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Digital selenium radiography: anti-scatter grid for chest radiography in a clinical study

BRITISH JOURNAL OF RADIOLOGY 2000年第873期73卷 963-968页

作者： Bernhardt, TM Rapp-Bernhardt, U Hausmann, T Reichel, G Krause, UW Doehring, W Otto Von Guericke Univ Univ Hosp Dept Diagnost Radiol D-39120 Magdeburg Germany

The purpose of this study was to evaluate the diagnostic performance of an additional stationary anti-scatter grid in digital selenium radiography (DSR) compared with images acquired with only an air gap. Chest radiographs were obtained with DSR in 100 patients with and without an anti-scatter grid. Four observers scored 12 anatomical landmarks, catheters and wire cerclages for their visualization in both subsets of images. Statistical analysis was performed using a paired t-test. Anatomical landmarks, catheters and wire cerclages were statistically better visualized in regions of high attenuation when the images were performed with an anti-scatter grid. No statistically significant difference was noted for peripheral regions, nor for sex and weight of the patient between the two modalities. Therefore, an anti-scatter grid is not recommended for chest radiography as it increases the radiation exposure of patients without having a significant impact on visualization for all regions of the chest.

关键词：辐射剂量 x线影像增强/仪器和设备放射摄影术胸部/仪器和设备散射辐射硒敏感性与特异性成年人老年人老年人 80以上女(雌)性人类男(雄)性中年人

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Quantitative methods in phase-contrast x-ray imaging

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JOURNAL OF DIGITAL IMAGING 2000年第2期13卷 121-126页

作者： Gureyev, TE Stevenson, AW Paganin, D Mayo, SC Pogany, A Gao, D Wilkins, SW CSIRO Clayton S MDC Vic 3169 Australia

A new method for extracting quantitative information from phase-contrast x-ray images obtained with microfocus x-ray sources is presented. The proposed technique allows rapid noninvasive characterization of the internal structure of thick optically opaque organic samples. The method does not generally involve any sample preparation and does not need any x-ray optical elements (such as monochromators, zone plates, or interferometers). As a consequence, samples can be imaged in vivo or in vitro, and the images are free from optical aberrations. While alternative techniques of x-ray phase-contrast imaging usually require expensive synchrotron radiation sources, our method can be implemented with conventional, albeit microfocus, x-ray tubes, which greatly enhances its practicality. In the present work, we develop the theoretical framework, perform numerical simulations, and present the first experimental results, demonstrating the viability of the proposed approach. We believe that this method should find wide-ranging applications in clinical radiology and medical research. Copyright (C) 2000 by W.B. Saunders Company.

关键词：图像处理计算机辅助/仪器和设备体模显象术 x线影像增强/仪器和设备 x线摄影放大/仪器和设备放射摄影术/仪器和设备动物人类小鼠

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Aerospace technology transfer to breast cancer imaging

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ACTA ASTRONAUTICA 1997年第4-10期41卷 515-523页

作者： Winfield, DL Res Triangle Inst Res Triangle Pk NC 27709 USA

In the United States in 1996, an estimated 44,560 women died of breast cancer, and 184,300 new cases were diagnosed. Advances in space technology are now making significant improvements in the imaging technologies used in managing this important foe. The first of these spinoffs, a digital spot mammography system used to perform stereotactic fine-needle breast biopsy, uses a backside-thinned CCD developed originally for the Space Telescope Imaging Spectrometer. This paper describes several successful biomedical applications which have resulted from collaborative technology transfer programs between the National Aeronautics and Space Administration (NASA), the National Cancer Institute (NCI), and the U.S. Dept. of Health and Human Services Office on Women's Health (OWH). These programs have accelerated the introduction of direct digital mammography by two years. In follow-on work, RTI is now assisting the HHS Office on Women's Health to identify additional opportunities for transfer of aerospace, defense, and intelligence technologies to image-guided detection, diagnosis. and treatment of breast cancer. The technology identification and evaluation effort culminated in a May 1997 workshop, and the formative technology development partnerships are discussed. (C) 1998 International Astronautical Federation. Published by Elsevier Science Ltd.

关键词：天文学活组织检查针吸/方法乳腺肿瘤/诊断乳腺肿瘤/放射摄影术结晶学 x线诊断计算机辅助/发展趋势图像处理计算机辅助机构间关系乳房x线摄影术/仪器和设备乳房x线摄影术/方法国立卫生研究院(美国) 神经网络(计算机) x线影像增强/仪器和设备 x线影像增强/方法 x线影像增强/发展趋势放射摄影影像解释计算机辅助技术转让远程医学/发展趋势美国美国卫生和人类服务部美国国家航空和宇宙航行管理局女(雌)性人类

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A new needle-crystalline computed radiography detector

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JOURNAL OF DIGITAL IMAGING 2000年第2期13卷 117-120页

作者： Leblans, P Struye, L Willems, P Agfa Gevaert NV B-2640 Mortsel Belgium

The most successful digital radiography detectors to date have been storage phosphor plates used in computed radiography (CR), The detector is cheap, has good producibility, and is robust. Direct radiography (DR) systems are being developed based on flat-panel technology. Better image quality is claimed for some DR systems. On the other hand, DR detectors have low producibility and robustness, and a high price. A new CR detector is being developed at Agfa that combines the advantages of CR and DR. It is a storage phosphor plate made up of needle-shaped crystals. The phosphor efficiently converts absorbed x-ray quanta into photostimulable centers for efficient read out. It has a large dynamic range and its emision is efficiently detected with both photomultiplier tube (PMT) and charge coupled device (CCD). It is shown that CR systems based on the new detector offer image quality that matches that of the best DR systems. Copyright (C) 2000 by W.B. Saunders Company.

