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Medical progress through technology最新文献

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The application of finite impulse response filters to the detection of fetal electrocardiogram signals. 有限脉冲响应滤波器在胎儿心电图信号检测中的应用。
Medical progress through technology Pub Date : 1993-01-01
R G Phoenix, J A Crowe, N M Gibson, W Peasgood, M S Woolfson, T R Faulkner
{"title":"The application of finite impulse response filters to the detection of fetal electrocardiogram signals.","authors":"R G Phoenix,&nbsp;J A Crowe,&nbsp;N M Gibson,&nbsp;W Peasgood,&nbsp;M S Woolfson,&nbsp;T R Faulkner","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>An investigation is made into the potential application of linear phase digital filters to the detection of fetal electrocardiogram signals buried in noise. Such an assessment is made by applying both matched and linear phase filters to six computer simulated fetal signals and also to experimental data. The number of times that the R-wave locations are correctly located (N), the RMS error in R-wave location (RMS) and the correlation coefficient between the averaged and clean signals are computed. It is found that the averaged fetal complexes computed using these two types of filter are almost identical. However, for three of the signals, the values for N and RMS obtained using the linear phase filter are inferior to the corresponding results obtained with the matched filter. It is suggested that the averaged complex obtained using the linear phase filter could be used as an approximation to the matched filter template; it is found that this procedure results in an effectiveness of detecting R-waves that is, for the most part, comparable with the performance of a matched filter based on the QRS complex.</p>","PeriodicalId":76136,"journal":{"name":"Medical progress through technology","volume":"19 2","pages":"89-103"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19101553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Anthropomorphic radiological phantoms for mammography. 乳房x线摄影的拟人化放射学幻象。
Medical progress through technology Pub Date : 1993-01-01
M J Yaffe, J W Byng, C B Caldwell, N R Bennett
{"title":"Anthropomorphic radiological phantoms for mammography.","authors":"M J Yaffe,&nbsp;J W Byng,&nbsp;C B Caldwell,&nbsp;N R Bennett","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Anthropomorphic radiological phantoms are useful in evaluating image quality in mammography by providing realistic detection tasks to the observer. Methods for creating such phantoms, based on original patient mammograms, are described. Photochemical enhancement techniques and application of fractal interpolation methods for improving the fine detail information contained in such phantoms are discussed. Approaches to incorporating additional calibrated test targets within the phantom are also described.</p>","PeriodicalId":76136,"journal":{"name":"Medical progress through technology","volume":"19 1","pages":"23-30"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19288830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Circuit model-based analysis of the impedance rheopneumogram. 基于电路模型的阻抗流变图分析。
Medical progress through technology Pub Date : 1993-01-01
T T Choy, J Ye
{"title":"Circuit model-based analysis of the impedance rheopneumogram.","authors":"T T Choy,&nbsp;J Ye","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Impedance rheopneumography, like other applications of electrical bio-impedance, is receiving increasing attention as a simple, non-invasive tool for clinical diagnosis of the pulmonary circulation. However, one major drawback of this method lies in the difficulty in computing accurately the time domain parameters therefrom for diagnostic purposes. This paper presents a model-oriented analysis technique based on physiological consideration of both the arterial and venous pathways of the pulmonary circulatory system. The technique involves a combination of a two-segment model and a modified form of the 'Windkessel' model, the summed response of which is curve-fitted to measurement data via the non-linear method of Marquardt to obtain the system parameters. A simple illustrative application is also given to explain the changes in wave morphology for a subject under measurement in the supine and sit-up positions. The result suggests that this technique shows promise of providing useful physiological information and better insight of system behaviour than existing technique.</p>","PeriodicalId":76136,"journal":{"name":"Medical progress through technology","volume":"19 4","pages":"179-85"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19049002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
On digital filtering of auditory brainstem responses. 听觉脑干反应的数字滤波研究。
Medical progress through technology Pub Date : 1993-01-01
T K Grönfors, M Juhola
{"title":"On digital filtering of auditory brainstem responses.","authors":"T K Grönfors,&nbsp;M Juhola","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Auditory brainstem responses are very short events. Therefore, their signal processing has to be executed really carefully. Their latency and amplitude parameters, which are employed to indicate pathological changes, are especially sensitive to digital filtering. Consequently, we have studied appropriate nonrecursive and recursive filters for signals of auditory brainstem responses. Our results seem to refer to rather similar effects of both nonrecursive and recursive filters on the parameters of auditory brainstem responses.</p>","PeriodicalId":76136,"journal":{"name":"Medical progress through technology","volume":"19 3","pages":"145-51"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19119682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
On-line image verification in radiation therapy: an early USA experience. 放射治疗中的在线图像验证:早期美国经验。
Medical progress through technology Pub Date : 1993-01-01
J W Wong, R L Gerber, J M Michalski, M L Graham, K J Halverson, A Y Cheng, P Grigsby, M Renna, P Sawyer, C A Perez
{"title":"On-line image verification in radiation therapy: an early USA experience.","authors":"J W Wong,&nbsp;R L Gerber,&nbsp;J M Michalski,&nbsp;M L Graham,&nbsp;K J Halverson,&nbsp;A Y Cheng,&nbsp;P Grigsby,&nbsp;M Renna,&nbsp;P Sawyer,&nbsp;C A Perez","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The intense effort in the past 5 to 10 years to develop on-line image verification (OLIV) systems is made partly in anticipation of the increased verification demands of complex 3-dimensional (3D) conformal radiation therapy, and partly to improve on the current practice of weekly treatment verification. These systems allow convenient acquisition of daily portal images or many images during one treatment session. Systems based on fluoroscopic and scanning approaches can now be purchased from various vendors and are being evaluated at several radiation therapy centers. The performances of these systems vary, but all appear to be adequate for clinical use. At the Mallinckrodt Institute of Radiology, we have been conducting clinical on-line imaging for the past 3 years using a fiber-optic fluoroscopic system. Daily operation of the system requires coordinated participation of the physics and radiation therapy technology staff. The major consideration is in the management and evaluation of the large amount of verification images about each individual patient. At present, it is not clear whether the technology would be cost-effective in the clinical setting. However, it is clear that OLIV provides a powerful tool in enhancing our knowledge of treatment variation. The information will be invaluable in the development of improved treatment techniques. It is also likely that these systems will play a important part in the verification of 3D conformal radiation therapy.</p>","PeriodicalId":76136,"journal":{"name":"Medical progress through technology","volume":"19 1","pages":"43-54"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19288834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Time series analysis of complex dynamics in physiology and medicine. 生理和医学中复杂动力学的时间序列分析。
