incorporated in the system to advise the surgeon when his hand motion approaches the borders of the allowed region of operation according to the preoperative plan such a warning signal may be generated by the robot control and could also be graduated such as in intensity tone or frequency to indicate the extent of deviation of the surgeon from the preoperative plan possible implementations of this warning signal could be by an audible signal or by a visual signal or by some form of tactic feedback provided by the robot to the surgeon 39 s hand reference is now made to fig3 which shows an additional exemplary application of the hand held robot of fig1 for performing a targeted procedure in a region 20 of soft tissue of a subject close to a sensitive anatomical structure such as a nerve or a critical blood vessel 25 contact with the sensitive anatomical structure could be damaging to the subject examples of such a procedure could be in tumor removal biopsy performance precise drug delivery and others the surgeon or physician can be warned of the presence of the hazardous feature either by an imaging system such as a fluoroscopic system or by an ultrasonic imaging system a probe of which 24 is shown in fig3 or by means of a proximity sensor 29 attached to the needle 22 or surgical tool which provides a warning signal when the sensor approaches the hazardous feature by a predetermined distance techniques such as doppler ultrasound flow detection can be used to detect blood vessels by the flow of blood therein and neuro monitors can be used to detect the presence and position of nerve structures the proximity sensor can advantageously deliver its warning.