关键词：计算机存储设备设备设计 x线影像增强/仪器和设备工艺学放射学体层摄影术 x线计算机/仪器和设备 x线增感屏人类

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Temporomandibular joint pantomography using charge-coupled device, photostimulable phosphor, and film receptors: A comparison

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JOURNAL OF DIGITAL IMAGING 1999年第2期12卷 9-13页

作者： Farman, TT Farman, AG Univ Louisville Sch Dent Div Radiol & Imaging Sci Louisville Hlth Sci Ctr Louisville KY 40292 USA

Our objective was to compare the accuracy and practicality in use of three available imaging receptors for temporomandibular joint (TMJ) imaging;namely, two computer-assisted and one traditional analog x-ray film system. A standardized tissue-equivalent encased human skull specimen was imaged using lateral and posteroanterior (PA) pantomographic projections with the Orthopantomograph OP 100 (Instrumentarium imaging, Tuusula, Finland) and three different receptor modalities: (1) Ektavision film with Ektavision screens (Eastman Kodak, Rochester, NY);(2) DenOptix photostimulable phosphor screens (Dentsply/Gendex, Chicago, IL);and (3) the charge-coupled device (CCD) receptor, DigiPan (TREx/Trophy Radiology, Marne-laVallee, France). The effective focal trough was found for each receptor using lead resolution grids placed at fractional millimeter distances along empirically determined beam projection angulations, The time to acquire and process images was also established. We found that the CCD system permitted real-time display, whereas the use of traditional film took 2 minutes to load the cassette in a darkroom and perform the exposure, and then a further 2 minutes to unload and process, The storage phosphor took 3 minutes to unload the cassette and process the image and a further 20 seconds to clear the plate following laser scanning, Film produced the greatest maximum resolution followed by the storage phosphor and the CCD. In conclusion, CCD-based TMJ pantomography provided an instant image, The photostimulable phosphor system used was the least satisfactory in terms of the time expended to obtain an image, but provided better spatial resolution than the CCD. Ektavision film/screens provided the best spatial resolution in this investigation. Copyright (C) 1999 by W,B. Saunders Company.

关键词：数据显示图像处理计算机辅助体模显象术 x线影像增强/仪器和设备 x线影像增强/方法放射摄影术全景/仪器和设备放射摄影术全景/方法颞下颌关节/诊断显像时间因素 x线胶片 x线增感屏人类

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Dose efficiency and low-contrast detectability of an amorphous silicon x-ray detector for digital radiography

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PHYSICS IN MEDICINE AND BIOLOGY 2000年第9期45卷 2653-2669页

作者： Aufrichtig, R xue, P Perkin Elmer GE Med Syst Xray Detector Engn Santa Clara CA 95054 USA GE Med Syst Xray Syst Engn Milwaukee WI USA

The effect of dose reduction on low-contrast detectability is investigated theoretically and experimentally for a production grade amorphous silicon (a-Si) x-ray detector and compared with a standard thoracic screen-film combination. A non-prewhitening matched filter observer model modified to include a spatial response function and internal noise for the human visual system (HVS) is used to calculate a signal-to-noise ratio (SNR) related to object detectability. Other inputs to the SNR calculation are the detective quantum efficiency (DQE) and the modulation transfer function (MTF) of the imaging system. Besides threshold detectability, the model predicts the equivalent perception dose ratio (EPDR), which is the fraction of the screen-him exposure for which the digital detector provides equal detectability. Images of a contrast-detail phantom are obtained with the digital detector at dose levels corresponding to 27%, 41%, 63% and 100% of the dose used for screen-film. The images are used in a four-alternative forced choice (4-AFC) observer perception study in order to measure threshold detectability. A statistically significant improvement in contrast detectability is measured with the digital detector at 100% and 63% of the screen-film dose. There is no statistical difference between screen-film and digital at 41% of the dose. On average, the experimental EPDR is 44%, which agrees well with the model prediction of 40%.

关键词：设备设计图像处理计算机辅助观察者偏差体模显象术量子论辐射剂量 x线影像增强/仪器和设备 x线影像增强/方法结果可重复性敏感性与特异性硅 x线增感屏人类

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直接数字化摄影在胸部检查中的应用价值

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中国校医 2017年第3期31卷 214-214页

作者：徐志鹏福州大学医院放射科福建福州350002

随着x线设备的发展和技术更新,数字探测器成功研制并大量应用于临床,使得直接数字化摄影（DR）也慢慢地在基层医院普及。DR的探测器是集影像采集与转换于一体,直接输出数字图像信息,采集时间短,成像环节少,成像时间短,因此可有效减少胸... 详细信息

随着x线设备的发展和技术更新,数字探测器成功研制并大量应用于临床,使得直接数字化摄影（DR）也慢慢地在基层医院普及。DR的探测器是集影像采集与转换于一体,直接输出数字图像信息,采集时间短,成像环节少,成像时间短,因此可有效减少胸部摄影中心脏搏动影响,减少了图像的噪音,提高了影像的对比度和分辨率。

关键词：胸部疾病/诊断 x线影像增强/仪器和设备

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