Pub Date : 2010-12-01DOI: 10.1109/ULTSYM.2010.5935492
L. Demi, M. Verweij, N. D. Jong, K. V. Dongen
Biomedical tissues usually show inhomogeneity in their acoustic medium parameters. These inhomogeneities cause refraction and scattering of diagnostic and therapeutic ultrasound waves. A method that is able to model the effects of inhomogeneity in the attenuation and in the nonlinearity is essential for the design of transducers for new ultrasound modalities and the development of novel ultrasound applications. The Iterative Nonlinear Contrast Source (INCS) method has originally been designed for the accurate modeling of nonlinear acoustic wave fields in homogeneous media. It considers the nonlinear term from the Westervelt equation as a distributed contrast source, and the corresponding integral equation is solved using an iterative Neumann scheme. This paper presents an extension of the INCS method that can handle inhomogeneity in the attenuation and in the coefficient of nonlinearity. Results are presented for the one-dimensional case. These show that in this case the presented method correctly predicts the effects related to nonlinear propagation and scattering by inhomogeneities in the attenuation and the coefficient of non-linearity.
{"title":"Modeling nonlinear acoustic wave fields in media with inhomogeneity in the attenuation and in the nonlinearity","authors":"L. Demi, M. Verweij, N. D. Jong, K. V. Dongen","doi":"10.1109/ULTSYM.2010.5935492","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935492","url":null,"abstract":"Biomedical tissues usually show inhomogeneity in their acoustic medium parameters. These inhomogeneities cause refraction and scattering of diagnostic and therapeutic ultrasound waves. A method that is able to model the effects of inhomogeneity in the attenuation and in the nonlinearity is essential for the design of transducers for new ultrasound modalities and the development of novel ultrasound applications. The Iterative Nonlinear Contrast Source (INCS) method has originally been designed for the accurate modeling of nonlinear acoustic wave fields in homogeneous media. It considers the nonlinear term from the Westervelt equation as a distributed contrast source, and the corresponding integral equation is solved using an iterative Neumann scheme. This paper presents an extension of the INCS method that can handle inhomogeneity in the attenuation and in the coefficient of nonlinearity. Results are presented for the one-dimensional case. These show that in this case the presented method correctly predicts the effects related to nonlinear propagation and scattering by inhomogeneities in the attenuation and the coefficient of non-linearity.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":"10 1","pages":"2056-2059"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78421687","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 : 2010-12-01DOI: 10.1109/ULTSYM.2010.5935903
K. Kooiman, M. Emmer, T. Kokhuis, J. Bosch, H. D. de Gruiter, M. V. van Royen, W. V. van Cappellen, A. Houtsmuller, A. V. D. van der Steen, N. de Jong
Ultrasound contrast agents consist of gas-filled coated microbubbles with diameters between 1 and 10 µm. Within an ultrasound field, high differences in responses of similar sized microbubbles have been reported. Heterogeneous coating properties have been suggested to be the underlying cause. Until now, properties of this coating, like viscosity have been studied dynamically using a set-up of vibrating microbubbles in an ultrasound field. This study focuses on determining the viscosity of the coating for lipid-coated microbubbles in a static set-up. The viscosity of the coating was determined by measuring the mobility of a fluorescent lipid using Fluorescence Recovery After Photobleaching (FRAP). We found a surface shear viscosity of 8×10−6 kg/s that was independent of the microbubble size. In addition, we found that the lipid distribution in the coating was heterogeneous and varied from microbubble to microbubble. In conclusion, this study shows that the static surface shear viscosity of the coating can be determined in an independent way which can now be used in microbubble dynamics models.
