<PAGE>

                                                                    Exhibit 10.6

                           IMPAC MEDICAL SYSTEMS, INC.

                                 1998 STOCK PLAN

     1.   Purposes of the Plan. The purposes of this 1998 Stock Plan are to
          --------------------
attract and retain the best available personnel for positions of substantial
responsibility, to provide additional incentive to Employees and Consultants of
the Company and its Subsidiaries and to promote the success of the Company's
business. Options granted under the Plan may be Incentive Stock Options (as
defined under Section 422 of the Code) or Nonstatutory Stock Options, as
determined by the Administrator at the time of grant of an Option and subject to
the applicable provisions of Section 422 of the Code, as amended, and the
regulations promulgated thereunder. Stock purchase rights may also be granted
under the Plan.

     2.   Definitions. As used herein, the following definitions shall apply:
          -----------

          (a)  "Administrator" means the Board or any of its Committees
                -------------
appointed pursuant to Section 4 of the Plan.

          (b)  "Affiliate" means an entity other than a Subsidiary (as defined
                ---------
below) in which the Company owns an equity interest.

          (c)  "Applicable Laws" means the legal requirements relating to the
                ---------------
administration of stock option plans under U.S. state corporate laws, U.S.
federal and state securities laws, the Code, any Stock Exchange and the
applicable laws of any other country or jurisdiction where Options are granted
under the Plan.

          (d)  "Board" means the Board of Directors of the Company.
                -----

          (e)  "Change in Control" means a sale of all or substantially all of
                -----------------
the Company's assets, or a merger, consolidation or other capital reorganization
of the Company with or into another corporation; provided however that a merger,
consolidation or other capital reorganization in which the holders of more than
50% of the shares of capital stock of the Company outstanding immediately prior
to such transaction continue to hold (either by the voting securities remaining
outstanding or by being converted into voting securities of the surviving
entity) more than 50% of the total voting power represented by the voting
securities of the Company, or such surviving entity, outstanding immediately
after such transaction shall not constitute a Change in Control.

          (f)  "Code" means the Internal Revenue Code of 1986, as amended.
                ----

          (g)  "Committee" means the Committee appointed by the Board of
                ---------
Directors to administer the Plan in accordance with Section 4 below.

          (h)  "Common Stock" means the Common Stock of the Company.
                ------------

<PAGE>

          (i)  "Company" means IMPAC Medical Systems, Inc., a California
                -------
corporation.

          (j)  "Consultant" means any person, including an advisor, who renders
                ----------
services to the Company, or any Parent, Subsidiary or Affiliate, and is
compensated for such services, and any director of the Company whether
compensated for such services or not.

          (k)  "Continuous Status as an Employee or Consultant" means the
                ----------------------------------------------
absence of any interruption or termination of service as an Employee or
Consultant. Continuous Status as an Employee or Consultant shall not be
considered interrupted in the case of: (i) sick leave; (ii) military leave;
(iii) any other leave of absence approved by the Administrator, provided that
such leave is for a period of not more than 90 days, unless reemployment upon
the expiration of such leave is guaranteed by contract or statute, or unless
provided otherwise pursuant to Company policy adopted from time to time; or (iv)
in the case of transfers between locations of the Company or between the
Company, its Parent(s), Affiliates, Subsidiaries or their respective successors.
For purposes of this Plan, a change in status from an Employee to a Consultant
or from a Consultant to an Employee will not constitute an interruption of
Continuous Status as an Employee or Consultant.

          (l)  "Director" means a member of the Board.
                --------

          (m)  "Employee" means any person, including officers and directors,
                --------
employed by the Company or any Parent, Subsidiary or Affiliate of the Company,
with the status of employment determined based upon such minimum number of hours
or periods worked as shall be determined by the Administrator in its discretion,
subject to any requirements of the Code. The payment by the Company of a
director's fee to a director shall not be sufficient to constitute "employment"
of such director by the Company.

          (n)  "Exchange Act" means the Securities Exchange Act of 1934, as
                ------------
amended.

          (o)  "Fair Market Value" means, as of any date, the fair market value
                -----------------
of Common Stock determined as follows:

               (i)  If the Common Stock is listed on any established stock
exchange or a national market system including without limitation the National
Market of the National Association of Securities Dealers, Inc. Automated
Quotation ("Nasdaq") System, its Fair Market Value shall be the closing sales
            ------
price for such stock (or the closing bid, if no sales were reported), as quoted
on such system or exchange, or the exchange with the greatest volume of trading
in Common Stock for the last market trading day prior to the time of
determination, as reported in The Wall Street Journal or such other source as
the Administrator deems reliable;

               (ii) If the Common Stock is quoted on the Nasdaq System (but not
on the National Market thereof) or regularly quoted by a recognized securities
dealer but selling prices are not reported, its Fair Market Value shall be the
mean between the high bid and low asked prices for the Common Stock for the last
market trading day prior to the time of

                                      -2-

<PAGE>

determination, as reported in The Wall Street Journal or such other source as
the Administrator deems reliable; or

               (iii) In the absence of an established market for the Common
Stock, the Fair Market Value thereof shall be determined in good faith by the
Administrator.

