation facility Biological small-angle x-ray scattering High-throughput screening Biological macromolecules
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Asymptomatic Screening of Clients on Opioid Substitution Therapy for Tuberculosis: An Experience from India
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作者 Banuru Muralidhara Prasad Mandeep Singh +4 位作者 Mukesh Gupta Thekkur K. Pruthu Rajeev Kumar Parmesh C. Bhatnagar Sarabjit Singh Chadha 《Journal of Tuberculosis Research》 2019年第3期131-134,共4页
Clients on Opioid Substitution Therapy (OST) may be at risk of TB. We screened for tuberculosis in asymptomatic OST clients using Chest-X-ray (CXR) and sputum from those with CXR suggestive of TB were tested using Xpe... Clients on Opioid Substitution Therapy (OST) may be at risk of TB. We screened for tuberculosis in asymptomatic OST clients using Chest-X-ray (CXR) and sputum from those with CXR suggestive of TB were tested using Xpert MTB/Rif. Among 472 who underwent CXR, 0.1% had CXR suggestive of TB. The number needed to screen was 118 clients for one CXR suggestive of TB. All four clients with CXR suggestive of TB underwent MTB/Rif assay and one was diagnosed with TB. The TB patient was asymptomatic and could have been missed through the passive approach. We recommend further studies to explore ACF among OST clients. 展开更多
关键词 OST TUBERCULOSIS Active Case Finding screenING CHEST x-ray
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A Study on Cascade R-CNN-Based Dangerous Goods Detection Using X-Ray Image
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作者 Sang-Hyun Lee 《Computers, Materials & Continua》 SCIE EI 2022年第11期4245-4260,共16页
X-ray inspection equipment is divided into small baggage inspection equipment and large cargo inspection equipment.In the case of inspection using X-ray scanning equipment,it is possible to identify the contents of go... X-ray inspection equipment is divided into small baggage inspection equipment and large cargo inspection equipment.In the case of inspection using X-ray scanning equipment,it is possible to identify the contents of goods,unauthorized transport,or hidden goods in real-time by-passing cargo through X-rays without opening it.In this paper,we propose a system for detecting dangerous objects in X-ray images using the Cascade Region-based Convolutional Neural Network(Cascade R-CNN)model,and the data used for learning consists of dangerous goods,storage media,firearms,and knives.In addition,to minimize the overfitting problem caused by the lack of data to be used for artificial intelligence(AI)training,data samples are increased by using the CP(copy-paste)algorithm on the existing data.It also solves the data labeling problem by mixing supervised and semi-supervised learning.The four comparative models to be used in this study are Faster Regionbased Convolutional Neural Networks Residual2 Network-101(Faster R-CNN_Res2Net-101)supervised learning,Cascade R-CNN_Res2Net-101_supervised learning,Cascade Region-based Convolutional Neural Networks Composite Backbone Network V2(CBNetV2)Network-101(Cascade R-CNN_CBNetV2Net-101)_supervised learning,and Cascade RCNN_CBNetV2-101_semi-supervised learning which are then compared and evaluated.As a result of comparing the performance of the four models in this paper,in case of Cascade R-CNN_CBNetV2-101_semi-supervised learning,Average Precision(AP)(Intersection over Union(IoU)=0.5):0.7%,AP(IoU=0.75):1.0%than supervised learning,Recall:0.8%higher. 展开更多
