Pub Date : 1997-10-05DOI: 10.1109/ULTSYM.1997.663066
S. Hongo, I. Naliamura, N. Hosokawa
A proximity sensor utilizing an evanescent acoustic field formed by flexural plate waves is proposed. When an object comes into the evanescent field, the acoustic radiation admittance of the bending vibrator may change. Hence, the proximity sensing can be achieved by measuring the electrical admittance of the piezoelectric flexural vibrator. To confirm the characteristics of the proximity sensor, some experiments were carried out using a flexural vibrator consisting of a 140/spl deg/ rotated Y-cut LiNbO/sub 3/ plate with a polarization-inverted layer. When an object was approached to the major surface of the vibrator, the admittance at a resonance of the bending vibrator decreased drastically according as the distance d between the object and the vibrator became short. On the other hand, when the object was approached to the tip of the vibrator, the Q-factor decreased in the range d>0.2 mm but increased again unexpectedly in the range d<0.2 mm.
{"title":"Proximity sensors utilizing an evanescent acoustic field formed by flexural plate waves","authors":"S. Hongo, I. Naliamura, N. Hosokawa","doi":"10.1109/ULTSYM.1997.663066","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663066","url":null,"abstract":"A proximity sensor utilizing an evanescent acoustic field formed by flexural plate waves is proposed. When an object comes into the evanescent field, the acoustic radiation admittance of the bending vibrator may change. Hence, the proximity sensing can be achieved by measuring the electrical admittance of the piezoelectric flexural vibrator. To confirm the characteristics of the proximity sensor, some experiments were carried out using a flexural vibrator consisting of a 140/spl deg/ rotated Y-cut LiNbO/sub 3/ plate with a polarization-inverted layer. When an object was approached to the major surface of the vibrator, the admittance at a resonance of the bending vibrator decreased drastically according as the distance d between the object and the vibrator became short. On the other hand, when the object was approached to the tip of the vibrator, the Q-factor decreased in the range d>0.2 mm but increased again unexpectedly in the range d<0.2 mm.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91137596","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661751
L. Zou, M. Sayer, C. Jen
Sol-gel fabricated thick film broadband piezoelectric ultrasonic transducers (UTs) operating at a frequency below 10 MHz are presented. The UTs are formed using thick PZT and LiNbO/sub 3/ films which are ceramic-ceramic composites formed by dispersing PZT and LiNbO/sub 3/ particles in a PZT and LiNbO/sub 3/ sol-gel solution, respectively. Films are directly deposited on stainless steel substrates. Excellent broadband signals have been experimentally obtained with piezoelectric PZT and LiNbO/sub 3/ films with 1 cm diameter and a thickness between 40-50 /spl mu/m.
{"title":"Sol-gel fabricated thick piezoelectric ultrasonic transducers for potential applications in industrial material processes","authors":"L. Zou, M. Sayer, C. Jen","doi":"10.1109/ULTSYM.1997.661751","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661751","url":null,"abstract":"Sol-gel fabricated thick film broadband piezoelectric ultrasonic transducers (UTs) operating at a frequency below 10 MHz are presented. The UTs are formed using thick PZT and LiNbO/sub 3/ films which are ceramic-ceramic composites formed by dispersing PZT and LiNbO/sub 3/ particles in a PZT and LiNbO/sub 3/ sol-gel solution, respectively. Films are directly deposited on stainless steel substrates. Excellent broadband signals have been experimentally obtained with piezoelectric PZT and LiNbO/sub 3/ films with 1 cm diameter and a thickness between 40-50 /spl mu/m.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88775552","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.662983
B. Sveshnikov, A. Shitvov
Resonant coupling between two non-waveguide acoustic channels is considered and analyzed in detail. A pair of electrically parallel, while placed in different channels, single-phase unidirectional transducers, loaded by matching inductance, may be used in order to fold the SAW propagation path. Such a possibility provides the additional degree of freedom in the design of SAW filters, being applicable even to weak piezocrystal cuts. Some device architectures are examined to demonstrate possible significant improvement of filter selectivity. It's shown that this aim may be achieved even when using unweighted SPUDTs by proper combinations of reflectivity and lengths of transducers and reflectors placed within each a channel. Influence of re-radiator's load on the filter performances is illustrated too.
