An automated implantation system assists the implantation of low dose radioisotope seeds in a patient as part of a brachytherapy procedure. The method includes directing broadband light by means of a sensing light path at an area of interest in the subject, at a target depth defined by the sensing light path and a reference light path. The voltage and current detecting units detect voltages and currents of the output terminals of the switching power supply, respectively. A second microswitch with a normal and an engaged position is mounted to the guide structure at a location above the first micro-switch and is adapted to be connected into a second electric circuit to control the energization thereof.