<PAGE>

                                                                 EXHIBIT 10.27

                        GUARANTY AND SECURITY AGREEMENT
                        -------------------------------

     This GUARANTY AND SECURITY AGREEMENT (as amended, supplemented, amended and
restated or otherwise modified from time to time, this "Guaranty and Security
                                                        ---------------------
Agreement"), dated as of September 21, 2001, is made by X-Ray Technology Corp.,
---------
a Delaware corporation, (the "Guarantor"), in favor of Foothill Capital
                              ---------
Corporation, as agent (together with its successor(s) thereto in such capacity,
the "Agent") on behalf of the Lenders from time to time party to the Loan
     -----
Agreement referred to below (the "Lenders", and collectively with the Agent, the
                                  -------
"Secured Parties" and each a "Secured Party").
 ---------------              -------------

                             W I T N E S S E T H :

     WHEREAS, Hologic, Inc., a Delaware corporation ("Parent"), FluoroScan
                                                      ------
Imaging Systems, Inc., a Delaware corporation ("FluoroScan"), and Direct
                                                ----------
Radiography Corp., a Delaware corporation ("DRC", and collectively with Parent
                                            ---
and FluoroScan, the "Borrowers"), on the one hand, and the Agent and the
                     ---------
Lenders, on the other hand, have entered into a Loan and Security Agreement
dated as of the date hereof (as amended, restated, supplemented, and/or
otherwise modified from time to time, the "Loan Agreement" pursuant to which the
                                           --------------
Agent and the Lenders have agreed, subject to the terms and conditions set forth
therein, to make revolving credit loans, term loans and other financial
accommodations to the Borrowers (the "Loans"); and
                                      -----

     WHEREAS, the Guarantor is a wholly-owned Subsidiary of Parent and an
Affiliate of each of the other Borrowers; and

     WHEREAS, it is a condition precedent to the effectiveness of the Loan
Agreement, that the Guarantor execute and deliver this Guaranty and Security
Agreement; and

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the Guarantor agrees, for the
benefit of each Secured Party, as follows:

                                   ARTICLE I
                                  DEFINITIONS

     SECTION 1.1.    Loan Agreement Definitions. Unless otherwise defined herein
                     --------------------------
or the context otherwise requires, capitalized terms used in this Guaranty and
Security Agreement, including its preamble and recitals, have the meanings
provided in the Loan Agreement.

     SECTION 1.2.    UCC Definitions.  Unless otherwise defined herein or in the
                     ---------------
Loan Agreement or the context otherwise requires, terms for which meanings are
provided in the Code are used in this Guaranty and Security Agreement, including
its preamble and recitals, with such meanings, as such meanings may from time to
time be amended.
<PAGE>

                                  ARTICLE II
                               SECURITY INTEREST

     SECTION 2.1.  Grant of Security Interest.
                   --------------------------

     SECTION 2.1.1.  The Guarantor hereby assigns, pledges, hypothecates,
charges, mortgages, delivers, and transfers to the Agent, for its benefit and
the ratable benefit of each other Secured Party, and hereby grants to the Agent,
for its benefit and the ratable benefit of each other Secured Party, a
continuing security interest in all of the Guarantor's right, title and interest
in, to and under the personal property, whether now or hereafter existing, owned
or acquired by the Guarantor (the "Collateral"), including:
                                   ----------

              (a)  investment property;

              (b)  goods (including, without limitation, inventory and equipment
     and any accessions thereto);

              (c)  instruments (including, without limitation, promissory
     notes);

              (d)  accounts;

              (e)  documents;

              (f)  chattel paper (whether tangible or electronic);

              (g)  deposit accounts;

              (h)  letter of credit rights;

              (i)  general intangibles (including, without limitation, payment
     intangibles and software); and

              (j)  all supporting obligations with respect to and any and all
     proceeds of the foregoing.

