Abstract: An introducer guide includes a guiding assembly to guide insertion an instrument, such as a biopsy needle, through a selected insertion point on a patient's body and along a selected insertion path. An imaging system, such as a CT scanner, is used to visualize portions of the guiding assembly in relation to the patient's tissues as the insertion path is adjusted. The guiding assembly includes a semicircular arch connected with a base plate by sliding hinges with a center of curvature of the arch centered on the insertion point. A guide body is slidably connected with the arch. Rotation of the arch about the hinges adjusts a first angle of the insertion path. Motion of the guide body along the arch adjusts a second angle of the insertion path. Linkages, such as linear actuation cables, rotary cables, or pneumatic or hydraulic actuators, connect the arch and guide body with remote operators. A practitioner aligns the guide assembly with the insertion point and fixes the base to the patient's skin.