{"title":"Lipid distribution and viscosity of coated microbubbles","authors":"K. Kooiman, M. Emmer, T. Kokhuis, J. Bosch, H. D. de Gruiter, M. V. van Royen, W. V. van Cappellen, A. Houtsmuller, A. V. D. van der Steen, N. de Jong","doi":"10.1109/ULTSYM.2010.5935903","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935903","url":null,"abstract":"Ultrasound contrast agents consist of gas-filled coated microbubbles with diameters between 1 and 10 µm. Within an ultrasound field, high differences in responses of similar sized microbubbles have been reported. Heterogeneous coating properties have been suggested to be the underlying cause. Until now, properties of this coating, like viscosity have been studied dynamically using a set-up of vibrating microbubbles in an ultrasound field. This study focuses on determining the viscosity of the coating for lipid-coated microbubbles in a static set-up. The viscosity of the coating was determined by measuring the mobility of a fluorescent lipid using Fluorescence Recovery After Photobleaching (FRAP). We found a surface shear viscosity of 8×10−6 kg/s that was independent of the microbubble size. In addition, we found that the lipid distribution in the coating was heterogeneous and varied from microbubble to microbubble. In conclusion, this study shows that the static surface shear viscosity of the coating can be determined in an independent way which can now be used in microbubble dynamics models.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":"87 1","pages":"900-903"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79884520","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 : 2010-12-01DOI: 10.1109/ULTSYM.2010.5935655
S. Takayanagi, T. Yanagitani, M. Matsukawa, Yoshiaki Watanabe
C-axis parallel-oriented ZnO piezoelectric films, (1120) or (1010) textured films, are good candidates for shear mode devices. Ion bombardment to the substrate during film deposition suppresses the usual (0001)-oriented grain growth, resulting in the preferential development of unusual (1120) or (1010) orientation. This is because the most densely packed (0001) plane should incur more damage by ion bombardment than the (1120) and (1010) planes. In this study, we propose RF substrate bias RF magnetron sputtering method to induce the ion bombardment to the substrate. This method made possible to form preferential (1120) or (1010) orientation in the conditions where these orientations could not be formed in case of DC bias.
{"title":"A simple technique for obtaining (1120) or (1010) textured ZnO films by RF bias sputtering","authors":"S. Takayanagi, T. Yanagitani, M. Matsukawa, Yoshiaki Watanabe","doi":"10.1109/ULTSYM.2010.5935655","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935655","url":null,"abstract":"C-axis parallel-oriented ZnO piezoelectric films, (1120) or (1010) textured films, are good candidates for shear mode devices. Ion bombardment to the substrate during film deposition suppresses the usual (0001)-oriented grain growth, resulting in the preferential development of unusual (1120) or (1010) orientation. This is because the most densely packed (0001) plane should incur more damage by ion bombardment than the (1120) and (1010) planes. In this study, we propose RF substrate bias RF magnetron sputtering method to induce the ion bombardment to the substrate. This method made possible to form preferential (1120) or (1010) orientation in the conditions where these orientations could not be formed in case of DC bias.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":"31 1","pages":"1060-1063"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86027616","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 : 2010-12-01DOI: 10.1109/ULTSYM.2010.5935775
J. Yao, Z. Yu, M. Pertijs, G. Meijer, C. Lancée, J. Bosch, N. de Jong
In this paper, a programmable time-gain-compensation amplifier dedicated to a 2D piezoelectric ultrasound transducer is presented. It uses an open-loop amplifier structure consisting of a voltage-to-current converter and a current-to-voltage converter. The circuit has been designed in a standard 0.35-μm CMOS process. Simulation and measurement results show that gains of 0dB, 12dB, 26dB and 40dB can be achieved for input signals centered at 6MHz with 80dB dynamic range (100μV to 1V). The measured gain errors at 6MHz are below 1dB for all gain settings. The amplifier consumes only 130μW when driving a 250fF load.
