SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549
               ---------------------------------------------------

                         AMENDMENT NO. 1 ON FORM 10-K/A
                                  TO FORM 10-K

(mark one)


[X]  Annual Report  Pursuant to Section 13 or 15(d) of the  Securities  Exchange
     Act of 1934

[ ]  Transition  Report  Pursuant  to Section  13 or 15(d) of the  Securities
     Exchange Act of 1934

                         Commission file number 1-11827

                            TREX MEDICAL CORPORATION
            (Exact name of Registrant as specified in its character)

Delaware                                                    06-1439626
(State or other jurisdiction of                         (I.R.S. Employer
incorporation or organization)                         Identification No.)

37 Apple Ridge Road
Danbury, Connecticut                                              06810
(Address of principal executive offices)                       (zip code)

       Registrant's telephone number, including area code: (781) 622-1000

           Securities registered pursuant to Section 12(b) of the Act:

                                                      Name of each exchange
Title of each class                                   on which registered
-------------------                                   ---------------------
Common Stock, $.01 par value                           American Stock Exchange

           Securities registered pursuant to section 12(g) of the Act:
                                      None

Indicate by check mark whether the Registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months, and (2) has been subject to the filing requirements for
at least the past 90 days. X No _____.

Indicate by check mark if disclosure of delinquent  filers  pursuant to Item 405
of Regulation  S-K is not contained  herein,  and will not be contained,  to the
best  of  the  Registrant's   knowledge,  in  definitive  proxy  or  information
statements  incorporated  by  reference  into  Part III of this Form 10-K or any
amendment to this Form 10-K. [ ]

The  aggregate  market  value of the voting stock held by  nonaffiliates  of the
Registrant as of October 29, 1999, was approximately $20,006,000.

As of October 29, 1999, the  Registrant  had  32,003,242  shares of Common Stock
outstanding.
<PAGE>

                       DOCUMENTS INCORPORATED BY REFERENCE

Portions of the  Registrant's  Annual Report to Shareholders for the fiscal year
ended October 2, 1999, are incorporated by reference into Parts I and II.

Items 10, 11, 12 & 13 of Part III of the Registrant's Annual Report on Form 10-K
for the fiscal year ended  October 2, 1999 are hereby  amended  and  restated in
their entirety as follows:

                                    Part III

Item 10 - DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT

Directors

      Set forth below are the names of the directors,  their ages, their offices
in the  Corporation,  if any, their  principal  occupation or employment for the
past five years,  the length of their tenure as directors and the names of other
public companies in which such persons hold directorships.

-------------------------------------------------------------------------------
Elias P. Gyftopoulos

                    Dr. Gyftopoulos,  72, has been a director of the Corporation
                    since November 1995. Dr.  Gyftopoulos is Professor  Emeritus
                    of the Massachusetts  Institute of Technology,  where he was
                    the Ford Professor of Mechanical  Engineering and of Nuclear
                    Engineering  for more than 20 years until his  retirement in
                    1996.   Dr.   Gyftopoulos  is  also  a  director  of  Thermo
                    BioAnalysis  Corporation,  Thermo Cardiosystems Inc., Thermo
                    Electron,    ThermoLase    Corporation    and    ThermoRetec
                    Corporation.
-------------------------------------------------------------------------------
Hal Kirshner

                    Mr.  Kirshner,  58, has been a director  of the  Corporation
                    since  its  inception  in  October  1995.  He was the  chief
                    executive  officer and  president  of the  Corporation  from
                    October 1995 through  December  13, 1998.  Mr.  Kirshner was
                    also president of the LORAD division of the Corporation from
                    1991 until 1997.
-------------------------------------------------------------------------------
John T. Keiser

                    Mr. Keiser, 63, has been a director of the Corporation since
                    June  1997.  He  has  been  the  chief  operating   officer,
                    biomedical,  of Thermo Electron since September 1998 and was
                    a vice president  from April 1997 until his  promotion.  Mr.
                    Keiser has been the president and chief executive officer of
                    Thermedics  Inc.,  a  majority-owned  subsidiary  of  Thermo
                    Electron,  since March 1998 and December 1998, respectively,
                    and was a senior vice president of Thermedics Inc. from 1994
                    until  his  promotion  to  president.  He has also  been the
                    president  of  Thermo  Electron's  wholly  owned  biomedical
                    group, a manufacturer of medical  equipment and instruments,
                    since  1994.  Mr.  Keiser is a director  of Metrika  Systems
                    Corporation,  Thermedics  Inc.,  Thermedics  Detection Inc.,
                    Thermo Cardiosystems Inc.,  ThermoLase  Corporation,  Thermo
                    Sentron Inc. and ThermoTrex Corporation.
-------------------------------------------------------------------------------
James W. May Jr .

                    Dr. May,  56, has been a director of the  Corporation  since
                    February  1996. He has been  Professor of Surgery at Harvard
                    Medical  School  since  1994  and  was  Associate   Clinical
                    Professor  of Surgery for more than five years prior to that
                    time.  He has also  been  Director  of  Plastic  Surgery  at
                    Massachusetts General Hospital since 1982.
------------------------------------------------------------------------------
Hutham S. Olayan

                    Ms. Olayan, 46, has been a director of the Corporation since
                    February  1996. She has served since 1995 as president and a
                    director  of  Olayan  America  Corporation,  a member of the
                    Olayan  Group,  and as president and a director of Competrol
                    Real Estate  Limited,  another  member of the Olayan  Group,
                    until its merger into Olayan  America  Corporation  in 1997.
                    The  surviving  company is  engaged in private  investments,
                    including real estate, and advisory services.  Ms. Olayan is
                    also      a      director      of      Thermo      Electron.
-------------------------------------------------------------------------------
Firooz  Rufeh

                    Mr. Rufeh, 62, has been a director of the Corporation  since
                    its inception in October 1995. Mr. Rufeh presently serves as
                    a  consultant  to Thermo  Electron.  Mr. Rufeh served as the
                    chief executive  officer of ThermoTrex from 1988 to February
                    1996,  and as the  president  of  ThermoTrex  from  1988  to
                    February  1997. Mr. Rufeh also served as a vice president of
                    Thermo  Electron from 1986 until his  retirement in February
                    1997.
-------------------------------------------------------------------------------
 William  J. Webb

                    Mr. Webb, 57, has been president,  chief  executive  officer
                    and a director of the  Corporation  since January 1999. From
                    1997 until his appointment, Mr. Webb served as the executive
                    vice  president,   global  sales  and  service,   of  Picker
                    International   Inc.,   a   manufacturer   and  marketer  of
                    diagnostic  imaging  equipment.  He served as the  executive
                    vice president,  sales and service for Picker  International
                    Inc.          from         1990         until          1997.
-------------------------------------------------------------------------------
<PAGE>

Committees of the Board of Directors and Meetings

      The board of directors  has  established  an audit  committee  and a human
resources  committee,  each consisting solely of directors who are not employees
of the Corporation, of Thermo Electron or of any other companies affiliated with
Thermo Electron (also referred to as "outside  directors").  The present members
of the audit committee are Ms. Olayan (Chairman),  Dr. May and Dr.  Gyftopoulos.
The  audit  committee  reviews  the scope of the  audit  with the  Corporation's
independent  public accountants and meets with them for the purpose of reviewing
the results of the audit  subsequent to its  completion.  The present members of
the human resources  committee are Dr. Gyftopoulos  (Chairman),  Dr. May and Ms.
Olayan. The human resources  committee reviews the performance of senior members
of management, approves executive compensation and administers the Corporation's
stock option and other stock-based  compensation plans. The Corporation does not
have a nominating  committee of the board of  directors.  The board of directors
met seven times,  the audit  committee  met three times and the human  resources
committee met five times during fiscal 1999. Each director attended at least 75%
of all  meetings of the board of  directors  and  committees  on which he or she
served that were held during fiscal 1999.

