1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)最新文献

{"title":"Experimental verification of acoustic saturation","authors":"J.M. Sempsrott, W. O’Brien","doi":"10.1109/ULTSYM.1999.849232","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849232","url":null,"abstract":"The maximum value of acoustic pressure within an ultrasonic beam is limited by acoustic saturation. The theoretical basis for acoustic saturation has been analyzed previously. In this work, a high-power pulse source is used to drive acoustic pressure levels from an ultrasonic beam to saturation. An automatic procedure determines the field's beam axis using a calibrated Marconi PVDF hydrophone. The hydrophone measured RF waveforms are recorded along the beam axis and analyzed off-line. The peak compressional pressure is evaluated as a function of distance along the beam axis. The overall maximum pressure is compared to theoretical predictions. Three-, six-, and nine-MHz center frequency, 19-mm-diameter transducers were analyzed. The longer focal length transducer saturation level was comparable to a theoretical prediction. However, the theoretical saturation level for the shorter focal length transducers underestimated experimental results.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115218242","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 contrast agents phagocytosed by neutrophils demonstrate acoustic activity","authors":"P. Dayton, J. Lindner, J. Chomas, K. Morgan, S. Simon, A. Lum, D. May, M. Coggins, K. Ferrara","doi":"10.1109/ULTSYM.1999.849326","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849326","url":null,"abstract":"Ultrasound contrast agents are microbubbles composed of a thin lipid or albumin shell filled with air or a high molecular weight gas. These microbubbles are used for contrast-enhanced ultrasound (CEU) assessment of organ perfusion. In regions of inflammation, microbubbles are phagocytosed intact by activated neutrophils adherent to the venular wall. The authors hypothesized that microbubbles remain acoustically active following phagocytosis. Accordingly, they assessed the physical responses of both phagocytosed and free microbubbles by direct microscopic observation during delivery of repetitive single pulses of ultrasound at various acoustic pressures. Insonation results in oscillation in the bubbles volume. Microbubbles were optically recorded during insonation with a high-speed imaging system and diameter-time curves were analyzed to determine the effect of phagocytosis. Phagocytosed microbubbles retained their acoustic activity, although the intracellular environment increased viscoelastic damping experienced by microbubbles. With a pulse of high acoustic intensity (>1 MPa), phagocytosed microbubbles expanded up to 500% of their initial radii, which occasionally resulted in neutrophil rupture. Primary radiation force displaced phagocytosed microbubbles a distance of 100 microns with an acoustic pressure of -240 kPa and a pulse repetition frequency of 10 kHz, thus providing further evidence of acoustic activity. The authors conclude that phagocytosed microbubbles exhibit viscoelastic damping and yet are susceptible to acoustic destruction. They can generate non-linear echoes on the same order of magnitude as free microbubbles. These results indicate that CEU may be used to identify and assess regions of inflammation by detecting acoustic signals from microbubbles that are phagocytosed by activated neutrophils. In addition, the rapid expansion of a microbubble at high acoustic pressure may present a means to rupture a neutrophil or drug capsule at a specific site, resulting in delivery of a drug.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131130456","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":"Analysis of resolution for an amplitude steered array","authors":"C. H. Frazier, W. Hughes, W. O’Brien","doi":"10.1109/ULTSYM.1999.849219","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849219","url":null,"abstract":"In 1976, Hughes and Thompson introduced the amplitude-steered array, which steered the maximum response of the linear array by amplitude weighting the output signals of the elements, thus eliminating the need for time delays or phase-shift networks. Currently that amplitude-steered array concept is being extended to a broadband two-dimensional array which can be used for real-time three-dimensional imaging. In shifting the use of the amplitude-steered array from underwater acoustic communications to imaging, one must consider different issues of the array's performance such as lateral and axial resolution. The authors show that both lateral and axial resolution are limited by the length of the array. The dependence of axial resolution on the length of the array is a unique feature of the amplitude-steered array, leading to an interesting tradeoff between lateral and axial resolution. The authors develop a theoretical basis for the dependence and give simulation results.