A radio-opaque plastic scintillator detector (PSD) for use in various medical applications and methods of making and using the PSD. The method requires coating a plastic scintillator fiber with a radio-opaque material; cutting the scintillator fiber; stripping the end of a plastic fiber optic fiber; cutting the naked end of a plastic fiber optic fiber; inserting a closely fitting guide tube over the naked end and inserting the cut scintillating fiber into the guide tube; coating the detector end of the cable with a light opaque polymer or jacket and adding a connector to the other end.