Compensation of Directors

      Cash Compensation

      Outside directors receive an annual retainer of $2,000 and a fee of $1,000
per meeting for  attending  regular  meetings of the board of directors and $500
per meeting for  participating  in  meetings of the board of  directors  held by
means of  conference  telephone  and for  participating  in certain  meetings of
committees  of the  board  of  directors.  Payment  of  directors'  fees is made
quarterly.  Mr. Keiser and Mr. Webb are both employees of Thermo Electron or its
subsidiaries and do not receive any cash  compensation  from the Corporation for
their services as directors.  Mr. Kirshner, who is currently a consultant to the
Corporation, does not receive any cash compensation from the Corporation for his
services  as a  director  during  the  term  of his  consulting  agreement.  See
"Executive  Compensation - Severance  Agreements." Directors are also reimbursed
for out-of-pocket expenses incurred in attending such meetings.

      Deferred Compensation Plan

      Under the  Corporation's  deferred  compensation  plan for directors  (the
"Deferred  Compensation Plan"), a director has the right to defer receipt of his
or her cash fees until he or she ceases to serve as a director,  dies or retires
from his or her  principal  occupation.  In the event of a change of  control or
proposed change of control of the Corporation  that is not approved by the board
of directors,  deferred amounts become payable immediately. Any of the following
are deemed to be a change of control:  (i) the  acquisition by any person of 40%
or more of the outstanding common stock or voting securities of Thermo Electron;
(ii) the failure of the Thermo Electron board of directors to include a majority
of directors who are  "continuing  directors",  which term is defined to include
directors  who were  members of Thermo  Electron's  board on July 1, 1999 or who
subsequent to that date were nominated or elected by a majority of directors who
were  "continuing  directors" at the time of such nomination or election;  (iii)
the consummation of a merger, consolidation, reorganization, recapitalization or
statutory  share  exchange  involving  Thermo  Electron  or the  sale  or  other
disposition of all or substantially  all of the assets of Thermo Electron unless
immediately  after such  transaction  (a) all holders of Thermo  Electron common
stock immediately prior to such transaction own more than 60% of the outstanding
voting securities of the resulting or acquiring corporation in substantially the
same  proportions as their ownership  immediately  prior to such transaction and
(b) no person after the transaction  owns 40% or more of the outstanding  voting
securities  of the  resulting  or  acquiring  corporation;  or (iv)  approval by
stockholders  of a  complete  liquidation  or  dissolution  of Thermo  Electron.
Amounts deferred  pursuant to the Deferred  Compensation  Plan are valued at the
end of each quarter as units of the  Corporation's  Common Stock.  When payable,
amounts deferred may be disbursed  solely in shares of Common Stock  accumulated
under the Deferred  Compensation  Plan. A total of 25,000 shares of Common Stock
has been  reserved for  issuance  under the Deferred  Compensation  Plan.  As of
October 2, 1999,  deferred units equal to  approximately  5,980 shares of Common
Stock were accumulated under the Deferred Compensation Plan.
<PAGE>

      Directors Stock Option Plan

      The  Corporation's  directors  stock  option plan (the  "Directors  Plan")
provides  for the grant of stock  options to purchase  shares of Common Stock of
the  Corporation  to outside  directors  as  additional  compensation  for their
service  as  directors.   Under  the  Directors  Plan,   outside  directors  are
automatically granted options to purchase 1,000 shares of Common Stock annually.
The annual  grant is made at the close of  business  on the date of each  Annual
Meeting of the  Stockholders  of the  Corporation to each outside  director then
holding office. Options evidencing annual grants are immediately  exercisable at
any time from and after the grant date of the  option and prior to the  earliest
to occur of (i) the  expiration  of the option on the third  anniversary  of the
grant date;  (ii) two years after the director  ceases to serve as a director of
the  Corporation;  or  (iii)  the  date of  dissolution  or  liquidation  of the
Corporation.  Shares  acquired  upon  exercise  of the  options  are  subject to
repurchase by the  Corporation at the exercise price if the recipient  ceases to
serve as a director of the Corporation or another Thermo Electron  company prior
to the first anniversary of the grant date.

      The exercise  price for options  granted under the  Directors  Plan is the
average of the closing  prices of the Common  Stock as reported on the  American
Stock  Exchange  (or other  principal  market on which the Common  Stock is then
traded) for the five trading days  immediately  preceding and including the date
of grant,  or, if the  shares are not then  traded,  at the last price per share
paid by third parties in an arms-length  transaction  prior to the option grant.
As of October 2, 1999,  options to purchase  120,000  shares of Common Stock had
been  granted and were  outstanding  under the  Directors  Plan,  no options had
lapsed or been exercised,  and options to purchase 80,000 shares of Common Stock
were reserved and available for grant.

Stock Ownership Policies for Directors

      The human resources  committee of the board of directors (the "Committee")
has  established a stock holding policy for directors.  The stock holding policy
requires  each  director  to hold a minimum  of 1,000  shares  of Common  Stock.
Directors are requested to achieve this  ownership  within a three-year  period.
The chief  executive  officer of the  Corporation  is  required to comply with a
separate stock holding policy  established by the Committee,  which is described
below.

      In addition, the Committee has a policy requiring directors to hold shares
of Common Stock equal to one-half of their net option exercises over a period of
five years.  The net option  exercise is determined by calculating the number of
shares  acquired upon exercise of a stock option,  after deducting the number of
shares  that could  have been  traded to  exercise  the option and the number of
shares that could have been  surrendered to satisfy tax withholding  obligations
attributable  to the exercise of the option.  This policy is also  applicable to
executive officers and is described below.

Executive Officers

      Reference  is made to Item 1(e) of this Report for  information  regarding
the Executive Officers of the Registrant.

