Pub Date : 1988-11-04DOI: 10.1109/IEMBS.1988.95015
M. Nadi, C. Marchal, G. Prieur, A. Tosser, J.P. Mabire
The authors suggest an alternative interstitial method operating at 27.12 MHz. Physically, the system is essentially capacitive and the heating is induced by the conduction current between the 'hot' electrode and the ground plane. Thermographic results obtained with a two-channel homemade apparatus are presented. The simplicity and low cost of the technology, the possibility of tailoring the electrodes to the geometry and the tumor site, and the radial and longitudinal uniformity of the heating represent the major advantages of this method. A commercial prototype with eight electrodes is presented.<>
{"title":"Design of an interstitial capacitive hyperthermia system operating at 27.12 MHz","authors":"M. Nadi, C. Marchal, G. Prieur, A. Tosser, J.P. Mabire","doi":"10.1109/IEMBS.1988.95015","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.95015","url":null,"abstract":"The authors suggest an alternative interstitial method operating at 27.12 MHz. Physically, the system is essentially capacitive and the heating is induced by the conduction current between the 'hot' electrode and the ground plane. Thermographic results obtained with a two-channel homemade apparatus are presented. The simplicity and low cost of the technology, the possibility of tailoring the electrodes to the geometry and the tumor site, and the radial and longitudinal uniformity of the heating represent the major advantages of this method. A commercial prototype with eight electrodes is presented.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122552957","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}
Pub Date : 1988-11-04DOI: 10.1109/IEMBS.1988.95262
G. Prieur, M. Nadi, C. Marchal, A. Chitnallah, P. Bey
The authors suggest the use of cylindrical piezoelectric transducers for intracavity hyperthermia treatment of vaginal or prostatic tumors, to take advantage of the deep penetration of ultrasound below 5 MHz. Different sizes and shapes of applicators operating around 1 MHz have been developed. The longest is 12 cm in length and 1.5 cm in diameter and uses two lead titanate zirconate transducers of 4-cm length each. Studies of power distributions in tissue-equivalent phantoms are presented, and the results are assessed.<>
{"title":"Development of new intracavitary ultrasound applicator","authors":"G. Prieur, M. Nadi, C. Marchal, A. Chitnallah, P. Bey","doi":"10.1109/IEMBS.1988.95262","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.95262","url":null,"abstract":"The authors suggest the use of cylindrical piezoelectric transducers for intracavity hyperthermia treatment of vaginal or prostatic tumors, to take advantage of the deep penetration of ultrasound below 5 MHz. Different sizes and shapes of applicators operating around 1 MHz have been developed. The longest is 12 cm in length and 1.5 cm in diameter and uses two lead titanate zirconate transducers of 4-cm length each. Studies of power distributions in tissue-equivalent phantoms are presented, and the results are assessed.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129809148","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}
Pub Date : 1988-11-01DOI: 10.1109/IEMBS.1988.94381
A. Sahakian, K. Ropella, J. Baerman, S. Swiryn
Fibrillatory rhythms are poorly characterized by traditional time-domain measures, such as rate. The authors describe two measures not commonly applied in intracardiac signal processing; the median frequency (MF) in the 2 to 9 Hz region of the power spectrum, and the magnitude-squared coherence (MSC) function. These two measures are formally defined. The MF is a robust measure of drug-induced changes in atrial fibrillation, and the MSC is a measure of the degree of organization of atrial and ventricular cardiac rhythms.<>
{"title":"Median frequency and coherence measures of atrial and ventricular fibrillation","authors":"A. Sahakian, K. Ropella, J. Baerman, S. Swiryn","doi":"10.1109/IEMBS.1988.94381","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.94381","url":null,"abstract":"Fibrillatory rhythms are poorly characterized by traditional time-domain measures, such as rate. The authors describe two measures not commonly applied in intracardiac signal processing; the median frequency (MF) in the 2 to 9 Hz region of the power spectrum, and the magnitude-squared coherence (MSC) function. These two measures are formally defined. The MF is a robust measure of drug-induced changes in atrial fibrillation, and the MSC is a measure of the degree of organization of atrial and ventricular cardiac rhythms.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116125859","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}
Pub Date : 1988-11-01DOI: 10.1109/IEMBS.1988.94395
L. Shyu, S. P. Reddy, J. Nagel, N. Schneiderman
Different techniques have been developed for parameter extraction and segmentation of the impedance cardiogram for improved reliability and precision of beat-to-beat determination of systolic time intervals, stroke volume, and related cardiac indices. The solutions presented improve on previous techniques by: (1) substantially reducing jitter in the localization of events within the cardiac cycle; (2) providing exact determination of signal amplitudes even in the presence of artifacts and interference signals; and (3) eliminating the influence of respiratory signal modulation on parameter extraction.<>