          (p)  "Incentive Stock Option" means an Option intended to qualify as
                ----------------------
an incentive stock option within the meaning of Section 422 of the Code, as
designated in the applicable written Option Agreement.

          (q)  "Listed Security" means any security of the Company which is
                ---------------
listed or approved for listing on a national securities exchange or designated
or approved for designation as a national market system security on an
interdealer quotation system by the National Association of Securities Dealers,
Inc.

          (r)  "Nonstatutory Stock Option" means an Option not intended to
                -------------------------
qualify as an Incentive Stock Option, as designated in the applicable written
Option Agreement.

          (s)  "Option" means a stock option granted pursuant to the Plan.
                ------

          (t)  "Option Agreement" means a written agreement between an Optionee
                ----------------
and the Company reflecting the terms of an Option granted under the Plan and
includes any documents attached to such Option Agreement, including, but not
limited to, a notice of stock option grant and a form of exercise notice.

          (u)  "Option Exchange Program" means a program whereby outstanding
                -----------------------
Options are exchanged for Options with a lower exercise price.

          (v)  "Optioned Stock" means the Common Stock subject to an Option or a
                --------------
Stock Purchase Right.

          (w)  "Optionee" means an Employee or Consultant who receives an Option
                --------
or a Stock Purchase Right.

          (x)  "Parent" means a "parent corporation," whether now or hereafter
                ------
existing, as defined in Section 424(e) of the Code, or any successor provision.

          (y)  "Plan" means this 1998 Stock Plan.
                ----

          (z)  "Reporting Person" means an officer, director, or greater than
                ----------------
10% shareholder of the Company within the meaning of Rule 16a-2 under the
Exchange Act, who is required to file reports pursuant to Rule 16a-3 under the
Exchange Act.

          (aa) "Restricted Stock" means shares of Common Stock acquired pursuant
                ----------------
to a grant of a Stock Purchase Right under Section 10 below.

                                      -3-

<PAGE>

          (bb) "Restricted Stock Purchase Agreement" means a written agreement
                -----------------------------------
between a holder of a Stock Purchase Right and the Company reflecting the terms
of a Stock Purchase Right granted under the Plan and includes any documents
attached to such agreement.

          (cc) "Rule 16b-3" means Rule 16b-3 promulgated under the Exchange Act,
                ----------
as the same may be amended from time to time, or any successor provision.

          (dd) "Share" means a share of the Common Stock, as adjusted in
                -----
accordance with Section 12 of the Plan.

          (ee) "Stock Exchange" means any stock exchange or consolidated stock
                --------------
price reporting system on which prices for the Common Stock are quoted at any
given time.

          (ff) "Stock Purchase Right" means the right to purchase Common Stock
                --------------------
pursuant to Section 10 below.

          (gg) "Subsidiary" means a "subsidiary corporation," whether now or
                ----------
hereafter existing, as defined in Section 424(f) of the Code, or any successor
provision.

     3.   Stock Subject to the Plan. Subject to the provisions of Section 12 of
          -------------------------
the Plan, the maximum aggregate number of Shares that may be optioned and sold
under the Plan is 300,000 Shares of Common Stock. The Shares may be authorized,
but unissued, or reacquired Common Stock. If an Option expires or becomes
unexercisable for any reason without having been exercised in full, or is
surrendered pursuant to an Option Exchange Program, the unpurchased Shares that
were subject thereto shall, unless the Plan shall have been terminated, become
available for future grant under the Plan. In addition, any Shares of Common
Stock that are retained by the Company upon exercise of an Option or Stock
Purchase Right in order to satisfy the exercise or purchase price for such
Option or Stock Purchase Right or any withholding taxes due with respect to such
exercise shall be treated as not issued and shall continue to be available under
the Plan. Shares repurchased by the Company pursuant to any repurchase right
that the Company may have shall not be available for future grant under the
Plan.

     4.   Administration of the Plan.
          --------------------------

          (a)  Initial Plan Procedure. Prior to the date, if any, upon which the
               ----------------------
Company becomes subject to the Exchange Act, the Plan shall be administered by
the Board or a Committee appointed by the Board.

          (b)  Plan Procedure After the Date, if any, Upon Which the Company
               -------------------------------------------------------------
Becomes Subject to the Exchange Act.
-----------------------------------

               (i)  Multiple Administrative Bodies. If permitted by Rule 16b-3,
                    ------------------------------
grants under the Plan may be made by different bodies with respect to Directors,
non-Director officers and Employees or Consultants who are not Reporting
Persons.