     SECTION 2.1.2.  The grant of the security interest in Section 2.1.1 above
                                                           -------------
is intended by each of the parties hereto to be a grant of a blanket security
interest in all of the Guarantor's property, and shall constitute a grant to the
Agent, for its benefit and the ratable benefit of each other Secured Party, of a
continuing security interest in all of the Guarantor's right, title and interest
in, to and under the following property, whether now or hereafter existing,
owned or acquired by the Guarantor, which property together with the Collateral
described in Sections 2.1.1 above, in applying the law of any such jurisdiction
             --------------
shall be deemed the "Collateral":
                     ----------
              (a)  all equipment of the Guarantor, including all parts thereof
     and all accessions, additions, attachments, improvements, substitutions and
     replacements thereto and therefor and all accessories related thereto;

                                       2
<PAGE>

          (b)  all inventory in all of its forms of the Guarantor, including (i)
     all raw materials and work in process therefor, finished goods thereof, and
     materials used or consumed in the manufacture or production thereof, (ii)
     all goods in which the Guarantor has an interest in mass or a joint or
     other interest or right of any kind (including goods in which the Guarantor
     has an interest or right as consignee), and (iii) all goods which are
     returned to or repossessed by the Guarantor, and all accessions thereto,
     products thereof and documents therefor;

          (c)  all accounts, accounts receivable, loans, contracts, contract
     rights, chattel paper, documents, instruments, investment property and
     general intangibles (including tax refunds) of the Guarantor, whether or
     not arising out of or in connection with the sale or lease of goods or the
     rendering of services;

          (d)  all intellectual property collateral of the Guarantor, including
     goodwill, patents, trade names, trademarks, servicemarks, copyrights,
     blueprints, drawings, purchase orders, customer lists, monies due or
     recoverable from pension funds, route lists, rights to payment and other
     rights under any royalty or licensing agreements, infringement claims,
     computer programs, information contained on computer disks or tapes,
     software, or literature;

          (e)  all chattel paper, documents and instruments of the Guarantor;

          (f)  all books, records, writings, data bases, information and other
     property relating to, used or useful in connection with, evidencing,
     embodying, incorporating or referring to, any of the foregoing;

          (g)  all of the Guarantor's other property and rights of every kind
     and description and interests therein; and

          (h)  all products, offspring, rents, issues, profits, returns, income
     and proceeds of and from any and all of the foregoing Collateral (including
     proceeds which constitute property of the types described in clauses (a)
                                                                  -----------
     through (g) above, and, to the extent not otherwise included, all payments
             ---
     under insurance (whether or not the Agent is the loss payee thereof), or
     any indemnity, warranty or guaranty, payable by reason of loss or damage to
     or otherwise with respect to any of the foregoing Collateral).

     SECTION 2.2.  Security for Obligations. This Guaranty and Security
                   ------------------------
Agreement and the Collateral in which the Secured Parties are granted a security
interest in hereunder secures the payment of all Obligations.

     SECTION 2.3.  Guarantor Remain Liable.  Anything herein to the contrary
                   -----------------------
notwithstanding,

          (a)  the Guarantor will remain liable under the contracts and
     agreements included in the Collateral to the extent set forth therein, and
     will perform all of its duties

                                       3
<PAGE>

     and obligations under such contracts and agreements to the same extent as
     if this Guaranty and Security Agreement had not been executed;

          (b)  the exercise by the Agent of any of its rights hereunder will not
     release the Guarantor from any of its duties or obligations under any such
     contracts or agreements included in the Collateral; and

          (c)  no Secured Party will have any obligation or liability under any
     contracts or agreements included in the Collateral by reason of this
     Guaranty and Security Agreement, nor will any Secured Party be obligated to
     perform any of the obligations or duties of the Guarantor thereunder or to
     take any action to collect or enforce any claim for payment assigned
     hereunder.

     SECTION 2.4.  Continuing Security Interest.  This Agreement shall create a
                   ----------------------------
continuing security interest in the Collateral and shall

          (a)  remain in full force and effect until the date (the "Final
                                                                    -----
     Payment Date") on which the Obligations shall have been finally,
     ------------
     indefeasibly and fully paid and performed and the Commitments shall have
     been terminated,

          (b)  be binding upon the Guarantor, its successors, transferees and
     assigns, and

          (c)  inure, together with the rights and remedies of the
     Administrative Agent hereunder, to the benefit of the Administrative Agent
     and each other Secured Party.

