Airborne Ultrasound and Millimeter Wave Wearable Continuous-Wave Doppler System for External Urodynamics Study

Abstract

Conventional uroflowmetry (UFM) performs an observation of time-serial urinary flow pattern, together with measurements for voided volume, flow rate, etc. Although it's a relatively simple and non-invasive examination, it is based on a urine receiving container like a toilet device equipped with various sensors in hospital. It also causes an unnatural urination due to such unnatural environment, and hence improper understanding of patient status. Our new UFM device aims to abolish the concept of equipping the toilet bowl with various sensors while satisfying the need of measuring urination anytime, anywhere in an easy, natural and repeated manner. We developed two new wearable finger-tip mounted continuous-wave Doppler UFM devices, one with 40KHz airborne ultrasound and the other with K-band (24GHz) millimeter wave. They provide time-series pattern of frequency spectrogram of the Doppler shifted echo of a urination. The Doppler spectrogram gives qualitatively and diagnostically equivalent impression to the urinary flow curve derived from conventional UFM devices. Furthermore, the system can estimate same parameters as conventional UFM devices by integrating locally weighted frequency spectra. It was confirmed that there is a potential for the clinical application of the new UFM devices.