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                                                                   EXHIBIT 10.17



                      FOURTH AMENDMENT TO CREDIT AGREEMENT


        THIS FOURTH AMENDMENT TO CREDIT AGREEMENT (this "Amendment") is entered
into as of December 1, 2000, by and between INVIVO CORPORATION , a Delaware
corporation ("Borrower"), and WELLS FARGO BANK, NATIONAL ASSOCIATION ("Bank").

                                    RECITALS

        WHEREAS, Borrower is currently indebted to Bank pursuant to the terms
and conditions of that certain Credit Agreement between Borrower and Bank dated
as of October 6, 1998, as amended from time to time ("Credit Agreement").

        WHEREAS, Bank and Borrower have agreed to certain changes in the terms
and conditions set forth in the Credit Agreement and have agreed to amend the
Credit Agreement to reflect said changes.

        NOW THEREFORE, for valuable consideration, the receipt and sufficiency
of which are hereby acknowledged, the parties hereto agree that the Credit
Agreement shall be amended as follows:

       1.      Section 1.2 (a) is hereby deleted in its entirety, and the
               following substituted therefor:

                  "(a)Line of Credit. Subject to the terms and conditions of
               this Agreement, Bank hereby agrees to make advances to Borrower
               from time to time up to and including December 1, 2001, not to
               exceed at any time the aggregate principal amount of One Million
               Dollars ($1,000,000.00) ("Line of Credit"), the proceeds of which
               shall be used (i) to provide working capital for Borrower and for
               Borrower's wholly-owned subsidiaries, G.C. Industries, Inc.,
               Linear Laboratories Corp[oration, Lumidor Safety Corporation,
               Sierra Precision and Invivo Research, Inc. (each, a "Subsidiary"
               and collectively, "Subsidiaries"), and (ii) to finance Borrower's
               repurchase of its stock in amounts not to exceed an aggregate of
               One Million dollars ($1,000,000.00) during the term of the Line
               of Credit. Borrower's obligation to repay advances under the Line
               of Credit shall be evidenced by a promissory note substantially
               in the form of Exhibit A attached hereto ("Line of Credit Note"),
               all terms of which are incorporated herein by this reference."

       2.      Section 4.8 (a) and (b) are hereby deleted in their entirety, and
               the following substituted herefor:

                      "(a) working Capital not at any time less than
               $13,000,000.00, with "Working Capital" defined as total current
               assets minus total current liabilities.

                      (b) Tangible Net Worth not at any time less than
               $30,000,000.00, with "Tangible Net worth" defined as the
               aggregate of total stockholders' equity plus subordinated debt
               less any intangible assets."

        3.     Except as specifically provided herein, all terms and conditions
               of the Credit Agreement remain in full force and effect, without
               waiver or modification. All terms defined in the Credit Agreement
               shall have the same meaning when used in this Amendment. This
               Amendment and the Credit Agreement shall be read together, as one
               document.

        4.     Borrower hereby remakes all representations and warranties
               contained in the Credit Agreement and reaffirms all covenants set
               forth therein. Borrower further certifies that as of the date of
               this Amendment there exists no Even of Default as defined in the
               Credit Agreement, nor any condition, act or event which with the
               giving of notice or the passage of time or both would constitute
               any such Even of Default.

        IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
executed as of the day and year first written above.

INVIVO CORPORATION                           WELLS FARGO BANK



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                                             NATIONAL ASSOCIATION


By:                                          By:
     ------------------------------               ------------------------------
     James B. Hawkins                             Gary Kurtzman
     President                                    Relationship Manager


By:
     ------------------------------
     John F. Glenn
     Vice President-Finance