Crystal Transducers for Harmonic Imaging

描述（由申请人提供）：造影剂谐波成像已成为研究血液灌注的非常重要的工具。由于恶性肿瘤周围发生大量的血管生成，超声造影剂的使用具有改善癌症诊断和指导治疗的潜力。然而，现有的换能器在它们从造影剂谐波形成图像的能力方面受到限制，因为它们缺乏足够的带宽。如果要使用二次谐波和次谐波两者来构建图像，则尤其如此。在第一阶段计划中，TRS Technologies，Blatek，Inc.，J&W Medical，LLC和托马斯杰斐逊大学医院通过使用单晶铁电体构建非常宽的频带换能器来展示该问题的解决方案。该材料（PbCM 1/sNb 2/PbTiO 3- PMN-PT）具有非常高的机电耦合系数（kss > 90%），使得由其构造的超声换能器具有固有的宽带宽。在第一阶段的计划，一个单一的元素，聚焦换能器是由晶体/环氧树脂1-3复合材料。换能器具有130%的带宽，在9和2.25 MHz（分别为4.5 MHz发射频率的二次和次谐波）处具有出色的接收灵敏度。通过使用换能器测量水中Sonazoid微泡产生的二次谐波信号的强度，证明了造影剂检测的可行性。对于II期计划，TRS建议通过构建宽带单晶线性阵列并将其用于兔VX 2肝肿瘤的造影剂增强成像来建立这些结果。

DESCRIPTION (provided by applicant): Contrast agent harmonic imaging has become a very important tool for studying blood perfusion. Due to the extensive amount of angiogenesis that occurs around malignant tumors, the use of ultrasound contrast agents has the potential to improve cancer diagnosis and to direct therapies. However, existing transducers are limited in their ability to form images from contrast agent harmonics because they lack sufficient bandwidth. This is especially true if both second and sub-harmonics are to be used to construct an image. In the Phase I program TRS Technologies, Blatek, Inc., J&W Medical, LLC, and Thomas Jefferson University Hospital demonstrated a solution to this problem by constructing a very broad band transducer using single crystal ferroelectric. This material (PbCMgi/sNb^CVPbTiOs - PMN-PT) has a very high electromechanical coupling coefficient (kss > 90%) so that ultrasound transducers constructed from it have an inherently broad bandwidth. In the Phase I program a single element, focused transducer was constructed from a crystal/epoxy 1-3 composite. The transducer had a bandwidth of 130% with excellent receive sensitivity at 9 and 2.25 MHz, the second and subharmonics, respectively, of the 4.5 MHz transmit frequency. Feasibility for contrast agent detection was demonstrated by using the transducer to measure the strength of 2nd harmonic signals generated by Sonazoid microbubbles in water. For the Phase II program, TRS proposes to build on these results by constructing a broad band single crystal linear array and using it for contrast agent enhanced imaging VX2 liver tumors in rabbits.