{"title":"Design of a low power time-gain-compensation amplifier for a 2D piezoelectric ultrasound transducer","authors":"J. Yao, Z. Yu, M. Pertijs, G. Meijer, C. Lancée, J. Bosch, N. de Jong","doi":"10.1109/ULTSYM.2010.5935775","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935775","url":null,"abstract":"In this paper, a programmable time-gain-compensation amplifier dedicated to a 2D piezoelectric ultrasound transducer is presented. It uses an open-loop amplifier structure consisting of a voltage-to-current converter and a current-to-voltage converter. The circuit has been designed in a standard 0.35-μm CMOS process. Simulation and measurement results show that gains of 0dB, 12dB, 26dB and 40dB can be achieved for input signals centered at 6MHz with 80dB dynamic range (100μV to 1V). The measured gain errors at 6MHz are below 1dB for all gain settings. The amplifier consumes only 130μW when driving a 250fF load.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":"23 1","pages":"841-844"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82131466","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 : 2010-12-01DOI: 10.1109/ULTSYM.2010.5935592
P. Sheeran, Vincent P. Wong, R. J. McFarland, William D. Ross, S. Feingold, T. Matsunaga, P. Dayton
Most gas-filled ultrasound contrast agents are produced range of several microns in diameter, which limits them to flow within intravascular space. One mechanism proposed to produce extravascular imaging agents is acoustic droplet vaporization. Liquid perfluorocarbon droplets can be manufactured in the sub-micron range and can then passively diffuse through leaky tumor vasculature. It is hypothesized that once extravasated, these droplets could be converted to microbubbles in the micron range through additional energy input in the form of ultrasound, resulting in enhanced imaging contrast. Recent studies show current formulations of phase-change contrast agents in the sub-micron range may require substantial acoustic energy to vaporize, which increases the chance of bioeffects. Thus, phase-change contrast agents with reduced acoustic activation energies would have significant advantages. In this study, the generation and activation of novel phase-change contrast agents formulated with perfluorobutane is demonstrated. Perfluorobutane — normally a gas at room temperature — can be incorporated into metastable liquid sub-micron droplets with lipid encapsulation methods. The resulting droplets are shown to be acoustically vaporizable with substantially less energy than other compounds proposed for phase-change contrast agents such as perfluoropentane and perfluorohexane.
{"title":"Efficacy of perfluorobutane as a phase-change contrast agent for low-energy ultrasonic imaging","authors":"P. Sheeran, Vincent P. Wong, R. J. McFarland, William D. Ross, S. Feingold, T. Matsunaga, P. Dayton","doi":"10.1109/ULTSYM.2010.5935592","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935592","url":null,"abstract":"Most gas-filled ultrasound contrast agents are produced range of several microns in diameter, which limits them to flow within intravascular space. One mechanism proposed to produce extravascular imaging agents is acoustic droplet vaporization. Liquid perfluorocarbon droplets can be manufactured in the sub-micron range and can then passively diffuse through leaky tumor vasculature. It is hypothesized that once extravasated, these droplets could be converted to microbubbles in the micron range through additional energy input in the form of ultrasound, resulting in enhanced imaging contrast. Recent studies show current formulations of phase-change contrast agents in the sub-micron range may require substantial acoustic energy to vaporize, which increases the chance of bioeffects. Thus, phase-change contrast agents with reduced acoustic activation energies would have significant advantages. In this study, the generation and activation of novel phase-change contrast agents formulated with perfluorobutane is demonstrated. Perfluorobutane — normally a gas at room temperature — can be incorporated into metastable liquid sub-micron droplets with lipid encapsulation methods. The resulting droplets are shown to be acoustically vaporizable with substantially less energy than other compounds proposed for phase-change contrast agents such as perfluoropentane and perfluorohexane.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":"33 1","pages":"904-907"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86824487","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 : 2010-12-01DOI: 10.1109/ULTSYM.2010.5935556
K. Naito, T. Sugiura
Nowadays nondestructive testing is noted due to the need of maintenance in structures, such as nuclear energy plants and aircrafts. However, detection and sizing of a closed crack are difficult by the conventional ultrasonic testing, because ultrasonic waves penetrate the contact area of the closed crack. Now nonlinear ultrasonic testing is attracting attention. Though there have been experimental reports on superharmonics or subharmonics and some theoretical researches accounting the superharmonics, so far there have yet been few reports that clarify the mechanism causing the subharmonics. Generation of superharmonics at a closed crack was theoretically explained by modeling the contact of the crack surfaces as a nonlinear spring. This modeling is based on the fact that, when the gap between the crack surfaces decreases, the contact pressure increases nonlinearly due to the asperity of the crack surfaces. In this study a closed crack was regarded as a nonlinear spring with up to the third order terms, and nonlinear analysis and numerical simulation were carried out. In experiment, two aluminum specimens strongly pressed were used in place of a metal block with a closed crack. Numerical simulation predicts generation of the subharmonics. They can appear if the input frequency close to twice the natural frequency. Conditions for the subharmonics can also be found analytically with respect to the input frequency and the input amplitude. Subharmonics were also confirmed by experiment. In conclusion, a possible mechanism causing the subharmonics at a closed crack was explained by regarding a closed crack as a nonlinear spring with up to the third order terms.
