TREX MEDICAL CORPORATION

                    DEFERRED COMPENSATION PLAN FOR DIRECTORS

                      As amended and restated as of June 18, 1999


Section 1. Participation. Any director of Trex Medical Corporation (the
"Company") may elect to have such percentage as he or she may specify of the
fees otherwise payable to him or her deferred and paid to him or her as provided
in this Plan. A director who is also an employee of the Company or any
subsidiary or parent of the Company, shall not be eligible to participate in
this Plan. Each election shall be made by notice in writing delivered to the
Secretary of the Company, in such form as the Secretary shall designate, and
each election shall be applicable only with respect to fees earned subsequent to
the date of the election for the period designated in the form. The term
"participant" as used herein refers to any director who shall have made an
election. No participant may defer the receipt of any fees to be earned after
the later to occur of either (a) the date on which the participant shall retire
from or otherwise cease to engage in his or her principal occupation or
employment or (b) the date on which he or she shall cease to be a director of
the Company, or such earlier date as the Board of Directors of the Company, with
the participant's consent, may designate (the "deferral termination date"). In
the event that the participant's deferral termination date is the date on which
he or she ceases to engage in his or her principal occupation or employment, the
participant or a personal representative shall advise the Company of that date
by written notice delivered to the Secretary of the Company.

Section 2. Establishment of Deferred Compensation Accounts. There shall be
established for each participant an account to be designated as that
participant's deferred compensation account.

Section 3. Allocations to Deferred Compensation Accounts. There shall be
allocated to each participant's deferred compensation account, as of the end of
each quarter, an amount equal to his or her fees for that quarter which that
participant shall have elected to have deferred pursuant to Section 1.

Section 4. Stock Units and Stock Unit Accounts. All amounts allocated to a
participant's deferred compensation account pursuant to Section 3 and Section 5
shall be converted, at the end of each quarter, into stock units by dividing the
accumulated balance in the deferred compensation account as of the end of that
quarter by the average last sale price per share of the Company's common stock
as reported in The Wall Street Journal, for the five business days up to and
including the last business day of that quarter. The number of stock units, so
determined, rounded to the nearest one-hundredth of a share, shall be credited
to a separate stock unit account to be established for the participant, and the
aggregate value thereof as of the last business day of that quarter shall be
charged to the participant's deferred compensation account. No amounts credited
to the participant's deferred compensation account pursuant to Section 5
subsequent to the close of the fiscal year in which occurs the participant's
deferral termination date shall be converted into stock units. Any such amount
shall be distributed in cash as provided in Section 8. A maximum number of
25,000 shares of the Company's common stock may be represented by stock units
credited under this Plan, subject to proportionate adjustment in the event of
any stock dividend, stock split or other capital change affecting the Company's
common stock.

Section 5. Cash Dividend Credits. Additional credits shall be made to a
participant's deferred compensation account, until all distributions shall have
been made from the participant's stock unit account, in amounts equal to the
cash dividends (or the fair market value of dividends paid in property other
than dividends payable in common stock of the Company) which the participant
would have received from time to time had he or she been the owner on the record
dates for the payment of such dividends of the number of shares of the Company's
common stock equal to the number of units in his or her stock unit account on
those dates.

Section 6. Stock Dividend Credits. Additional credits shall be made to a
participant's stock unit account, until all distributions shall have been made
from the participant's stock unit account, of a number of units equal to the
number of shares of the Company's common stock, rounded to the nearest
one-hundredth share, which the participant would have received from time to time
as stock dividends had he or she been the owner on the record dates for the
payments of such stock dividends of the number of units of the Company's common
stock equal to the number of units credited to his or her stock unit account on
those dates.

Section 7. Adjustments in the Event of Certain Transactions. In the event of a
stock dividend, stock split or combination of shares, or other distribution with
respect to holders of Common Stock other than normal cash dividends, the number
of units then credited to a partipant's stock unit account shall be
appropriately adjusted on the same basis. In the event of any recapitalization,
merger or consolidation involving the Company, any transaction in which the
Company becomes a subsidiary of another entity, any sale or other disposition of
all or a substantial portion of the assets of the Company or any similar
transaction, as determined by the Board, the Board in its discretion may
terminate the Plan pursuant to Section 11.