               (ii) Administration With Respect to Reporting Persons. With
                    ------------------------------------------------
respect to grants of Options or Stock Purchase Rights to Employees who are
Reporting Persons,

                                      -4-

<PAGE>

such grants shall be made by (A) the Board if the Board may make grants to
Reporting Persons under the Plan in compliance with Rule 16b-3, or (B) a
Committee designated by the Board to make grants to Reporting Persons under the
Plan, which Committee shall be constituted in such a manner as to permit grants
under the Plan to comply with Rule 16b-3. Once appointed, such Committee shall
continue to serve in its designated capacity until otherwise directed by the
Board. From time to time the Board may increase the size of the Committee and
appoint additional members thereof, remove members (with or without cause) and
appoint new members in substitution therefor, fill vacancies, however caused,
and remove all members of the Committee and thereafter directly make grants to
Reporting Persons under the Plan, all to the extent permitted by Rule 16b-3.

               (iii) Administration With Respect to Consultants and Other
                     ----------------------------------------------------
Employees. With respect to grants of Options or Stock Purchase Rights to
---------
Employees or Consultants who are not Reporting Persons, the Plan shall be
administered by (A) the Board or (B) a Committee designated by the Board, which
Committee shall be constituted in such a manner as to satisfy the Applicable
Laws. Once appointed, such Committee shall continue to serve in its designated
capacity until otherwise directed by the Board. From time to time the Board may
increase the size of the Committee and appoint additional members thereof,
remove members (with or without cause) and appoint new members in substitution
therefor, fill vacancies, however caused, and remove all members of the
Committee and thereafter directly administer the Plan, all to the extent
permitted by the Applicable Laws.

          (c)  Powers of the Administrator. Subject to the provisions of the
               ---------------------------
Plan and in the case of a Committee, the specific duties delegated by the Board
to such Committee, and subject to the approval of any relevant authorities,
including the approval, if required, of any Stock Exchange, the Administrator
shall have the authority, in its discretion:

               (i)   to determine the Fair Market Value of the Common Stock, in
accordance with Section 2(o) of the Plan;

               (ii)  to select the Consultants and Employees to whom Options and
Stock Purchase Rights or any combination thereof may from time to time be
granted hereunder;

               (iii) to determine whether and to what extent Options and Stock
Purchase Rights or any combination thereof are granted hereunder;

               (iv)  to determine the number of shares of Common Stock to be
covered by each such award granted hereunder;

               (v)   to approve forms of agreement for use under the Plan;

               (vi)  to determine the terms and conditions, not inconsistent
with the terms of the Plan, of any award granted hereunder, which terms and
conditions include but are not limited to the exercise or purchase price, the
time or times when Options or Stock Purchase Rights may be exercised (which may
be based on performance criteria), any vesting acceleration or waiver of
forfeiture restrictions, and any restriction or limitation regarding any Option,

                                      -5-

<PAGE>

Optioned Stock, Stock Purchase Right or Restricted Stock, based in each case on
such factors as the Administrator, in its sole discretion, shall determine;

               (vii)  to determine whether and under what circumstances an
Option may be settled in cash under Section 9(g) instead of Common Stock;

               (viii) to reduce the exercise price of any Option to the then
current Fair Market Value if the Fair Market Value of the Common Stock covered
by such Option shall have declined since the date the Option was granted;

               (ix)   to determine the terms and restrictions applicable to
Stock Purchase Rights and the Restricted Stock purchased by exercising such
Stock Purchase Rights;

               (x)    to initiate an Option Exchange Program;

               (xi)   to construe and interpret the terms of the Plan and awards
granted under the Plan; and

               (xii)  in order to fulfill the purposes of the Plan and without
amending the Plan, to modify grants of Options or Stock Purchase Rights to
participants who are foreign nationals or employed outside of the United States
in order to recognize differences in local law, tax policies or customs.

          (d)  Effect of Administrator's Decision. All decisions, determinations
               ----------------------------------
and interpretations of the Administrator shall be final and binding on all
holders of Options or Stock Purchase Rights.

     5.   Eligibility.
          -----------

          (a)  Recipients of Grants. Nonstatutory Stock Options and Stock
               --------------------
Purchase Rights may be granted to Employees and Consultants. Incentive Stock
Options may be granted only to Employees; provided however that Employees of
Affiliates shall not be eligible to receive Incentive Stock Options. An Employee
or Consultant who has been granted an Option or Stock Purchase Right may, if he
or she is otherwise eligible, be granted additional Options or Stock Purchase
Rights.

          (b)  Type of Option. Each Option shall be designated in the Option
               --------------
Agreement as either an Incentive Stock Option or a Nonstatutory Stock Option.
However, notwithstanding such designations, to the extent that the aggregate
Fair Market Value of Shares with respect to which Options designated as
Incentive Stock Options are exercisable for the first time by any Optionee
during any calendar year (under all plans of the Company or any Parent or
Subsidiary) exceeds $100,000, such excess Options shall be treated as
Nonstatutory Stock Options. For purposes of this Section 5(b), Incentive Stock
Options shall be taken into account in the order in which they were granted, and
the Fair Market Value of the Shares subject to an Incentive Stock Option shall
be determined as of the date of the grant of such Option.