{"title":"A possible mechanism causing subharmonics in ultrasonic testing of a closed crack","authors":"K. Naito, T. Sugiura","doi":"10.1109/ULTSYM.2010.5935556","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935556","url":null,"abstract":"Nowadays nondestructive testing is noted due to the need of maintenance in structures, such as nuclear energy plants and aircrafts. However, detection and sizing of a closed crack are difficult by the conventional ultrasonic testing, because ultrasonic waves penetrate the contact area of the closed crack. Now nonlinear ultrasonic testing is attracting attention. Though there have been experimental reports on superharmonics or subharmonics and some theoretical researches accounting the superharmonics, so far there have yet been few reports that clarify the mechanism causing the subharmonics. Generation of superharmonics at a closed crack was theoretically explained by modeling the contact of the crack surfaces as a nonlinear spring. This modeling is based on the fact that, when the gap between the crack surfaces decreases, the contact pressure increases nonlinearly due to the asperity of the crack surfaces. In this study a closed crack was regarded as a nonlinear spring with up to the third order terms, and nonlinear analysis and numerical simulation were carried out. In experiment, two aluminum specimens strongly pressed were used in place of a metal block with a closed crack. Numerical simulation predicts generation of the subharmonics. They can appear if the input frequency close to twice the natural frequency. Conditions for the subharmonics can also be found analytically with respect to the input frequency and the input amplitude. Subharmonics were also confirmed by experiment. In conclusion, a possible mechanism causing the subharmonics at a closed crack was explained by regarding a closed crack as a nonlinear spring with up to the third order terms.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":"20 1","pages":"2392-2395"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83923857","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 : 2010-12-01DOI: 10.1109/ULTSYM.2010.5935805
S. Yoon, S. Mallidi, J. Tam, Justina Tam, Avinash K. Murthy, K. Johnston, K. Sokolov, S. Emelianov
Plasmonic nanoparticles have been widely used for various biomedical applications such as biological imaging, sensing, and cancer therapy. Specifically, gold nanospheres, nanorods, and nanoshells are used as contrast agents for photoacoustic imaging due to their strong absorptive property. However, there are concerns about using these nanoparticles in-vivo because they are not biodegradable and cannot be cleared from the body. Recently, biodegradable nanoclusters have been reported. The biodegradable nanoparticles are composed of primary 4-nm gold nanoparticles and stabilized by a biodegradable polymer binder. In this study, we demonstrated the utility of biodegradable nanoclusters as a contrast agent in photoacoustic imaging. The tissue mimicking phantoms were used for ultrasound and photoacoustic imaging. The results show that the biodegradable plasmonic nanoclusters can be used as photoacoustic contrast agent.
