1. A method comprising: providing a first set of three-dimensional data from a subject; scanning the subject with a scanner to acquire one or more additional three-dimensional images; test fitting each one of the one or more additional three-dimensional images to the first set of three-dimensional data with a processor in real time, and providing real time visual feedback to a user in a display relating to a success of the test fitting for each one of the one or more additional three-dimensional images in real time at a frame rate at which each one of the one or more additional three-dimensional images is acquired, the real time visual feedback including a display of a current video image from the scanner in which the first set of three-dimensional data is superimposed on and aligned with the current video image when test fitting is successful, and the real time visual feedback further including a display of the current video image from the scanner along with a previous video image from the scanner when the test fitting is not successful, thereby providing an indication to the user of when newly acquired data is being successfully fitted to the first set of three-dimensional data.