Pub Date : 1999-10-19DOI: 10.1109/ULTSYM.1999.849482
S. Sherrit, B. Dolgin, Y. Bar-Cohen, D. Pal, J. Kroh, Tom Peterson Cybersonics
JPL has a requirement for telerobotic tools for planetary sample acquisition, which require low power and have the ability to work in harsh environments. We are currently investigating the possibility of using ultrasonic horns to develop a family of ultrasonic tools for these environments. In an effort to determine control parameters a one-dimensional Mason's model for a stepped ultrasonic horn assembly was developed which includes the effects of mechanical and electrical losses in the piezoelectric material and acoustic elements. The model is separated into three regions; the piezoelectric stack including stress bolt, the backing layer and the horn. The model is found to predict the impedance data of the horn assembly very accurately up to the first coupled (radial) resonance. The model also allows for the calculation of the velocity and force and power delivered to each acoustic element. FEM modeling and accelerometer data from the horn tip were used to corroborate the model. The difficulties associated with modeling the load impedance of various devices will be discussed and current directions noted.
{"title":"Modeling of horns for sonic/ultrasonic applications","authors":"S. Sherrit, B. Dolgin, Y. Bar-Cohen, D. Pal, J. Kroh, Tom Peterson Cybersonics","doi":"10.1109/ULTSYM.1999.849482","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849482","url":null,"abstract":"JPL has a requirement for telerobotic tools for planetary sample acquisition, which require low power and have the ability to work in harsh environments. We are currently investigating the possibility of using ultrasonic horns to develop a family of ultrasonic tools for these environments. In an effort to determine control parameters a one-dimensional Mason's model for a stepped ultrasonic horn assembly was developed which includes the effects of mechanical and electrical losses in the piezoelectric material and acoustic elements. The model is separated into three regions; the piezoelectric stack including stress bolt, the backing layer and the horn. The model is found to predict the impedance data of the horn assembly very accurately up to the first coupled (radial) resonance. The model also allows for the calculation of the velocity and force and power delivered to each acoustic element. FEM modeling and accelerometer data from the horn tip were used to corroborate the model. The difficulties associated with modeling the load impedance of various devices will be discussed and current directions noted.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134348290","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849290
H. Kanai, Y. Koiwa
The authors previously (1996, 1997) developed a new method, the phased tracking method, for accurately tracking the movement of the heart wall and arterial wall based on both the phase and magnitude of the demodulated signals to determine the instantaneous position of an object. With this method, the local change in wall thickness during one heartbeat can be determined. They have now developed a real-time system for continuously measuring the change in thickness of the myocardium and arterial wall. In this system, four high-speed digital signal processing chips are employed for realizing the initially developed method in real time. The tracking results for both sides of the wall are superimposed on the M (motion)-mode image. The change in thickness of the arterial wall as small as several micrometers can be successfully detected in real time with good reproducibility. The elasticity of the arterial wall is derived from the blood pressure. In in vivo experiments, the rapid response of the change in wall thickness of the carotid artery to the administration of nitroglycerine (NTG) is evaluated for a young healthy subject and a young smoker. When the change in thickness is plotted against the simultaneously measured pressure, such curves also change due to the administration of NTG. This is shown every 35 seconds after the administration. This new real-time system offers potential for quantitative diagnosis of early-stage atherosclerosis by evaluation of the rapid response of the cardiovascular system to NTG.
{"title":"Real-time evaluation of transient response of arterial wall elasticity to administration of nitroglycerine","authors":"H. Kanai, Y. Koiwa","doi":"10.1109/ULTSYM.1999.849290","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849290","url":null,"abstract":"The authors previously (1996, 1997) developed a new method, the phased tracking method, for accurately tracking the movement of the heart wall and arterial wall based on both the phase and magnitude of the demodulated signals to determine the instantaneous position of an object. With this method, the local change in wall thickness during one heartbeat can be determined. They have now developed a real-time system for continuously measuring the change in thickness of the myocardium and arterial wall. In this system, four high-speed digital signal processing chips are employed for realizing the initially developed method in real time. The tracking results for both sides of the wall are superimposed on the M (motion)-mode image. The change in thickness of the arterial wall as small as several micrometers can be successfully detected in real time with good reproducibility. The elasticity of the arterial wall is derived from the blood pressure. In in vivo experiments, the rapid response of the change in wall thickness of the carotid artery to the administration of nitroglycerine (NTG) is evaluated for a young healthy subject and a young smoker. When the change in thickness is plotted against the simultaneously measured pressure, such curves also change due to the administration of NTG. This is shown every 35 seconds after the administration. This new real-time system offers potential for quantitative diagnosis of early-stage atherosclerosis by evaluation of the rapid response of the cardiovascular system to NTG.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115487603","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849263
F. Lizzi, C. Deng, D. Coleman, R. Silverman, R. Bernardi, C. Vecchio
This report describes therapeutic ultrasound transducers comprising a spherically focused annular array with a central rectangular cutout, which houses a diagnostic ultrasound array used for aiming and monitoring. Simulations have been conducted to compute the axially-asymmetric, multi-lobed beams produced by these transducers and to evaluate the spatio-temporal distribution of induced temperature rises in treated tissues. It is shown that, for typical 5-s exposures, thermal conduction can spatially smooth these temperature rises to produce useful lesion features. Thermal conduction can also reduce undesired effects due to spurious axial maxima in intensity, which can occur when the focal length of the therapy array is varied electronically.