{"title":"Photoacoustic imaging with biodegradable plasmonic nanoclusters","authors":"S. Yoon, S. Mallidi, J. Tam, Justina Tam, Avinash K. Murthy, K. Johnston, K. Sokolov, S. Emelianov","doi":"10.1109/ULTSYM.2010.5935805","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935805","url":null,"abstract":"Plasmonic nanoparticles have been widely used for various biomedical applications such as biological imaging, sensing, and cancer therapy. Specifically, gold nanospheres, nanorods, and nanoshells are used as contrast agents for photoacoustic imaging due to their strong absorptive property. However, there are concerns about using these nanoparticles in-vivo because they are not biodegradable and cannot be cleared from the body. Recently, biodegradable nanoclusters have been reported. The biodegradable nanoparticles are composed of primary 4-nm gold nanoparticles and stabilized by a biodegradable polymer binder. In this study, we demonstrated the utility of biodegradable nanoclusters as a contrast agent in photoacoustic imaging. The tissue mimicking phantoms were used for ultrasound and photoacoustic imaging. The results show that the biodegradable plasmonic nanoclusters can be used as photoacoustic contrast agent.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":" 9","pages":"1011-1014"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91409583","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 : 2010-12-01DOI: 10.1109/ULTSYM.2010.5935706
T. Faez, M. Emmer, M. Docter, M. Versluis, N. de Jong
We have investigated the subharmonic vibration of BR14 (Bracco Research S.A., Geneva, Switzerland) contrast agent microbubbles between 8–11 MHz. The response of the bubbles is recorded optically with the ultrafast recording camera (Brandaris 128) at three acoustic pressures 50, 100 and 120 kPa. The vibration of the microbubbles as a function of excitation frequency is measured and frequency content is determined. 40% of studied bubbles show subharmonic oscillations. For bubbles smaller than 3μm in diameter the driving frequency of maximum subharmonic response increases for increasing pressures opposite to what has been reported for larger bubbles (> 3μm).
我们研究了BR14 (Bracco Research s.a.， Geneva, Switzerland)造影剂微泡在8-11 MHz之间的次谐波振动。在50、100和120 kPa三种声压下，用超快记录相机(Brandaris 128)光学记录气泡的响应。测量了微气泡的振动随激振频率的变化规律，确定了激振频率的含量。40%的气泡表现出次谐波振荡。对于直径小于3μm的气泡，最大次谐波响应的驱动频率随着压力的增加而增加，而对于直径大于3μm的气泡，则相反。
{"title":"Subharmonic spectroscopy of ultrasound contrast agents","authors":"T. Faez, M. Emmer, M. Docter, M. Versluis, N. de Jong","doi":"10.1109/ULTSYM.2010.5935706","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935706","url":null,"abstract":"We have investigated the subharmonic vibration of BR14 (Bracco Research S.A., Geneva, Switzerland) contrast agent microbubbles between 8–11 MHz. The response of the bubbles is recorded optically with the ultrafast recording camera (Brandaris 128) at three acoustic pressures 50, 100 and 120 kPa. The vibration of the microbubbles as a function of excitation frequency is measured and frequency content is determined. 40% of studied bubbles show subharmonic oscillations. For bubbles smaller than 3μm in diameter the driving frequency of maximum subharmonic response increases for increasing pressures opposite to what has been reported for larger bubbles (> 3μm).","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":"37 1","pages":"1732-1734"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81180176","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 : 2010-12-01DOI: 10.1109/ULTSYM.2010.5935699
G. Renaud, J. Bosch, A. V. D. van der Steen, N. de Jong
The Luxembourg-Gorky effect, defined as a transfer of amplitude-modulation from one wave to a second wave, is applied to lipid-coated microbubbles tailored for nonlinear contrast ultrasound imaging. This nonlinear effect is non-classical because not created in micro-homogeneous media. A simple experimental set-up allowing the dual-frequency dual-beam insonification of single bubbles was developed to study the interaction between a high-frequency probing ultrasonic wave and an amplitude-modulated low-frequency wave. Low-amplitude acoustic pressures are employed for both waves to reduce acoustically induced non-reversible processes. The frequency of the probing wave lies above the resonance frequency of microbubbles such that the pressure amplitude scattered by a single bubble is proportional to its diameter. As a result the bubble radial oscillation induced by the low-frequency wave produces an amplitude modulation and a phase modulation in the high-frequency signal scattered by single bubbles. The analysis of the latter signal provides direct access to the LF radial motion of bubbles. Using the high-frequency signal recorded before and after the LF manipulation as a reference, we show how the Luxembourg-Gorky effect can be used to quantify the asymmetry in acoustical induced vibrations of lipid-coated microbubbles. Among 220 investigated single bubbles, 49% exhibited full compression-only behavior. This low-amplitude highly nonlinear behavior is of great interest for medical contrast ultrasound imaging. Further work will aim at developing an ”single-bubble acoustical camera” able to derive the absolute value of the radial oscillation.
