With the development of bioengineering technologies, medical ultrasound systems have evolved and advanced over the years, including the transition of ultrasound machines from analog devices to digital systems and improvements in transducer assembly from piezoelectric ceramics to single crystals. In the past several years, the further miniaturization of ultrasound units has become possible with the advancement of computer chip manufacturing and production. Most recently, a new handheld ultrasound system has been developed by the startup company Butterfly Network, using an innovative CMUT/CMOS-based probe technique. This paper will review the history, technology and features of this new device, as well as discuss its future potential as a personal sonoscope.

With the rapid development of microelectronics, handheld ultrasound devices emerged and have a widespread use in the field of medicine and healthcare. The handheld ultrasound is a modality of medical ultrasonic device that is portable (i.e., carried by hand), easy to operate and in some cases even combine the scanner with the host system. It normally has the characteristics of light weight, small size and low power consumption. With the wireless imaging transmission technique, remote and intelligent diagnosis is possible for the doctors using handheld ultrasound devices. As soon as the low-cost, highperformance handheld ultrasound device was launched, it attracted clinical attention and received a warm welcome from primary doctors and clinicians, thereby accelerating the development of ultrasonic clinical visualization. In this paper, we will illustrate the status and roles of handheld ultrasound for its clinical settings and applications in the past, current, and future.