Item 11 - EXECUTIVE COMPENSATION

Summary Compensation Table

      The following table summarizes  compensation  during the last three fiscal
years for services to the Corporation in all capacities awarded to, earned by or
paid to the Corporation's  chief executive  officer,  its former chief executive
officer and its  executive  officers  whose total  annual  salary and bonus,  as
determined  in  accordance  with  the  rules  of  the  Securities  and  Exchange
Commission,  was greater than $100,000, and who were employed by the Corporation
as of the end of fiscal  1999.  The table also  includes  information  as to two
executives  who were not serving as  executive  officers as of the end of fiscal
1999. These officers are together referred to as the "named executive officers."
<PAGE>

      The  Corporation  is required to appoint  certain  executive  officers and
full-time employees of Thermo Electron as executive officers of the Corporation,
in accordance with the Thermo Electron Corporate  Charter.  The compensation for
these executive officers is determined and paid entirely by Thermo Electron. The
time and effort  devoted by these  individuals to the  Corporation's  affairs is
provided to the Corporation under the corporate  services  agreement between the
Corporation and Thermo Electron. See Item 13 - Certain Relationships and Related
Transactions.  Accordingly,  the  compensation  for  these  individuals  is  not
reported in the following table.
<TABLE>
<CAPTION>
<S>                       <C>              <C>          <C>              <C>             <C>                 <C>
                                   Summary Compensation Table
-------------------------------------------------------------------------------------------------------------------------
                         Annual Compensation                          Long Term Compensation
                         -------------------                          -----------------------
                                                                      Restricted      Securities
    Name and             Fiscal                                         Stock         Underlying            All Other
Principal Position        Year          Salary (1)     Bonus (2)      Awards (3)       Options           Compensation (5)
------------------       -----          ----------     --------       ----------     -----------         ----------------
William J. Webb (6)      1999           $173,077       150,000        $247,500 (TXM) 400,00(TXM)            $145,113 (7)
 President and                                                                        40,000(TMO)
 Chief Executive                                                                      70,000(TKN)
 Officer
--------------------------------------------------------------------------------------------------------------------------
Hal Kirshner (8)         1999           $ 68,365          N/A           --              -- --               $169,100
 Former President        1998           $218,750       $100,000         --             8,250 (TXM)            $5,625
 and Chief                                                                             7,600 (TMO)
 Executive Officer                                                                     2,000 (MKA)
                                                                                       2,000 (ONX)
                                                                                      20,000 (RGI)
                                                                                       2,000 (TDX)
                                                                                       1,000 (TISI)
                                                                                      30,000 (TLZ)
                                                                                       2,000 (TRIL)
                                                                                       1,500 (VIZ)
                                                                                       2,000 (TRCC)
                         1997           $197,500       $200,000         --               300 (TMO)            $5,344
--------------------------------------------------------------------------------------------------------------------------
John M. Brenna (10)      1999           $139,587          N/A           --              -- --                 $7,200
 Former Vice             1998           $134,875       $ 82,000                         -- --                 $1,654
 President,              1997           $128,750       $ 63,000                        30,000 (TXM)
 Marketing                                                                            10,000 (TMO)
---------------------------------------------------------------------------------------------------------------------------
Walter F. Schneider (11) 1999           $178,993       $200,000       $173,250 (TXM)  50,000 (TXM)
 Former Senior                                                                           100 (TMO)
 Vice President,
 Operations
---------------------------------------------------------------------------------------------------------------------------
Ira S. Miller (12)       1999           $100,384       $ 55,000         --           100,000 (TXM)            $131,952 (13)
 Senior Vice
 President, Sales &
 Marketing
---------------------------------------------------------------------------------------------------------------------------
Gerald R. Roda (14)      1999           $ 81,462       $ 30,000         --           100,000 (TXM)            $109,975 (15)
 Senior Vice
 President, Finance
---------------------------------------------------------------------------------------------------------------------------
</TABLE>

(1)   Annual compensation for executive officers is reviewed and determined on a
      calendar  year basis,  even though the  Corporation's  fiscal year ends in
      September.

(2)   The bonus  amount  represents  the bonus paid for  performance  during the
      calendar year in which the Corporation's fiscal year-end occurred.

(3)   In fiscal 1999, Mr. Webb and Mr.  Schneider were awarded 44,000 and 30,800
      shares, respectively,  of restricted stock of the Corporation with a value
      of $247,500 and $173,250,  respectively, on the grant date. The restricted
      stock  awards  vest  33%,  33% and 34% on June 18,  2000,  2001 and  2002,
      respectively.  Any dividends  paid on restricted  stock are entitled to be
      retained by the recipient without regard to vesting.  At the end of fiscal
      1999,  Mr.  Webb and Mr.  Schneider  held  44,000  and  30,800  shares  of
      restricted  stock,  respectively,  with an aggregate value of $167,750 and
      $117,425, respectively.
<PAGE>

(4)   Options  granted by the  Corporation are designated in the table as "TXM."
      In addition,  the named executive  officers have also been granted options
      to purchase the common stock of the following  Thermo  Electron  companies
      during  the last three  fiscal  years as part of Thermo  Electron's  stock
      option program:  Thermo Electron (designated in the table as TMO), Metrika
      Systems  Corporation  (designated in the table as MKA),  ONIX Systems Inc.
      (designated   in  the  table  as  ONX),  The  Randers  Killam  Group  Inc.
      (designated in the table as RGI), Thermedics Detection Inc. (designated in
      the table as TDX), Thermo  Information  Solutions Inc.  (designated in the
      table as TISI),  ThermoLase Corporation  (designated in the table as TLZ),
      Thermo Trilogy Corporation  (designated in the table as TRIL),  ThermoTrex
      Corporation  (designated in the table as TKN),  Thermo Vision  Corporation
      (designated  in the  table  as VIZ) and  Trex  Communications  Corporation
      (designated in the table as TRCC).

(5)   Represents the amount of matching  contributions  made by the individual's
      employer  on behalf of  executive  officers  participating  in the  Thermo
      Electron 401(k) plan, except where otherwise noted.

(6)   Mr.  Webb was  appointed  president  and chief  executive  officer  of the
      Corporation effective January 7, 1999. The salary reported for fiscal 1999
      represents  the amount paid for the fiscal year from the  commencement  of
      his employment through October 2, 1999.

(7)   Represents  $4,803  attributable to an interest-free  loan provided to Mr.
      Webb pursuant to the Corporation's Stock Holding Assistance Plan (see Item
      13 -  Certain  Relationships  and  Related  Transactions  - Stock  Holding
      Assistance  Plan),  the  reimbursement  by the  Corporation  of $80,310 in
      expenses  associated with Mr. Webb's  relocation to Danbury,  Connecticut,
      and an additional  $60,000  signing bonus paid by the  Corporation  to Mr.
      Webb.

(8)   Mr.  Kirshner  resigned as president  and chief  executive  officer of the
      Corporation  effective  December  13,  1998  and his  employment  with the
      Corporation  was terminated  effective  December 31, 1998. He continues to
      serve  as a  director  and  consultant  to the  Corporation.  See  Item 11
      Executive Compensation - Severance Agreement.

(9)   In addition to a $350 matching  contribution  referred to in footnote (5),
      this amount  includes  $168,750  paid by the  Corporation  for  consulting
      services  performed by Mr. Kirshner  pursuant to the terms of a consulting
      agreement  with  the  Corporation.  See Item 11 -  Executive  Compensation
      Severance Agreement.

