2010 IEEE International Ultrasonics Symposium最新文献

{"title":"Molecular diagnosis of cancer using multiplex photoacoustic imaging with targeted nanorods","authors":"Carolyn L. Bayer, Yun-Sheng Chen, Seungsoo Kim, S. Mallidi, K. Sokolov, S. Emelianov","doi":"10.1109/ULTSYM.2010.5935741","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935741","url":null,"abstract":"The diagnosis and treatment of cancerous tumors remains a challenge due to the inherent heterogeneity of the tumors and variation in treatment response between patients. A molecular imaging technique which provides high resolution at a depth of several centimeters could provide important information about the composition of heterogeneous cancerous tissues to aid in the diagnosis and monitoring of the treatment of cancer. Photoacoustic imaging, which can achieve high resolution at a clinically relevant tissue depth, combined with targeted contrast agents whose properties can be tuned to achieve distinct photoacoustic signals, provides a molecular imaging technique which is non-invasive, non-ionizing, and cost-competitive in comparison to existing molecular imaging methods. The research presented here describes combined photoacoustic and ultrasound imaging using tunable gold nanorods which have been targeted to unique cell types or molecular processes, and then distinguished by acquiring photoacoustic images at laser wavelengths spanning the optical absorption spectra of the nanoparticles. The results obtained using tissue models consisting of various cancer cells, overexpressing different receptors, indicate that photoacoustic imaging is capable of identifying multiple molecular targets or cell types within a tissue.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78186534","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":"Change in mode configurations and propagation velocity of guided waves through an elbow section of a pipe","authors":"Satoru Furuhashi, Kazuhiro Sorimachi, T. Sugiura","doi":"10.1109/ULTSYM.2010.5935617","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935617","url":null,"abstract":"Guided waves, propagating over long distances with low damping along the longitudinal direction of pipes, are expected as an efficient method for non-destructive testing of such long structures. In industrial applications, structures to be inspected often have both straight sections and curved sections. Therefore, it is important to consider appropriate conditions for transmitting guided waves propagating with less damping through multiple areas with different shapes. This research theoretically analyzes and experimentally verifies propagation of guided waves from a straight section to an elbow section of a pipe, and discusses change of the mode configurations and the propagation velocity under the influence of the elbow curvature of the pipe. The results show a good possibility of predicting the receiver signals detecting guided waves through an elbow section of a pipe, by clarifying change of the mode configurations and the propagation velocity under the influence of the elbow curvature in a semi-analytical way. The approach shown in this study will be useful for propagating guided waves efficiently in pipes with elbow sections.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86951486","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":"Real-time monitoring of thermal and mechanical response to sub-therapeutic HIFU beams in vivo","authors":"Dalong Liu, Jing Jiang, J. Bischof, J. Ballard, E. Ebbini","doi":"10.1109/ULTSYM.2010.5935932","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935932","url":null,"abstract":"We present first in vivo results of realtime 2D imaging of thermal and mechanical response to sub-therapeutic HIFU beams in a small-animal tumor model. A 2.5 MHz focused transducer with fnumber = 1.05 was used to generate short (≈ 1.5 sec) exposure in LNCap tumors implanted in the hindlimb of nude mice with power levels suitable to produce 4–6 °C rise in tissue (based on results in thermally-calibrated tissue mimicking phantoms). Beamformed RF data was collected at 99 frames per second to allow for capturing tissue displacements due to both temperature and breathing cycles. To ascertain the system's capability to cover an adequate range of periodic tissue motion, the sub-therapeutic HIFU beams were sinusoidally modulated at frequencies higher than the pulsatory frequency in the mouse model. Results from our previously published 2D temperature imaging algorithm demonstrate the capture of strains due to temperature change, pulsatory motions near arteries, and sinusoidal oscillations due to acoustic radiation force effects due to the HIFU-beam modulation. To reduce the effects of mechanical strains due to motion and ARF modulation, an iterative image reconstruction algorithm was used. The method employs alternating projections that employ the non-negativity constraints (TΔ(r, t) ≥ 0) and a multi-dimensional time-varying Gaussian filter derived from the spatio-temporal impulse response of the transient bioheat transfer equation (tBHTE) in each iteration. This method of projection onto convex sets (POCS) allows for the removal of artifacts inconsistent with the temperature evolution model in tissue media while preserving real temperature data until convergence is achieved. Our in vivo results show that the POCS algorithm achieves significant reduction in the temperature artifacts due to breathing and pulsations while preserving true temperature profiles with excellent spatial and temporal resolution. These results clearly demonstrate the sensitivity and specificity of ultrasound thermography to the spatially-confined sub-therapeutic HIFU beams. This performance is unmatched by other noninvasive methods for imaging temperature.