{"title":"The Luxembourg-Gorky effect for in vitro characterization of lipid-coated microbubbles","authors":"G. Renaud, J. Bosch, A. V. D. van der Steen, N. de Jong","doi":"10.1109/ULTSYM.2010.5935699","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935699","url":null,"abstract":"The Luxembourg-Gorky effect, defined as a transfer of amplitude-modulation from one wave to a second wave, is applied to lipid-coated microbubbles tailored for nonlinear contrast ultrasound imaging. This nonlinear effect is non-classical because not created in micro-homogeneous media. A simple experimental set-up allowing the dual-frequency dual-beam insonification of single bubbles was developed to study the interaction between a high-frequency probing ultrasonic wave and an amplitude-modulated low-frequency wave. Low-amplitude acoustic pressures are employed for both waves to reduce acoustically induced non-reversible processes. The frequency of the probing wave lies above the resonance frequency of microbubbles such that the pressure amplitude scattered by a single bubble is proportional to its diameter. As a result the bubble radial oscillation induced by the low-frequency wave produces an amplitude modulation and a phase modulation in the high-frequency signal scattered by single bubbles. The analysis of the latter signal provides direct access to the LF radial motion of bubbles. Using the high-frequency signal recorded before and after the LF manipulation as a reference, we show how the Luxembourg-Gorky effect can be used to quantify the asymmetry in acoustical induced vibrations of lipid-coated microbubbles. Among 220 investigated single bubbles, 49% exhibited full compression-only behavior. This low-amplitude highly nonlinear behavior is of great interest for medical contrast ultrasound imaging. Further work will aim at developing an ”single-bubble acoustical camera” able to derive the absolute value of the radial oscillation.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":"84 1","pages":"786-789"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76048128","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 : 2010-12-01DOI: 10.1109/ULTSYM.2010.5935430
J. Albinsson, S. Brorsson, F. Lindgren, Å. R. Ahlgren, M. Cinthio
A novel 2D particle tracking method, that uses 1) iteration, 2) fast quadratic sub-pixel estimation (with only 28 multiplications per movement), and 3) a previous kernel, has been evaluated and compared with a full-search block-matching method. The comparison with high-frequency ultrasound data (40 MHz) was conducted in silico and on phantoms, which comprised lateral, diagonal, and ellipsoidal movement patterns with speeds of 0–15 mm/s. The mean tracking error was reduced by 68% in silico and 71% for the phantom measurements. When only sub-pixel estimation was used, the decrease in the tracking error was 61% in silico and 57% for the phantom measurements. As well as decreasing the tracking error, the new method only used 70% of the computational time needed by the full-search block-matching method. With a fast method having good tracking ability for high-frequency ultrasound data, we now have a tool to better investigate tissue movements and its dynamic functionality.
{"title":"Combined use of iteration, quadratic interpolation and an extra kernel for high-resolution 2D particle tracking: A first evaluation","authors":"J. Albinsson, S. Brorsson, F. Lindgren, Å. R. Ahlgren, M. Cinthio","doi":"10.1109/ULTSYM.2010.5935430","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935430","url":null,"abstract":"A novel 2D particle tracking method, that uses 1) iteration, 2) fast quadratic sub-pixel estimation (with only 28 multiplications per movement), and 3) a previous kernel, has been evaluated and compared with a full-search block-matching method. The comparison with high-frequency ultrasound data (40 MHz) was conducted in silico and on phantoms, which comprised lateral, diagonal, and ellipsoidal movement patterns with speeds of 0–15 mm/s. The mean tracking error was reduced by 68% in silico and 71% for the phantom measurements. When only sub-pixel estimation was used, the decrease in the tracking error was 61% in silico and 57% for the phantom measurements. As well as decreasing the tracking error, the new method only used 70% of the computational time needed by the full-search block-matching method. With a fast method having good tracking ability for high-frequency ultrasound data, we now have a tool to better investigate tissue movements and its dynamic functionality.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":"1 1","pages":"2000-2003"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72631666","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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