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

几十年来，超声成像一直是从肿瘤学到心脏病学，从皮肤科到眼科的众多医学学科中最不可或缺的工具之一，因为它的便携性和易用性。然而，在内窥镜、血管内和导管内的应用中，即在身体成像系统内，传统的超声成像仪在功率消耗和尺寸太大方面显示出严重的缺点。由首席调查员的研究团队开发的一个独特的平台，可以实现高性能光子设备与快速复杂晶体管的紧密共集成，将作为实现个性化、便携式诊断系统的工具，可以为人类生理带来新的曙光。这种系统以高灵敏度、微米级的光学传感器为核心，可以以超低的功率和尺寸，在不牺牲关键系统属性的情况下确保人体内的安全运行。这些光学传感器可以提供实时的3D成像，并为实现第一个小型化的光学超声接收探头铺平了道路。该系统的光子性质还将使超声、光声成像等应用成为可能，这些应用可以帮助诊断和治疗从乳腺癌到心血管等广泛的重要疾病。这一框架以及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的复杂、多学科性质的新工程师。拟议的研究将开发第一个具有数千个传感器元件的光学超声探头，能够以高功率和高面积效率(目标：0.5W，5mm3)进行实时三维成像。超声波信号在光域中的传输将使渴求能量的接收电子设备远离探头管之外，从而使人体远离。因此，外部可以获得更多的功率来降低接收器噪声，而不会导致探头过热。微环谐振器将被用作主要的传感元件，已经被证明可以缓解它们的压电式和CMUT式谐振器的灵敏度-带宽权衡。更换电子换能器还将极大地简化包装，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传输超声波调制。电子-光子联合设计将导致超高效的热调谐控制电路放置在芯片上，非常接近光学元件。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封装使我们能够瞄准新兴应用，如光声成像，这些应用需要高灵敏度、高频率和高分辨率。这项工作将研究一种全光学多模式超声成像，将传统超声与光声学相结合，生成高对比度图像，以帮助诊断和治疗从乳腺癌到心血管等广泛的重要疾病。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.