SECURITIES AND EXCHANGE COMMISSION

                              Washington, DC 20549

                     ---------------------------------------

                                    FORM 10-Q

    (mark one)

    [ X ] Quarterly Report Pursuant to Section 13 or 15(d) of the Securities
          Exchange Act of 1934 for the Quarter Ended April 4, 1998.

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

                         Commission File Number 1-12745

                            THERMEDICS DETECTION INC.
             (Exact name of Registrant as specified in its charter)

    Massachusetts                                                  04-3106698
    (State or other jurisdiction of                          (I.R.S. Employer
    incorporation or organization)                        Identification No.)

    220 Mill Road
    Chelmsford, Massachusetts                                      01824-4178
    (Address of principal executive offices)                       (Zip Code)

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

         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
         (or for such shorter period that the Registrant was required to
         file such reports), and (2) has been subject to such filing
         requirements for the past 90 days. Yes [ X ] No [  ]

         Indicate the number of shares outstanding of each of the
         issuer's classes of Common Stock, as of the latest practicable
         date.

                    Class                    Outstanding at May 1, 1998
         ----------------------------        --------------------------
         Common Stock, $.10 par value           13,355,459 Actual
                                                19,316,684 Pro Forma
PAGE
<PAGE>
    PART I - FINANCIAL INFORMATION

    Item 1 - Financial Statements
    -----------------------------

                            THERMEDICS DETECTION INC.

                           Consolidated Balance Sheet
                                   (Unaudited)

                                     Assets


                                                      April 4,    January 3,
    (In thousands)                                        1998          1998
    ------------------------------------------------------------------------
    Current Assets:
      Cash and cash equivalents                       $ 28,065      $ 46,352
      Accounts receivable, less allowances of $1,128
        and $1,127                                      15,788        18,223
      Inventories:
        Raw materials                                    9,783         9,698
        Work in process and finished goods               8,844         7,957
      Prepaid and refundable income taxes                3,631         3,595
      Prepaid expenses                                   1,160         1,439
                                                      --------      --------
                                                        67,271        87,264
                                                      --------      --------

    Property, Plant, and Equipment, at Cost              9,474        10,697
      Less: Accumulated depreciation and amortization    5,375         6,686
                                                      --------      --------
                                                         4,099         4,011
                                                      --------      --------
    Other Assets                                         1,193         1,198
                                                      --------      --------
    Cost in Excess of Net Assets of Acquired
      Companies                                         55,306        55,792
                                                      --------      --------
                                                      $127,869      $148,265
                                                      ========      ======== 



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<PAGE>
                            THERMEDICS DETECTION INC.

                     Consolidated Balance Sheet (continued)
                                   (Unaudited)

                    Liabilities and Shareholders' Investment


                                                      April 4,  January 3,
    (In thousands except share amounts)                   1998        1998
    -----------------------------------------------------------------------
    Current Liabilities:
      Promissory note to parent company               $      -    $ 21,200
      Accounts payable                                   4,531       3,868
      Accrued payroll and employee benefits              2,140       3,852
      Accrued income taxes                               1,878       2,331
      Accrued installation and warranty expenses         1,148       1,154
      Deferred revenue                                   1,820       1,689
      Other accrued expenses                             4,322       5,410
      Due to Thermo Electron Corporation and
        affiliated companies                             1,777       1,415
                                                      --------    --------
                                                        17,616      40,919
                                                      --------    --------

    Shareholders' Investment:
      Common stock, $.10 par value, 50,000,000
        shares authorized; 19,316,684 shares issued
        and outstanding                                  1,932       1,932
      Capital in excess of par value                    94,781      93,755
      Retained earnings                                 15,256      13,206
      Accumulated other comprehensive items (Note 3)    (1,716)     (1,547)
                                                      --------    --------
                                                       110,253     107,346
                                                      --------    --------
                                                      $127,869    $148,265
                                                      ========    ========


    The accompanying notes are an integral part of these consolidated
    financial statements.





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                            THERMEDICS DETECTION INC.

