A Flexible Ultrasound Transducer Array for Deep Vein Thrombosis Monitoring

Deep vein thrombosis (DVT) and its complication, pulmonary embolism (PE), pose serious threats to human health. However, conventional ultrasound transducers face limitations in long-term wearability and continuous monitoring, making it challenging to achieve real-time tracking of thrombus dynamics. In recent years, flexible ultrasound transducers have emerged as a promising direction for continuous health monitoring and deep tissue imaging due to their conformability and comfort. In this study, we designed and fabricated a bendable ultrasound transducer based on a flexible printed circuit (FPC) substrate using microfabrication techniques. The transducer employs PZT-5H as the piezoelectric layer, an array of 64 elements, a pitch of 0.3 mm, and a kerf of 0.06 mm. Its performance was characterized through impedance analysis, pulse-echo experiments, and phantom imaging. The results show that the transducer exhibits a resonant frequency of approximately 4.2 MHz and a −6 dB bandwidth of about 54%. In standard phantom imaging, it achieved a lateral resolution of 1.46 mm and an axial resolution of 1.30 mm at a depth of 20 mm. These findings demonstrate that the proposed flexible ultrasound transducer not only ensures favorable acoustic performance but also effectively adapts to the curvature of the skin surface, highlighting its potential for long-term continuous monitoring of DVT.