{"title":"SPUDT-based tunable resonant coupling of different acoustic channels","authors":"B. Sveshnikov, A. Shitvov","doi":"10.1109/ULTSYM.1997.662983","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.662983","url":null,"abstract":"Resonant coupling between two non-waveguide acoustic channels is considered and analyzed in detail. A pair of electrically parallel, while placed in different channels, single-phase unidirectional transducers, loaded by matching inductance, may be used in order to fold the SAW propagation path. Such a possibility provides the additional degree of freedom in the design of SAW filters, being applicable even to weak piezocrystal cuts. Some device architectures are examined to demonstrate possible significant improvement of filter selectivity. It's shown that this aim may be achieved even when using unweighted SPUDTs by proper combinations of reflectivity and lengths of transducers and reflectors placed within each a channel. Influence of re-radiator's load on the filter performances is illustrated too.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84053601","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661770
A. Saied, B. Dehecq, M. Savoldelli, B. Briat, J. Legeais, G. Berger
In a previous preliminary study the authors have shown that 50 MHz ultrasound microscope coupled with the spectral analysis of radio frequency signal enable the imaging and evaluation of the biointegration of polymer implants used as support of keratoprosthesis (artificial cornea). In particular, the authors have demonstrated that the level of apparent backscatter was sensitive to the change in the polymer pore content (fluid or cells). In the current study, a larger number of polymer implants (n=21) at different colonization stages were explored in vitro and the authors investigated the potential of the frequency variation of both ultrasonic backscatter and attenuation coefficients to control and assess in situ the progressive biocolonization of the material. Quantitative echographic findings were correlated to histologic data which established the cell density in each specimen.
{"title":"Evaluation of keratoprosthesis biointegration in situ with quantitative ultrasound backscatter microscopy","authors":"A. Saied, B. Dehecq, M. Savoldelli, B. Briat, J. Legeais, G. Berger","doi":"10.1109/ULTSYM.1997.661770","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661770","url":null,"abstract":"In a previous preliminary study the authors have shown that 50 MHz ultrasound microscope coupled with the spectral analysis of radio frequency signal enable the imaging and evaluation of the biointegration of polymer implants used as support of keratoprosthesis (artificial cornea). In particular, the authors have demonstrated that the level of apparent backscatter was sensitive to the change in the polymer pore content (fluid or cells). In the current study, a larger number of polymer implants (n=21) at different colonization stages were explored in vitro and the authors investigated the potential of the frequency variation of both ultrasonic backscatter and attenuation coefficients to control and assess in situ the progressive biocolonization of the material. Quantitative echographic findings were correlated to histologic data which established the cell density in each specimen.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85501562","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663088
D. Xi
In this article we have studied resonant second-harmonic generation accompanying nonlinear Love-wave propagation in an isotropic waveguide consisting of a solid layer and a semi-infinite solid. Generally, the amplitude of the second harmonic arising from the self-interaction of shear wave is independent of propagation distance, i.e., there is no effect of cumulative growth. However, for Love-wave propagation case, there are two shear partial waves in the solid layer deposited on the semi-infinite solid, and the cross-interaction between two shear waves may cause the "resonance" of the driving second harmonic once the phase velocity of the Love-wave equals the longitudinal velocity of the solid layer. Through second-harmonic boundary conditions and initial conditions of excitation, we formally obtain the analytical expressions for the case of resonant second-harmonic generation. The present analysis yields clearly physical insight into the process of resonant second-harmonic generation accompanying nonlinear Love-wave propagation not previously available.
