HUMaN: Handheld Ultrasound System with Magnetic Needle Navigation

Needle tip localization during ultrasound-guided procedures is challenging when the needle is poorly visualized. This study aimed to develop and evaluate a handheld ultrasound system with magnetic needle navigation (HUMaN) that integrates ultrasound imaging and real-time three-dimensional magnetic tracking within a compact form factor.

HUMaN was designed using a dual-board architecture that incorporates an ultrasound probe, a real-time imaging system, and a magnetic needle guidance module that detects magnetic field disturbances to estimate needle position and orientation. The tracked needle trajectory is superimposed onto ultrasound images, and an active cooling mechanism with optimized airflow was implemented to maintain thermal stability. In vivo imaging feasibility was assessed under institutional review board approval. Needle localization accuracy was evaluated using a custom jig at multiple depths, and surface temperatures were continuously monitored during extended operation.

The system achieved sub-millimeter needle localization accuracy, with a mean bias within 0.1 mm and a precision within 0.3 mm at both 10-mm and 20-mm depths. In vivo ultrasound imaging was successfully demonstrated. Thermal evaluations showed that the device surface temperature remained well below the IEC 60601-1 safety limit (39°C) during 80 minutes of continuous operation.

HUMaN provides accurate needle localization together with fully integrated ultrasound imaging in a handheld, bracket-free design. These findings suggest that the system is well-suited for point-of-care ultrasound procedures that require portability and ease of use.