ULTRASOUND HYDROPHONE AND ITS CALIBRATION UP TO 100 MHz

超声波水听器及其高达 100 MHz 的校准

• 批准号: 6415671
• 负责人: Peter A. Lewin
• 金额: $ 23.05万
• 依托单位: DREXEL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-30 至 2004-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6415671
• 关键词: bioimaging /biomedical imaging; biomedical equipment development; clinical biomedical equipment; fiber optics; sound frequency; ultrasonography

DESCRIPTION (Provided by Applicant): This work proposes development and implementation of acoustic and optic measurement methods capable of determining absolute sensitivity of miniature ultrasonic hydrophone probes over a wide, 100 M}Iz bandwidth. Absolutely calibrated probes are needed to determine and monitor acoustic output of ultrasound imaging devices, which presently account for about 30 percent of all imaging procedures. Although a majority of clinical imaging is performed at frequencies less than 15 MHz, due to the nonlinear propagation effect in tissue, which constitutes the basis of harmonic imaging, diagnostic pulses can have spectral content from 100 kHz to 100 MHz. Also catheter based systems routinely use frequencies beyond 20 MHz. Moreover, to properly measure mechanical bioeffects exposure index (MI) and to comply with regulatory guidelines, the hydrophone probes should be calibrated in the frequency range extending to 8 times center frequency of the imaging transducer. In addition, dermatological, ophthalmological and pre-clinical applications of ultrasound utilize imaging transducers in the frequency range 20-100 MHz. However, currently used calibration technology is usually limited to approximately 20 MHz and therefore, there is a need for research and development of high frequency calibration techniques capable of determining frequency response of the miniature ultrasound hydrophone probes. In the United States, the national laboratory traceable data are limited to approximately 21 MHz and are available at discrete frequencies only. The outcome of this work will facilitate characterization of high frequency medical ultrasonic fields and assessment of the safety of diagnostic ultrasound devices operating at frequencies beyond 20 MHz or containing harmonics in the signal due to nonlinear propagation phenomena. Globally, no reference laboratory succeeded so far in providing virtually continuous calibration data that are expected to be available as the result of this research. The proposed research will also provide a tool to calculate Mechanical and Thermal Indices in case of conventional 3-12 MHz equipment operating at high pressure amplitudes. The indices are widely accepted as predictors of potential bioeffects. Also, the results of this research are applicable to design and optimization of ultrasound imaging transducers. PIs have succeeded in fabricating fiber optic tips having diameters equal to a fraction of a wavelength at 100 MHz and are hopeful that these fiber optic probes will be suitable to replace piezoelectric hydrophones in measurements where spatial averaging errors are unacceptable.

描述（由申请人提供）：这项工作提出了发展和 能够确定的声学和光学测量方法的实施 超声波水听器探头的绝对灵敏度 M}Iz带宽。 需要绝对校准的探头来确定和监测声学 超声成像设备的输出，目前约占30 占所有成像程序的百分比。尽管大多数临床成像是 由于非线性传播，在小于15 MHz的频率下执行 组织中的影响，这构成了谐波成像的基础，诊断 脉冲可以具有从100 kHz到100 MHz的频谱内容。也基于导管 系统通常使用超过20 MHz的频率。此外，要正确衡量 机械生物效应暴露指数（MI），并符合法规要求 根据指南，水听器探头应在频率范围内进行校准 扩展到成像换能器的中心频率的8倍。此外，本发明还提供了一种方法， 超声波在皮肤科、眼科和临床前的应用 使用频率范围为20-100 MHz的成像换能器。然而，在这方面， 当前使用的校准技术通常限于大约20 因此，有必要研究和开发高 频率校准技术能够确定的频率响应 微型超声水听器探头。在美国，国家 实验室可追踪数据限于约21 MHz， 仅在离散频率下。 这项工作的结果将有助于表征高频率 医用超声场与超声诊断安全性评价 工作频率超过20 MHz或在 信号由于非线性传播现象。在全球范围内，没有参考 到目前为止，一个实验室成功地提供了几乎连续的校准数据 这些都是本研究的成果。拟议 研究还将提供一种计算机械和热指数的工具 在高压下操作的常规3-12 MHz设备的情况下 振幅这些指数被广泛接受为潜在的预测指标 生物效应同时，本文的研究结果也可用于设计和 超声成像换能器的优化。PI成功地 制造直径等于直径的几分之一的光纤尖端 波长在100兆赫，并希望这些光纤探头将是 适用于在空间测量中替代压电水听器， 平均误差是不可接受的。