                                      -6-

<PAGE>

          (c)  At-Will Relationship. The Plan shall not confer upon the holder
               --------------------
of any Option or Stock Purchase Right any right with respect to continuation of
employment or consulting relationship with the Company, nor shall it interfere
in any way with such holder's right or the Company's right to terminate his or
her employment or consulting relationship at any time, with or without cause.

     6.   Term of Plan. The Plan shall become effective upon its adoption by the
          ------------
Board. It shall continue in effect for a term of ten years unless sooner
terminated under Section 15 of the Plan.

     7.   Term of Option. The term of each Option shall be the term stated in
          --------------
the Option Agreement; provided, however, that the term shall be no more than ten
years from the date of grant thereof or such shorter term as may be provided in
the Option Agreement. However, in the case of an Incentive Stock Option granted
to an Optionee who, at the time the Option is granted, owns stock representing
more than 10% of the total combined voting power of all classes of stock of the
Company or any Parent or Subsidiary, the term of the Option shall be five years
from the date of grant thereof or such shorter term as may be provided in the
Option Agreement.

     8.   Option Exercise Price and Consideration.
          ---------------------------------------

          (a)  The per share exercise price for the Shares to be issued pursuant
to exercise of an Option shall be such price as is determined by the Board and
set forth in the Option Agreement, but shall be subject to the following:

               (i)   In the case of an Incentive Stock Option that is:

                     (A)  granted to an Employee who, at the time of the grant
of such Incentive Stock Option, owns stock representing more than 10% of the
total combined voting power of all classes of stock of the Company or any Parent
or Subsidiary, the per Share exercise price shall be no less than 110% of the
Fair Market Value per Share on the date of grant.

                     (B)  granted to any other Employee, the per Share exercise
price shall be no less than 100% of the Fair Market Value per Share on the date
of grant.

               (ii)  In the case of a Nonstatutory Stock Option that is:

                     (A)  granted to a person who, at the time of the grant of
such Option, owns stock representing more than 10% of the total combined voting
power of all classes of stock of the Company or any Parent or Subsidiary, the
per Share exercise price shall be no less than 110% of the Fair Market Value per
Share on the date of the grant.

                     (B)  granted to any other eligible person, the per Share
exercise price shall be no less than 85% of the Fair Market Value per Share on
the date of grant.

               (iii) Notwithstanding the foregoing, Options may be granted with
a per Share exercise price other than as required above pursuant to a merger or
other corporate transaction.

                                       -7-

<PAGE>

          (b)  The consideration to be paid for the Shares to be issued upon
exercise of an Option, including the method of payment, shall be determined by
the Administrator (and, in the case of an Incentive Stock Option, shall be
determined at the time of grant) and may consist entirely of (1) cash, (2)
check, (3) promissory note, (4) cancellation of indebtedness, (5) other Shares
that (x) in the case of Shares acquired upon exercise of an Option, have been
owned by the Optionee for more than six months on the date of surrender or such
other period as may be required to avoid a charge to the Company's earnings, and
(y) have a Fair Market Value on the date of surrender equal to the aggregate
exercise price of the Shares as to which such Option shall be exercised, (6)
authorization for the Company to retain from the total number of Shares as to
which the Option is exercised that number of Shares having a Fair Market Value
on the date of exercise equal to the exercise price for the total number of
Shares as to which the Option is exercised, (7) delivery of a properly executed
exercise notice together with such other documentation as the Administrator and
the broker, if applicable, shall require to effect an exercise of the Option and
delivery to the Company of the sale or loan proceeds required to pay the
exercise price and any applicable income or employment taxes, (8) delivery of an
irrevocable subscription agreement for the Shares that irrevocably obligates the
option holder to take and pay for the Shares not more than twelve months after
the date of delivery of the subscription agreement, (9) any combination of the
foregoing methods of payment, or (10) such other consideration and method of
payment for the issuance of Shares to the extent permitted under the Applicable
Laws. In making its determination as to the type of consideration to accept, the
Administrator shall consider if acceptance of such consideration may be
reasonably expected to benefit the Company.

     9.   Exercise of Option.
          ------------------

          (a)  Procedure for Exercise; Rights as a Shareholder. Any Option
               -----------------------------------------------
granted hereunder shall be exercisable at such times and under such conditions
as determined by the Administrator and reflected in the Option Agreement, which
may include vesting requirements and/or performance criteria with respect to the
Company and/or the Optionee; provided however, that any Option granted prior to
the date, if any, upon which the Common Stock becomes a Listed Security shall
become exercisable at the rate of at least 20% per year over five years from the
date the Option is granted. In the event that any of the Shares issued upon
exercise of an Option (which exercise occurs prior to the date, if any, upon
which the Common Stock becomes a Listed Security) should be subject to a right
of repurchase in the Company's favor, such repurchase right shall lapse at the
rate of at least 20% per year over five years from the date the Option is
granted. Notwithstanding the above, in the case of an Option granted to an
officer, Director or Consultant of the Company or any Parent or Subsidiary of
the Company, the Option may become fully exercisable, or a repurchase right, if
any, in favor of the Company shall lapse, at any time or during any period
established by the Administrator. The Administrator shall have the discretion to
determine whether and to what extent the vesting of Options shall be tolled
during any unpaid leave of absence; provided however that in the absence of such
determination, vesting of Options shall be tolled during any such leave.