(10)  Mr. Brenna resigned as a vice president of the Corporation effective as of
      June 18,  1999 and his  employment  with the  Corporation  was  terminated
      effective  October 1, 1999. The salary reported for fiscal 1999 represents
      the amount paid for the entire fiscal year.

(11)  Mr. Schneider was appointed senior vice president,  operations on March 5,
      1999 and  resigned  effective  October 15, 1999.  The salary  reported for
      fiscal 1999 represents the amount paid for the entire fiscal year.

(12)  Mr.  Miller  was  appointed  senior  vice  president,  sales  &  marketing
      effective  March 15, 1999. The salary  reported for fiscal 1999 represents
      the  amount  paid  for  the  fiscal  year  from  the  commencement  of his
      employment through October 2, 1999.

(13)  Represents  the  reimbursement  by the  Corporation of $51,952 in expenses
      associated with Mr. Miller's  relocation to Danbury,  Connecticut,  and an
      additional $80,000 signing bonus paid by the Corporation to Mr. Miller.

(14)  Mr. Roda was appointed senior vice president,  finance effective March 22,
      1999. The salary  reported for fiscal 1999  represents the amount paid for
      the fiscal year from the commencement of his employment through October 2,
      1999.

(15)  Represents  the  reimbursement  by the  Corporation of $64,975 in expenses
      associated  with Mr.  Roda's  relocation to Danbury,  Connecticut,  and an
      additional $45,000 signing bonus paid by the Corporation to Mr. Roda.

Stock Options Granted During Fiscal 1999

      The following table sets forth information concerning individual grants of
stock  options  made during  fiscal 1999 to the  Corporation's  named  executive
officers.  It has not been the  Corporation's  policy in the past to grant stock
appreciation rights, and no such rights were granted during fiscal 1999.



<PAGE>



<TABLE>
<CAPTION>
<S>                    <C>            <C>           <C>         <C>            <C>             <C>

                          Option Grants in Fiscal 1999
-------------------------------------------------------------------------------
                                                                           Potential Realizable
                                   Percent of                                Value at Assumed
             Number of Securities  Total Options                           Annual Rates of Stock
               Underlying Options  Granted to     Exercise                 Price Appreciation for
                  Granted and      Employees in   Price Per   Expiration       Option Term (2)
Name                Company (1)    Fiscal Year    Share          Date          5%        10%
----------          --------        ----------    ---------    --------     --------  ----------
William J. Webb    400,000 (TXM)     33.9%         $8.41        01/07/06    $1,369,480    $3,191,480
                    40,000 (TMO)      0.8% (3)    $17.09        01/21/06      $278,290      $648,544
                    70,000 (TKN)     17.7%         $8.55        01/07/06      $243,650      $567,805
-------------------------------------------------------------------------------
Hal Kirshner          -- --            --           --            --           --              --
-------------------------------------------------------------------------------
John M. Brenna        -- --            --           --            --           --              --
-------------------------------------------------------------------------------
Walter F. Schneider 50,000 (TXM)     4.2%          $7.71       03/05/06       $156,940      $365,730
                    10,000 (TXM)     0.8%         $17.40       10/28/08       $138,480      $372,087
                       100 (TMO)     0.002% (3)   $14.81       09/22/04           $410          $904
                     5,000 (TMO)     0.1% (3)     $18.08       09/24/09        $71,950      $193,314
-------------------------------------------------------------------------------
Ira S. Miller      100,000 (TXM)     8.5%          $6.55       03/15/06       $266,650      $621,410
-------------------------------------------------------------------------------
Gerald R. Roda     100,000 (TXM)     8.5%          $7.78       03/22/06       $316,720      $738,100
-------------------------------------------------------------------------------
</TABLE>

(1)   All  of the  options  granted  during  the  fiscal  year  are  immediately
      exercisable  as of the end of the fiscal  year.  In all cases,  the shares
      acquired upon  exercise are subject to repurchase by the granting  company
      at the exercise price if the optionee  ceases to be employed by, or ceases
      to serve as a  director  of,  such  company  or  another  Thermo  Electron
      company.  The granting  company may exercise its repurchase  rights within
      six months  after the  termination  of the  optionee's  employment  or the
      cessation  of  directorship,  as the case may be.  The  repurchase  rights
      generally lapse ratably over a one- to ten-year  period,  depending on the
      option  term,  which  may vary from five to  twelve  years,  provided  the
      optionee  continues  to be  employed  by or  serve  as a  director  of the
      granting company or another Thermo Electron company.  The granting company
      may permit the holder of options to  exercise  options  and to satisfy tax
      withholding  obligations by surrendering shares equal in fair market value
      to the exercise price or withholding  obligation.  Please see footnote (4)
      under Summary Compensation Table above for the company  abbreviations used
      in this table.

(2)   The amounts shown in this table represent hypothetical gains that could be
      achieved for the respective  options if exercised at the end of the option
      term.  These gains are based on assumed rates of stock  appreciation of 5%
      and 10%  compounded  annually  from the date the  respective  options were
      granted to their  expiration  date.  The gains shown are net of the option
      exercise price, but do not include  deductions for taxes or other expenses
      associated  with the  exercise.  Actual  gains,  if any,  on stock  option
      exercises will depend on the future performance of the common stock of the
      granting  company,  the  optionee's  continued  employment or service as a
      director  through the option  period and the date on which the options are
      exercised.

(3)   These options were granted  under stock option plans  maintained by Thermo
      Electron  companies  other  than the  Corporation  and,  accordingly,  are
      reported as a percentage of total  options  granted to employees of Thermo
      Electron and its subsidiaries.

<PAGE>

Stock Options Exercised During Fiscal 1999 and Fiscal Year-End Option Values

      The following  table reports  certain  information  regarding stock option
exercises  during fiscal 1999 and  outstanding  stock options held at the end of
fiscal 1999 by the Corporation's named executive officers. No stock appreciation
rights were exercised or were outstanding during fiscal 1999.