{"title":"Effects of beam asymmetry on ultrasonic thermal lesions","authors":"F. Lizzi, C. Deng, D. Coleman, R. Silverman, R. Bernardi, C. Vecchio","doi":"10.1109/ULTSYM.1999.849263","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849263","url":null,"abstract":"This report describes therapeutic ultrasound transducers comprising a spherically focused annular array with a central rectangular cutout, which houses a diagnostic ultrasound array used for aiming and monitoring. Simulations have been conducted to compute the axially-asymmetric, multi-lobed beams produced by these transducers and to evaluate the spatio-temporal distribution of induced temperature rises in treated tissues. It is shown that, for typical 5-s exposures, thermal conduction can spatially smooth these temperature rises to produce useful lesion features. Thermal conduction can also reduce undesired effects due to spurious axial maxima in intensity, which can occur when the focal length of the therapy array is varied electronically.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115642862","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849131
E. Adler
A matrix method is given for calculating the frequency responses for the excitation amplitudes of the three acoustic modes in transducer-substrate geometries and in resonators. The effectiveness of the method is illustrated for typical resonator and transducer structures. Transducers and resonators can be multilayer; viscosity are taken into account. A bulk-acoustic-wave transducer used to excite one of the three bulk modes of a substrate material to which it is coupled is equivalent to a mechanically loaded resonator. In practice all three acoustic bulk modes get generated due to orientation tolerances in transducer and substrate cuts and alignment errors with respect to the substrate. The matrix method for finding the acoustic mode amplitudes in transducers or resonator geometries allows an explicit calculation of: 1. The electrical driving point impedance, insertion loss, and scattering coefficients; 2. The electrical power supplied by the source; 3. The amplitudes of the three bulk modes excited in the substrate; 4. The total acoustic power and the power for each mode in the substrate. These quantities are calculated as a function of frequency using formulas which follow directly from the electrical and mechanical boundary condition matrix equations for the structure. The computation uses only the orientations and thicknesses of the materials, their thermodynamic constants, and the device area.
{"title":"Calculating multimode generation in BAW transducers and resonators","authors":"E. Adler","doi":"10.1109/ULTSYM.1999.849131","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849131","url":null,"abstract":"A matrix method is given for calculating the frequency responses for the excitation amplitudes of the three acoustic modes in transducer-substrate geometries and in resonators. The effectiveness of the method is illustrated for typical resonator and transducer structures. Transducers and resonators can be multilayer; viscosity are taken into account. A bulk-acoustic-wave transducer used to excite one of the three bulk modes of a substrate material to which it is coupled is equivalent to a mechanically loaded resonator. In practice all three acoustic bulk modes get generated due to orientation tolerances in transducer and substrate cuts and alignment errors with respect to the substrate. The matrix method for finding the acoustic mode amplitudes in transducers or resonator geometries allows an explicit calculation of: 1. The electrical driving point impedance, insertion loss, and scattering coefficients; 2. The electrical power supplied by the source; 3. The amplitudes of the three bulk modes excited in the substrate; 4. The total acoustic power and the power for each mode in the substrate. These quantities are calculated as a function of frequency using formulas which follow directly from the electrical and mechanical boundary condition matrix equations for the structure. The computation uses only the orientations and thicknesses of the materials, their thermodynamic constants, and the device area.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"464 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123052677","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849524
E. Moreno, F. García, M. Castillo
The measurement of the time propagation of ultrasonic pulses is a very important tool in ultrasonics. In this paper, a method based on the continuous wavelet transform (CWT) is presented. Experiments have been made on steel and acrylic, this last one as a case of viscoelastic material, where the CWT shows better properties than other digital methods.