     An Option may not be exercised for a fraction of a Share.

                                      -8-

<PAGE>

         An Option shall be deemed exercised when written notice of such
exercise has been given to the Company in accordance with the terms of the
Option by the person entitled to exercise the Option and the Company has
received full payment for the Shares with respect to which the Option is
exercised. Full payment may, as authorized by the Administrator, consist of any
consideration and method of payment allowable under Section 8(b) of the Plan.
Until the issuance (as evidenced by the appropriate entry on the books of the
Company or of a duly authorized transfer agent of the Company) of the stock
certificate evidencing such Shares, no right to vote or receive dividends or any
other rights as a shareholder shall exist with respect to the Optioned Stock,
not withstanding the exercise of the Option. The Company shall issue (or cause
to be issued) such stock certificate promptly upon exercise of the Option. No
adjustment will be made for a dividend or other right for which the record date
is prior to the date the stock certificate is issued, except as provided in
Section 12 of the Plan.

         Exercise of an Option in any manner shall result in a decrease in the
number of Shares that thereafter may be available, both for purposes of the Plan
and for sale under the Option, by the number of Shares as to which the Option is
exercised.

               (b) Termination of Employment or Consulting Relationship. Subject
                   ----------------------------------------------------
to Section 9(c) below, in the event of termination of an Optionee's Continuous
Status as an Employee or Consultant with the Company, such Optionee may, but
only within three months (or such other period of time not less than 30 days as
is determined by the Administrator, with such determination in the case of an
Incentive Stock Option being made at the time of grant of the Option and not
exceeding three months) after the date of such termination (but in no event
later than the expiration date of the term of such Option as set forth in the
Option Agreement), exercise his or her Option to the extent that the Optionee
was entitled to exercise it at the date of such termination. To the extent that
the Optionee was not entitled to exercise the Option at the date of such
termination, or if the Optionee does not exercise such Option to the extent so
entitled within the time specified herein, the Option shall terminate and the
Optioned Stock underlying the unexercised portion of the Option shall revert to
the Plan. No termination shall be deemed to occur and this Section 9(b) shall
not apply if (i) the Optionee is a Consultant who becomes an Employee, or (ii)
the Optionee is an Employee who becomes a Consultant.

               (c) Disability of Optionee.
                   ----------------------

                   (i)   Notwithstanding Section 9(b) above, in the event of
termination of an Optionee's Continuous Status as an Employee or Consultant as a
result of his or her total and permanent disability (within the meaning of
Section 22(e)(3) of the Code), such Optionee may, but only within twelve months
from the date of such termination (but in no event later than the expiration
date of the term of such Option as set forth in the Option Agreement), exercise
the Option to the extent otherwise entitled to exercise it at the date of such
termination. To the extent that the Optionee was not entitled to exercise the
Option at the date of termination, or if the Optionee does not exercise such
Option to the extent so entitled within the time specified herein, the Option
shall terminate and the Optioned Stock underlying the unexercised portion of the
Option shall revert to the Plan.

                                      -9-

<PAGE>

                   (ii)  In the event of termination of an Optionee's Continuous
Status as an Employee or Consultant as a result of a disability which does not
fall within the meaning of total and permanent disability (as set forth in
Section 22(e)(3) of the Code), such Optionee may, but only within six months
from the date of such termination (but in no event later than the expiration
date of the term of such Option as set forth in the Option Agreement), exercise
the Option to the extent otherwise entitled to exercise it at the date of such
termination. However, to the extent that such Optionee fails to exercise an
Option which is an Incentive Stock Option (within the meaning of Section 422 of
the Code) within three months of the date of such termination, the Option will
not qualify for Incentive Stock Option treatment under the Code. To the extent
that the Optionee was not entitled to exercise the Option at the date of
termination, or if the Optionee does not exercise such Option to the extent so
entitled within six months from the date of termination, the Option shall
terminate and the Optioned Stock underlying the unexercised portion of the
Option shall revert to the Plan.

               (d) Death of Optionee. In the event of the death of an Optionee
                   -----------------
during the period of Continuous Status as an Employee or Consultant since the
date of grant of the Option, or within 30 days following termination of the
Optionee's Continuous Status as an Employee or Consultant, the Option may be
exercised, at any time within six months following the date of death (but in no
event later than the expiration date of the term of such Option as set forth in
the Option Agreement), by such Optionee's estate or by a person who acquired the
right to exercise the Option by bequest or inheritance, but only to the extent
of the right to exercise that had accrued at the date of death or, if earlier,
the date of termination of the Optionee's Continuous Status as an Employee or
Consultant. To the extent that the Optionee was not entitled to exercise the
Option at the date of death or termination, as the case may be, or if the
Optionee does not exercise such Option to the extent so entitled within the time
specified herein, the Option shall terminate and the Optioned Stock underlying
the unexercised portion of the Option shall revert to the Plan.