                   Aggregated Option Exercises In Fiscal 1999
                     And Fiscal 1999 Year-End Option Values
--------------------------------------------------------------------------------
<TABLE>
<CAPTION>
<S>                  <C>       <C>         <C>         <C>                      <C>
                                                                             Value of
                                                                           Unexercised
                                                   Number of               In-the-Money
                                                    Securities             Options at
                                                    Underlying              Fiscal at
                                                  Unexercised Options      Fiscal Year-
                              Shares             at Fiscal Year-End            End
                            Acquired on   Value    (Exercisable/           (Exercisable
Name               Company    Exercise  Realized  Unexercisable) (1)       Unexercisable)
----------         --------   --------  ---------   -------------            ------------
William J. Webb      TXM          --        --       400,000  /0                 $0/--
                     TMO          --        --        40,000  /0                 $0/--
                     TKN          --        --        70,000  /0                 $0/--
--------------------------------------------------------------------------------
Hal Kirshner          --          --        --         -- --                     -- --
--------------------------------------------------------------------------------
John M. Brenna       TXM          --        --        50,000  /0                 $0/--
                     TMO          --        --        10,000  /0                 $0/--
--------------------------------------------------------------------------------
Walter F.            TXM          --        --        90,000  /0                 $0/--
                     TMO          --        --         5,100  /0                 $0/--
--------------------------------------------------------------------------------
Ira S. Miller        TXM          --        --       100,000  /0                 $0/--
--------------------------------------------------------------------------------
Gerald R. Roda       TXM          --        --       100,000  /0                 $0/--
--------------------------------------------------------------------------------
</TABLE>

(1)   All of the options reported outstanding at the end of the fiscal year were
      immediately  exercisable  as of the end of the fiscal year.  In all cases,
      the shares acquired upon exercise of the options reported in the table are
      subject to repurchase by the granting company at the exercise price if the
      optionee  ceases to be employed  by, or ceases to serve as a director  of,
      such company or another Thermo Electron company.  The granting company may
      exercise its repurchase  rights within six months after the termination of
      the optionee's  employment or the cessation of  directorship,  as the case
      may be. The  repurchase  rights  generally  lapse  ratably over a four- to
      ten-year period, depending on the option term, which may vary from five to
      twelve years,  provided  that the optionee  continues to be employed by or
      serve as a director of the  granting  company or another  Thermo  Electron
      company.  The  granting  company may permit the holder of such  options to
      exercise   options  and  to  satisfy  tax   withholding   obligations   by
      surrendering  shares equal in fair market  value to the exercise  price or
      withholding obligation. Please see footnote (4) under Summary Compensation
      Table above for the company abbreviations used in this table.

Severance Agreement

      Mr. Hal Kirshner  resigned as president and chief executive officer of the
Corporation  effective  as of  December  13,  1998 and his  employment  with the
Corporation  was  terminated   effective  December  31,  1998  (the  "Employment
Termination Date"). In connection with his resignation,  the Corporation entered
into an agreement with Mr. Kirshner  providing that in addition to receiving his
regular  salary through the Employment  Termination  Date, Mr.  Kirshner will be
paid a bonus for the 1998  calendar  year in an amount  equal to  $100,000.  The
agreement  also  provides  for an ongoing  consulting  relationship  between Mr.
Kirshner  and the  Corporation  for the two year period from  January 1, 1999 to
December 31, 2000. For his consulting services,  Mr. Kirshner will be paid a fee
at a rate of $225,000 per year,  payable  monthly in arrears.  Mr. Kirshner will
continue to serve as a director of the Corporation.

Executive Employment Agreements

      Mr.  William  J.  Webb  joined  the  Corporation  as  president  and chief
executive  officer in January  1999. In connection  therewith,  the  Corporation
entered into an agreement with Mr. Webb providing for severance pay

<PAGE>

equal to one year  salary  and  bonus  (with a  minimum  payment  of  $450,000),
reimbursement of relocation expenses (including broker's fee and assistance with
down payment on a new  residence),  an interest free loan to purchase  shares of
the Common Stock of the Corporation in compliance with the  Corporation's  stock
holding  policy and stock  holding  assistance  plan (see  "Committee  Report on
Executive Compensation - Stock Ownership Policies"), and enhanced life insurance
coverage. In addition,  Mr. Webb is entitled to a minimum incentive compensation
award  of  $200,000  in each of  calendar  1999 and 2000  payable  quarterly  in
arrears.  Mr. Webb must be actively employed at the end of each calendar quarter
to receive such bonus payments.

      Mr. Ira S. Miller joined the Corporation as senior vice  president,  sales
and marketing in March 1999. In connection  therewith,  the Corporation  entered
into an agreement with Mr. Miller  providing for severance pay equal to one year
salary and bonus, reimbursement for country club membership and reimbursement of
relocation expenses. In addition,  Mr. Miller is entitled to a minimum incentive
compensation  award of $110,000 for a one year period  commencing  April 1, 1999
payable quarterly in arrears. Mr. Miller must be actively employed at the end of
each calendar quarter to receive such incentive compensation awards.

Executive Retention Agreements

      Thermo  Electron  has  entered  into  agreements  with  certain  executive
officers and key employees of Thermo Electron and its subsidiaries  that provide
severance  benefits if there is a change in control of Thermo Electron and their
employment is terminated by Thermo Electron "without cause" or by the individual
"for  good  reason",  as those  terms  are  defined  therein,  within  18 months
thereafter.  For purposes of these  agreements,  a change in control exists upon
(i) the acquisition by any person of 40% or more of the outstanding common stock
or voting securities of Thermo Electron; (ii) the failure of the Thermo Electron
board of  directors  to  include a majority  of  directors  who are  "continuing
directors",  which  term is defined to  include  directors  who were  members of
Thermo  Electron's  board on the date of the agreement or who  subsequent to the
date of the agreement  were  nominated or elected by a majority of directors who
were  "continuing  directors" at the time of such nomination or election;  (iii)
the consummation of a merger, consolidation, reorganization, recapitalization or
statutory  share  exchange  involving  Thermo  Electron  or the  sale  or  other
disposition of all or substantially  all of the assets of Thermo Electron unless
immediately  after such  transaction  (a) all holders of Thermo  Electron common
stock immediately prior to such transaction own more than 60% of the outstanding
voting securities of the resulting or acquiring corporation in substantially the
same  proportions as their ownership  immediately  prior to such transaction and
(b) no person after the transaction  owns 40% or more of the outstanding  voting
securities  of the  resulting  or  acquiring  corporation;  or (iv)  approval by
stockholders of a complete liquidation or dissolution of Thermo Electron.

      In 1999, Thermo Electron  authorized an executive retention agreement with
Mr. Webb.  This  agreement  provides that in the event Mr. Webb's  employment is
terminated  under the  circumstances  described above, he would be entitled to a
lump sum  payment  equal to the sum of (a) one times  his  highest  annual  base
salary in any 12 month period during the prior  five-year  period,  plus (b) one
times his highest annual bonus in any 12 month period during the prior five-year
period.  In  addition,  Mr. Webb would be provided  benefits for a period of one
year after such termination  substantially equivalent to the benefits package he
would have been otherwise entitled to receive if he was not terminated. Further,
all repurchase  rights of Thermo  Electron and its  subsidiaries  shall lapse in
their entirety with respect to all options that he holds in Thermo  Electron and
its  subsidiaries,  including the  Corporation,  as of the date of the change in
control.  Finally, Mr. Webb would be entitled to a cash payment equal to $15,000
to be used toward outplacement services.

      Assuming  that the  severance  benefits  would  have  been  payable  as of
November 30, 1999, the lump sum salary and bonus payment under such agreement to
Mr.  Webb would have been  approximately  $450,000.  In the event that  payments
under this  agreement  are deemed to be so called  "excess  parachute  payments"
under the applicable provisions of the Internal Revenue Code of 1986, as amended
(the "Internal Revenue Code"),  Mr. Webb would be entitled to receive a gross-up
payment  equal to the amount of any excise  tax  payable by him with  respect to
such  payment,  plus the amount of all other  additional  taxes  imposed on him,
attributable to the receipt of such gross-up payment.