                        Consolidated Statement of Income
                                   (Unaudited)


                                                       Three Months Ended
                                                     ----------------------

                                                     April 4,     March 29,
    (In thousands except per share amounts)              1998          1997
    -----------------------------------------------------------------------
    Revenues:
      Product revenues                                $19,451       $21,794
      Service revenues                                  4,256         3,738
                                                      -------       -------
                                                       23,707        25,532
                                                      -------       -------

    Costs and Operating Expenses:
      Cost of product revenues                          9,010         9,926
      Cost of service revenues                          1,989         1,579
      Selling, general, and administrative expenses     6,952         8,061
      Research and development expenses                 2,687         2,123
                                                      -------       -------
                                                       20,638        21,689
                                                      -------       -------

    Operating Income                                    3,069         3,843

    Interest Income                                       591           203
    Interest Expense, Related Party                      (303)         (306)
    Other Income (Expense), Net                             4            (4)
                                                      -------       -------
    Income Before Provision for Income Taxes            3,361         3,736
    Provision for Income Taxes                          1,311         1,494
                                                      -------       -------
    Net Income                                        $ 2,050       $ 2,242
                                                      =======       =======
    Basic and Diluted Earnings per Share (Note 2)     $   .11       $   .13
                                                      =======       =======
    Weighted Average Shares (Note 2):
      Basic                                            19,317        16,937
                                                      =======       =======
      Diluted                                          19,326        16,952
                                                      =======       =======


    The accompanying notes are an integral part of these consolidated
    financial statements.


                                        4PAGE
<PAGE>
                            THERMEDICS DETECTION INC.

                      Consolidated Statement of Cash Flows
                                   (Unaudited)


                                                       Three Months Ended
                                                     ----------------------
                                                     April 4,    March 29,
    (In thousands)                                       1998         1997
    -----------------------------------------------------------------------
    Operating Activities:
      Net income                                     $  2,050     $  2,242
      Adjustments to reconcile net income to net
        cash provided by operating activities:
          Depreciation and amortization                   813          776
          Provision for losses on accounts
            receivable                                     49           33
          Other noncash expenses                          339          318
          Changes in current accounts:
            Accounts receivable                         2,347        1,873
            Inventories                                (1,342)      (1,110)
            Other current assets                          230          160
            Accounts payable                              667          688
            Other current liabilities                  (2,835)       2,368
                                                     --------     --------
    Net cash provided by operating activities           2,318        7,348
                                                     --------     --------

    Investing Activities:
      Purchases of property, plant, and equipment        (578)        (693)
      Proceeds from sale of property, plant, and
        equipment                                         122            -
      Other                                                (3)          82
                                                     --------     --------
    Net cash used in investing activities                (459)        (611)
                                                     --------     --------

    Financing Activities:
      Net proceeds from issuance of Company
        common stock                                        -       28,121
      Orion Research net transfers (to) from parent 
        company                                         1,026         (825)
      Repayment of promissory note to parent 
        company                                       (21,200)           -
      Other                                                 -          (18)
                                                     --------     --------
    Net cash provided by (used in) financing 
      activities                                      (20,174)      27,278
                                                     --------     --------
    Exchange Rate Effect on Cash                           28         (264)
                                                     --------     --------
    Increase (Decrease) in Cash and Cash Equivalents  (18,287)      33,751
    Cash and Cash Equivalents at Beginning of
      Period                                           46,352       14,264
                                                     --------     --------
    Cash and Cash Equivalents at End of Period       $ 28,065     $ 48,015
                                                     ========     ========


    The accompanying notes are an integral part of these consolidated
    financial statements.
                                        5PAGE
<PAGE>
                            THERMEDICS DETECTION INC.

                   Notes to Consolidated Financial Statements

    1.  General

        The interim consolidated financial statements presented have been
    prepared by Thermedics Detection Inc. (the Company) without audit and, in
    the opinion of management, reflect all adjustments of a normal recurring
    nature necessary for a fair statement of the financial position at April
    4, 1998, and the results of operations and cash flows for the three-month
    periods ended April 4, 1998, and March 29, 1997. Interim results are not
    necessarily indicative of results for a full year.

