DigiPalp: Quantifying palpation of tissue hardness and surface geometry with a smart sensor-equipped glove

Manual palpation is a cornerstone of medical assessment, yet its subjective nature limits its ability to provide quantitative data of characteristics like tissue hardness. Here, we introduce DigiPalp, a wearable smart glove designed to enable real-time 4D tactile scanning, combining 3D surface mapping with a tissue hardness measurement at each point. This quick (typically <0.5 seconds) and noninvasive measurement is achieved through a fusion of custom piezoresistive pressure sensors and magnetic position sensors embedded into the glove's fingertips. By featuring silicone-encapsulated stretchable wiring, the hand's natural range of motion is maintained to support a workflow like conventional palpation. We show that the system can reliably differentiate six hardness levels across the soft tissue range, identify small, harder nodules (down to 5-millimeter radius) embedded in silicone phantoms, mimicking tumor detection, and demonstrate the system's capability on complex tissue through a full 4D scan of the torso of a living person.