<PAGE>


Stock Ownership Policies

      The  Corporation's  compensation  program is also  designed  to  encourage
executives  to own  shares of the  Corporation's  Common  Stock.  The  Committee
believes that  encouraging  executives to own and retain stock acquired  through
its stock-based  compensation program or otherwise provides additional incentive
for executive officers to follow strategies designed to maximize long-term value
to Stockholders.

      The Committee established a stock holding policy for executive officers of
the  Corporation  that  required  executive  officers to own a multiple of their
compensation  in shares of Common Stock.  For the chief executive  officer,  the
multiple is one times his base salary and  reference  bonus for the fiscal year.
For all other  officers,  the multiple was one times the officer's  base salary.
The  Committee  deemed  it  appropriate  to permit  officers  to  achieve  these
ownership levels over a three-year  period. The policy has been amended to apply
only to the chief executive officer.

      In order to assist executive  officers in complying with this policy,  the
Committee  also  adopted  a  stock  holding  assistance  plan  under  which  the
Corporation was authorized to make interest-free  loans to executive officers to
enable them to purchase shares of Common Stock in the open market. This plan was
also  amended  to apply  only to the  chief  executive  officer.  The  loans are
required to be repaid upon the earlier of demand or the tenth anniversary of the
date of the loan,  unless  otherwise  determined by the Committee.  In 1999, Mr.
Webb  received a loan in the  principal  amount of $250,000  under this plan, of
which the entire  amount  was  outstanding  as of  October 2, 1999.  See Item 13
Certain Relationships and Related Transactions - Stock Holding Assistance Plan.

      The  Committee  also has  established  a policy  requiring  its  executive
officers  to hold  shares of Common  Stock equal to one-half of their net option
exercises over a period of five years.  The net option exercise is determined by
calculating the number of shares acquired upon exercise of a stock option, after
deducting  the  number of shares  that could have been  traded to  exercise  the
option and the number of shares that could have been  surrendered to satisfy tax
withholding obligations attributable to the exercise of the option.

Item 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

      The following  table sets forth the beneficial  ownership of Common Stock,
as well as the common stock of ThermoTrex, the Corporation's parent company, and
of Thermo Electron,  ThermoTrex's  parent company, as of November 30, 1999, with
respect to (i) each director,  (ii) each person who was known by the Corporation
to own  beneficially  more than 5% of the  outstanding  shares of Common  Stock,
(iii) each executive officer named in the summary  compensation  table set forth
below  under  the  heading   "Executive   Compensation"  (the  "named  executive
officers") and (iv) all directors and current executive  officers as a group. In
addition,  the  following  table sets forth the  beneficial  ownership of Common
Stock, as of November 30, 1999, with respect to each person who was known by the
Corporation to own beneficially more than 5% of the outstanding shares of Common
Stock.

      While certain directors and executive officers of the Corporation are also
directors and executive  officers of Thermo Electron or its  subsidiaries  other
than the  Corporation,  all such persons  disclaim  beneficial  ownership of the
shares of Common Stock beneficially owned by Thermo Electron.



<PAGE>


<TABLE>
<CAPTION>
<S>                                     <C>               <C>                  <C>
                                   Trex Medical        ThermoTrex        Thermo Electron
          Name (1)                 Corporation (2)    Corporation (3)     Corporation (4)
         -----------               ------------        ---------           -----------
Thermo Electron Corporation (5)..... 25,800,230             N/A                  N/A
John M. Brenna......................     51,500              0                  10,000
Elias P. Gyftopoulos................     41,550              0                  76,041
John T. Keiser......................     20,000         92,823                 314,601
Hal Kirshner........................    276,750         33,344                  42,596
James W. May Jr.....................     42,676              0                       0
Ira S. Miller.......................    100,000              0                       0
Hutham S. Olayan....................     47,783              0                  33,988
Gerald R. Roda......................    100,000              0                       0
Firooz Rufeh........................     40,000         31,000                  74,703
Walter F. Schneider.................     11,000              0                   1,600
William J. Webb.....................    485,200         70,000                  40,000
All directors and current executive
  officers as a group (13 persons)..  1,279,459        238,642               1,237,774
</TABLE>


(1)   Except as reflected in the  footnotes to this table,  shares  beneficially
      owned  consist of shares owned by the  indicated  person or by that person
      for the benefit of minor children,  and all share ownership  includes sole
      voting and investment power.

(2)   Shares of Common Stock beneficially owned by Mr. Brenna, Dr.  Gyftopoulos,
      Mr. Keiser,  Mr. Kirshner,  Dr. May, Mr. Miller, Ms. Olayan, Mr. Roda, Mr.
      Rufeh, Mr.  Schneider,  Mr. Webb, and all directors and current  executive
      officers as a group  include  50,000,  40,000,  20,000,  158,250,  40,000,
      100,000,  40,000, 100,000,  40,000, 11,000, 400,000, and 1,059,250 shares,
      respectively, that such person or group has the right to acquire within 60
      days of November 30, 1999,  through the exercise of stock options.  Shares
      beneficially  owned  by Dr.  Gyftopoulos,  Dr.  May,  Ms.  Olayan  and all
      directors and current  executive  officers as a group include 550,  2,646,
      2,783, and 5,979 shares,  respectively,  allocated through October 2, 1999
      to their  respective  accounts  maintained  pursuant to the  Corporation's
      Deferred Compensation Plan for Directors. Shares beneficially owned by Ms.
      Olayan do not  include  350,000  shares  owned by  Crescent  International
      Holdings Ltd., a member of the Olayan Group which is indirectly controlled
      by Suliman S. Olayan, Ms. Olayan's father. Ms. Olayan disclaims beneficial
      ownership  of the shares  owned by Crescent  International  Holdings  Ltd.
      Except for Mr.  Webb,  who  beneficially  owned  1.5% of the Common  Stock
      outstanding  as of November  30,  1999,  no  director  or named  executive
      officer beneficially owned more than 1% of the Common Stock as of November
      30,  1999;  all  directors  and  current  executive  officers  as a  group
      beneficially owned 3.67% of the Common Stock outstanding as of such date.

(3)   Shares of ThermoTrex common stock  beneficially  owned by Mr. Keiser,  Mr.
      Kirshner,  Mr. Rufeh,  Mr. Webb,  and all directors and current  executive
      officers as a group include 91,023,  23,023,  31,000,  70,000, and 222,605
      shares,  respectively,  that such person or group has the right to acquire
      within  60 days of  November  30,  1999,  through  the  exercise  of stock
      options.  No director or named executive officer  beneficially  owned more
      than 1% of the common stock of  ThermoTrex  as of November  30, 1999;  all
      directors and current  executive  officers as a group  beneficially  owned
      1.06% of the common stock of ThermoTrex outstanding as of such date.