Medical progress through technology Pub Date : 1993-01-01
L Glass, D Kaplan
{"title":"Time series analysis of complex dynamics in physiology and medicine.","authors":"L Glass,&nbsp;D Kaplan","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A variety of mathematical methods have been developed to characterize complex rhythms that are observed in physiological systems. These methods include classical techniques such as the mean, standard deviation, and power spectrum, as well as newer methods suggested by nonlinear dynamics including the dimension, Lyapunov number, and entropy. This paper reviews the various ways in which these measures have been applied to analyze physiological dynamics with emphasis on the potential advantages and pitfalls of the various approaches. We conclude that these methods may be useful to help characterize complex time series, but only rarely is it possible to use these methods to establish deterministic chaos in a given time series.</p>","PeriodicalId":76136,"journal":{"name":"Medical progress through technology","volume":"19 3","pages":"115-28"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19119013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Assessment of cardiac output during exercise. Transthoracic impedance vs. heart rate alone. 运动时心输出量的评估。经胸阻抗vs单独心率。
Medical progress through technology Pub Date : 1993-01-01
E Horstmann, B Könn
{"title":"Assessment of cardiac output during exercise. Transthoracic impedance vs. heart rate alone.","authors":"E Horstmann,&nbsp;B Könn","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Previous investigators demonstrated divergent results, when comparing impedance to other established methods for the assessment of cardiac output. Cardiac output is defined as stroke volume multiplied by heart rate. Heart rate is easy to measure and the main determinant of cardiac output during exercise under physiologic conditions. Therefore, cardiac output (CO) by tetrapolar impedance cardiography (TIC) was compared to thermodilution (TD) in 35 patients (P). In a second step it was examined how heart rate alone would perform as a predictor of CO under exercise. Measurements were done at rest, 25, 50, 75, and 100 w. Results were corrected for hematocrit (HCT). There was no correlation between CO by TD and by TIC at rest (r = -0.006). Under exercise correlation was somewhat better with r = 0.45 despite correction for HCT. Mean values were similar, but scatter was wide. Relative increase in CO by both methods was also correlated (r = 0.46), while heart rate alone correlated best to TD (r = 0.65). Transthoracic impedance cardiography is not a reliable technique to measure absolute values of cardiac output at rest. During exercise large scatter limits this method to the measurement of CO in larger groups. At exercise heart rate alone appears to be a better indicator of increase of cardiac output than impedance cardiography.</p>","PeriodicalId":76136,"journal":{"name":"Medical progress through technology","volume":"19 4","pages":"173-8"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19049008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A measurement system of head movements for the vestibulo-ocular reflex. 用于前庭眼反射的头部运动测量系统。
Medical progress through technology Pub Date : 1993-01-01
H Aalto, M Juhola, I Pyykkö
{"title":"A measurement system of head movements for the vestibulo-ocular reflex.","authors":"H Aalto,&nbsp;M Juhola,&nbsp;I Pyykkö","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>This paper describes an efficient technique to record head movement signals for the computer analysis of vestibulo-ocular reflex. The technique has essentially lower costs than the method of rotatory chair. It is easy to operate and yields recordings of high quality. The system is connected to our analysis program of vestibulo-ocular reflex, the results of which are briefly presented.</p>","PeriodicalId":76136,"journal":{"name":"Medical progress through technology","volume":"19 3","pages":"153-7"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19119683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Direct digital mammography using a scanned-slot CCD imaging system. 使用扫描槽CCD成像系统的直接数字乳房x线摄影。
Medical progress through technology Pub Date : 1993-01-01
M J Yaffe
{"title":"Direct digital mammography using a scanned-slot CCD imaging system.","authors":"M J Yaffe","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In this paper, the rationale for digital mammography is presented in terms of the limitations of conventional mammography. Various approaches to digital image acquisition are discussed and the design of a scanned-slot digital mammography system currently under development is described. Preliminary results including an image of an anthropomorphic breast phantom are presented.</p>","PeriodicalId":76136,"journal":{"name":"Medical progress through technology","volume":"19 1","pages":"13-21"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19288829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Technological improvements in mammography over the past 20 years. 过去20年乳房x光检查技术的进步。
Medical progress through technology Pub Date : 1993-01-01
A G Haus
{"title":"Technological improvements in mammography over the past 20 years.","authors":"A G Haus","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>During the past twenty years many significant technological improvements in mammographic X-ray equipment and screen-film-processing systems have occurred. Today it is possible to obtain mammograms with higher image quality at a significantly lower radiation dose compared to mammograms dating back about 20 years. In this review article, X-ray spectra, limiting geometric resolution, characteristic (H & D) curves, modulation transfer function (MTF) and noise power spectra (NPS) are used to demonstrate technological improvements in mammographic screen-film image quality.</p>","PeriodicalId":76136,"journal":{"name":"Medical progress through technology","volume":"19 1","pages":"31-42"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19288832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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