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126342765","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":"MRI controlled HIFU treatment of breast tissue","authors":"J. Spoo, I. Simiantonakis, J. Jenne, R. Rastert, C. Bohris, M. Hlavác, J. Debus, P. Huber","doi":"10.1109/ULTSYM.1999.849259","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849259","url":null,"abstract":"It was the objective of this study to test the feasibility of MRI (Magnetic Resonance Imaging)-monitored focused ultrasound surgery (FUS or HIFU: High Intensity Focused Ultrasound) for the treatment of breast glandular tissue in animals. The authors treated 15 \"L\"-shaped target volumes in the sheep breast applying 30 to 128 ultrasound pulses at a frequency of 1.7 MHz and an electrical power of 25-75 W per pulse. Therapy was performed with a newly designed fully MRI compatible ultrasound therapy unit. By means of a MRI T1w (T1-weighted) TurboFLASH sequence positions of the ultrasound foci could clearly be detected. Conventional T1w and T2w MR imaging was carried out for assessing therapy effects. After treatments the animals were sacrificed and a histologic workout was preceded. Planning the target volume in MR images, application of ultrasound and temperature monitoring by T1w MRI were feasible in the authors' experimental setup. Ultrasound foci could be localized by MR thermometry. Lesions induced were detectable in T2w MR imaging and post contrast T1w sequences. The histologic workout displayed coagulative necroses in the treated tissue areas, fibrosis was present in long-term evaluations. Treatment with the authors' specially designed and constructed MR compatible FUS unit was feasible in breast tissue, therapeutic effects could be proved in both, radiologic imaging and histology.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128211914","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":"A prototype of tunable surface acoustic wave filter","authors":"Jiahua Zhu, N. Emanetoglu, Yicheng Lu, J. Kosinski, R. Pastore, A. Lepore","doi":"10.1109/ULTSYM.1999.849353","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849353","url":null,"abstract":"A prototype of tunable surface acoustic wave filter has been developed. The device consists of 11 interdigital transducers paralleled in the SAW propagation path. Different SAW filter configurations are realized by selecting or combining various IDTs, resulting in the tunability of both center frequency and 3 dB bandwidth. The center frequencies of the SAW filter ranges from 126.8 MHz to 199.1 MHz while the 3 dB bandwidth range from 18.8 MHz to 58.9 MHz. Changes between different SAW filter configurations is implemented by RF switches.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132448208","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":"Time-domain solution of the temperature increase induced by diagnostic ultrasound","authors":"M. Goueygou, J.G. Harris, W. O’Brien","doi":"10.1109/ULTSYM.1999.849254","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849254","url":null,"abstract":"Presents a complete time-domain solution to estimate the temperature increase induced by pulsed ultrasonic fields, such as those used in diagnostic applications. The authors' computational model includes 3 steps: (1) calculation of the acoustic field, (2) of the rate of heat generation and (3) of the temperature distribution. For step 1 and 3, the acoustic and thermal fields are computed by integrating the known acoustic and thermal Green functions of the homogenous medium, respectively, over the surface of the transducer and over the volume of interest. For step 2, the authors derive a new expression for the instantaneous rate of heat generation. Previous expressions gave only the average rate of heat for a single frequency excitation. The authors finally present computational results of the temperature increase induced by a point source and by a circular focused transducer.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127458323","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":"Ultrasonic characterization of emulsions: milk and water in oil","authors":"R. Higuti, E. Bacaneli, C. M. Furukawa, J. Adamowski","doi":"10.1109/ULTSYM.1999.849514","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849514","url":null,"abstract":"Measurements of ultrasonic attenuation and velocity in milk and low concentration water-in-oil (W/O) emulsion were conducted, using a measurement cell with a double-element transducer that eliminates diffraction losses. The milk is characterized by the attenuation coefficient, while in the case of water-in-oil emulsions, the characterization is best represented by the propagation velocity.