(4)   Shares of Thermo Electron common stock  beneficially  owned by Mr. Brenna,
      Dr.  Gyftopoulos,  Mr. Keiser,  Mr. Kirshner,  Ms. Olayan,  Mr. Rufeh, Mr.
      Schneider,  Mr. Webb and all directors and current executive officers as a
      group include 10,000,  12,442,  267,448,  40,098,  12,442,  74,703, 1,000,
      40,000 and 1,030,289 shares,  respectively,  that such person or group has
      the right to acquire  within 60 days of  November  30,  1999,  through the
      exercise of stock options.  Shares  beneficially owned by Dr. Gyftopoulos,
      Ms. Olayan,  and all directors and current  executive  officers as a group
      include 1,020, 19,296, and 20,316 shares, respectively,  allocated through
      October 2, 1999,  to their  respective  accounts
<PAGE>

maintained  pursuant  to  Thermo  Electron's  Deferred   Compensation  Plan  for
Directors.  Shares  beneficially  owned by Ms.  Olayan do not include  6,150,000
shares  owned by Crescent  Holding  GmbH,  a member of the Olayan Group which is
indirectly  controlled  by Suliman S. Olayan,  Ms.  Olayan's  father.  Ms Olayan
disclaims  beneficial ownership of the shares owned by Crescent Holding GmbH. No
director or named executive  officer  beneficially  owned more than 1% of Thermo
Electron's  common stock  outstanding as of such date; all directors and current
executive  officers  as a group  beneficially  owned  less than 1% of the common
stock of Thermo Electron outstanding as of such date.

(5)   Thermo Electron  beneficially owned 79.16% of the Common Stock outstanding
      as of November 30, 1999,  of which 72.15% is owned through  ThermoTrex,  a
      majority-owned subsidiary of Thermo Electron. Shares beneficially owned by
      Thermo  Electron  include  678,541  shares  issuable  upon  conversion  of
      $8,000,000 in principal amount of a 4.2%  convertible  debenture issued by
      the Corporation  and due in 2000.  Thermo  Electron's  address is 81 Wyman
      Street, Waltham, Massachusetts 02454-9046. As of November 30, 1999, Thermo
      Electron, through ThermoTrex, had the power to elect all of the members of
      the Corporation's board of directors.

Section 16(a) Beneficial Ownership Reporting Compliance

      Section  16(a) of the  Securities  Exchange  Act of 1934,  as amended (the
"Exchange Act"),  requires the Corporation's  directors and executive  officers,
and  beneficial  owners of more  than 10% of the  Common  Stock,  such as Thermo
Electron, to file with the Securities and Exchange Commission initial reports of
ownership  and periodic  reports of changes in  ownership  of the  Corporation's
securities.  Based  upon a review of such  filings,  all  Section  16(a)  filing
requirements  applicable to such persons were complied with during 1999,  except
in the following  instances:  Mr. Ira S. Miller,  an officer of the Corporation,
filed his Form 3 late.  Thermo  Electron filed a total of six late  transactions
associated with the  cancellation  and grant of options to purchase Common Stock
granted to employees under its stock option program.

 Item 13 -  CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

      Thermo  Electron has, from time to time,  caused certain  subsidiaries  to
sell  minority  interests to  investors,  resulting  in several  majority-owned,
private and publicly-held  subsidiaries.  ThermoTrex has created the Corporation
as a majority-owned,  publicly-held  subsidiary.  The Corporation and such other
majority-owned  Thermo Electron  subsidiaries are hereinafter referred to as the
"Thermo Subsidiaries."

      Thermo  Electron and each of the Thermo  Subsidiaries  recognize  that the
benefits and support that derive from their  affiliation are essential  elements
of their individual  performance.  Accordingly,  Thermo Electron and each of the
Thermo Subsidiaries, including the Corporation, have adopted the Thermo Electron
Corporate  Charter (the "Charter") to define the relationships and delineate the
nature of such cooperation  among  themselves.  The purpose of the Charter is to
ensure  that  (1)  all of the  companies  and  their  stockholders  are  treated
consistently and fairly,  (2) the scope and nature of the cooperation  among the
companies, and each company's responsibilities, are adequately defined, (3) each
company has access to the  combined  resources  and  financial,  managerial  and
technological  strengths of the others,  and (4) Thermo  Electron and the Thermo
Subsidiaries, in the aggregate, are able to obtain the most favorable terms from
outside parties.

      To achieve these ends, the Charter identifies the general principles to be
followed  by the  companies,  addresses  the  role and  responsibilities  of the
management of each company,  provides for the sharing of group  resources by the
companies  and  provides  for  centralized  administrative,  banking  and credit
services to be performed  by Thermo  Electron.  The services  provided by Thermo
Electron include collecting and managing cash generated by members, coordinating
the access of Thermo Electron and the Thermo  Subsidiaries  (the "Thermo Group")
to external  financing  sources,  ensuring  compliance  with external  financial
covenants  and internal  financial  policies,  assisting in the  formulation  of
long-range planning and providing other banking and credit services. Pursuant to
the  Charter,  Thermo  Electron  may also  provide  guarantees  of debt or other
obligations of the Thermo  Subsidiaries or may obtain external  financing at the
parent level for the benefit of the Thermo  Subsidiaries.  In certain instances,
the Thermo  Subsidiaries  may  provide  credit  support to, or on behalf of, the
consolidated  entity or may obtain  financing  directly from external  financing
sources. Under the Charter,  Thermo Electron is responsible for determining that
the Thermo Group  remains in compliance  with all covenants

<PAGE>

imposed by external financing sources, including covenants related to borrowings
of Thermo  Electron or other members of the Thermo Group,  and for  apportioning
such  constraints  within  the  Thermo  Group.  In  addition,   Thermo  Electron
establishes  certain internal  policies and procedures  applicable to members of
the Thermo Group.  The cost of the services  provided by Thermo  Electron to the
Thermo  Subsidiaries  is covered under existing  corporate  services  agreements
between Thermo Electron and the Thermo Subsidiaries.

      The Charter currently provides that it shall continue in effect so long as
Thermo Electron and at least one Thermo Subsidiary participate.  The Charter may
be amended at any time by agreement of the participants.  Any Thermo Subsidiary,
including the Corporation,  can withdraw from  participation in the Charter upon
30 days' prior notice. In addition, Thermo Electron may terminate a subsidiary's
participation in the Charter in the event the subsidiary ceases to be controlled
by Thermo  Electron  or ceases to comply with the  Charter or the  policies  and
procedures  applicable  to the  Thermo  Group.  A  withdrawal  from the  Charter
automatically  terminates  the corporate  services  agreement and tax allocation
agreement  (if  any) in  effect  between  the  withdrawing  company  and  Thermo
Electron.  The  withdrawal  from  participation  does not terminate  outstanding
commitments  to third  parties  made by the  withdrawing  company,  or by Thermo
Electron  or other  members of the Thermo  Group,  prior to the  withdrawal.  In
addition,  a  withdrawing  company is  required  to  continue to comply with all
policies and  procedures  applicable to the Thermo Group and to provide  certain
administrative  functions mandated by Thermo Electron so long as the withdrawing
company is controlled by or affiliated with Thermo Electron.