{"title":"Resonant second-harmonic generation accompanying nonlinear Love-wave propagation in an isotropic waveguide","authors":"D. Xi","doi":"10.1109/ULTSYM.1997.663088","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663088","url":null,"abstract":"In this article we have studied resonant second-harmonic generation accompanying nonlinear Love-wave propagation in an isotropic waveguide consisting of a solid layer and a semi-infinite solid. Generally, the amplitude of the second harmonic arising from the self-interaction of shear wave is independent of propagation distance, i.e., there is no effect of cumulative growth. However, for Love-wave propagation case, there are two shear partial waves in the solid layer deposited on the semi-infinite solid, and the cross-interaction between two shear waves may cause the \"resonance\" of the driving second harmonic once the phase velocity of the Love-wave equals the longitudinal velocity of the solid layer. Through second-harmonic boundary conditions and initial conditions of excitation, we formally obtain the analytical expressions for the case of resonant second-harmonic generation. The present analysis yields clearly physical insight into the process of resonant second-harmonic generation accompanying nonlinear Love-wave propagation not previously available.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85367497","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661859
L. M. Hinkelman, T. Mast, M. J. Orr, R. Waag
Wavefront propagation through the abdominal wall was investigated by measurements employing full-thickness specimens and their individual fat and muscle layers. These measurements confirm that both fat and muscle produce significant wavefront distortion and focus degradation. However, the spatial characteristics of the distortion produced by fat and muscle differ, and the total distortion produced by the abdominal wall is not the arithmetic sum of that produced by the individual layers. The interface between the muscle and subcutaneous fat layers, which consists of a thin layer of connective tissue, was found to be smooth or slightly curved. Distortion produced by different tissues was further characterized by simulations using a finite-difference time-domain implementation of the linearized wave propagation equations for a lossless inhomogeneous fluid. Scanned images of six human abdominal wall cross sections provided the data for the propagation media in the simulation. The images were mapped into regions of fat, muscle, and connective tissue, each of which was assigned a uniform sound speed and density obtained from literature values. The computed wavefronts contained arrival time, energy level, and wave shape distortion similar to that in measurements. Visualization of wave propagation within the tissue cross sections suggests that most arrival time distortion is produced by acoustic path length differences while amplitude and waveform variations are the result of scattering from inhomogeneities. Many arrival time fluctuation and energy level fluctuation features could be traced to specific anatomical structures. These results indicate that wavefront distortion, apart from bulk attenuation effects, is primarily caused by tissue structures and inhomogeneities rather than refraction at layer interfaces.
{"title":"Effects of abdominal wall morphology on ultrasonic pulse distortion","authors":"L. M. Hinkelman, T. Mast, M. J. Orr, R. Waag","doi":"10.1109/ULTSYM.1997.661859","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661859","url":null,"abstract":"Wavefront propagation through the abdominal wall was investigated by measurements employing full-thickness specimens and their individual fat and muscle layers. These measurements confirm that both fat and muscle produce significant wavefront distortion and focus degradation. However, the spatial characteristics of the distortion produced by fat and muscle differ, and the total distortion produced by the abdominal wall is not the arithmetic sum of that produced by the individual layers. The interface between the muscle and subcutaneous fat layers, which consists of a thin layer of connective tissue, was found to be smooth or slightly curved. Distortion produced by different tissues was further characterized by simulations using a finite-difference time-domain implementation of the linearized wave propagation equations for a lossless inhomogeneous fluid. Scanned images of six human abdominal wall cross sections provided the data for the propagation media in the simulation. The images were mapped into regions of fat, muscle, and connective tissue, each of which was assigned a uniform sound speed and density obtained from literature values. The computed wavefronts contained arrival time, energy level, and wave shape distortion similar to that in measurements. Visualization of wave propagation within the tissue cross sections suggests that most arrival time distortion is produced by acoustic path length differences while amplitude and waveform variations are the result of scattering from inhomogeneities. Many arrival time fluctuation and energy level fluctuation features could be traced to specific anatomical structures. These results indicate that wavefront distortion, apart from bulk attenuation effects, is primarily caused by tissue structures and inhomogeneities rather than refraction at layer interfaces.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79864138","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661725
