1. System for re-positioning a portion of the body of a patient at the same therapeutic position and orientation as an initial therapeutic position and orientation relative to a therapeutic device for medically retreating a selected tissue of the body automatically, during multiple therapeutic sessions, the system comprising: a positioning user interface; a position and orientation detector for detecting a multiple axis electromagnetic field and producing a respective electrical analog signal associated with said multiple axis electromagnetic field, said position and orientation detector being located at a selected fixed location associated with said selected tissue; an electromagnetic medical positioning system, coupled with a storage unit, with said positioning user interface and with said position and orientation detector, said medical positioning system being predeterminedly calibrated with said therapeutic device, said medical positioning system including: a plurality of electromagnetic transmitters for transmitting said multiple axis electromagnetic field; and a position and orientation processor coupled with said transmitters for determining said position and orientation of said position and orientation detector relative to said therapeutic device, according to said respective electrical analog signal; said medical positioning system determining an initial position and orientation of said position and orientation detector, during a first therapeutic session, while said selected tissue is placed in said initial therapeutic position and orientation, said medical positioning system indicating, during the multiple therapeutic sessions, via said positioning user interface when said position and orientation detector is placed again in said initial position and orientation, thereby establishing that said selected tissue is placed again in said initial therapeutic position and orientation; at least one moving mechanism coupled with said therapeutic device; and a controller coupled with said at least one moving mechanism directing said at least one moving mechanism to move said therapeutic device such that said therapeutic device medically treats at least a portion of said selected tissue.