Frameless stereotactic surgical apparatus

摘要

An imaging apparatus (18) includes a frameless stereotactic arm apparatus (30) including a first base portion (42) mounted in a fixed relationship to the imaging device. A second free end (40) of the arm assembly is adapted to move into varied positions near a specimen disposed on the imaging apparatus. At least one pivot joint (44, 48, 52, 56, 60) is provided between the first base portion and the free end of the arm for permitting selective relevant movement between the arm members. Electro-mechanical and electro-magnetic brake devices are provided at respective joints to selectively lock the free end of the arm assembly to the base portion. The brakes are responsive to a brake command signal generated by the imaging device. A low pass filter conditions the brake command signal to substantially eliminate high frequency electromagnetic switching noise in the stereotactic arm. So that the arm is movable in emergency situations, the brakes are adapted to release in response to application of a force in excess of a predetermined breakaway threshold force.