EXHIBIT 10.18 AMENDMENT TO EMPLOYMENT AGREEMENT This Amendment ("Amendment") to the Employment Agreement ("Agreement"), dated as of July 1, 1996, between Image Guided Technologies, Inc., a Colorado corporation (the "Company"), and Jeffrey J. Hiller ("Hiller"), is entered into as of September 6, 1996. 1. Section 2 of the Agreement is hereby amended by changing the first sentence thereof to read in full as follows: Subject to earlier termination as provided in Section 5, the employment hereunder shall be for a period of thirty months, commencing on July 1, 1996 (the "Commencement Date") and ending on December 31, 1998. 2. All other terms and conditions of the Agreement shall remain in full force and effect. IMAGE GUIDED TECHNOLOGIES, INC. By: /s/ Robert E. Silligman -------------------------------------- Robert E. Silligman /s/ Jeffrey J. Hiller -------------------------------------- Jeffrey J. Hiller