关键词 Cascade R-CNN model faster R-CNN model x-ray screening equipment Res2Net supervised learning semi-supervised learning
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Using Prostatic Fluid Levels of Some Trace Elements and Their Combinations in Non-Invasive and Highly Accurate Screening for Prostate Cancer
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作者 Vladimir Zaichick 《Journal of Cancer Therapy》 2020年第1期1-17,共17页
Objective: Prostate specific antigen (PSA) does not provide the high reliability and precision that is required for an accurate screening for prostate cancer?(PCa). The aim of our study was to search for a simple, rap... Objective: Prostate specific antigen (PSA) does not provide the high reliability and precision that is required for an accurate screening for prostate cancer?(PCa). The aim of our study was to search for a simple, rapid, direct, preferably non-invasive, and highly accurate biomarker and procedure for the screening for PCa. Method: The levels of trace elements (TE) Br, Fe, Rb, Sr,?and Zn were prospectively evaluated in expressed prostatic fluid (EPF). Also?Zn/Br, Zn/Fe, Zn/Rb, Zn/Sr concentration ratios as well as ZnRb and (ZnRb)/Fe concentration combinations were calculated for EPF samples, obtained from 38 apparently healthy males and from 33, 51, and 24 patients with chronic prostatitis, benign prostatic hyperplasia, and PCa, respectively. Measurements were performed using an energy dispersive X-ray fluorescent (EDXRF) microanalysis. Results: It was found that in the EPF of cancerous prostates the levels of Rb, Zn, Zn/Br, Zn/Fe, Zn/Sr, ZnRb, and (ZnRb)/Fe were significantly lower in comparison with those in the EPF of normal, inflamed, and hyperplastic prostates. For example, in comparison hyperplastic?with cancerous prostates p values obtained using Student’s t-test and?Wilcoxon-Mann-Whitney U-test were Conclusions: The levels of TE and their combinations in EPF, obtained by EDXRF, is a fast, reliable, andnon-invasive diagnostic tool that can be successfully used by local, non- urologist physicians at the point-of-care to provide a highly effective PCa screening and as an additional confirmatory test before a prostate gland biopsy. 展开更多
关键词 UROLOGY screening Prostate Cancer EXPRESSED PROSTATIC Fluid Trace Element Content Energy-Dispersive x-ray Fluorescent Analysis
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Most Intense X-Ray Lines of the Helium Isoelectronic Sequence for Plasmas Diagnostic
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作者 Ibrahima Sakho 《Journal of Modern Physics》 2020年第4期487-501,共15页