        Historical financial results have been restated to include Orion
    Research Inc., which was acquired in a transaction accounted for in a
    manner similar to a pooling of interests (Note 4). The consolidated
    financial statements and notes are presented as permitted by Form 10-Q
    and do not contain certain information included in the annual
    consolidated financial statements and notes of the Company. The
    consolidated financial statements and notes included herein should be
    read in conjunction with the consolidated financial statements and notes
    included in the Company's Annual Report on Form 10-K for the fiscal year
    ended January 3, 1998, filed with the Securities and Exchange Commission.

    2.  Earnings per Share

        Basic and diluted earnings per share were calculated as follows:

                                                       Three Months Ended
                                                     ----------------------
                                                     April 4,     March 29,
    (In thousands except per share amounts)              1998          1997
    -----------------------------------------------------------------------
    Basic
    Net income                                        $ 2,050       $ 2,242
                                                      -------       -------

    Weighted average shares                            13,356        10,976

    Shares issuable in connection with the 
      acquisition of Orion Research Inc.                5,961         5,961
                                                      -------       -------
    Weighted average shares                            19,317        16,937
                                                      -------       -------
    Basic earnings per share                          $   .11       $   .13
                                                      =======       =======

    Diluted
    Net income                                        $ 2,050       $ 2,242
                                                      -------       -------

    Basic weighted average shares                      19,317        16,937
    Effect of stock options                                 9            15
                                                      -------       -------
    Weighted average shares                            19,326        16,952
                                                      -------       -------
    Diluted earnings per share                        $   .11       $   .13
                                                      =======       =======

                                        6PAGE
<PAGE>
                            THERMEDICS DETECTION INC.

    2.  Earnings per Share (continued)

        The computation of diluted earnings per share for quarter ended April
    4, 1998, excludes the effect of assuming the exercise of certain
    outstanding stock options because the effect would be antidilutive. As of
    April 4, 1998, there were 340,000 of such options outstanding, with
    exercise prices ranging from $10.75 to $12.46 per share.

    3.  Comprehensive Income

        During the first quarter of 1998, the Company adopted Statement of
    Financial Accounting Standards (SFAS) No. 130, "Reporting Comprehensive
    Income." This pronouncement sets forth requirements for disclosure of the
    Company's comprehensive income and accumulated other comprehensive items.
    In general, comprehensive income combines net income and "other
    comprehensive items" which represent foreign currency translation
    adjustments, reported as a component of shareholders' investment in the
    accompanying balance sheet. During the first quarter of 1998 and 1997,
    the Company's comprehensive income totaled $1,881,000 and $1,586,000,
    respectively.

    4.  Acquisition

        On April 14, 1998, the Company announced its intention to acquire
    Orion Research Inc., a wholly owned subsidiary of Thermedics Inc., in a
    merger in which 5,961,225 shares of the Company's common stock would be
    issued in exchange for all of the outstanding shares of Orion Research.
    On May 6, 1998, the transaction was completed, subject to shareholder
    approval of the issuance of the shares of Company common stock to
    Thermedics in the merger. Orion Research manufactures electrode-based
    chemical-measurement products that determine the quality of a wide
    variety of substances by measuring components, such as pH, ion, dissolved
    oxygen, and conductivity levels. These products are used in the
    agricultural, biomedical research, food-processing, and pharmaceutical
    industries. In 1997, Orion Research's revenues and net income were
    $53,054,000 and $6,437,000, respectively.

        Because the Company and Orion Research were deemed for accounting
    purposes to be under control of their common majority owner, Thermedics,
    the transaction has been accounted for at historical cost in a manner
    similar to a pooling of interests. Accordingly, all historical financial
    information presented has been restated to include the acquisition of
    Orion Research. The 5,961,225 shares of the Company's common stock
    issuable in the merger will not be issued until the listing of such
    shares for trading upon American Stock Exchange has been approved by the
    Company's shareholders. Because Thermedics is the majority shareholder
    and intends to vote its shares in favor of such listing, the approval is
    assured and, therefore, the shares are considered to be outstanding as of
    December 29, 1996, for purposes of computing weighted average shares. 