               (e) Extension of Exercise Period. The Administrator shall have
                   ----------------------------
full power and authority to extend the period of time for which an Option is to
remain exercisable following termination of an Optionee's Continuous Status as
an Employee or Consultant from the periods set forth in Sections 10(b), 10(c)
and 10(d) above or in the Option Agreement to such greater time as the Board
shall deem appropriate, provided, that in no event shall such option be
exercisable later than the date of expiration of the term of such Option as set
forth in the Option Agreement.

               (f) Rule 16b-3. Options granted to Reporting Persons shall comply
                   ----------
with Rule 16b-3 and shall contain such additional conditions or restrictions as
may be required thereunder to qualify for the maximum exemption for Plan
transactions.

               (g) Buy-Out Provisions. The Administrator may at any time offer
                   ------------------
to buy out for a payment in cash or Shares an Option previously granted based on
such terms and conditions as the Administrator shall establish and communicate
to the Optionee at the time such offer is made.

                                      -10-

<PAGE>

         10.   Stock Purchase Rights.
               ---------------------

               (a) Rights to Purchase. Stock Purchase Rights may be issued
                   ------------------
either alone, in addition to, or in tandem with other awards granted under the
Plan and/or cash awards made outside of the Plan. After the Administrator
determines that it will offer Stock Purchase Rights under the Plan, it shall
advise the offeree in writing of the terms, conditions and restrictions related
to the offer, including the number of Shares that such person shall be entitled
to purchase, the price to be paid (which price shall not be less than 85% of the
Fair Market Value of the Shares as of the date of the offer, or, in the case of
a person owning stock representing more than 10% of the total combined voting
power of all classes of stock of the Company or any Parent or Subsidiary, the
price shall not be less than 100% of the Fair Market Value of the Shares as of
the date of the offer), and the time within which such person must accept such
offer, which shall in no event exceed 30 days from the date upon which the
Administrator made the determination to grant the Stock Purchase Right. The
offer shall be accepted by execution of a Restricted Stock Purchase Agreement in
the form determined by the Administrator.

               (b) Repurchase Option. Unless the Administrator determines
                   -----------------
otherwise, the Restricted Stock Purchase Agreement shall grant the Company a
repurchase option exercisable upon the voluntary or involuntary termination of
the purchaser's employment with the Company for any reason (including death or
disability). The purchase price for Shares repurchased pursuant to the
Restricted Stock Purchase Agreement shall be the original purchase price paid by
the purchaser and may be paid by cancellation of any indebtedness of the
purchaser to the Company. The repurchase option shall lapse at such rate as the
Administrator may determine; provided, however, that with respect to an Optionee
who is not an officer, director or Consultant of the Company or of any Parent or
Subsidiary of the Company, it shall lapse at a minimum rate of 20% per year.

               (c) Other Provisions. The Restricted Stock Purchase Agreement
                   ----------------
shall contain such other terms, provisions and conditions not inconsistent with
the Plan as may be determined by the Administrator in its sole discretion. In
addition, the provisions of Restricted Stock Purchase Agreements need not be the
same with respect to each purchaser.

               (d) Rights as a Shareholder. Once the Stock Purchase Right is
                   -----------------------
exercised, the purchaser shall have the rights equivalent to those of a
shareholder, and shall be a shareholder when his or her purchase is entered upon
the records of the duly authorized transfer agent of the Company. No adjustment
will be made for a dividend or other right for which the record date is prior to
the date the Stock Purchase Right is exercised, except as provided in Section 12
of the Plan.

         11.   Stock Withholding to Satisfy Withholding Tax Obligations. At the
               --------------------------------------------------------
discretion of the Administrator, Optionees may satisfy withholding obligations
as provided in this paragraph. When an Optionee incurs tax liability in
connection with an Option or Stock Purchase Right, which tax liability is
subject to tax withholding under applicable tax laws, and the Optionee is
obligated to pay the Company an amount required to be withheld under applicable
tax laws, the Optionee may satisfy the withholding tax obligation by one or some
combination of the following methods: (a) by cash or check payment, (b) out of
the Optionee's current compensation, (c) if

                                      -11-

<PAGE>

permitted by the Administrator, in its discretion, by surrendering to the
Company Shares that (i) in the case of Shares previously acquired from the
Company, have been owned by the Optionee for more than six months on the date of
surrender, and (ii) have a Fair Market Value on the date of surrender equal to
or less than the amount required to be withheld, or (d) by electing to have the
Company withhold from the Shares to be issued upon exercise of the Option, or
the Shares to be issued in connection with the Stock Purchase Right, if any,
that number of Shares having a Fair Market Value equal to the amount required to
be withheld. For this purpose, the Fair Market Value of the Shares to be
withheld shall be determined on the date that the amount of tax to be withheld
is to be determined (the "Tax Date").
                          --------

         Any surrender by a Reporting Person of previously owned Shares to
satisfy tax withholding obligations arising upon exercise of this Option must
comply with the applicable provisions of Rule 16b-3.

