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                                                                   Exhibit 10.10

                            SIXTH AMENDMENT AGREEMENT

        This Amendment Agreement is made and entered as of June 5, 1998, by and
between AMERICAN SHARED RADIOSURGERY SERVICES, INC. ("ASRS"), and GKV
INVESTMENTS, INC. ("GKV").

        WHEREAS, ASRS AND GKV are parties to that certain Operating Agreement
for GK Financing, LLC dated as of October 17, 1995, as amended (the "Operating
Agreement");

        WHEREAS, ASRS AND GKV desire to amend the Operating Agreement in certain
respects;

        NOW THEREFORE, in consideration of the mutual covenants contained
herein, ASRS and GKV agree as follows:

        1. Defined Terms.

        All capitalized terms used herein which are defined in the Operating
Agreement shall have the meaning set forth in the Operating Agreement.

        2. Amendment.

        Paragraph 2.14A of the Operating Agreement is hereby amended whereby the
amount of cash reserve to be maintained by the Company is reduced from $600,000
to $50,000.

        3. Full Force and Effect.

        Except as explicitly amended by this Sixth Amendment Agreement, the
provisions of the Operating Agreement shall remain in full force and effect.


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        IN WITNESS WHEREOF, the parties hereto have hereunto set their hands and
seals as of the date first above-written.


                                            GKV INVESTMENTS, INC.



                                            By:  Jonas Serlachius
                                               ---------------------------------
                                            Title:  V.P.
                                                  ------------------------------



                                            AMERICAN SHARED RADIOSURGERY 
                                            SERVICES, INC.


                                            
                                            By:  Ernest A. Bates
                                               ---------------------------------
                                            Title:  CEO
                                                  ------------------------------