                                          7PAGE
<PAGE>
                            THERMEDICS DETECTION INC.

    4.  Acquisition (continued)

    Revenues and net income as previously reported for the separate entities
    prior to the acquisition and as restated for the combined Company are as
    follows:

                                                         Three Months Ended
    (In thousands)                                         March 29, 1997
    -----------------------------------------------------------------------
    Revenues:
      Historical                                               $12,429
      Orion Research                                            13,103
                                                               -------
                                                               $25,532
                                                               =======

    Net Income:
      Historical                                               $ 1,024
      Orion Research                                             1,218
                                                               -------
                                                               $ 2,242
                                                               =======

    Item 2 - Management's Discussion and Analysis of Financial Condition and
    ------------------------------------------------------------------------
             Results of Operations
             ---------------------

        Forward-looking statements, within the meaning of Section 21E of the
    Securities Exchange Act of 1934, are made throughout this Management's
    Discussion and Analysis of Financial Condition and Results of Operations.
    For this purpose, any statements contained herein that are not statements
    of historical fact may be deemed to be forward-looking statements.
    Without limiting the foregoing, the words "believes," "anticipates,"
    "plans," "expects," "seeks," "estimates," and similar expressions are
    intended to identify forward-looking statements. There are a number of
    important factors that could cause the results of the Company to differ
    materially from those indicated by such forward-looking statements,
    including those detailed under the heading "Risk Factors" included in the
    Company's Annual Report on Form 10-K for the fiscal year ended January 3,
    1998, filed with the Securities and Exchange Commission.

    Overview

        The Company develops, manufactures, and markets high-speed detection
    and measurement systems used in on-line industrial process applications,
    laboratory analysis, and security.

        The Company's industrial process instruments use ultratrace chemical
    detectors, X-ray imaging, near-infrared spectroscopy, and other
    technologies for quality assurance of in-process or finished products,
    primarily in the food, beverage, pharmaceutical, forest products,
    chemical, and other consumer products industries. The Company's Alexus(R)
    systems detect trace amounts of contaminants in refillable plastic
    bottles for the beverage industry. The Company's InScan(TM) systems use
    high-speed X-ray imaging to determine accurate fill volume, net volume,

                                        8PAGE
<PAGE>
                            THERMEDICS DETECTION INC.

    Overview (continued)

    and package integrity for a variety of products in cans, bottles, boxes,
    and other containers. In addition, the Company's moisture analyzers
    measure moisture and other product constituents, such as fats, proteins,
    oils, flavorings, solvents, adhesives, and coatings, in a broad range of
    products as they move along manufacturing lines.

        The Company's laboratory products use high-speed gas chromatography,
    electrochemistry, and other technologies for quality assurance and
    regulatory compliance, primarily in the environmental, food, beverage,
    chemical, pharmaceutical, and biomedical research industries. The
    Company's Flash-GC(TM) gas chromatograph provides -- at speeds 20 to 50
    times faster -- the same information that conventional gas chromatographs
    provide on the chemical composition of a wide range of substances,
    including pharmaceuticals, chemicals, food, beverages, soil, and water.
    The Company's recently acquired Orion Research Inc. subsidiary (Note 4)
    is a worldwide leading manufacturer of electrode-based, chemical
    measurement products that determine the quality of various substances,
    from food and pharmaceuticals to water and wastewater, by measuring their
    pH, ion, dissolved oxygen, and conductivity levels.

        In addition, the Company makes explosives-detection equipment that
    uses simultaneous trace particle- and vapor-detection techniques based on
    its proprietary chemiluminescence and high-speed gas chromatography
    technologies. Customers use these explosives-detection systems to detect
    plastic and other explosives at airports and border crossings, for other
    high-security screening applications, and for forensics and search
    applications.

        The Company also performs contract research and development services
    for government and industry customers and earns service revenues through
    long-term contracts.

