1. A medical system, comprising: a medical device inserted into a target object and configured to remove a lesion within the target object; an ultrasound data acquisition unit configured to transmit and receive ultrasound signals to and from the target object to output ultrasound data; and a processing unit in communication with the ultrasound data acquisition unit, the processing unit being configured to form a plurality of ultrasound images based on the ultrasound data and perform an image processing upon each of the ultrasound images to detect a position of the medical device.