We report accurate wavelengths for the three most intense lines (resonance line: 1s2 1S0 - 1s2p 1P1, intercombination line: 1s2 1S0 - 1s2p 3P1 and forbidden line: 1s2 1S0 - 1s2s 3S1) along with wavelengths for the 1s2... We report accurate wavelengths for the three most intense lines (resonance line: 1s2 1S0 - 1s2p 1P1, intercombination line: 1s2 1S0 - 1s2p 3P1 and forbidden line: 1s2 1S0 - 1s2s 3S1) along with wavelengths for the 1s2 1S0 - 1snp1P1 and 1S0 - 1snp3P2 (2 ≤ n ≤ 25) transitions in He-like systems (Z = 2 – 13). The first spectral lines that belong to the above transitions are established in the framework of the Screening Constant per Unit Nuclear Charge method. The results obtained agree excellently with various experimental and theoretical literature data. The uncertainties in wavelengths between the present calculations and the available literature data are less than 0.004&Aring;. A host of new data listed in this paper may be of interest in astrophysical and laboratory plasmas diagnostic. 展开更多
关键词 HE-LIKE Systems SEMI-EMPIRICAL screening Constant Per Unit Nuclear Charge Excited States x-ray Spectra
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像增强器亮度增益测试的重复性研究 被引量:9
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作者 拜晓锋 尹雷 +2 位作者 胡文 师宏立 贺英萍 《红外与激光工程》 EI CSCD 北大核心 2013年第2期495-498,共4页
亮度增益是衡量微光像增强器图像增强能力的一个重要技术指标,其直接影响着微光夜视系统的观察效果。为了提高像增强器亮度增益测试的重复性,在给像增强器提供稳定供电的条件下研究了光源色温、光源输出光亮度以及荧光屏发光亮度随时间... 亮度增益是衡量微光像增强器图像增强能力的一个重要技术指标,其直接影响着微光夜视系统的观察效果。为了提高像增强器亮度增益测试的重复性,在给像增强器提供稳定供电的条件下研究了光源色温、光源输出光亮度以及荧光屏发光亮度随时间的变化过程,分析了光源色温和光源输出光亮度对于亮度增益的影响机理以及荧光屏发光亮度对于亮度增益测试的影响过程,确定了光源的预热时间不少于15 min且像增强器的工作时间不少于1 min的结论。实际测试结果表明:当光源充分预热且严格控制像增强器的工作时间时测量得到的像增强器亮度增益的重复性优于3%。 展开更多
关键词 亮度增益 重复性 像增强器 色温 荧光屏
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高性能近贴式像增强器的调制传递函数分析 被引量:16
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作者 陶禹 金伟其 +2 位作者 王瑶 石峰 郭宏 《光子学报》 EI CAS CSCD 北大核心 2016年第6期162-167,共6页
为了提升微光夜视系统中高性能近贴式像增强器极限分辨力,在归纳近贴式像增强器及其部件调制传递函数模型的基础上,结合高性能超二代和超三代像增强器的结构和电参量以及典型产品性能值,研究分析了像增强器及其部件调制传递函数分布特... 为了提升微光夜视系统中高性能近贴式像增强器极限分辨力,在归纳近贴式像增强器及其部件调制传递函数模型的基础上,结合高性能超二代和超三代像增强器的结构和电参量以及典型产品性能值,研究分析了像增强器及其部件调制传递函数分布特性参数,及它们对像增强器极限分辨力和综合评价参量-信道宽度的影响.研究结果表明:进一步提升像增强器性能需要提升荧光屏的性能或改善调制传递函数分布特征;信道宽度参量可作为评价像增强器调制传递函数曲线分布特征的有效参量.研究结论对于进一步提升高性能像增强器的性能具有理论指导意义. 展开更多
关键词 近贴式像增强器 调制传递函数 荧光屏 分辨力 信道宽度
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新型X射线影像增强系统分辨率数学模型 被引量:4
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作者 喻春雨 常本康 魏殿修 《光电工程》 EI CAS CSCD 北大核心 2006年第11期120-122,127,共4页
课题组设计了新型的X射线影像增强系统。由于它是由多个光电器件级联而成的链状成像系统,在组成器件之间存在着一定的分辨率函数关系,并且这种函数关系会随着成像视野的变化而变化。鉴于此种关系,建立了系统的分辨率数学模型,对多种器... 课题组设计了新型的X射线影像增强系统。由于它是由多个光电器件级联而成的链状成像系统,在组成器件之间存在着一定的分辨率函数关系,并且这种函数关系会随着成像视野的变化而变化。鉴于此种关系,建立了系统的分辨率数学模型,对多种器件组合效果进行理论分析。结果表明分辨率理论计算值和实验测量值比较吻合,所以分辨率数学模型节省了系统的设计时间和费用,对提高系统分辨率起着理论指导作用。 展开更多
关键词 X射线影像增强系统 增感屏 亮度像增强器 分辨率 数学模型
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树脂纳米铈防辐射复合材料的制备及其性能研究 被引量:8
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作者 安骏 刘吉华 辛寅昌 《工程塑料应用》 CAS CSCD 北大核心 2006年第8期20-23,共4页
利用强酸性苯乙烯系阳离子交换树脂制备防中低强度的X射线辐射的树脂纳米铈复合材料,用透射电镜观察它的粒度和形貌,发现铈粒径在20nm左右且分布均匀。利用具有中低强度的X射线的CT扫描仪对该种树脂纳米铈复合材料扫描,发现在相同含量... 利用强酸性苯乙烯系阳离子交换树脂制备防中低强度的X射线辐射的树脂纳米铈复合材料,用透射电镜观察它的粒度和形貌,发现铈粒径在20nm左右且分布均匀。利用具有中低强度的X射线的CT扫描仪对该种树脂纳米铈复合材料扫描,发现在相同含量的条件下树脂纳米铈复合材料比普通硝酸铈对X射线的衰减能力高许多。另外由于纳米铈的小尺寸效应和特殊的轨道特征,树脂纳米铈复合材料还可作为增感屏使用,是一种具有多功能的防辐射材料。 展开更多
关键词 树脂 纳米铈复合材料 CT X射线 衰减 增感屏
