A system and method for assembling a 3D ultrasound image representation from multiple two-dimensional ultrasound images utilises a magnetic position detection system to detect the ultrasound probe position and allow mapping of the multiple two-dimensional ultrasound images into a three-dimensional frame of reference. The magnetic position detection system may use magnetic markers positioned on the subject or fixed in space around the subject. The position detection may use magnetic model fitting, look-up table, triangulation or distance measurement techniques to determine the position of the ultrasound probe relative to the magnetic markers. The ultrasound probe includes a magnetometric detector to detect the field generated by the magnetic markers.