    Results of Operations

    First Quarter 1998 Compared With First Quarter 1997
    ---------------------------------------------------

        Revenues in the first quarter of 1998 decreased to $23.7 million from
    $25.5 million in the first quarter of 1997. Product revenues decreased to
    $19.5 million in 1998 from $21.8 million in 1997, while service revenues
    increased to $4.3 million in 1998 from $3.7 million in 1997. Revenues
    from the Company's industrial process instruments and related services
    decreased to $7.1 million in 1998 from $10.6 million in 1997, primarily
    due to a decrease in Alexus-related revenues offset in part by an
    increase in InScan product sales. First quarter 1997 revenues included
    $2.2 million from a mandated Alexus product-line upgrade of The Coca-Cola
    Company's existing installed base. This upgrade was completed in 1997.
    Revenues from industrial process instruments also declined due to a $0.5
    million decrease in revenues from moisture analyzers, primarily due to a
    slowdown in product demand in North America. Revenues from the Company's
    laboratory products instruments and related services increased to $14.2
    million in 1998 from $13.4 million in 1997, primarily due to higher
    demand in domestic markets. Revenues from the Company's EGIS(R)

                                        9PAGE
<PAGE>
                            THERMEDICS DETECTION INC.

    First Quarter 1998 Compared With First Quarter 1997 (continued)
    ---------------------------------------------------

    explosives-detection systems and related services increased to
    $2.4 million in 1998 from $1.0 million in 1997, primarily due to $1.1
    million of shipments under a contract with the U.S. Federal Aviation
    Administration (FAA), which was awarded to the Company in May 1997.
    Product shipments under this contract were completed in the first quarter
    of 1998. The Company's backlog decreased during the first quarter of 1998
    by $2.4 million, including the effect of completing the FAA order. The
    Company believes that its backlog at any date is not necessarily
    indicative of future demand for its products.

        The gross profit margin decreased to 54% in the first quarter of 1998
    from 55% in the first quarter of 1997. The gross profit margin on product
    revenues remained consistent at 54% in 1998 and 1997. The gross profit
    margin on service revenues decreased to 53% in 1998 from 58% in 1997,
    primarily due to a decrease in higher-margin Alexus service revenues, as
    well as higher costs relating to the Company's contract with the FAA.

        Selling, general, and administrative expenses as a percentage of
    revenues decreased to 29% in the first quarter of 1998 from 32% in the
    first quarter of 1997, primarily due to a decrease in international
    distributor sales commissions due to a lower volume of revenue from
    distributors, and, to a lesser extent, a decrease in certain marketing
    and administration costs. Research and development expenses increased to
    $2.7 million in 1998 from $2.1 million in 1997, primarily due to costs
    associated with developing a low-cost portable security detection device,
    improving and expanding the product lines of the Company's moisture
    systems and laboratory products businesses, and development costs
    associated with the EZ Flash(R), expected to be introduced in May 1998.
        Interest income increased to $0.6 million in the first quarter of
    1998 from $0.2 million in the first quarter of 1997, primarily due to
    interest income earned on invested proceeds from the Company's March 1997
    initial public offering.

        Interest expense, related party, of $0.3 million in the first quarter
    of 1998 and 1997 relates to a $21.2 million promissory note issued to
    Thermedics Inc., which was repaid in March 1998.

        The effective tax rates were 39% and 40% in the first quarter of 1998
    and 1997, respectively. The effective tax rates in both periods exceeded
    the statutory federal income tax rate primarily due to the impact of
    state income taxes.

    Liquidity and Capital Resources

        Consolidated working capital was $49.7 million at April 4, 1998,
    compared with $46.3 million at January 3, 1998. Included in working
    capital are cash and cash equivalents of $28.1 million at April 4, 1998,
    compared with $46.4 million at January 3, 1998.

                                       10PAGE
<PAGE>
                            THERMEDICS DETECTION INC.

    Liquidity and Capital Resources (continued)

        During the first quarter of 1998, $2.3 million of cash was provided
    by operating activities. During this period, $2.3 million of cash was
    provided by a decrease in accounts receivable. This source of cash was
    offset in part by $2.8 million of cash used to reduce other current
    liabilities, including $1.7 million of accrued payroll and employee
    benefits and $0.5 million of accrued income taxes. In addition, cash of
    $1.3 million was used to fund an increase in inventories, primarily
    relating to purchases for the production of the EZ Flash beginning in May
    1998.