                                  ARTICLE III
                              GUARANTY PROVISIONS

     SECTION 3.1.  Guaranty.  The Guarantor hereby jointly and severally
                   --------
absolutely, unconditionally and irrevocably:

     SECTION 3.1.1.  guarantees the full and punctual payment when due, whether
at stated maturity, by required prepayment, declaration, acceleration, demand or
otherwise, of all Obligations of the Borrowers now or hereafter existing,
whether for principal, interest (including interest accruing at the then
applicable rate provided in the Loan Agreement after the occurrence of any
Default set forth in the Loan Agreement, whether or not a claim for post-filing
or post-petition interest is allowed under applicable law following the
institution of a proceeding under bankruptcy, insolvency or similar laws), fees,
expenses or otherwise (including all such amounts which would become due but for
the operation of the automatic stay under Section 362(a) of the United States
Bankruptcy Code, 11 U.S.C. Section 362(a), and the operation of Sections 502(b)
and 506(b) of the United States Bankruptcy Code, 11 U.S.C. Section 502(b) and
Section 506(b)); and

     SECTION 3.1.2.  indemnifies and holds harmless each Secured Party for any
and all costs and expenses (including reasonable attorneys' fees and expenses)
incurred by such Secured Party in enforcing any rights under this Guaranty;

                                       4
<PAGE>

provided, however, that the Guarantor shall only be liable under this Guaranty
--------  -------
for the maximum amount of such liability that can be hereby incurred without
rendering this Guaranty, as it relates to the Guarantor, voidable under
applicable law relating to fraudulent conveyance or fraudulent transfer, and not
for any greater amount.  This Guaranty constitutes a guaranty of payment when
due and not of collection, and the Guarantor specifically agrees that it shall
not be necessary or required that any Secured Party exercise any right, assert
any claim or demand or enforce any remedy whatsoever against any Loan Party or
any other Person before or as a condition to the obligations of the Guarantor
hereunder.

     SECTION 3.2.  Reinstatement, etc.  The Guarantor hereby agrees that this
                   ------------------
Guaranty shall continue to be effective or be reinstated, as the case may be, if
at any time any payment (in whole or in part) of any of the Obligations is
invalidated, declared to be fraudulent or preferential, set aside, rescinded or
must otherwise be restored by any Secured Party, including upon the occurrence
of any Default or Event of Default or otherwise, all as though such payment had
not been made.

     SECTION 3.3.  Guaranty Absolute, etc. This Guaranty shall in all respects
                   ----------------------
be a continuing, absolute, unconditional and irrevocable guaranty of payment,
and shall remain in full force and effect until the Final Payment Date. The
Guarantor guarantees that the Obligations will be paid strictly in accordance
with the terms of each Loan Document under which they arise, regardless of any
law, regulation or order now or hereafter in effect in any jurisdiction
affecting any of such terms or the rights of any Secured Party with respect
thereto. The liability of the Guarantor under this Guaranty shall be absolute,
unconditional and irrevocable irrespective of:

     SECTION 3.3.1.  any lack of validity, legality or enforceability of any
other Loan Document;

     SECTION 3.3.2.  the failure of any Secured Party

          (a)  to assert any claim or demand or to enforce any right or remedy
     against any Loan Party or any other Person (including any other guarantor)
     under the provisions of any Loan Document or otherwise, or

          (b)  to exercise any right or remedy against any other guarantor
     (including the Guarantor) of, or collateral securing, any Obligations;

     SECTION 3.3.3.  any change in the time, manner or place of payment of, or
in any other term of, all or any part of the Obligations, or any other
extension, compromise or renewal of any Obligation;

     SECTION 3.3.4.  any reduction, limitation, impairment or termination of any
Obligations for any reason, including any claim of waiver, release, surrender,
alteration or compromise, and shall not be subject to (and the Guarantor hereby
waives any right to or claim of) any defense or setoff, counterclaim, recoupment
or termination whatsoever by reason of the invalidity, illegality,
nongenuineness, irregularity, compromise, unenforceability of, any Obligations
(other than the payment and performance in full of the Obligations) or
otherwise;

                                       5
<PAGE>

     SECTION 3.3.5.  any amendment to, rescission, waiver, or other modification
of, or any consent to or departure from, any of the terms of any Loan Document;

     SECTION 3.3.6.  any addition, exchange or release of any collateral or of
the Guarantor of the Obligations, or any surrender or non-perfection of any
collateral, or any amendment to or waiver or release or addition to, or consent
to or departure from, any other guaranty held by any Secured Party securing any
of the Obligations; or

     SECTION 3.3.7.  any other circumstance which might otherwise constitute a
defense available to, or a legal or equitable discharge of, any Loan Party, any
surety or any guarantor.

