$\phi$-Fetus: A Phantom In-utero Fetus for Fetal Heart Simulation

Kefan Song, Alexander T Adams

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Keywords: fetal monitoring, phantom, sensor validation

Abstract: Bench-top performance evaluation of novel continuous fetal heart monitoring sensors that utilizes surface mechanical vibrations is hampered by the absence of a physical phantom that is able to simulate fetal heartbeat realistically in the frequency and amplitude domains. In this work, we present the design of $\phi$-Fetus, a phantom in-utero fetus built with a medical gel and interchangeable actuators. The medical gel was molded for a shape and size that match the maternal abdominal dimensions. Under the square wave excitation of the speaker actuator at 2-2.8 Hz, the phantom delivers accurate and consistent surface vibration responses, as recorded by an accelerometer, validating its precision in frequency control. By pumping the balloon with specific initial volume and pumping volume that correlates to respective cardiac volume and stroke volume of the fetus from 20 to 40 weeks of gestation, the phantom delivers peak accelerations that matches actual data points through interpolation, thus validating its realistic simulation of fetal heartbeat. These results demonstrate that the phantom is able to provide a tunable, repeatable, and physiologically relevant platform for testing and benchmarking of novel fetal heart monitoring sensors, and enables quantitative validation of wearable sensors applicable to future prenatal sensing research.

Track: 13. General sensing and systems

NominateReviewer: Kefan Song, [e-mail]

Submission Number: 111