Abstract: A probe is connected to a probe carrier that is positioned with respect to the body of a patient. The probe is moved into or out of the body incrementally by means of a driver mechanism and flexible coupler. The flexible coupler in one embodiment comprises a flexible sheath with a flexible driver shaft that can be passed within the flexible sheath and can be rotated or pushed forward and backward with respect to the sheath by a driver element thereby causing translational movement of probe. Several forms of probes, flexible coupling elements, and driver apparatus as well as methods of applications accommodate specific objectives.