{"title":"New signal processing techniques for improved reliability of impedance cardiography","authors":"L. Shyu, S. P. Reddy, J. Nagel, N. Schneiderman","doi":"10.1109/IEMBS.1988.94395","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.94395","url":null,"abstract":"Different techniques have been developed for parameter extraction and segmentation of the impedance cardiogram for improved reliability and precision of beat-to-beat determination of systolic time intervals, stroke volume, and related cardiac indices. The solutions presented improve on previous techniques by: (1) substantially reducing jitter in the localization of events within the cardiac cycle; (2) providing exact determination of signal amplitudes even in the presence of artifacts and interference signals; and (3) eliminating the influence of respiratory signal modulation on parameter extraction.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133997041","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}
Pub Date : 1988-11-01DOI: 10.1109/IEMBS.1988.94380
S. Greenhut, B.H. Chadi, J.W. Lee, J. Jenkins, J. Nicklas
A template boundary algorithm that quantitatively determines repolarization variability in a normal population has been developed. The algorithm defines an initial ST-T template for comparison with successive beats. Variability is quantified using boundary limits around the template, which are widened, when necessary, to include incoming ST-T segments. The boundaries at the end of each hour are stored and the collection of boundaries over a set of normal subjects quantifies the normal variation over the entire ST-T segment. The algorithm can be used to determine prospectively normal ST-T variability based on a regression analysis of R-wave or T-wave amplitude, and QT interval. Application of these boundary predictions should be useful in distinguishing repolarization changes secondary to ischemia from normal variability.<>
{"title":"A template boundary algorithm for ST-T segment analysis","authors":"S. Greenhut, B.H. Chadi, J.W. Lee, J. Jenkins, J. Nicklas","doi":"10.1109/IEMBS.1988.94380","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.94380","url":null,"abstract":"A template boundary algorithm that quantitatively determines repolarization variability in a normal population has been developed. The algorithm defines an initial ST-T template for comparison with successive beats. Variability is quantified using boundary limits around the template, which are widened, when necessary, to include incoming ST-T segments. The boundaries at the end of each hour are stored and the collection of boundaries over a set of normal subjects quantifies the normal variation over the entire ST-T segment. The algorithm can be used to determine prospectively normal ST-T variability based on a regression analysis of R-wave or T-wave amplitude, and QT interval. Application of these boundary predictions should be useful in distinguishing repolarization changes secondary to ischemia from normal variability.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114753735","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}
Pub Date : 1988-11-01DOI: 10.1109/IEMBS.1988.95021
J. Fouke, J. Teeter, G. Saidel
Mechanical properties of the human respiratory system are studied using input-output pressure-flow relationships. This input impedance data is fitted to lumped electrical analogs of the system, and the estimated parameters are then assigned a physiological significance. The authors present a technique to refine the interpretation of these parameters. They independently obtain geometrical information describing the large airways and calculate its contribution to the system impedance. Simulations show that this part acts as a resistive-inertial element.<>
{"title":"Contribution of large airways to respiratory system input impedance","authors":"J. Fouke, J. Teeter, G. Saidel","doi":"10.1109/IEMBS.1988.95021","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.95021","url":null,"abstract":"Mechanical properties of the human respiratory system are studied using input-output pressure-flow relationships. This input impedance data is fitted to lumped electrical analogs of the system, and the estimated parameters are then assigned a physiological significance. The authors present a technique to refine the interpretation of these parameters. They independently obtain geometrical information describing the large airways and calculate its contribution to the system impedance. Simulations show that this part acts as a resistive-inertial element.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132414886","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}
Pub Date : 1988-11-01DOI: 10.1109/IEMBS.1988.94955
P. Campbell, R. Normann, K. Horch
Electrical stimulation of the visual cortex causes subjects to see spots of light (phosphenes) in their visual fields. The authors have developed arrays of penetrating electrodes which can form the basis of a visual prosthesis centred around electrical stimulation of the visual cortex. These arrays have been constructed of inert materials, and have been implanted into cats to test array insertability and biocompatibility. Tests to determine electrode wire insertion force have also been performed. Preliminary acute histological results have shown little cortical damage due to the implants.<>
{"title":"Noble metal penetrating cortical stimulating electrode array: preliminary results","authors":"P. Campbell, R. Normann, K. Horch","doi":"10.1109/IEMBS.1988.94955","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.94955","url":null,"abstract":"Electrical stimulation of the visual cortex causes subjects to see spots of light (phosphenes) in their visual fields. The authors have developed arrays of penetrating electrodes which can form the basis of a visual prosthesis centred around electrical stimulation of the visual cortex. These arrays have been constructed of inert materials, and have been implanted into cats to test array insertability and biocompatibility. Tests to determine electrode wire insertion force have also been performed. Preliminary acute histological results have shown little cortical damage due to the implants.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132418399","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}
