2010 IEEE International Ultrasonics Symposium最新文献

{"title":"Structure and ferroelectric properties of sputtered Pb(Mn, Nb)O3-PZT thin films","authors":"K. Wasa, K. Kawano, H. Adachi, T. Matsushima, K. Nishida, T. Yamamoto, I. Kanno, H. Kotera","doi":"10.1109/ULTSYM.2010.5935495","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935495","url":null,"abstract":"Heteroepitaxial thin films of PZT-based ternary perovskite, xPb(Mn, Nb)O3-(1−x)PZT, were fabricated by magnetron sputtering on (001)SrTiO3 and (001)MgO substrates. The heteroepitaxial thin films showed single c-domain /single crystal structure and exhibit hard piezoelectric behavior with high Ec, Ec>180kV/cm, at x=0.06 for the film thickness, 300nm–5mm. The ternary perovskite thin films showed relaxed structure at the film thickness > 0.5mm. However, Curie temperature Tc is 600°C which is 250°C higher than bulk ceramic values. The sputtered thin films exhibit remnant polarization being as high as 100mC/cm2. The in-plane compression model is ruled out for a mechanism of the present higher Tc phenomena, since the sputtered thin films show relaxed structure. The mechanism of the higher Tc is unclear. The present thin films of PZT-based ternary perovskite are exotic materials. This paper describes the structure and the exotic ferroelectric properties in relation to the possible application for piezoelectric MEMS.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80541236","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}

{"title":"Quantitative evaluation of correlation-based 3D vs. 2D speckle tracking using finite element cardiac mechanical model and in-vitro phantom","authors":"S. Tripathy, M. Simon, K. Kim","doi":"10.1109/ULTSYM.2010.5935680","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935680","url":null,"abstract":"Two-dimensional (2D) speckle tracking (ST) has been used extensively over the years in many different ultrasound (US) elasticity imaging applications with some limitations. 2D ST is limited especially for cardiac applications because of the 3D and complex motion of the heart. Out-of-plane motion is a major source of decorrelation for 2D ST. Recently 3D ST based on full 3D kernel search has been developed to overcome these limitations. In this study, the improvement of 3D ST performance compared to 2D ST is quantitatively analyzed via both a finite element (FE) based cardiac mechanical model and water tank experiments using a tissue phantom. Finite element based analysis suggested an improvement of about two folds in the errors. Considerable improvement in the quality of the displacement estimate images was observed in the experiments.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80566342","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}

{"title":"Ultrasound compatible RF ablation electrode design for catheter based guidance of RF ablation — In vivo results with thermal strain imaging","authors":"D. Stephens, J. Cannata, C. Seo, J. Jeong, Enwei Sun, W. Cao, A. Nikoozadeh, O. Oralkan, A. de la Rama, T. Nguyen, A. Dentinger, Feng Lin, Suhyun Park, D. Wildes, K. Thomenius, K. Shung, K. Shivkumar, A. Mahajan, U. Truong, M. O’Donnell, P. Khuri-Yakub, D. Sahn","doi":"10.1109/ULTSYM.2010.5935664","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935664","url":null,"abstract":"Currently the feedback guidance of intracardiac radiofrequency ablation (RFA) is very limited, offering only a catheter electrode (not tissue) temperature estimation and a means to titrate radiofrequency (RF) power delivery to the tissue. Our \"MicroLinear\" (ML) forward imaging ultrasound catheter design, now at a true 9F (3mm) in size, has been optimized with several features to simultaneously permit, a) high quality intracardiac steering and imaging, b) tracking of 3D position with electroanatomical mapping, c) RF ablation, and d) tissue thermal strain (TS) estimation for direct tissue temperature feedback. Two types of ML catheters have been built and tested in 3 porcine animal models. The first type, in its third generation, is based on a PZT transducer array; the second type, in its second generation, is based on a CMUT array with custom integrated interface circuitry. Both types of devices are true 9F in size and performed well in imaging tests in recent in vivo studies. Both the ML-PZT and ML-CMUT arrays, as described previously, have a fine pitch (65 and 63 micron respectively) 24 element phased arrays operating at 14 MHz which project a B-mode plane directly out from the tip of the catheter. Intracardiac imaging performance was documented to show that the very small array apertures of the ML design (1.2mm × 1.58mm, and 1.1mm × 1.4mm) permit good, high resolution imaging to depths as great as 4 cm. The ML-PZT catheter was equipped with a special low profile ablation tip which allowed simultaneous imaging and ablation at the distal end of the catheter. TS data were acquired during tissue ablations in right atrium (RA) and right ventricle (RV). The TS data of the RF ablations were processed off line. In vivo use of this new technology has shown for the first time the very substantial potential for a single, low profile catheter to simultaneously image within the heart and perform intracardiac ablation therapy with tissue temperature guidance produced from the incorporation of TS imaging. Work is underway to further assess the temperature estimation accuracy and to integrate the TS processing for real time displays.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80584008","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}

