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                                  EXHIBIT 4.6

                                AMENDMENT NO. 5
                                       TO
                               ADAC LABORATORIES
                             1992 STOCK OPTION PLAN



                 The 1992 Stock Option Plan (the "Plan") of ADAC Laboratories,
a California corporation (the "Company"), is hereby amended in the following
respects:

                 1.       Section 3, entitled "Stock Subject to the Plan," is
hereby amended to delete the first sentence and to add a new first sentence as
follows:

                          "Subject to the provisions of Section 11 and Section
         4(b)(xi) below, the maximum aggregate number of shares that may be
         optioned and sold under the Plan is 3,801,000 shares of Common Stock."

This amendment reflects an increase in the number of authorized shares by
1,355,000 shares.

                 2.       Section 4(b), entitled "Administration of the Plan
- - Powers of the Board," is hereby amended to add a new subparagraph (xi) as
follows:

                          "(xi)  Notwithstanding the number of shares set forth
         in Section 3, the maximum aggregate number of shares subject to the
         Plan may be automatically increased by the Board, at its discretion
         and without shareholder approval, if the Board determines in
         connection with an acquisition of another business (whether by merger,
         consolidation or purchase of assets or otherwise) that it is necessary
         to grant a substantial number of new options to employees of, or
         persons holding options in, such acquired business to replace existing
         options, to grant new options to incentivize the employees or replace
         other equity rights previously granted to such persons by the acquired
         business.  The amount of the additional number of shares to become
         subject to the Plan shall not exceed the number of new options granted
         in connection with such acquisition."

                 3.       Section 7, entitled "Term of Option," is hereby
amended to delete the last sentence and to replace such sentence with a new
sentence as follows:

                          "The term of a Non-qualified Option shall be for a
         period of not to exceed ten (10) years from the date on which it is
         granted, as determined by the Board of Directors or the Committee."
         
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Amendment No. 5 to ADAC Laboratories
1992 Stock Option Plan




                 4.       Section 11(d), entitled "Adjustments - Change in
Control," is hereby deleted in its entirety and the following subsection 11(d)
is substituted in its place as follows:

                          "(d)    Change in Control.


                                  "(i)     Except and to the extent provided
         otherwise in, or limited by, employment, severance or similar written
         agreements between the Company and an Optionee, ten (10) days prior to
         a "Change in Control" (as defined below), all stock options which are
         then not exercisable shall immediately vest and become exercisable,
         regardless of the original vesting schedule.  A "Change in Control" of
         the Company shall be deemed to have occurred if (a) any "person" or
         "group" (as defined in or pursuant to Sections 13(d) or 14(d) of the
         Securities Exchange Act of 1934, as amended (the "Exchange Act")),
         becomes the "beneficial owner" (as defined in Rule 13d-3 promulgated
         under the Exchange Act), directly or indirectly, of securities of the
         Company representing 40% or more of the voting power of the common
         stock outstanding which votes generally for the election of directors;
         (b) as a result of market or corporate transactions or shareholder
         action, the individuals who constitute the Board of Directors of the
         Company at the beginning of any period of 12 consecutive months (but
         commencing not earlier than July 1, 1995), plus any new directors
         whose election or nomination was approved by a vote of at least
         two-thirds of the directors still in office who were directors at the
         beginning of such period of 12 consecutive months, cease for any
         reason during such period of 12 consecutive months to constitute at
         least two-thirds of the members of such Board; or (c) the Company
         sells, through merger, assignment or otherwise, in one or more
         transactions other than in the ordinary course of business, assets
         which provided at least 2/3 of the revenues or pre-tax net income of
         the Company and its subsidiaries on a consolidated basis during the
         most recently-completed fiscal year.

                          "(ii)  Notwithstanding paragraph (i) above, the
         following events shall not constitute a Change in Control: any
         acquisition of beneficial ownership pursuant to (a) a
         reclassification, however effected, of the Company's authorized common
         stock, or (b) a corporate reorganization involving the Company or any
         of its subsidiaries which does not result in a material change in the
         ultimate ownership by the shareholders of the Company (through their
         ownership of the Company or its successor resulting from the
         reorganization) of the assets of the Company and its subsidiaries, but
         only if





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Amendment No. 5 to ADAC Laboratories
1992 Stock Option Plan





         such reclassification or reorganization has been approved by the
         Company's Board of Directors."

                 5.       Except as amended above, in all other respects the
Plan is hereby ratified and confirmed.  The above amendments shall be deemed
effective and applicable to all future grants of options and all presently
outstanding option grants under the terms of the Plan.

                 6.       The amendments to the Plan herein set forth have been
approved by the Board of Directors on November 2, 1995 and approved by the
shareholders on March 6, 1996, and are effective as of such later date.

                                        By order of the Board of Directors:




                                        By:/s/ David L. Lowe               
                                        -------------------------------
                                               David L. Lowe,
                                               Chairman of the Board






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