         All elections by an Optionee to have Shares withheld to satisfy tax
withholding obligations shall be made in writing in a form acceptable to the
Administrator and shall be subject to the following restrictions:

               (a) the election must be made on or prior to the applicable Tax
Date;

               (b) once made, the election shall be irrevocable as to the
particular Shares of the Option or Stock Purchase Right as to which the election
is made; and

               (c) all elections shall be subject to the consent or disapproval
of the Administrator.

         In the event the election to have Shares withheld is made by an
Optionee and the Tax Date is deferred under Section 83 of the Code because no
election is filed under Section 83(b) of the Code, the Optionee shall receive
the full number of Shares with respect to which the Option or Stock Purchase
Right is exercised but such Optionee shall be unconditionally obligated to
tender back to the Company the proper number of Shares on the Tax Date.

         12.   Adjustments Upon Changes in Capitalization, Merger or Certain
               -------------------------------------------------------------
Other Transactions.
------------------

               (a) Changes in Capitalization. Subject to any required action by
                   -------------------------
the shareholders of the Company, the number of shares of Common Stock covered by
each outstanding Option or Stock Purchase Right, and the number of shares of
Common Stock that have been authorized for issuance under the Plan but as to
which no Options or Stock Purchase Rights have yet been granted or that have
been returned to the Plan upon cancellation or expiration of an Option or Stock
Purchase Right, as well as the price per share of Common Stock covered by each
such outstanding Option or Stock Purchase Right, shall be proportionately
adjusted for any increase or decrease in the number of issued shares of Common
Stock resulting from a stock split, reverse stock split, stock dividend,
combination, recapitalization or reclassification of the Common Stock, or any
other increase or decrease in the number of issued shares of Common Stock
effected without receipt of consideration by the Company; provided,

                                      -12-

<PAGE>

however, that conversion of any convertible securities of the Company shall not
be deemed to have been "effected without receipt of consideration." Such
adjustment shall be made by the Board, whose determination in that respect shall
be final, binding and conclusive. Except as expressly provided herein, no
issuance by the Company of shares of stock of any class, or securities
convertible into shares of stock of any class, shall affect, and no adjustment
by reason thereof shall be made with respect to, the number or price of shares
of Common Stock subject to an Option or Stock Purchase Right.

               (b) Dissolution or Liquidation. In the event of the proposed
                   --------------------------
dissolution or liquidation of the Company, the Board shall notify the Optionee
at least 15 days prior to such proposed action. To the extent it has not been
previously exercised, the Option or Stock Purchase Right will terminate
immediately prior to the consummation of such proposed action.

               (c) Change in Control. In the event of a Change in Control, each
                   -----------------
outstanding Option or Stock Purchase Right shall be assumed or an equivalent
option or right shall be substituted by the successor corporation or a Parent or
Subsidiary of such successor corporation, unless such successor corporation does
not agree to assume the outstanding Options or Stock Purchase Rights or to
substitute equivalent options or rights, in which case such Options or Stock
Purchase Rights shall terminate upon the consummation of the transaction.

               For purposes of this Section 12(c), an Option or a Stock Purchase
Right shall be considered assumed, without limitation, if, at the time of
issuance of the stock or other consideration upon such Change in Control, each
holder of an Option or Stock Purchase Right would be entitled to receive upon
exercise of the Option or Stock Purchase Right the same number and kind of
shares of stock or the same amount of property, cash or securities as such
holder would have been entitled to receive upon the occurrence of the
transaction if the holder had been, immediately prior to such transaction, the
holder of the number of Shares of Common Stock covered by the Option or the
Stock Purchase Right at such time (after giving effect to any adjustments in the
number of Shares covered by the Option or Stock Purchase Right as provided for
in this Section 12); provided however that if such consideration received in the
Change in Control was not solely common stock of the successor corporation or
its Parent, the Administrator may, with the consent of the successor
corporation, provide for the consideration to be received upon exercise of the
Option to be solely common stock of the successor corporation or its Parent
equal to the Fair Market Value of the per Share consideration received by
holders of Common Stock in the transaction.

               (d) Certain Distributions. In the event of any distribution to
                   ---------------------
the Company's shareholders of securities of any other entity or other assets
(other than dividends payable in cash or stock of the Company) without receipt
of consideration by the Company, the Administrator may, in its discretion,
appropriately adjust the price per Share of Common Stock covered by each
outstanding Option or Stock Purchase Right to reflect the effect of such
distribution.