        During the first quarter of 1998, the Company expended $0.6 million
    on purchases of property, plant, and equipment. During the remainder of
    1998, the Company expects to make capital expenditures of approximately
    $2.0 million.

        In March 1998, the Company repaid its $21.2 million promissory note
    to Thermedics. 

        Although the Company expects to have positive cash flow from its
    existing operations, the Company anticipates it will require significant
    amounts of cash for the possible acquisition of complementary businesses
    and technologies. While the Company currently has no agreement to make an
    acquisition, except as discussed in Note 4 to the consolidated financial
    statements, it expects that it would finance any acquisition through a
    combination of internal funds, additional debt or equity financing,
    and/or short-term borrowings from Thermedics or Thermo Electron
    Corporation, although it has no agreement with these companies to ensure
    that funds will be available on acceptable terms or at all. The Company
    believes that its existing resources are sufficient to meet the capital
    requirements of its existing businesses for the foreseeable future.

    PART II - OTHER INFORMATION

    Item 2 - Use of Proceeds
    ------------------------

        The Company sold 2,671,292 shares of common stock, par value $.01 per
    share, pursuant to a Registration Statement on Form S-1 (File
    No. 333-19199), which was declared effective by the Securities and
    Exchange Commission on February 21, 1997. The managing underwriters of
    the offering were NatWest Securities Limited and Lehman Brothers. The
    aggregate gross proceeds of the offering were $30,720,000. The Company's
    total expenses in connection with the offering were $2,642,000, of which
    $1,718,000 was for underwriting discounts and commissions, $878,000 was
    for other expenses paid to persons other than directors or officers of
    the Company, persons owning more than 10 percent of any class of equity
    securities of the Company or affiliates of the Company (collectively,
    Affiliates), and $46,000 was paid to Thermo Electron for certain services
    rendered in connection with the offering. The Company's net proceeds from
    the offering were $28,078,000. As of April 4, 1998, the Company had 

                                       11PAGE
<PAGE>
                            THERMEDICS DETECTION INC.

    Item 2 - Use of Proceeds (continued)
    ------------------------

    expended $1,222,000 of such net proceeds for the purchase of property,
    plant, and equipment, $6,667,000 for research and development, and
    $9,403,000 for working capital needs. As of April 4, 1998, the Company
    had expended an aggregate of $17,292,000 of such net proceeds. The
    Company invested, from time to time, the balance of such net proceeds
    primarily in investment grade-interest- or dividend-bearing instruments.
    As of April 4, 1998, $10,786,000 was invested pursuant to a repurchase
    agreement with Thermo Electron. As of April 4, 1998, the Company had
    $28,065,000 of cash and cash equivalents.

    Item 6 - Exhibits
    -----------------

        See Exhibit Index on the page immediately preceding exhibits.








                                       12PAGE
<PAGE>
                            THERMEDICS DETECTION INC.

                                   SIGNATURES


        Pursuant to the requirements of the Securities Exchange Act of 1934,
    the Registrant has duly caused this report to be signed on its behalf by
    the undersigned thereunto duly authorized as of the 12th day of May 1998.

                                             THERMEDICS DETECTION INC.



                                             Paul F. Kelleher
                                             ---------------------------
                                             Paul F. Kelleher
                                             Chief Accounting Officer



                                             John N. Hatsopoulos
                                             ---------------------------
                                             John N. Hatsopoulos
                                             Chief Financial Officer and
                                               Senior Vice President



                                       13PAGE
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                            THERMEDICS DETECTION INC.

                                  EXHIBIT INDEX


    Exhibit
    Number      Description of Exhibit
    ------------------------------------------------------------------------

      2.3       Agreement and Plan of Reorganization dated as of May 6, 1998
                by and among the Registrant, Orion Acquisition Inc.,
                Thermedics Inc., and Orion Research Inc. Pursuant to Item
                601(b)(2) of Regulation S-K, schedules to this Agreement
                have been omitted. The Registrant hereby undertakes to
                furnish supplementally a copy of such schedules to the
                Commission upon request.

     27         Financial Data Schedule.