1. A medical method for observing the local motion of a medical implement in a lung of a subject comprising the steps of: a) receiving first image data of the lung in a first state; b) receiving second image data of the lung in a second state; c) registering the first image data and the second image data with one another using a reference feature; d) deforming at least one of the following: i) the first image data of the lung to match the second image data of the lung, and ii) the second image data of the lung to match the first image data of the lung; and e) generating a motion vector field of the magnitude and direction of local motion of lung tissue based on the deforming step.