I-Corps: Networking Medical Implants Through Ultrasounds

截至目前，现有的无线医疗植入物是通过射频(RF)电磁波连接的。基于射频的解决方案倾向于几乎盲目地将传统无线技术(例如Wi-Fi、蓝牙、Zigbee)缩减到体内环境，而很少或根本没有关注人体的特殊特征和安全要求。事实上，人体由高达65%的水组成，而水是一种射频波不能很好传播的介质。此外，射频频谱稀缺，而且已经挤满了许多相互干扰的设备。因此，基于射频的技术引起了人们对现有射频通信系统的潜在干扰的严重担忧，这些干扰可能会无意中破坏可植入网络的可靠性和安全性，并最终损害患者的安全。该团队开发了超声波宽带(UsWB)技术，这是一种通过超声波(即不可听频率的声波)进行无线通信的网络平台。事实证明，与基于人体射频(RF)的解决方案相比，超声波无线通信和网络技术(即基于不可听频率的声波)具有显著优势。超声波在人体组织中的传播比射频更好，从而(I)降低了能量消耗，(Ii)减少了对组织的加热。长期以来，超声波也被用于医学成像，并被证明是安全的。而且，与射频不同，超声波在低功率的情况下不能从体外穿透到体内，反之亦然。因此，超声波通信链路可能更安全，因为它们不太容易受到无意或恶意干扰。在这个阶段，该团队已经开发出第一个非集成和不可植入的UsWB原型，该原型使用现成的高频超声波换能器，通过模拟生物组织中高保真的声传播的介质，即所谓的超声波模体，实现超声波的传输和接收。

As of today, existing wireless medical implants are connected through radio frequency (RF) electromagnetic waves. RF-based solutions tend to almost blindly scale down traditional wireless technologies (e.g., Wi-Fi, Bluetooth, Zigbee) to the intra-body environment, with little or no attention to the peculiar characteristics and safety requirements of the human body. The human body is in fact composed up to 65% of water, a medium through which RF waves do not propagate well. In addition, the RF frequency spectrum is scarce and already crowded with many devices interfering with one another. Therefore, RF-based technologies raise serious concerns about potential interference from existing RF communication systems that can unintentionally undermine the reliability and security of the implantable network, and ultimately the safety of the patient. This team has developed the ultrasonic wideband (UsWB) technology, a networking platform that enables wireless communications through ultrasounds (i.e., acoustic waves at non-audible frequencies).Ultrasonic wireless communications and networking technology (i.e., based on acoustic waves at non-audible frequencies) is proven to have significant advantages with respect to radio-frequency (RF)-based solutions in the human body. Ultrasounds propagate better than RF waves in human tissues, leading to (i) lower energy consumption and (ii) reduced heating of tissues. Ultrasounds have also been long used for medical imaging and are proven to be safe. And, unlike RF waves, ultrasonic waves do not penetrate from outside-the-body to inside-the-body, and vice versa, at low transmission powers. Therefore, ultrasonic communication links are potentially more secure as they are less prone to unintentional or malicious interference. At this stage, the team has developed the first, non-integrated and non-implantable UsWB prototype that uses off-the-shelf high-frequency ultrasonic transducers to enable transmission and reception of ultrasonic waves, through media that emulate with high fidelity acoustic propagation in biological tissues, i.e., so-called ultrasonic phantoms.