Development in High Frequency Ultrasonic Imaging and Transducers

2002 ◽  
Author(s):  
K. Kirk Shung
Keyword(s):  
High Frequency ◽  
Ultrasonic Imaging ◽  
Piezoelectric Element ◽  
Large Degree ◽  
Imaging Systems ◽  
High Frequency Ultrasound ◽  
High Frequencies ◽  
Recent Developments ◽  
Supporting Structures ◽  
Frequency Ultrasound

There has been intense interest recently in ultrasonic imaging in the frequency range from 20 MHz and beyond in biomedicine. High frequency ultrasound has applications in dermatology, ophthalmology and intravascular imaging because of its superior resolution. The performance of ultrasonic imaging systems especially at high frequencies depends critically upon the transducers/arrays, the design of which in turn is determined to a large degree by the materials and fabrication methodology of the piezoelectric element and supporting structures. Recent developments in these areas are discussed in this paper.

scholarly journals Optimization of subharmonic generation from ultrasound contrast agents at high frequency ultrasound

2021 ◽  
Author(s):  
Sara Iradji
Keyword(s):  
Contrast Agents ◽  
High Frequency ◽  
Ultrasound Contrast Agents ◽  
Surrounding Tissue ◽  
High Frequency Ultrasound ◽  
High Frequencies ◽  
Ultrasound Contrast ◽  
Wide Range ◽  
Frequency Ultrasound

The microcirculation can be differentiated from the surrounding tissue using high frequency ultrasound subharmonic imaging. This imaging technique relies on the detection of energy scattered from ultrasound contrast agents at half the transmit frequency due to their resonant oscillations. The current contrast agents and the subharmonic imaging parameters have not been optimized for high frequencies. Moreover, the origin of subharmonic generation from submicron bubbles is not well-understood. The size distribution of Definity™ phospholipid-shelled microbubbles was altered to find the optimal bubble size to be resonant over a wide range of high frequencies. The resonant behaviour of bubbles was investigated through in vitro attenuation measurements. The transmit frequency and pressure were varied to optimize the backscattered subharmonic signal. Alteration of Definity™ population significanatly improved the scattering for subharmonic imaging at 20 MHz. A peak negative pressure between 400 to 600 kPa is suggested for this frequency range.

scholarly journals Optimization of subharmonic generation from ultrasound contrast agents at high frequency ultrasound

2021 ◽  
Author(s):  
Sara Iradji
Keyword(s):  
Contrast Agents ◽  
High Frequency ◽  
Ultrasound Contrast Agents ◽  
Surrounding Tissue ◽  
High Frequency Ultrasound ◽  
High Frequencies ◽  
Ultrasound Contrast ◽  
Wide Range ◽  
Frequency Ultrasound

The microcirculation can be differentiated from the surrounding tissue using high frequency ultrasound subharmonic imaging. This imaging technique relies on the detection of energy scattered from ultrasound contrast agents at half the transmit frequency due to their resonant oscillations. The current contrast agents and the subharmonic imaging parameters have not been optimized for high frequencies. Moreover, the origin of subharmonic generation from submicron bubbles is not well-understood. The size distribution of Definity™ phospholipid-shelled microbubbles was altered to find the optimal bubble size to be resonant over a wide range of high frequencies. The resonant behaviour of bubbles was investigated through in vitro attenuation measurements. The transmit frequency and pressure were varied to optimize the backscattered subharmonic signal. Alteration of Definity™ population significanatly improved the scattering for subharmonic imaging at 20 MHz. A peak negative pressure between 400 to 600 kPa is suggested for this frequency range.

Development of a Bipolar Pulse Generator for High-Frequency Ultrasound Imaging System

2013 ◽  
Vol 311 ◽  
pp. 217-221 ◽  
Author(s):  
Jian Xing Wu ◽  
Pei Jarn Chen ◽  
Yi Chun Du ◽  
Chien Lin Wang ◽  
Guan Chun Chen ◽  
...  
Keyword(s):  
Ultrasound Imaging ◽  
High Frequency ◽  
Pulse Generator ◽  
Ultrasound Image ◽  
Imaging Systems ◽  
Bipolar Pulse ◽  
High Frequency Ultrasound ◽  
Image System ◽  
High Frequency Ultrasound Imaging ◽  
Frequency Ultrasound

The pulse generator is the critical component in high-frequency ultrasound imaging systems. Currently, there still exist some shortcomings about commercial ultrasound image systems and devices such as 5900 PR …etc.. However, to achieve a higher sensitivity and high performance, a programmable pulser generator is desired to match the requirements of high frequency ultrasound image system. In this study, we utilized a novel bipolar pulse generator method to overcome those issues in developed high resolution image system. As the needs of application in clinic, a real –time of high-frequency ultrasound imaging systems, including pulse generator, high speed scanning mechanism, high voltage protection and FPGA trigger control circuit, was developed in our Laboratory. This paper will focus to compare the performance of the bipolar generator and unipolar generator as used in pulse generator device respectively. Finally, the developed bipolar pulse generator show the better performance than the unipolar generator does. The bipolar system can generate clean N-cycle bipolar pulses and improve the center frequency of transducer up to 60 MHz. The axial resolution of scan system has been improved to around 60 μm. In addition, the result indicated that the proposed bipolar pulser could increase 4 dB for pulse/echo waveforms amplitude.

scholarly journals Recent developments in high‐frequency ultrasound imaging

1993 ◽  
Vol 93 (4) ◽  
pp. 2330-2330
Author(s):  
F. S. Foster ◽  
G. R. Lockwood ◽  
L. K. Ryan ◽  
K. A. Harasiewicz ◽  
D. H. Turnbull ◽  
...  
Keyword(s):  
Ultrasound Imaging ◽  
High Frequency ◽  
High Frequency Ultrasound ◽  
High Frequency Ultrasound Imaging ◽  
Recent Developments ◽  
Frequency Ultrasound
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