N. Abboud, J. Mould, G. Wojcik, D. Vaughan, D. Powell, V. Murray, C. Maclean
Thermal management is an important consideration in ultrasound transducer design. It arises in satisfying regulatory and safety requirements in diagnostic and therapeutic ultrasound, as well as in sustaining performance in high power applications such as underwater sonar. A finite element modeling approach was developed to aid in the analysis of this coupled electro-mechanical-thermal problem. The finite element model tracks the damping losses in the electromechanical portion of the problem and converts the lost energy into a thermal dose which constitutes the "input" to the thermal portion of the problem. The resultant temperature spatial and temporal distribution is then solved for. This modeling approach was used to study several 1-3 piezocomposite high power transducers for which experimental data was available. Previous experimental evaluation has demonstrated that these devices can suffer from a degradation in performance due to significant temperature rises at power levels of approximately 2 W/cm/sup 2/ for continuous operation, whereas they can operate efficiently at power levels greater than 20 W/cm/sup 2/ when the duty cycle is reduced below 10%. A detailed thermal analysis of these transducers with respect to efficiency of the thermal dissipation within them is required with a view to understanding and consequently improving the high drive performance of these devices. The goal of this preliminary study is to evaluate the modeling approach and identify key parameters to which the solution is sensitive. Parameters so identified, be they material constants or modeling approaches, will be subject to more complete characterization in follow-up studies aimed at quantitative validation of computational modeling of thermal management in ultrasonic applications.
{"title":"Thermal generation, diffusion and dissipation in 1-3 piezocomposite sonar transducers: finite element analysis and experimental measurements","authors":"N. Abboud, J. Mould, G. Wojcik, D. Vaughan, D. Powell, V. Murray, C. Maclean","doi":"10.1109/ULTSYM.1997.661725","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661725","url":null,"abstract":"Thermal management is an important consideration in ultrasound transducer design. It arises in satisfying regulatory and safety requirements in diagnostic and therapeutic ultrasound, as well as in sustaining performance in high power applications such as underwater sonar. A finite element modeling approach was developed to aid in the analysis of this coupled electro-mechanical-thermal problem. The finite element model tracks the damping losses in the electromechanical portion of the problem and converts the lost energy into a thermal dose which constitutes the \"input\" to the thermal portion of the problem. The resultant temperature spatial and temporal distribution is then solved for. This modeling approach was used to study several 1-3 piezocomposite high power transducers for which experimental data was available. Previous experimental evaluation has demonstrated that these devices can suffer from a degradation in performance due to significant temperature rises at power levels of approximately 2 W/cm/sup 2/ for continuous operation, whereas they can operate efficiently at power levels greater than 20 W/cm/sup 2/ when the duty cycle is reduced below 10%. A detailed thermal analysis of these transducers with respect to efficiency of the thermal dissipation within them is required with a view to understanding and consequently improving the high drive performance of these devices. The goal of this preliminary study is to evaluate the modeling approach and identify key parameters to which the solution is sensitive. Parameters so identified, be they material constants or modeling approaches, will be subject to more complete characterization in follow-up studies aimed at quantitative validation of computational modeling of thermal management in ultrasonic applications.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80250719","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.662994
W. Liu, P.M. Smith
Electrode interactions are a major cause of in-band ripples in SAW filters. In the past, the effect of these interactions has been modeled on devices with periodic electrodes either with the aid of Coupling of Modes (COM) theory, or by adopting the quasi-static Green's function method. In this paper, we extend the quasi-static Green's function to include electro-acoustic regeneration in transducers with non-periodic electrodes. The simulation of a dispersive delay line is given as an example.