Section 8. Distribution of Stock and Cash After Participant's Deferral
Termination Date. When a participant's deferral termination date shall occur,
the Company shall become obligated to make the distributions prescribed in the
following paragraphs (a) and (b).

        (a) The Company shall distribute to the participant the number of shares
of the common stock of the Company which shall equal the total number of units
accumulated in his or her stock unit account as of the close of the fiscal year
in which the participant's deferral termination date occurs. Such distribution
of stock shall be made in ten annual installments, unless, at least six months
prior to his or her deferral termination date, the participant shall have
elected, by notice in writing filed with the Secretary of the Company, to have
such distribution made in five annual installments. In either such case, the
installments shall be of as nearly equal number of shares as practicable,
adjusted to reflect any changes pursuant to Sections 6 and 7 in the number of
units remaining in the participant's stock unit account. The first such
installment shall be distributed within 60 days after the close of the fiscal
year in which the participant's deferral termination date occurs. The remaining
installments shall be distributed at annual intervals thereafter. Anything
herein to the contrary notwithstanding, the Company shall have the option, if
its Board of Directors shall by resolution so determine, in lieu of making
distribution in ten or five annual installments as set forth above, with the
participant's consent, to distribute stock or any remaining installments thereof
in a single distribution at any time following the close of the fiscal year in
which the participant's deferral termination date occurs. Distribution of stock
made hereunder may be made from shares of common stock held in the treasury
and/or from shares of authorized but previously unissued shares of common stock.

        (b) The Company shall distribute to the participant sums in cash equal
to the balance credited to his or her deferred compensation account as of the
close of the fiscal year in which his or her deferral termination date occurs
plus such additional amounts as shall be credited thereto from time to time
thereafter pursuant to Section 5. The cash distribution shall be made on the
same dates as the annual distributions made pursuant to paragraph (a) above, and
each cash distribution shall consist of the entire balance credited to the
participant's deferred compensation account at the time of the annual
distribution.

        If a participant's deferral termination date shall occur by reason of
his or her death or if he or she shall die after his or her deferral termination
date but prior to receipt of all distributions of stock and cash provided for in
this Section 8, all stock and cash remaining distributable hereunder shall be
distributed to such beneficiary as the participant shall have designated in
writing and filed with the Secretary of the Company or, in the absence of
designation, to the participant's personal representative. Such distributions
shall be made in the same manner and at the same intervals as they would have
been made to the participant had he or she continued to live.

Section 9. Participant's Rights Unsecured. The right of any participant to
receive distributions under Section 8 shall be an unsecured claim against the
general assets of the Company. The Company may but shall not be obligated to
acquire shares of its outstanding common stock from time to time in anticipation
of its obligation to make such distributions, but no participant shall have any
rights in or against any shares of stock so acquired by the Company. All such
stock shall constitute general assets of the Company and may be disposed of by
the Company at such time and for such purposes as it may deem appropriate.

10.     Change in Control

        10.1   Impact of Event

In the event of a "Change in Control" as defined in Section 10.2, the Plan shall
terminate and full distribution shall be made from all participants' deferred
compensation accounts and stock unit accounts effective upon the Change of
Control.

        10.2   Definition of "Change in Control"

        "Change in Control" means an event or occurrence set forth in any one or
more of subsections (a) through (d) below (including an event or occurrence that
constitutes a Change in Control under one of such subsections but is
specifically exempted from another such subsection):

