Crystal Transducers for Harmonic Imaging

描述(申请人提供)：造影剂谐波成像已成为研究血流灌注的非常重要的工具。由于恶性肿瘤周围大量的血管生成，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，现有的传感器由于缺乏足够的带宽，其从造影剂谐波形成图像的能力受到限制。如果要同时使用二次和次次谐波来构建图像，这一点尤其正确。在第一阶段计划TRS Technologies中，Blatek，Inc.、J&W Medical，LLC和Thomas Jefferson University Hospital展示了通过使用单晶铁电构建非常宽频带换能器来解决此问题的解决方案。这种材料(PbCMgi/SNB、CVPbTios-PMN-PT)具有非常高的机电耦合系数(KSS&GT；90%)，因此用它构建的超声换能器具有固有的宽频带。在第一阶段程序中，由晶体/环氧1-3复合材料构造了单个元件聚焦换能器。该换能器具有130%的带宽，在4.5 MHz发射频率的2次和2次谐波分别为9 MHz和2.25 MHz时具有良好的接收灵敏度。利用该传感器测量水中Sonazid微泡产生的二次谐波信号强度，验证了造影剂检测的可行性。对于第二阶段计划，TRS建议在这些结果的基础上构建宽带单晶线阵列，并将其用于兔VX2肝脏肿瘤的造影剂增强成像。

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.