      As provided in the  Charter,  the  Corporation  and Thermo  Electron  have
entered into a Corporate  Services  Agreement (the "Services  Agreement")  under
which  Thermo  Electron's   corporate  staff  provides  certain   administrative
services, including general legal advice and services, risk management, employee
benefit administration,  tax advice and preparation of tax returns,  centralized
cash management and certain financial and other services to the Corporation. The
Corporation  was  assessed  an  annual  fee  equal to 0.8% of the  Corporation's
revenues for these  services in fiscal 1999.  The annual fee will remain at 0.8%
of the  Corporation's  total  revenues  for  fiscal  2000.  The fee is  reviewed
annually and may be changed by mutual  agreement of the  Corporation  and Thermo
Electron.   During  fiscal  1999,   Thermo  Electron  assessed  the  Corporation
$1,948,000 in fees under the Services  Agreement.  Management  believes that the
charges under the Services  Agreement are  reasonable  and that the terms of the
Services  Agreement are fair to the  Corporation.  In 1999, the Corporation paid
Thermo  Electron  an  additional  $85,000 for  certain  administrative  services
required by the Corporation that were not covered by the Services Agreement. The
Services Agreement  automatically  renews for successive  one-year terms, unless
canceled  by the  Corporation  upon 30 days'  prior  notice.  In  addition,  the
Services Agreement terminates  automatically in the event the Corporation ceases
to be a member of the Thermo Group or ceases to be a participant in the Charter.
In the event of a termination of the Services Agreement, the Corporation will be
required  to pay a  termination  fee  equal  to the  fee  that  was  paid by the
Corporation for services under the Services  Agreement for the nine-month period
prior to termination. Following termination, Thermo Electron may provide certain
administrative  services  on an  as-requested  basis  by the  Corporation  or as
required in order to meet the Corporation's  obligations under Thermo Electron's
policies and procedures. Thermo Electron will charge the Corporation a fee equal
to the market rate for comparable  services if such services are provided to the
Corporation following termination.

      From time to time,  the  Corporation  may  transact  business  with  other
companies in the Thermo Group.

      The  Corporation  has an arrangement  with the Tecomet  division of Thermo
Electron for the manufacture of the  Corporation's  proprietary HTC grid.  Under
this arrangement, Tecomet manufacturers the grid for the Corporation pursuant to
written purchase orders.  The Corporation owns the intellectual  property rights
to the  grid.  During  fiscal  1999,  the  Corporation  purchased  grids  for an
aggregate purchase price of $1,352,000 under this arrangement.

      ThermoLase Corporation, a majority-owned subsidiary of ThermoTrex, engaged
the  Corporation  to  design  and  manufacture  the laser  used in  ThermoLase's
laser-based  hair-removal  system.  During fiscal 1999 the Corporation  recorded
$3,414,000 of revenue under this arrangement.  As a result of ThermoLase exiting
the  hair-removal  business,  the  Corporation  does not expect  future sales to
ThermoLase.

<PAGE>


      In October 1995, the  Corporation  and  ThermoTrex  entered into a license
agreement  under which the  Corporation  undertook  to fund  approximately  $6.0
million  of   ThermoTrex's   research  and   development   efforts   related  to
direct-detection  digital imaging  technology in certain medical imaging fields.
In fiscal 1998 and 1997, the  Corporation  recorded  $2,200,000 and  $2,000,000,
respectively,  of expense under this agreement,  which concluded in fiscal 1998.
In fiscal 1999, the Corporation paid $500,000 to ThermoTrex for certain research
and development efforts related to digital mammography technology.

      As  of  October  2,  1999,  the  Corporation  owed  ThermoTrex  $8,000,000
principal amount pursuant to a 4.2% subordinated convertible note, due September
2000,  convertible into shares of the  Corporation's  common stock at $11.79 per
share.

      As of October 3, 1998,  $34,054,000 of the corporation's  cash equivalents
were  invested  in a  repurchase  agreement  with  Thermo  Electron.  Under this
agreement,  the company in effect lent  excess  cash to Thermo  Electron,  which
Thermo  Electron  collateralized  with  investments  principally  consisting  of
corporate notes, U.S.  government  agency  securities,  commercial paper,  money
market funds, and other marketable securities, in the amount of at least 103% of
such  obligation.  The company's funds subject to the repurchase  agreement were
readily convertible into cash by the company.  The repurchase agreement earned a
rate based on the 90-day  Commercial  Paper Composite Rate plus 25 basis points,
set at the beginning of each quarter. Effective June 1999, the company adopted a
new cash management  arrangement  with Thermo Electron,  described  below,  that
replaces the repurchase agreement.

      As of October 2, 1999,  $8,801,000 of the  corporation's  cash equivalents
were invested in a cash management  arrangement with Thermo Electron,  which was
effective June 1999.  Under the cash  management  arrangement,  the  corporation
lends  its  excess  cash to Thermo  Electron  and has the  contractual  right to
withdraw  its  invested  funds upon 30 days' prior  notice.  Thermo  Electron is
contractually  required to maintain cash, cash equivalents,  and/or  immediately
available  bank lines of credit equal to at least 50% of all the funds  invested
under  the   arrangement  by  all  Thermo  Electron   subsidiaries   other  than
wholly-owned  subsidiaries.   The  corporation's  funds  invested  in  the  cash
management  arrangement earn a rate equal to the 30-day Dealer  Commercial Paper
Rate as reported in The Wall Street  Journal  plus 50 basis  points,  set at the
beginning of each month.

 Stock Holding Assistance Plan

      The human resources committee of the Corporation's board of directors (the
"Committee") established a stock holding policy that required executive officers
of the  Corporation  to  acquire  and hold a minimum  number of shares of Common
Stock. In order to assist the executive  officers in complying with this policy,
the  Committee  also  adopted a stock  holding  assistance  plan under which the
Corporation  may make  interest-free  loans to the executive  officers to enable
them to purchase  Common Stock in the open market.  The stock holding policy and
the stock holding  assistance plan were both subsequently  amended to apply only
to the  chief  executive  officer.  In 1999,  Mr.  Webb  received  a loan in the
principal amount of $250,000 under the stock holding assistance plan to purchase
41,200 shares of Common Stock,  of which the entire amount was outstanding as of
October 2, 1999. The loan to Mr. Webb is repayable upon the earlier of demand or
the tenth  anniversary of the date of the loan,  unless otherwise  determined by
the Committee.

                                   SIGNATURES

Pursuant to the  requirements of Section 13 or 15(d) of the Securities  Exchange
Act of 1934,  the Registrant has duly caused this Amendment No. 1 on Form 10-K/A
to be signed by the undersigned, duly authorized.

                                             TREX MEDICAL CORPORATION


                                             By:  / s /  Sandra L. Lambert
                                                 --------------------------
                                                 Sandra L. Lambert
                                                      Secretary