        (a) the acquisition by an individual, entity or group (within the
meaning of Section 13(d)(3) or 14(d)(2) of the Exchange Act) (a "Person") of
beneficial ownership of any capital stock of Thermo Electron Corporation
("Thermo Electron") if, after such acquisition, such Person beneficially owns
(within the meaning of Rule 13d-3 promulgated under the Exchange Act) 40% or
more of either (i) the then-outstanding shares of common stock of Thermo
Electron (the "Outstanding TMO Common Stock") or (ii) the combined voting power
of the then-outstanding securities of Thermo Electron entitled to vote generally
in the election of directors (the "Outstanding TMO Voting Securities");
provided, however, that for purposes of this subsection (a), the following
acquisitions shall not constitute a Change in Control: (i) any acquisition by
Thermo Electron, (ii) any acquisition by any employee benefit plan (or related
trust) sponsored or maintained by Thermo Electron or any corporation controlled
by Thermo Electron, or (iii) any acquisition by any corporation pursuant to a
transaction which complies with clauses (i) and (ii) of subsection (c) of this
definition; or

        (b) such time as the Continuing Directors (as defined below) do not
constitute a majority of the Board of Directors of Thermo Electron (the "Thermo
Board") (or, if applicable, the Board of Directors of a successor corporation to
Thermo Electron), where the term "Continuing Director" means at any date a
member of the Thermo Board (i) who was a member of the Thermo Board as of July
1, 1999 or (ii) who was nominated or elected subsequent to such date by at least
a majority of the directors who were Continuing Directors at the time of such
nomination or election or whose election to the Thermo Board was recommended or
endorsed by at least a majority of the directors who were Continuing Directors
at the time of such nomination or election; provided, however, that there shall
be excluded from this clause (ii) any individual whose initial assumption of
office occurred as a result of an actual or threatened election contest with
respect to the election or removal of directors or other actual or threatened
solicitation of proxies or consents, by or on behalf of a person other than the
Thermo Board; or

        (c) the consummation of a merger, consolidation, reorganization,
recapitalization or statutory share exchange involving Thermo Electron or a sale
or other disposition of all or substantially all of the assets of Thermo
Electron in one or a series of transactions (a "Business Combination"), unless,
immediately following such Business Combination, each of the following two
conditions is satisfied: (i) all or substantially all of the individuals and
entities who were the beneficial owners of the Outstanding TMO Common Stock and
Outstanding TMO Voting Securities immediately prior to such Business Combination
beneficially own, directly or indirectly, more than 60% of the then-outstanding
shares of common stock and the combined voting power of the then-outstanding
securities entitled to vote generally in the election of directors,
respectively, of the resulting or acquiring corporation in such Business
Combination (which shall include, without limitation, a corporation which as a
result of such transaction owns Thermo Electron or substantially all of Thermo
Electron's assets either directly or through one or more subsidiaries) (such
resulting or acquiring corporation is referred to herein as the "Acquiring
Corporation") in substantially the same proportions as their ownership,
immediately prior to such Business Combination, of the Outstanding TMO Common
Stock and Outstanding TMO Voting Securities, respectively; and (ii) no Person
(excluding the Acquiring Corporation or any employee benefit plan (or related
trust) maintained or sponsored by Thermo Electron or by the Acquiring
Corporation) beneficially owns, directly or indirectly, 40% or more of the then
outstanding shares of common stock of the Acquiring Corporation, or of the
combined voting power of the then-outstanding securities of such corporation
entitled to vote generally in the election of directors; or

        (d) approval by the stockholders of Thermo Electron of a complete
liquidation or dissolution of Thermo Electron.

Section 11. Amendment and Termination of the Plan. The Board of Directors of the
Company may amend or terminate the Plan at any time and from time to time,
provided, however, that no amendment adversely affecting credits already made to
any participant's deferred compensation account or stock unit account may be
made without the consent of that participant or, if that participant has died,
that participant's beneficiary. Upon termination of the Plan, the Company shall
be obligated to distribute to the participant either of the following as the
Board of Directors of the Company, in its sole discretion, may determine: (i)
the number of shares of the common stock of the Company which shall equal the
total number of units accumulated in the participant's stock unit account as of
the effective date of termination of the Plan or (ii) a sum in cash equal to the
balance credited to the participant's deferred compensation account as of the
effective date of termination of the Plan.