OuSense: Electronic-Photonic System-on-Chip for Real-time Endoscopic Ultrasound 3D Imaging

几十年来，超声成像一直是众多医学学科中最不可或缺的工具之一，从肿瘤学到心脏病学，从皮肤病学到眼科，因为它的便携性和易用性。然而，在内窥镜、血管内和导管内应用，即人体内部成像系统中，传统的超声成像仪在功耗和体积过大方面存在严重缺陷，这些系统构成了医疗现场应用的很大一部分。首席研究员的研究团队开发了一个独特的平台，可以将高性能光子器件与快速复杂的晶体管紧密协集成，这将成为实现个性化便携式诊断系统目标的载体，可以为人类生理学带来新的亮点。该系统的核心是高灵敏度的微尺度光学传感器，可以实现超低功耗和尺寸，在不牺牲关键系统属性的情况下确保人体内部的安全运行。这些光学传感器可以实时提供3D成像，为实现同类首个小型化光学超声接收探头铺平了道路。该系统的光子特性也将使超声光声成像等应用能够帮助诊断和治疗从乳腺癌到心血管疾病的广泛重要疾病。这个框架，连同相关的教育材料和经验，将有助于培养一批能够处理生物医学成像和传感系统复杂、多学科性质的新工程师。该研究将开发首个具有数千个传感器元件的光学超声探头，具有高功率和高面积效率（目标：0.5W, 5mm3）的实时3d成像能力。超声信号在光域中的转导将使耗电的接收电子设备远离探针管，从而远离人体。因此，更多的功率将在外部可用，以降低接收器噪声，而不有助于探头加热。将用作主要传感元件的微环谐振器已被证明可以减轻其压电和CMUT对应物的灵敏度-带宽权衡。更换电子换能器也将大大简化封装，消除大多数电气连接和接口，依靠极其紧凑的光纤阵列而不是微同轴电缆来进行超声波调制。电子-光子协同设计将导致芯片上放置超高效的热调谐控制电路，靠近光学器件。这一努力的结果将是第一个同时询问多个光学传感器的光学超声接收系统。数千个传感元件的密集包装使其能够瞄准新兴应用，如光声成像，这需要高灵敏度，高频率和高分辨率。这项工作将研究一种全光学多模态超声成像，将传统超声与光声相结合，产生高对比度的图像，可以帮助诊断和治疗从乳腺癌到心血管疾病的广泛重要疾病。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

For decades, ultrasound imaging has been one of the most indispensable tools in numerous medical disciplines ranging from oncology to cardiology and from dermatology to ophthalmology because of its portability and ease of use. However, in endoscopic, intravascular and catheterized applications, i.e., inside the body imaging systems, which constitute a huge part of the Point-of-Care spectrum of applications, traditional ultrasonic imagers have demonstrated serious shortcomings in terms of power dissipation and being too large in size. A unique platform developed by the Principal Investigator's research team, which enables tight co-integration of high-performance photonic devices with fast sophisticated transistors will serve as the vehicle towards achieving the goal of personalized, portable diagnostic systems that can shine new light INTO human physiology. Such a system, with highly sensitive, micro-scale optical sensors in its core, can be ultra-low power and size, ensuring safe operation inside the human body without sacrificing key system attributes. These optical sensors can provide 3D imaging in real time and pave the way towards the realization of a first of its kind miniaturized optical ultrasonic reception probe. The photonic nature of this system will also enable the applications such as ultrasound photoacoustic imaging that can assist the diagnosis and treatment of a wide range of important diseases from breast cancer to cardiovascular. This framework, along with associated educational materials and experiences will help create a new crop of engineers who are capable of tackling the complex, multidisciplinary nature of biomedical imaging and sensing systems.The proposed research will develop first of its kind optical ultrasound probe with thousands of sensor elements, capable of real-time 3-D imaging with high power and area efficiency (target: 0.5W, 5mm3. Transduction of the ultrasonic signal in the optical domain will remote the power hungry receive electronics outside the probe tube, and consequently the human body. Thus, more power will be externally available to lower receiver noise, without contributing to probe heat-up. The micro-ring resonators that will be used as the main sensing element have been proven to mitigate the sensitivity-bandwidth tradeoff of their piezo and CMUT counterparts. Replacing electrical transducers will also greatly simplify packaging, eliminating most electrical connections and interfaces, relying on extremely compact optic fiber arrays instead of micro-coax cables to carry the ultrasonic modulation. Electronic-photonic co-design will result in ultra-efficient thermal tuning control circuitry placed on-chip, in close proximity to the optics. The result of this effort will be the first optical ultrasound reception system simultaneously interrogating multiple optical sensors. Dense packing of thousands of sensing elements enables targeting the emerging applications like photoacoustic imaging, which require high sensitivity, frequency and resolution. This work will investigate an all-optical multi-modal ultrasound imaging, combining traditional ultrasound with photoacoustics to generate high contrast images that can assist the diagnosis and treatment of a wide range of important diseases from breast cancer to cardiovascular.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.