An ultrasound catheter includes a hollow body and a plurality of ultrasound sensing regions. The hollow body is made of a flexible circuit board. The ultrasound sensing regions are disposed on a periphery of the hollow body, wherein each of the ultrasound sensing regions has a plurality of channels, and the channels of each ultrasound sensing region are arranged along an axial direction of the hollow body. A medical system using the ultrasound catheter is also provided.