Pub Date : 1988-11-01DOI: 10.1109/IEMBS.1988.94516
K. Cheng, D. Isaacson, J. Newell, D. Gisser
Different current patterns used in electric-current computed tomography (ECCT) were compared for their sensitivity to noise. This comparison was made by examining the error produced in reconstructing one voltage pattern from measurements made using another. It was found that the adjacent-pair current pattern is more sensitive to noise than spatial trigonometric current patterns. The measured spatial trigonometric voltage patterns were not degraded when a simulated electrode contact impedance was introduced.<>
{"title":"Error comparison for different current patterns in electrical impedance imaging","authors":"K. Cheng, D. Isaacson, J. Newell, D. Gisser","doi":"10.1109/IEMBS.1988.94516","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.94516","url":null,"abstract":"Different current patterns used in electric-current computed tomography (ECCT) were compared for their sensitivity to noise. This comparison was made by examining the error produced in reconstructing one voltage pattern from measurements made using another. It was found that the adjacent-pair current pattern is more sensitive to noise than spatial trigonometric current patterns. The measured spatial trigonometric voltage patterns were not degraded when a simulated electrode contact impedance was introduced.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127845191","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}
Pub Date : 1988-11-01DOI: 10.1109/IEMBS.1988.95245
F. Bersani, C. Franceschi, D. Monti, A. Bologni, C. Gatti, R. Cadossi, M. Nichelatti, G. Moschini, A. Cossarizza
The effect of extremely-low-frequency electromagnetic fields on in-vitro mitogen-induced lymphocyte proliferation was studied in two groups of healthy subjects (23 and 85 years, mean ages). An increase of cell proliferation was observed to be much higher in the group of aged subjects. The effects depended on the mitogen dose and involved interleukin-2 production and/or utilization. The DNA repair capability and cell survival in the exposed cultures after gamma irradiation was also evaluated, and no genotoxic effect was found.<>
{"title":"The effects of extremely low frequency pulsed electromagnetic fields (ELF) on human lymphocyte proliferation in vitro and DNA repair","authors":"F. Bersani, C. Franceschi, D. Monti, A. Bologni, C. Gatti, R. Cadossi, M. Nichelatti, G. Moschini, A. Cossarizza","doi":"10.1109/IEMBS.1988.95245","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.95245","url":null,"abstract":"The effect of extremely-low-frequency electromagnetic fields on in-vitro mitogen-induced lymphocyte proliferation was studied in two groups of healthy subjects (23 and 85 years, mean ages). An increase of cell proliferation was observed to be much higher in the group of aged subjects. The effects depended on the mitogen dose and involved interleukin-2 production and/or utilization. The DNA repair capability and cell survival in the exposed cultures after gamma irradiation was also evaluated, and no genotoxic effect was found.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121416510","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}
Pub Date : 1988-11-01DOI: 10.1109/IEMBS.1988.94636
K. Gingrich, R. Roy, R. Vishnoi, C. Yu, G. Neat
A nonlinear descriptive single-input-multiple-output (SIMO) model of the hemodynamic response (cardiac output and mean arterial pressure) in acute ischemic heart failure to the inotropic drug dopamine was developed to facilitate the design of closed-loop control systems. The structure of the cardiac-output component is a first order system with a sigmoidal relationship, while the mean-arterial-pressure component is a first-order system with a threshold. Overall, the model gave good approximations of mean empirical responses. Parameter identification was performed on positive step (drug on) and negative step (drug off) testing using multiple (2 mcg/kg/min-6 mcg/min) infusions of dopamine in a canine model of acute ischemic heart failure. Parameter estimation utilized a least-squares objective function and a linearized form of the step response of the model in the time domain.<>
{"title":"Modeling the hemodynamic response to dopamine in acute heart failure","authors":"K. Gingrich, R. Roy, R. Vishnoi, C. Yu, G. Neat","doi":"10.1109/IEMBS.1988.94636","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.94636","url":null,"abstract":"A nonlinear descriptive single-input-multiple-output (SIMO) model of the hemodynamic response (cardiac output and mean arterial pressure) in acute ischemic heart failure to the inotropic drug dopamine was developed to facilitate the design of closed-loop control systems. The structure of the cardiac-output component is a first order system with a sigmoidal relationship, while the mean-arterial-pressure component is a first-order system with a threshold. Overall, the model gave good approximations of mean empirical responses. Parameter identification was performed on positive step (drug on) and negative step (drug off) testing using multiple (2 mcg/kg/min-6 mcg/min) infusions of dopamine in a canine model of acute ischemic heart failure. Parameter estimation utilized a least-squares objective function and a linearized form of the step response of the model in the time domain.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121440482","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}
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