     SECTION 3.4.  Setoff. The Guarantor hereby irrevocably authorizes the Agent
                   ------
and each Lender, without the requirement that any notice be given to the
Guarantor (such notice being expressly waived by the Guarantor), upon the
occurrence and during the continuance of any Default described in the Loan
Agreement or, with the consent of the Required Lenders, upon the occurrence and
during the continuance of any other Event of Default, to set-off and appropriate
and apply to the payment of the Obligations (whether or not then due, and
whether or not any Secured Party has made any demand for payment of the
Obligations), any and all balances, claims, credits, deposits (general or
special, time or demand, provisional or final), accounts or money of the
Guarantor then or thereafter maintained with such Secured Party and apply the
same pursuant to the Loan Agreement.  Each Secured Party agrees to notify the
Guarantor and the Agent after any such setoff and application made by such
Secured Party; provided, that the failure to give such notice shall not affect
               --------
the validity of such setoff and application.  The rights of each Secured Party
under this Section are in addition to other rights and remedies (including other
rights of setoff under applicable law or otherwise) which such Secured Party may
have.

     SECTION 3.5.  Waiver, etc. The Guarantor hereby waives promptness,
                   -----------
diligence, notice of acceptance and any other notice with respect to any of the
Obligations and this Guaranty and any requirement that any Secured Party
protect, secure, perfect or insure any Lien, or any property subject thereto, or
exhaust any right or take any action against any Loan Party or any other Person
(including any other guarantor) or entity or any collateral securing the
Obligations, as the case may be.

     SECTION 3.6.  Postponement of Subrogation, etc. The Guarantor agrees that
                   --------------------------------
it will not exercise any rights which it may acquire by way of rights of
subrogation under any Loan Document to which it is a party, nor shall the
Guarantor seek or be entitled to seek any contribution or reimbursement from any
Loan Party, in respect of any payment made under any Loan Document or otherwise,
until following the Final Payment Date. Any amount paid to the Guarantor on
account of any such subrogation rights prior to the Final Payment Date shall be
held in trust for the benefit of the Secured Parties and shall immediately be
paid and turned over to the Agent for the benefit of the Secured Parties in the
exact form received by the Guarantor (duly endorsed in favor of the Agent, if
required), to be credited and applied against the Obligations, whether matured
or unmatured, in accordance with Section 2.7; provided, however, that if the
                                 -----------  --------  -------
Guarantor has made payment to the Secured Parties of all or any part of the
Obligations and the Final Payment Date has occurred, then at the Guarantor's
request, the Agent (on behalf of the Secured Parties) will, at the expense of
the Guarantor, execute and deliver to the

                                       6
<PAGE>

Guarantor appropriate documents (without recourse and without representation or
warranty) necessary to evidence the transfer by subrogation to the Guarantor of
an interest in the Obligations resulting from such payment. In furtherance of
the foregoing, at all times prior to the Final Payment Date, the Guarantor shall
refrain from taking any action or commencing any proceeding against any Loan
Party (or its successors or assigns, whether in connection with a bankruptcy
proceeding or otherwise) to recover any amounts in respect of payments made
under this Guaranty to any Secured Party.

     SECTION 3.7.  Payments; Application.  The Guarantor hereby agrees with each
                   ---------------------
Secured Party that (a) all payments made hereunder shall be applied upon receipt
as set forth in Section 2.4 (b) of the Loan Agreement and (b) all payments made
                ---------------
by the Guarantor hereunder will be made in Dollars to the Agent, without set-
off, counterclaim or other defense and in accordance with the Loan Agreement,
free and clear of and without deduction for any Taxes, the Guarantor hereby
agreeing to comply with and be bound by the provisions of the Loan Agreement in
respect of all payments made by it hereunder and the provisions of which
Sections are hereby incorporated into and made a part of this Guaranty and
Security Agreement by this reference as if set forth herein; provided, that
                                                             --------
references to the "Borrower" or "Borrowers" in such Sections shall be deemed to
be references to the Guarantor, and references to "this Agreement" in such
Sections shall be deemed to be references to this Guaranty.

                                  ARTICLE IV
                         REPRESENTATIONS AND WARRANTIES

     In order to induce the Secured Parties to enter into the Loan Agreement and
make Loans thereunder, the Guarantor represents and warrants to each Secured
Party as set forth below.

     SECTION 4.1.  As to Collateral, etc. The Guarantor has no material property
                   ---------------------
other than (a) those patents and trademarks set forth on Schedule I hereto (the
                                                         ----------
"Intellectual Property Collateral") and (b) the bank account listed on Schedule
 --------------------------------                                      --------
II hereto. The Guarantor is a Delaware corporation.
--

     SECTION 4.2.  Ownership, No Liens, etc.  The Guarantor owns its Collateral
                   ------------------------
free and clear of any Lien, except for Permitted Liens.  No effective financing
statement or other filing similar in effect covering any Collateral is on file
in any recording office, except those filed in favor of the Agent relating to
this Agreement.

