A system and method for tracking the position of a region in a subject using an ultrasound system is provided. Training data that indicates the position of the region is acquired from the subject while ultrasound data is acquired from the subject using the ultrasound system. A position mapping table is formed using the training data and ultrasound data; this table relates position information contained in the training data to the acquired ultrasound data. The position of the region is tracked by acquiring additional ultrasound data from the subject using the ultrasound system. This additional ultrasound data is compared to the ultrasound data contained in the position mapping table to identify the position of the region based on a unique relationship between the position of the region and ultrasound echo signatures of the ultrasound data acquired in both the training and motion tracking stages.