LightProbe: A Digital Ultrasound Probe for Software-Defined Ultrafast Imaging.

Digital ultrasound probes integrate the analog front-end in the housing of the probe handle and provide a digital interface instead of requiring an expensive coaxial cable harness to connect. Current digital probes target the portable market and perform the bulk of the processing (beamforming) on the probe, which enables the probe to be connected to commodity devices such as tablets or smartphones running an ultrasound app to display the image and control the probe. Thermal constraints limit the number of front-end channels as well as the complexity of the processing. This prevents current digital probes to support advanced modalities such as Vector Flow or Elastography requiring high-frame rate (HFR) imaging. In this paper, we present LightProbe, a digital ultrasound probe, which integrates a 64-channel 100 Vpp TX/RX front-end including analog-to-digital conversion (up to 32.5 MS/s @ 12 bit), and is equipped with an optical high-speed link (26.4 Gb/s) providing sustainable raw samples access to all channels, which allows the processing to be performed on the connected device without thermal power constraints. By connecting the probe to a GPU-equipped PC, we demonstrate the flexibility of software-defined B-mode imaging using conventional and ultrafast methods. We achieve plane-wave and synthetic aperture imaging with frame-rates from 30 Hz up to 500 Hz consuming between 5.6 W and 10.7 W. By using a combination of power and thermal management techniques, we demonstrate that the probe can remain within operating temperature limits even without active cooling, while never having to turn the probe off for cooling hence providing a consistent Quality of Service for the operator.