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78674576","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":"Comparing tumor response to VEGF blockade therapy using high frequency ultrasound imaging with size-selected microbubble contrast agents","authors":"S. Sirsi, M. Borden, Cherry C. Chen, S. Hernandez, Jianzhong Huang, Tessa B. Johung, D. Yamashiro, J. Kandel, S. Homma","doi":"10.1109/ULTSYM.2010.5935801","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935801","url":null,"abstract":"Vascular endothelial growth factors (VEGF) are key mediators in tumor growth and angiogenesis. Suppression of tumor growth by VEGF-blockade therapy is a popular approach towards improving cancer treatment. Bevacizumab (BV) is monoclonal antibody used to inhibit VEGF that has shown promise in treating several forms of cancer. However, BV is ineffective in certain forms of cancer, presumably due to unpredicted compensatory mechanisms of VEGF deficient tumors. In clinical practice, it would be advantageous to determine as early as possible whether a particular cancer would be responsive to BV treatment. In this study, we evaluate the vascular response (perfusion and molecular expression) of two human cancer cell lines (SKNEP and NGP) implanted in mice to BV therapy using high-frequency ultrasound imaging. Size-selected, lipid-coated microbubbles were used as vascular probes.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73105926","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":"An intravascular photoacoustic imaging catheter","authors":"K. Jansen, Geert Springeling, C. Lancée, R. Beurskens, F. Mastik, A. V. D. van der Steen, G. van Soest","doi":"10.1109/ULTSYM.2010.5935713","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935713","url":null,"abstract":"We developed an integrated intravascular photoacoustic (IVPA) and ultrasound (IVUS) catheter to image atherosclerotic plaque structure and composition, which are important determinants of plaque vulnerability. Our catheter comprises an angle-polished optical fiber and a 30 MHz single-element piezoelectric transducer. The ultrasonic transducer was optically isolated to eliminate artifacts in the photoacoustic (PA) image. We showed its imaging performance using a vessel phantom and quantified its imaging characteristics by doing measurements on isolated point targets. The axial and lateral point spread function widths were 110 µm and 550 µm respectively for IVPA imaging and 89 µm and 420 µm respectively for IVUS imaging. The signal to noise ratios were 50 dB (PA) and 54 dB (US).","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90963206","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":"Transducer design for second harmonic 3D transesophageal echocardiography","authors":"S. Blaak, P. van Neer, C. Prins, J. Bosch, C. Lancée, N. de Jong","doi":"10.1109/ULTSYM.2010.5935701","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935701","url":null,"abstract":"Three dimensional transesophageal echocardiography (3D TEE) provides images that can give information on the three-dimensional anatomy and function of the heart, such as the left ventricular volume and the movements of the valves. Current 3D TEE probes use fundamental imaging. We believe 3D TEE images can benefit from second harmonic (2H) imaging. In the design the transducer is divided in a transmit and receive sub-array. This ensures that the low voltage receive electronics are separated from the high voltages required for the transmitter. It enables us to optimize both the transmit and receive array for their specific acoustic role. In this paper the optimal element geometry of the transmit array is investigated. 3D FEM simulations are performed to determine the optimal element width and length. Laser interferometer and acoustic measurements are performed on a prototype. Good agreement was achieved between FEM simulations and optical measurements. The peak transmit transfer in air was 3 nm/V at 2.4 MHz for both simulation and experiment. FEM simulations of the prototype loaded by water show a peak transmit transfer of 43 kPa/V and a −6 dB bandwidth of 50%. Acoustic measurements with a hydrophone setup resulted in 55 kPa/V peak transmit transfer at 2.5 MHz and 30 kPa/V at 3 MHz. The acoustic field of an individual array element had a lateral −6 dB beamwidth of 46 mm at 40 mm depth and a peak pressure of ∼70 Pa/V. Extrapolating to the full array we obtained ∼1 MPa/120 V at 40 mm depth, which is assumed sufficient for 2H imaging. The transmit array presented here has suitable characteristics for its role in a 3D 2H TEE.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90710208","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":"Contrast-enhanced intravascular ultrasound 3D reconstruction of a vasa vasorum mimicking model","authors":"D. Maresca, M. Emmer, Geert Springeling, F. Mastik, G. van Soest, N. de Jong, A. V. D. van der Steen","doi":"10.1109/ULTSYM.2010.5935756","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935756","url":null,"abstract":"It is increasingly recognized that the development of new microvessels (vasa vasorum) within and surrounding atherosclerotic plaques is essential to enable artery lesion growth and plays a central role in rendering it vulnerable to rupture. Currently, there is no established clinical technique capable of imaging the vasa vasorum (VV) in the coronary arteries of humans. It has been shown that contrast-enhanced intravascular ultrasound (CE-IVUS) is capable of imaging VV in vivo. This study aims at reconstructing in three dimensions (3D) a VV model using CE-IVUS with a clinical coronary imaging catheter. A polyvinyl alcohol based VV model was manufactured, exhibiting a VV mimicking branch pattern with a diameter ranging from 200 to 100 um. After perfusion of the VV model with the ultrasound contrast agent Definity®, a manual pullback consisting of 93 cross sectional IVUS images spaced every 200 µm was performed. Perfused areas were segmented in two registered CE-IVUS planes and compared to coregistered 10 um thick slices of the VV model. The VV mimicking microchannel diameters measured with CE-IVUS agreed within 30% with the slice diameters. As CE-IVUS imaging can be carried out in-vivo, this method could be used during clinical IVUS investigations as an additional diagnostic for plaque vulnerability.