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"257 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121178298","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":"High-contrast RF correlation imaging of defects in food package seals","authors":"Qi Tian, A. Ozguler, Scott A Morris, William D O 'brien","doi":"10.1109/ULTSYM.1999.849520","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849520","url":null,"abstract":"Previous research work to detect channel defect in package seals using pulse-echo ultrasound inspired the Backscattered Amplitude Integral (BAI) imaging and RF sample (RFS) imaging techniques. The two former image formation techniques, as well as the newly proposed technique, are evaluated from the same acquired pulse-echo RF data set. All images are formed with a 17.3-MHz 6.35-mm-diameter focused ultrasound transducer (f/2, 173-μm-6 dB pulse-echo lateral beamwidth at the focus, λ-86 μm) scanned over a rectangular grid, keeping the package material in the focal region. All techniques are evaluated with the same set of laboratory-made channel defects: plastic and aluminum foil trilaminate film with 6-, 10-, 15-, 38- and 50-μm-diameter channels filled with water or air. The new RF correlation image technique is formed from the correlation coefficient of each RF echo signal relative to a reference signal that does not pass through a channel defect. Prior to processing, the acquired RF echo signals are first windowed to match within the sample the range where the two materials are bonded, that is, the range where channel defects occur. The statistical study on the laboratory-made channel defects shows that RF correlation technique has the highest detection rate relative to BAI-mode and RFS-mode image for 15-, 10- and 6-μm channel defects. It also is the most effective at smoothing the background, leading to the greatest CNR enhancement.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121469107","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":"Experimental studies of using of split beam transducer for prostate cancer therapy in comparison to single beam transducer","authors":"J. Wu, N. Sanghvi, M. Phillips, M. Kunetsov, R. Foster, R. Bihrle, T. A. Gardner, S. Umemura","doi":"10.1109/ULTSYM.1999.849268","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849268","url":null,"abstract":"A \"split beam\" transducer arrangement was adapted for the existing benign prostatic hyperplasia (BPH) high intensity focused ultrasound (HIFU) treatment device, Sonablate-200/sup TM/ (manufactured by Focus Surgery Inc., Indianapolis, IN) for the treatment of localized prostate cancer. In the split beam configuration the HIFU beam is divided into several beams to create a larger treatment volume per ultrasound exposure which can reduce the overall treatment time. The objective of current study was to compare the necrosis volume and temperature patterns produced from \"single beam\" and \"split beam\" operating configurations. Experiments were performed on different test objects including Mylar strip, plexiglass, turkey breast tissue (in-vitro) and in vivo dog prostates. The results showed that the split beam configuration created larger lesion volume for the same exposure time while keeping the temperature near the rectal wall at the safe levels. Thus split beam transducer (SET) configuration should be effective and efficient in clinical application for the prostate cancer treatment.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127351865","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":"Fast beam shape computation and wave propagation via the Radon transform","authors":"T. Pitts, J. Greenleaf","doi":"10.1109/ULTSYM.1999.849221","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849221","url":null,"abstract":"An M-dimensional (M/spl ges/2) linear shift-invariant operator equation may be reduced to a set of decoupled (M-1)-dimensional equations via the Radon transform. This decoupling allows the solution of each reduced equation separately on different processors in parallel. The solution to the full M-dimensional equation is then recovered via an inverse Radon transform. This solution method is particularly well suited to computation of beam shape and wave propagation in a homogeneous medium. For beam shape computation, Huygens' integration over a two-dimensional aperture is reduced to a set of one-dimensional integrations (the number of one-dimensional integrations is determined via Shannon sampling theory from the highest angular harmonic present in the aperture distribution). The method is applied to computation of a wide bandwidth pulse distribution from a semi-circular aperture with a center frequency of 2.25 MHz. The results are compared with the full two-dimensional surface integration. Discussion of the increase in computational speed and sampling considerations affecting the accuracy of the distributed one-dimensional computations are presented.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"12 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114036649","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}