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影响超二代像增强器最高增益的因数分析 被引量:7
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作者 李晓峰 杜木林 +3 位作者 徐传平 黄丽书 陈俊宇 常乐 《光子学报》 EI CAS CSCD 北大核心 2022年第3期123-134,共12页
在阴极灵敏度、微通道板固有增益、屏效以及屏压一定的条件下,超二代像增强器的最高亮度增益由微通道板增益所决定。实验中发现微通道板增益存在一个最高值,当微通道板增益超过最高值时,像增强器会产生自激发光。像增强器产生自激发光时... 在阴极灵敏度、微通道板固有增益、屏效以及屏压一定的条件下,超二代像增强器的最高亮度增益由微通道板增益所决定。实验中发现微通道板增益存在一个最高值,当微通道板增益超过最高值时,像增强器会产生自激发光。像增强器产生自激发光时,图像的对比度、分辨力消失,图像亮度的增强作用失去意义。因此超二代像增强器的最高亮度增益受自激发光的影响。超二代像增强器产生自激发光的原因是像增强器内部微通道板电子倍增形成了正反馈。微通道板的最高增益与光电阴极灵敏度、荧光屏铝膜的透过率成反比,所以在阴极灵敏度一定的条件下,影响微通道板最高增益的因数是荧光屏铝膜的透过率。在微通道板固有增益一定的条件下,提高微通道板的板压不会影响像增强器的分辨力和等效背景照度,但会降低像增强器的信噪比,因此信噪比又是影响超二代像增强器最高亮度增益的一个因数。要进一步提高超二代像增强器的最高亮度增益,在阴极灵敏度、屏效以及屏压一定的条件下,需要提高微通道板的固有增益,同时减小荧光屏铝膜的透过率。 展开更多
关键词 像增强器 正反馈 微通道板 光电阴极 荧光屏 暗发射
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X射线增感屏的图象信息传输特性分析 被引量:3
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作者 王义 杜宏亮 +3 位作者 王经瑾 王奎禄 刘国治 朱国富 《光子学报》 EI CAS CSCD 1999年第2期155-160,共6页
本文采用MonteCarlo方法详细模拟了不同能量光子与增感屏的作用过程,对于一种稀土(Gd2O2S∶Tb)增感屏,计算了出射可见光子数的概率分布、平均出射光子数、统计因子、X射线检测效率以及DQE等增感屏出射可见... 本文采用MonteCarlo方法详细模拟了不同能量光子与增感屏的作用过程,对于一种稀土(Gd2O2S∶Tb)增感屏,计算了出射可见光子数的概率分布、平均出射光子数、统计因子、X射线检测效率以及DQE等增感屏出射可见光子数的概率分布曲线均有三个峰,随着入射X射线能量的增加,各峰之间距离增大,相对强弱对比增大;其余各曲线在Gd原子K壳层结合能(5024keV)附近,均有突变这些结果提供了增感屏图象信息传输性能的基本参数。 展开更多
关键词 增感屏 统计因子 量子效率 图象信息传输 X射线
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一种应用于X射线成象系统的多CCD图象传感器 被引量:2
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作者 王义 王经瑾 +3 位作者 王奎禄 刘国治 朱国富 杜宏亮 《光子学报》 EI CAS CSCD 1999年第1期51-56,共6页
我们设计了一种基于多CCD的X射线图象传感器.这种图象传感器由X射线增感屏、光学系统和多个CCD传感器组成.与传统的单CCD图象传感器相比,本传感器不但成象面积大,空间分辨力高,而且图象在信噪比,病灶检测灵敏度等方面... 我们设计了一种基于多CCD的X射线图象传感器.这种图象传感器由X射线增感屏、光学系统和多个CCD传感器组成.与传统的单CCD图象传感器相比,本传感器不但成象面积大,空间分辨力高,而且图象在信噪比,病灶检测灵敏度等方面都有所改善,并且系统具有较高的效费比.研究了多CCD图象传感器的成象形式、图象几何失真(主要是桶形失真)的矫正方法、亮度矫正方法及图象重建方法.实验系统(增感屏+2×2CCD)的实验结果验证了设计思想的可行性和系统的实用性. 展开更多
关键词 增感屏 CCD 传感器 X射线成象系统
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X射线增感屏用纳米CaWO4的Pechini溶胶-凝胶法制备及其光学性能 被引量:4
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作者 杨志平 赵金鑫 +5 位作者 李小宁 刘海燕 李盼来 李旭 刘冲 杨勇 《发光学报》 EI CAS CSCD 北大核心 2008年第2期279-282,共4页
采用Pechini溶胶-凝胶法制得纳米级CaWO4荧光粉,通过X射线衍射图、扫描电镜和发射光谱对其形貌和发光性能进行了研究,结果表明750℃条件下所得样品为纯相CaWO4晶体,在X射线激发下发射峰位于420nm,与感蓝胶片的光谱灵敏度匹配良好。其粒... 采用Pechini溶胶-凝胶法制得纳米级CaWO4荧光粉,通过X射线衍射图、扫描电镜和发射光谱对其形貌和发光性能进行了研究,结果表明750℃条件下所得样品为纯相CaWO4晶体,在X射线激发下发射峰位于420nm,与感蓝胶片的光谱灵敏度匹配良好。其粒径在纳米量级且粒度分布集中是该方法所得CaWO4荧光粉的突出优点。将此荧光粉制成X射线增感屏并与市售同类产品相比,该增感屏可使感光片的成像质量显著提高。 展开更多
关键词 Pechini溶胶-凝胶法 X射线增感屏用荧光粉 CAWO4
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光谱匹配在X光机设计中的应用 被引量:1
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作者 喻春雨 常本康 +2 位作者 刘铁兵 王世允 张俊举 《光子学报》 EI CAS CSCD 北大核心 2006年第12期1875-1877,共3页
将X射线成像技术和微光成像技术相结合,设计了组合新型的X射线影像增强系统·为了得到满意的成像性能,在设计前研究了Gd2O2S∶Tb和CaWO4两种X射线屏和SuperS251和SuperS252两种光电阴极之间的四种屏-光电阴极组合的光谱匹配特征,对... 将X射线成像技术和微光成像技术相结合,设计了组合新型的X射线影像增强系统·为了得到满意的成像性能,在设计前研究了Gd2O2S∶Tb和CaWO4两种X射线屏和SuperS251和SuperS252两种光电阴极之间的四种屏-光电阴极组合的光谱匹配特征,对应的光谱匹配系数值分别为0.644,0.761,0.369,0.571·以光谱匹配曲线及光谱匹配系数计算数据为理论依据,最终选择Gd2O2S∶TbX射线屏和SuperS252光电阴极的组合作为该新型X射线影像增强系统的主要器件,得到了成像性能令人满意的X光机· 展开更多
关键词 X射线学 X光机 X射线像增强系统 X射线屏 微光像增强器 光谱响应
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