∗","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91123692","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":"Giant shear mode electromechanical coupling coefficient k15 in c-axis tilted ScAlN films","authors":"T. Yanagitani, K. Arakawa, K. Kano, Akihiko Teshigahara, M. Akiyama","doi":"10.1109/ULTSYM.2010.5935791","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935791","url":null,"abstract":"Giant shear mode electromechanical coupling coeficient k<inf>15</inf>' of 0.32 (k<inf>15</inf>²=10 %) were found in the c-axis 33° tilted ScAlN films. High k<inf>15</inf> values were observed even in the high temperature of 600 °C. TCF values were deteriorated in ScAlN film compared with non-doped AlN crystal. Shear mode ScAlN films should be a good candidate for liquid SH-SAW and FBAR sensors in the high temperature.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81827668","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":"Deposition techniques of c-axis-tilted ScAlN films by conventional RF magnetron sputtering","authors":"K. Arakawa, T. Yanagitani, K. Kano, Akihiko Teshigahara, M. Akiyama","doi":"10.1109/ULTSYM.2010.5935747","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935747","url":null,"abstract":"It is difficult to synthesize c-axis tilted ScAlN films by using co-sputtering because unidirectional oblique incident of sputtered particles is needed to obtain c-axis tilted structure. To realize the oblique incident single source sputtering technique was proposed for c-axis tilted film deposition. ScAl alloy target was used to achieve ScAlN film synthesis instead of co-sputtering. As a result c-axis highly tilted ScAlN film (tilt angle =33 °) was obtained by using this deposition technique. From the result of film transducer loss measurement we found that longitudinal and shear elasticity of AlN decreases by adding Sc. c-axis highly tilted ScAlN film showed giant k15' values of 0.32 in spite of its low degree of orientation.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79682722","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 comparative study of optimal fundamental, second- and superharmonic imaging","authors":"P. van Neer, M. Danilouchkine, G. Matte, M. Voormolen, M. Verweij, N. de Jong","doi":"10.1109/ULTSYM.2010.5935761","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935761","url":null,"abstract":"A number of ultrasound methods are available for medical imaging. Fundamental imaging uses the echoes from the same spectral band as the transmitted pulse. Tissue harmonic imaging (THI) utilizes frequencies at multiple(s) of the fundamental and effectively suppresses reverberations, and off-axis and near-field artifacts. Two types of THI comprise second- and superharmonic imaging (SHI). The former uses the second harmonic of the echoes and the latter combines the third to fifth harmonics. Clinical research showed that the optimal transmit frequency for fundamental and second harmonic cardiac imaging is 3.5 and 1.8 MHz respectively. As the level of the harmonics is determined by a balance of nonlinear propagation and attenuation, the optimal frequency for SHI is expected to be lower. The first goal of this study was to investigate the optimal transmit frequency for SHI by simulating the entire imaging chain based on an adapted SONAR equation. Two simulation cases are examined: the first uses cardiac tissue properties and the second is based on a mix of 50% cardiac tissue and 50% blood. Using the SONAR equation the signal-to-noise ratio (SNR) for the second to fifth harmonics was computed up to 15 cm for 1–2.5 MHz transmit frequencies. The transducer's transmit and receive transfer was modeled, as well as its noise. The adaptation included nonlinear forward propagation calculated with axisymmetric KZK, the backpropagation was linear. The highest frequency yielding a 30 dB dynamic range at the required imaging depth was assumed optimal. The second goal of this study was to compare the beams produced by optimal fundamental, second — and SHI for cardiac applications. To this end we used a 3D KZK implementation for rectangular apertures. The optimal transmit frequency for SHI was 1.0–1.2 MHz at 13 cm using cardiac tissue properties, this increased to 1.7 MHz if the properties of the cardiac tissue/blood mix were used. The −6 dB lateral beam width of the optimal fundamental, second- and SHI at 10 cm was 1.2, 1 and 0.7 cm respectively. The normalized intensity 1 cm off the beam axis was −14, −20 and −25 dB for the fundamental, second harmonic and superharmonic respectively. The optimal transmit frequency for cardiac SHI is 1.0–1.7 MHz providing a feasible dynamic range. The lateral resolution of SHI in the far field is higher compared to fundamental and second harmonic imaging.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74370758","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}