{"title":"Measurement of ultrasonic velocity in viscoelastic materials using the wavelet transform","authors":"E. Moreno, F. García, M. Castillo","doi":"10.1109/ULTSYM.1999.849524","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849524","url":null,"abstract":"The measurement of the time propagation of ultrasonic pulses is a very important tool in ultrasonics. In this paper, a method based on the continuous wavelet transform (CWT) is presented. Experiments have been made on steel and acrylic, this last one as a case of viscoelastic material, where the CWT shows better properties than other digital methods.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116661555","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849417
S. Ichikawa, S. Mitobe, M. Koshino, Y. Ebata
A high performance and novel SAW IF 210 MHz filter for CDMA (PCS) system is developed on LBO substrate. The filter consists of double-tracked filters which are connected in parallel on one chip. The main track-filter is RSPUDT filter having grating reflectors, and mainly performs low loss pass-band of the total filter. The sub-track filter consists of SPUDTs arranged either side of grating reflectors. It is set to be phase-inversion at the cutoff frequency region to improve the skirt slope of the main-track filter, but is suppressed at the pass-band to avoid degrading the insertion loss of main-track filter. The minimum insertion loss of 3.5 dB, the phase linearity of 3.3° rms and the stop band attenuation better than 35 dB are achieved successfully. The developed IF filter fits into small sized ceramic package (7.0×5.0×1.6 mm3) and has high performances of the frequency characteristics.
{"title":"A low loss CDMA-IF filter based on RSPUDT on LBO substrate","authors":"S. Ichikawa, S. Mitobe, M. Koshino, Y. Ebata","doi":"10.1109/ULTSYM.1999.849417","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849417","url":null,"abstract":"A high performance and novel SAW IF 210 MHz filter for CDMA (PCS) system is developed on LBO substrate. The filter consists of double-tracked filters which are connected in parallel on one chip. The main track-filter is RSPUDT filter having grating reflectors, and mainly performs low loss pass-band of the total filter. The sub-track filter consists of SPUDTs arranged either side of grating reflectors. It is set to be phase-inversion at the cutoff frequency region to improve the skirt slope of the main-track filter, but is suppressed at the pass-band to avoid degrading the insertion loss of main-track filter. The minimum insertion loss of 3.5 dB, the phase linearity of 3.3° rms and the stop band attenuation better than 35 dB are achieved successfully. The developed IF filter fits into small sized ceramic package (7.0×5.0×1.6 mm3) and has high performances of the frequency characteristics.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116940956","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849240
K. Nightingale, R. Nightingale, M. Palmeri, G. Trahey
An ultrasonic radiation force-based method for remote palpation of tissue is investigated. The use of radiation force to image tissue stiffness has been proposed by several researchers. In this paper, the potential for using a diagnostic ultrasound system to both apply radiation force and track the resulting tissue displacements is investigated using Finite Element Methods (FEM), and the results are compared with experimental results. Remote palpation is accomplished by interspersing high intensity pushing beams with low intensity tracking beams. This generates localized radiation forces which can be applied throughout the tissue, with the resulting displacement patterns determined using correlation techniques. An area that is stiffer than the surrounding medium distributes the force, resulting in larger regions of displacement, and smaller maximum displacements. The resulting displacement maps provide information as to the location and size of regions of increased stiffness. The authors have developed an FEM model that predicts displacements resulting from acoustic radiation force fields generated by diagnostic transducers in various complex media. They perform a parametric analysis of varying tissue and acoustic beam characteristics on radiation force induced tissue displacements. Displacements are on the order of microns, with considerable differences in displacement patterns in the presence and absence of a lesion (or stiff inclusion). Initial experimental results are presented that support the findings in the model.
{"title":"Finite element analysis of radiation force induced tissue motion with experimental validation","authors":"K. Nightingale, R. Nightingale, M. Palmeri, G. Trahey","doi":"10.1109/ULTSYM.1999.849240","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849240","url":null,"abstract":"An ultrasonic radiation force-based method for remote palpation of tissue is investigated. The use of radiation force to image tissue stiffness has been proposed by several researchers. In this paper, the potential for using a diagnostic ultrasound system to both apply radiation force and track the resulting tissue displacements is investigated using Finite Element Methods (FEM), and the results are compared with experimental results. Remote palpation is accomplished by interspersing high intensity pushing beams with low intensity tracking beams. This generates localized radiation forces which can be applied throughout the tissue, with the resulting displacement patterns determined using correlation techniques. An area that is stiffer than the surrounding medium distributes the force, resulting in larger regions of displacement, and smaller maximum displacements. The resulting displacement maps provide information as to the location and size of regions of increased stiffness. The authors have developed an FEM model that predicts displacements resulting from acoustic radiation force fields generated by diagnostic transducers in various complex media. They perform a parametric analysis of varying tissue and acoustic beam characteristics on radiation force induced tissue displacements. Displacements are on the order of microns, with considerable differences in displacement patterns in the presence and absence of a lesion (or stiff inclusion). Initial experimental results are presented that support the findings in the model.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117167220","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849206
J. Zara, S. Bobbio, S. Goodwin-Johansson, S.W. Smith
Catheter based intracardiac ultrasound offers the potential for improved guidance of interventional cardiac procedures. The objective of this work is the development of catheter based, forward-looking mechanical sector scanners incorporating high frequency ultrasound transducers operating at frequencies up to 20 MHz. The current transducer assembly consists of a single 20 MHz PZT piston mounted on a polyimide table that pivots on gold plated polyimide hinges. This table-mounted transducer is tilted using a linear MEMS actuator to produce a sector scan. The prototype transducer/actuator assembly was fabricated and interfaced with a personal computer to create a single channel ultrasound scanner. This paper discusses the development of and results obtained by this real time scanning system.