{"title":"An efficient method of including electrode interactions in the Green's function model for SAW interdigital transducers","authors":"W. Liu, P.M. Smith","doi":"10.1109/ULTSYM.1997.662994","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.662994","url":null,"abstract":"Electrode interactions are a major cause of in-band ripples in SAW filters. In the past, the effect of these interactions has been modeled on devices with periodic electrodes either with the aid of Coupling of Modes (COM) theory, or by adopting the quasi-static Green's function method. In this paper, we extend the quasi-static Green's function to include electro-acoustic regeneration in transducers with non-periodic electrodes. The simulation of a dispersive delay line is given as an example.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82774859","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663002
T. Shiba, Y. Fujita, N. Kamogawa, N. Hosaka, S. Ogawa, K. Oda, M. Hikita
A fully comprehensive electrical admittance matrix composition technique including the effects of residual electrical elements (capacitance, inductance and resistance) will be reported corresponding the various kind of the devices. An automatic design technique based on the optimization method is applied using the above composition routine. The automatic design procedure determines the parameters for SAW Filter elements and the external circuit element. It is possible that the procedure perform using measured admittance matrix elements. In order to verify the technique dual band filters and duplexers for digital mobile terminals were designed using the above procedure. The performance of these devices was found to be in good agreement with the design predictions.
{"title":"Automatic design procedure using circuit composition technique for SAW devices","authors":"T. Shiba, Y. Fujita, N. Kamogawa, N. Hosaka, S. Ogawa, K. Oda, M. Hikita","doi":"10.1109/ULTSYM.1997.663002","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663002","url":null,"abstract":"A fully comprehensive electrical admittance matrix composition technique including the effects of residual electrical elements (capacitance, inductance and resistance) will be reported corresponding the various kind of the devices. An automatic design technique based on the optimization method is applied using the above composition routine. The automatic design procedure determines the parameters for SAW Filter elements and the external circuit element. It is possible that the procedure perform using measured admittance matrix elements. In order to verify the technique dual band filters and duplexers for digital mobile terminals were designed using the above procedure. The performance of these devices was found to be in good agreement with the design predictions.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82847792","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663301
D. Simpson, P. Burns
A novel technique for the selective detection of ultrasound contrast agents, called pulse inversion Doppler, has been developed. In this technique, a conventional Doppler pulse sequence is modified by inverting every second transmit pulse. Either conventional or harmonic Doppler processing is then performed on the received echoes. In the resulting Doppler spectra, Doppler shifts from linear and nonlinear scattering are separated into two distinct regions which can be analyzed separately or combined to estimate the ratio of nonlinear to linear scattering from a region of tissue. The maximum Doppler shift which can be detected is 1/2 the normal Nyquist limit. In vitro measurements comparing flowing agent and cellulose particles suggest that pulse inversion Doppler can provide 3 to 10 dB more agent to tissue contrast than harmonic imaging with similar pulses. Similar measurements suggest that broadband pulse inversion Doppler can provide up to 16 dB more contrast than broadband conventional Doppler.
{"title":"Pulse inversion Doppler: a new method for detecting nonlinear echoes from microbubble contrast agents","authors":"D. Simpson, P. Burns","doi":"10.1109/ULTSYM.1997.663301","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663301","url":null,"abstract":"A novel technique for the selective detection of ultrasound contrast agents, called pulse inversion Doppler, has been developed. In this technique, a conventional Doppler pulse sequence is modified by inverting every second transmit pulse. Either conventional or harmonic Doppler processing is then performed on the received echoes. In the resulting Doppler spectra, Doppler shifts from linear and nonlinear scattering are separated into two distinct regions which can be analyzed separately or combined to estimate the ratio of nonlinear to linear scattering from a region of tissue. The maximum Doppler shift which can be detected is 1/2 the normal Nyquist limit. In vitro measurements comparing flowing agent and cellulose particles suggest that pulse inversion Doppler can provide 3 to 10 dB more agent to tissue contrast than harmonic imaging with similar pulses. Similar measurements suggest that broadband pulse inversion Doppler can provide up to 16 dB more contrast than broadband conventional Doppler.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82896728","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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