         13.   Non-Transferability of Options and Stock Purchase Rights.
               --------------------------------------------------------
Options and Stock Purchase Rights may not be sold, pledged, assigned,
hypothecated, transferred, or disposed of in any manner other than by will or by
the laws of descent or distribution and may be exercised or purchased during the
lifetime of the Optionee or the holder of Stock Purchase Rights only by

                                      -13-

<PAGE>

the Optionee or holder of Stock Purchase Rights; provided however that, after
the date, if any, upon which the Common Stock becomes a Listed Security, the
Administrator may in its discretion grant transferable Nonstatutory Stock
Options pursuant to Option Agreements specifying (i) the manner in which such
Nonstatutory Stock Options are transferable and (ii) that any such transfer
shall be subject to the Applicable Laws. The designation of a beneficiary by an
Optionee will not constitute a transfer. An Option or Stock Purchase Right may
be exercised, during the lifetime of the holder of the Option or Stock Purchase
Right, only by such holder or a transferee permitted by this Section 13.

         14.   Time of Granting Options and Stock Purchase Rights. The date of
               --------------------------------------------------
grant of an Option or Stock Purchase Right shall, for all purposes, be the date
on which the Administrator makes the determination granting such Option or Stock
Purchase Right, or such other date as is determined by the Board; provided,
however, that in the case of any Incentive Stock Option, the grant date shall be
the later of the date on which the Administrator makes the determination
granting such Incentive Stock Option or the date of commencement of the
Optionee's employment relationship with the Company. Notice of the determination
shall be given to each Employee or Consultant to whom an Option or Stock
Purchase Right is so granted within a reasonable time after the date of such
grant.

         15.   Amendment and Termination of the Plan.
               -------------------------------------

               (a) Authority to Amend or Terminate. The Board may at any time
                   -------------------------------
amend, alter, suspend or discontinue the Plan, but no amendment, alteration,
suspension or discontinuation shall be made that would impair the rights of any
Optionee under any grant theretofore made, without his or her consent. In
addition, to the extent necessary and desirable to comply with Rule 16b-3 or
with Section 422 of the Code (or any other applicable law or regulation,
including the requirements of any Stock Exchange), the Company shall obtain
shareholder approval of any Plan amendment in such a manner and to such a degree
as required.

               (b) Effect of Amendment or Termination. No amendment or
                   ----------------------------------
termination of the Plan shall adversely affect Options already granted, unless
mutually agreed otherwise between the Optionee and the Administrator, which
agreement must be in writing and signed by the Optionee and the Company.

         16.   Conditions Upon Issuance of Shares. Shares shall not be issued
               ----------------------------------
pursuant to the exercise of an Option or Stock Purchase Right unless the
exercise of such Option or Stock Purchase Right and the issuance and delivery of
such Shares pursuant thereto shall comply with all relevant provisions of law,
including, without limitation, the Securities Act of 1933, as amended, the
Exchange Act, the rules and regulations promulgated thereunder, and the
requirements of any Stock Exchange.

         As a condition to the exercise of an Option, the Company may require
the person exercising such Option to represent and warrant at the time of any
such exercise that the Shares are being purchased only for investment and
without any present intention to sell or distribute such Shares if, in the
opinion of counsel for the Company, such a representation is required by law.

                                      -14-

<PAGE>

         17.  Reservation of Shares. The Company, during the term of this Plan,
              ---------------------
will at all times reserve and keep available such number of Shares as shall be
sufficient to satisfy the requirements of the Plan. The inability of the Company
to obtain authority from any regulatory body having jurisdiction, which
authority is deemed by the Company's counsel to be necessary to the lawful
issuance and sale of any Shares hereunder, shall relieve the Company of any
liability in respect of the failure to issue or sell such Shares as to which
such requisite authority shall not have been obtained.

         18.  Agreements.  Options and Stock Purchase Rights shall be evidenced
              ----------
by written Option Agreements and Restricted Stock Purchase Agreements,
respectively, in such form(s) as the Administrator shall approve from time to
time.

         19.  Shareholder Approval. Continuance of the Plan shall be subject to
              --------------------
approval by the shareholders of the Company within twelve months before or after
the date the Plan is adopted. Such shareholder approval shall be obtained in the
degree and manner required under applicable state and federal law and the rules
of any Stock Exchange upon which the Common Stock is listed. All Options and
Stock Purchase Rights issued under the Plan shall become void in the event such
approval is not obtained.

         20.  Information and Documents to Optionees and Purchasers. The Company
              -----------------------------------------------------
shall provide financial statements at least annually to each Optionee and to
each individual who acquired Shares pursuant to the Plan, during the period such
Optionee or purchaser has one or more Options or Stock Purchase Rights
outstanding, and in the case of an individual who acquired Shares pursuant to
the Plan, during the period such individual owns such Shares. The Company shall
not be required to provide such information if the issuance of Options or Stock
Purchase Rights under the Plan is limited to key employees whose duties in
connection with the Company assure their access to equivalent information. In
addition, at the time of issuance of any securities under the Plan, the Company
shall provide to the Optionee or the purchaser a copy of the Plan and any
agreement(s) pursuant to which securities granted under the Plan are issued.

                                      -15-