Fiducials (50) are disposed in an imaging region (14) along with a subject. The fiducials are mounted either to the subject itself, a surgical tool (52), an imaging probe or receive coil (80), or the like. The fiducials are filled with a liquid or gel of a fluorine 19 (Fl¹⁹) compound which has a resonance frequency that is only 6% off from the resonance frequency of protons. This enables a common transmitter (22), transmit and receive coils, and receiver (34) to be utilized for both proton and fluorine 19 imaging. The proton and fluorine resonance signals are separately reconstructed into corresponding image memories (42, 64). From the positions of the fiducials, a position calculator (66) determines the position of a fiducial carrying surgical tool or probe relative to the proton image. A depiction of the tool or probe from a look-up table (70) is appropriately positioned and rotated (68) and superimposed on the proton image by a video processor (44).