Apparatus for safely and accurately positioning the fingertip of a physician (or technician) performing a biopsy procedure, e.g., to excise a core tissue samples of the male prostate or other internal organs, to avoid injury (e.g., a needle stick) from the sharpened distal end of a biopsy needle assembly. Such apparatus comprises an open tubular member defining an elongated passageway through which a biopsy needle assembly, when actuated, can be made to pass and to extend a predetermined distance along an external path in order to effect the core sampling of a biological mass of interest. The tubular housing supports a safety flange at its distal end, such flange having a flat surface adapted to be engaged by the fingertip of the physician prior to actuation of the biopsy needle assembly. Preferably, the engaged surface of the safety flange defines a physical fiducial adapted to be sensed by theuser's fingertip, such fiducial being located a predetermined safe distance from the external path traveled by the needle assembly, whereby the physician is assured that his or her fingertip is safely spaced from the needle assembly when actuated, and the distal end of the tubular housing is precisely positioned relative to a biological mass of interest.