{"title":"Phase shift variance imaging for contrast agent detection","authors":"M. Siepmann, M. Mienkina, G. Schmitz, S. Fokong, Zhe Liu, F. Kiessling, J. Gatjens","doi":"10.1109/ULTSYM.2010.5935663","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935663","url":null,"abstract":"A novel ultrasound contrast agent detection method that selectively detects microbubble (MB) destruction is presented. The detection is based on the variance of the phase shift of consecutive echoes. The variance for stationary echoes or motion at constant speed is determined by the noise of the acquisition system and is theoretically predicted. We hypothesize that the phase shift variance of ultrasound echoes increases during MB destruction. It is expected that this PSV is higher than the PSV for stationary echoes or motion thus allowing the detection of the agent. The hypothesis is experimentally verified in a motion phantom. In a second experiment, MB in very low concentrations are imaged to demonstrate the sensitivity of the method. The results show good agreement with theory and exhibit a clear increase in PSV for MB vs. tissue (44.8 dB). Thus, the phase shift variance can be utilized for ultrasound contrast agent detection. Microbubbles in a concentration of 100 bubbles per ml are sufficient to cause detectable signals with a contrast to tissue ratio of up to 34.7 dB. The acquisition is implemented on a free programmable clinical device. No additions or hardware modifications are necessary making the method easily translatable to most clinical systems.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83743840","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}

{"title":"Convertible perfluorocarbon droplets for cancer detection and therapy","authors":"Ross Williams, Amanda L. Martin, N. Reznik, I. Gorelikov, N. Matsuura, S. Foster, P. Burns","doi":"10.1109/ULTSYM.2010.5935976","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935976","url":null,"abstract":"To enhance the detection and treatment of solid tumours, submicron droplets of liquid perfluorocarbon (PFC) have been developed which can accumulate in tumours by extravasation, and which can subsequently convert to highly echogenic gas bubbles using bursts of high-pressure ultrasound. One aim of droplet formulation is to balance the requirements of physical stability with acoustic convertibility. In this study, droplets ranging in size from 200nm to 2μm, composed of liquid perfluoropentane (PFP) or pefluorohexane (PFH) encapsulated by a fluorosurfactant were synthesized by extrusion and sonication. Droplet stability was assessed using fluorescence microscopy of incorporated quantum dots following incubation with macrophage cells over 4 hours. The impact on stability of depositing 1–3 layers of polyelectrolytes on the droplet surface was also assessed. The rate of coalescence was significantly reduced for droplets coated with 3 polyelectrolyte layers. At 10 MHz, the conversion threshold MI decreased from greater than 4 for 200nm PFP to less than 2 for 2μm PFP droplets, and did not depend strongly on the addition of polyelectrolytes. Resulting bubbles from vaporization persisted for at least 1s and were detectable using clinical nonlinear contrast detection pulse sequences, however, the conversion of droplets within cells resulted in cell death.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83775527","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}

{"title":"Radial extensional mode AlN-film resonator with high coupling factor","authors":"A. Isobe, K. Asai","doi":"10.1109/ULTSYM.2010.5935436","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935436","url":null,"abstract":"There is strong demand for MHz-band resonators integrated in IC chips. Although AlN-film resonators, such as FBARs, have good compatibility with CMOS fabrication, it is difficult to produce low-frequency devices because the vibration mode is thickness extension. It has recently been reported that a disc-type AlN-film resonator can excite radial extensional (RE) modes strongly [6]. In this study, the electrical characteristics of the fundamental RE mode were focused on, and the relation between the Q value and the structure of the resonator was investigated. Because the RE resonator, such as a disc-type resonator, had a null point at the center of the resonant part, it was difficult to connect an electric lead line at the null point using conventional AlN-film fabrication processes. We adopted a tuning-fork-type structure, which consisted of two RE resonant parts, a connecting part, and two supporting beams. Because the tuning-fork-type resonator had a null point at the center of the connecting part between the RE resonant parts, it was easy to connect the supporting beams, which acted as the electric lead lines too, at the null point. A fabricated RE resonator exhibited a high coupling factor of 2.8% and a high Q value of 3000 at the series resonant frequency and 4000 at the parallel resonant frequency. The figure of merit was 71 at the series resonant frequency and 94 at the parallel resonant frequency. These are the highest values for contour-mode AlN resonators so far reported and indicate that the RE resonator integrated in an IC chip is suitable for oscillator and filter applications.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83561464","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}