{"title":"Intracardiac ultrasound catheter using a micromachine (MEMS) actuator","authors":"J. Zara, S. Bobbio, S. Goodwin-Johansson, S.W. Smith","doi":"10.1109/ULTSYM.1999.849206","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849206","url":null,"abstract":"Catheter based intracardiac ultrasound offers the potential for improved guidance of interventional cardiac procedures. The objective of this work is the development of catheter based, forward-looking mechanical sector scanners incorporating high frequency ultrasound transducers operating at frequencies up to 20 MHz. The current transducer assembly consists of a single 20 MHz PZT piston mounted on a polyimide table that pivots on gold plated polyimide hinges. This table-mounted transducer is tilted using a linear MEMS actuator to produce a sector scan. The prototype transducer/actuator assembly was fabricated and interfaced with a personal computer to create a single channel ultrasound scanner. This paper discusses the development of and results obtained by this real time scanning system.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125837318","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849307
E. Konofagou, T. Harrigan, J. Ophir, T. Krouskop
In the field of elastography, biological tissues are typically assumed to be purely linear elastic solids. However, several tissues including brain, cartilage and edematous soft tissues, have long been known to be poroelastic. The authors recently developed a method to estimate the local Poisson's ratio in linear elastic solids (see Ultrasound in Medicine and Biology, vol. 24, no. 8, p. 1183-99, 1998). In the current study the authors use the same method to measure the time-dependent effective Poisson's ratio in poroelastic materials. The resulting time-sequenced poroelastograms show the spatial distribution of the fluid within the solid at each time instant and give insight into the Poisson's ratio of the solid and its permeability to the fluid. Results were obtained from both finite-element simulations and experimental poroelastic phantoms.
{"title":"Poroelastography: estimating and imaging the poroelastic properties of tissues","authors":"E. Konofagou, T. Harrigan, J. Ophir, T. Krouskop","doi":"10.1109/ULTSYM.1999.849307","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849307","url":null,"abstract":"In the field of elastography, biological tissues are typically assumed to be purely linear elastic solids. However, several tissues including brain, cartilage and edematous soft tissues, have long been known to be poroelastic. The authors recently developed a method to estimate the local Poisson's ratio in linear elastic solids (see Ultrasound in Medicine and Biology, vol. 24, no. 8, p. 1183-99, 1998). In the current study the authors use the same method to measure the time-dependent effective Poisson's ratio in poroelastic materials. The resulting time-sequenced poroelastograms show the spatial distribution of the fluid within the solid at each time instant and give insight into the Poisson's ratio of the solid and its permeability to the fluid. Results were obtained from both finite-element simulations and experimental poroelastic phantoms.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114956644","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849251
H. Takigawa, Y. Furumoto, R. Hatakeyama, N. Tagawa, T. Moriya
By measuring the characteristic impedance of tissues, we can differentiate between various types of biological tissue. This capability may lead to early diagnosis of cancer and other diseases that cause changes in the characteristic impedance of tissues. We have developed a new method for measuring the characteristic impedance of biological tissues. However, the accuracy of this method was found to be insufficient for differentiating between tissues that are only subtly different. Therefore, a new impedance transformer was developed which enables accurate measurement of biological samples. The present paper describes a method for measuring complex acoustic impedance of biological tissues using an impedance transformer.
{"title":"An accurate method for measuring complex acoustic impedance of biological tissues using an impedance transformer","authors":"H. Takigawa, Y. Furumoto, R. Hatakeyama, N. Tagawa, T. Moriya","doi":"10.1109/ULTSYM.1999.849251","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849251","url":null,"abstract":"By measuring the characteristic impedance of tissues, we can differentiate between various types of biological tissue. This capability may lead to early diagnosis of cancer and other diseases that cause changes in the characteristic impedance of tissues. We have developed a new method for measuring the characteristic impedance of biological tissues. However, the accuracy of this method was found to be insufficient for differentiating between tissues that are only subtly different. Therefore, a new impedance transformer was developed which enables accurate measurement of biological samples. The present paper describes a method for measuring complex acoustic impedance of biological tissues using an impedance transformer.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115245898","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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