100 MHz Acousto-optic Hydrophone Probe for Biomedical Ultrasound Applications

描述(由申请人提供)：我们建议设计、开发和实验验证一种高度创新的亚毫米分辨率声光测量系统的性能，适合于描述临床应用中遇到的超声场的特征。这里提出的具有空间和时间分辨率的这种系统目前还不存在。拟议研究的创新要素包括开发有效直径约为5-7微米(微米)的锥形光纤(FO)传感器，该传感器在0.1-100 MHz的频率范围内工作，足以测量用于治疗恶性组织的高频聚焦超声(HIFU)换能器产生的磁场。传感器的小物理尺寸将消除对空间平均校正的需要，从而可以准确地记录真实的压力-时间(p-t)波形。为了确定所有临床相关的安全指标，如机械和热指数，这些波形的记录至关重要。FO传感器的灵敏度将与目前使用的典型水听器探头相当。由于光纤天生不受非光电磁场刺激的影响，因此该系统具有几乎不受电磁场干扰(EMI)影响的潜力。此外，光纤固有的坚固特性构成了一个吸引人的特点，因为现有的超声波水听器探头很脆弱，在实践中无法用于治疗性HIFU领域。此外，光纤传感器的微型物理尺寸使其有可能非常适合活体测量，而目前可用的超声波水听器探头几乎不可能做到这一点。初步数据表明，一旦完全开发和校准，声光系统将在诊断和治疗领域的声学测量方面形成重要突破。这一成果也将加速超声在医学上的应用的进一步进展。这些进展很重要，因为超声提供了与组织的非电离相互作用，与其他成像和介入手段相比，具有经济上的优势。

DESCRIPTION (provided by applicant): We propose to design, develop and experimentally verify the performance of a highly innovative, acoustooptic measurement system with sub-millimeter resolution, appropriate for characterization of ultrasound fields encountered in clinical applications. Such a system with spatial and temporal resolutions proposed here is not currently available. The innovative elements of the proposed research include the development of a tapered fiber optic (FO) sensor with an active diameter on the order of 5-7 mu m (microns) that operates in the frequency range from 0.1 - 100 MHz and is sufficiently robust to measure fields generated by High Frequency Focused Ultrasound (HIFU) transducers used for treatment of malignant tissues. The small physical dimensions of the sensor will obviate the need for spatial averaging corrections so that true pressure-time (p-t) waveforms can be faithfully recorded. The recording of these waveforms is essential in order to determine all clinically relevant safety indicators, such as Mechanical and Thermal Indices. The sensitivity of the FO sensor will be comparable with that typical of currently used hydrophone probes. As optical fibers are inherently immune to non-optical electromagnetic fields stimuli, this proposed system has a potential of being nearly immune to Electromagnetic Field Interference (EMI). In addition, the intrinsically rugged characteristics of the fiber constitute an attractive feature as the existing ultrasound hydrophone probes are fragile and, in practice, cannot be used in therapeutic HIFU fields. Also, the miniature physical dimensions of the fiber optic sensor make it potentially well suited for in vivo measurements, virtually impossible with the currently available ultrasound hydrophone probes. Preliminary data indicate that once fully developed and calibrated, the acousto-optic system will form an important breakthrough in acoustic measurements of both diagnostic and therapeutic fields. Such outcome will also accelerate further advances of ultrasound applications in medicine. These advances are important because ultrasound offers nonionizing interaction with tissue and is economically favorable in comparison with other imaging and interventional modalities.