{"title":"Lesion generation through ribs without aberration correction using cavitational therapy","authors":"Yohan Kim, Tzu-yin Wang, Zhen Xu, C. Cain","doi":"10.1109/ULTSYM.2010.5935776","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935776","url":null,"abstract":"Acoustic aberration from bones can cause significant decrease of peak focal pressure and induce the formation of secondary lobes in the focal profile. Thermal tissue ablation techniques require correction mechanisms when bones such as ribs are present in the acoustic window in order to reduce bone overheating and improve treatment accuracy. In this study we investigated the effects of rib obstruction in pulsed cavitational therapy, or histotripsy. To produce tissue fractionation using histotripsy, the initiation of a cavitation bubble cloud is required, which only occurs when the pressure is above a distinct threshold. We hypothesize that histotripsy can generate precise lesions even under aberration from rib bones, as long as the main beam retains its shape and is above the cavitation cloud initiation threshold while secondary lobes are below the threshold. To test this hypothesis, a 750 kHz, spherically focused transducer was used to generate 87 lesions in tissue-mimicking phantoms with and without rib aberration by a polycarbonate rib phantom and porcine rib sections placed between the transducer and its focus. All lesions were created by the application of 8000 pulses with 13–15 MPa peak rarefactional pressure at a pulse repetition frequency of 100 Hz. No aberration correction mechanisms were applied. A high-speed camera was used to observe bubble cloud formation and lesion development in the phantoms. Results showed that well-confined lesions were created in all cases, with comparable main lesion sizes and minimal collateral damage observed in lesions generated through the rib aberrators. These results support our hypothesis, suggesting that histotripsy can generate precise lesions through rib obstruction without requiring aberration correction mechanisms.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83393873","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}

{"title":"Refraction and time of flight corrections in 3D ultrasound computed tomography","authors":"A. Koch, C. Hansen, N. Huttebrauker, H. Ermert","doi":"10.1109/ULTSYM.2010.5935522","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935522","url":null,"abstract":"Previous research showed that 2D refraction and time of flight (TOF) corrections in full angle spatial compounding (FASC) can improve image quality significantly. In this paper we focus on three dimensional beamline corrections (i.e. TOF and refraction) in 3D FASC. A tissue mimicking phantom was imaged using a conventional ultrasound scanner and a custom made mechanical applicator. The phantom contains a reservoir, filled with an NaCl solution to realize an inhomogeneous distribution of speed of sound (SOS). Two wires are placed inside the reservoir to verify the system's ability to image 3D structures with sub-wavelength dimensions. Pulse-echo-data was recorded fully around the object and in multiple cross-sectional planes. Via a reflector the SOS distribution in the imaged volume was reconstructed with the algebraic reconstruction technique (ART). In a second compounding process ultrasound beamlines were corrected in 3D for refraction at the surface and TOF inside the phantom using the reconstructed SOS distribution. Finally, corrected volume data sets from all viewing angles were superimposed to form a new FASC volume data set, corrected for refraction and TOF. With this method, spatial courses of thin structures can be imaged in 3D, with suppression of double line artifacts and correction of geometrical distortions.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89276565","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}

{"title":"Improved C-scan imaging using a Bayesian approach","authors":"K. S. Ho, S. Pierce, M. H. Li, G. Hayward, M. Sultan","doi":"10.1109/ULTSYM.2010.5935517","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935517","url":null,"abstract":"Conventional ultrasonic C-scan imaging in composite materials typically employs peak amplitude extraction where the obtained image quality is extremely dependent on the gate setup on the ultrasonic acquisition hardware. Additionally structural noise created by scattering phenomenon is often high enough to bury meaningful reflection echoes, due to the non-homogeneous nature of such materials. This paper investigates the use of Bayesian inference as a method to construct C-scan images of composite material. The approach was implemented using experimental pulse-echo data, obtained by single-sided inspection of carbon fibre reinforced composite plates containing impact damages. The results were compared to through-transmission measurements and show that the defect image contrast can be improved by using the Bayes' method.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87217633","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}

{"title":"Design of a programmable micro-ultrasound research platform","authors":"Harry C. T. Chiu, Lequan Zhang, D. Cheung, Chang-Hong Hu, K. Shung, A. Yu","doi":"10.1109/ULTSYM.2010.5935688","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935688","url":null,"abstract":"To foster innovative uses of micro-ultrasound in biomedicine, it is beneficial to develop flexible research-purpose systems that allow researchers to easily reconfigure its system-level operations such as transmit firing sequence and receive processing. In this paper, we present the development of a programmable micro-ultrasound research platform that is capable of realizing various micro-imaging algorithms. The research platform comprises a linear-array-based scanning front-end and a PC-based data processing back-end, which employs a graphical processing unit (GPU) as the processor core. The front-end operations can be configured from the PC via the parallel port and the two blocks are synchronized by an external clock. Acquired data from the front-end is first digitized and relayed to the PC through an data acquisition card (200 MHz, 14-bit). They are then transferred to the GPU (GTX 275) in which the image formation is carried out via multi-thread processing. Results are displayed on-screen in real-time and can be saved to the PC's hard disk for offline analysis. Through a module-based programming approach, this platform can facilitate realization of custom-designed imaging algorithms developed by researchers. In this work, B-mode imaging and adaptive color flow imaging have been implemented as demonstrations of the research platform's programmability. The performance results show that real-time processing frame rates can be achieved for both imaging modes.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87239887","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}