An apparatus for light beam guided biopsy

An apparatus (1) for assisting percutaneous light beam (10'; 48') guided biopsy, having means for rotating a laser device (10'; 48') about first (43') and second (45') rotation axis, said laser device (48) providing its laser beam along an axis intersecting an intersection point between said first and second rotation axis and at right angles thereto. Inclinometers (50, 51) are installed for providing signal values as a function of two- or three-dimensional orientation directions of said laser device (48) relative to direction of gravitation. Encoder means (19'; 33') provide feedback of rotary position information of the laser device. Comparator means (32') compare set calculated instrument insertion angle values, provided from an input device (17, 20), with encoder feedback signals and inclinometer signals and inhibits rotation operation of said laser device upon reaching specific threshold values.