     SECTION 4.3.  Intellectual Property Collateral. With respect to each item
                   --------------------------------
of Intellectual Property Collateral (other than items of Intellectual Property
Collateral which are not, individually or in the aggregate, material):

          (a)  such Intellectual Property Collateral is subsisting and has not
     been adjudged invalid or unenforceable, in whole or in part;

          (b)  to the knowledge of the Guarantor, such Intellectual Property
     Collateral is valid and enforceable;

                                       7
<PAGE>

          (c)  the Guarantor has made all necessary filings and recordations to
     protect its interest in such Intellectual Property Collateral, including,
     where requested by the Agent, recordations of all of its interests in any
     of the patents or trademarks listed on Schedule I hereto in the United
     States Patent and Trademark Office;

          (d)  the Guarantor is the owner of such right, title and interest in
     and to such Intellectual Property Collateral as is necessary for the
     conduct of its business and no claim has been made that the use of such
     Intellectual Property Collateral does or may violate the asserted rights of
     any third party; and

          (e)  the Guarantor has performed and will continue to perform all acts
     and has paid and will continue to pay all required fees and taxes to
     maintain each and every such item of Intellectual Property Collateral in
     full force and effect so as to avoid a Material Adverse Change.

To the knowledge of the Guarantor, the Guarantor owns directly or is entitled to
use by license or otherwise, all patents, trademarks, trade secrets, copyrights,
mask works, licenses, technology, know-how, processes and rights with respect to
any of the foregoing used in, necessary for or of importance to the conduct of
the Guarantor's business.

     SECTION 4.4.  Validity, etc. This Guaranty and Security Agreement creates a
                   -------------
valid security interest in the Collateral securing the payment of the
Obligations. The Guarantor acknowledges that the Lender intends to or has filed
or caused to be filed all statements in the appropriate offices therefor (or has
executed and delivered to the Agent originals thereof suitable for filing in
such offices) and has taken all of the actions necessary to create perfected
first-priority security interests in any Collateral in which a security interest
may be perfected by the filing of a financing statement.

     SECTION 4.5.  Authorization, Approval, etc. Except as have been obtained or
                   ----------------------------
made and are in full force and effect, no authorization, approval or other
action by, and no notice to or filing with, any governmental authority or
regulatory body (other than in connection with the perfection of the Liens
hereof) is required either

          (a)  for the grant by the Guarantor of the security interest granted
     hereby, the pledge by the Guarantor of any Collateral pursuant hereto or
     for the execution, delivery and performance of this Guaranty and Security
     Agreement by the Guarantor; or

          (b)  for the exercise by the Agent of the voting or other rights
     provided for in this Guaranty and Security Agreement.

     SECTION 4.6.  Compliance with Laws. The Guarantor is in material compliance
                   --------------------
with the requirements of all applicable laws (including the provisions of the
Fair Labor Standards Act), rules and regulations, the non-compliance with any of
which could reasonably be expected to materially adversely affect the value of
the Collateral.

     SECTION 4.7.  Best Interests.  It is in the best interests of the Guarantor
                   --------------
to execute this Agreement inasmuch as the Guarantor will, as a result of being a
wholly-owned subsidiary of

                                       8
<PAGE>

Parent and a sister corporation of the other Borrowers, derive substantial
direct and indirect benefits from the Loans made from time to time to the
Borrowers by the Agent and the other Lenders pursuant to the Credit Agreement,
and the Guarantor agrees that the Secured Parties are relying on this
representation in agreeing to make Loans to the Borrowers.

                                   ARTICLE V
                                   COVENANTS

     The Guarantor covenants and agrees that, from the Effective Date until the
Final Payment Date, the Guarantor will perform, comply with and be bound by the
obligations set forth below.

     SECTION 5.1.   As to Intellectual Property Collateral.  The Guarantor
                    --------------------------------------
covenants and agrees to comply with the following provisions as such provisions
relate to any item of Intellectual Property Collateral (other than items of
Intellectual Property Collateral which are not, individually or in the
aggregate, material):

          (a)       the Guarantor shall promptly notify the Agent if it knows,
     or has reason to know, that any application or registration relating to any
     material item of the Intellectual Property Collateral may become abandoned
     or dedicated to the public or placed in the public domain or invalid or
     unenforceable, or of any adverse determination or development (including
     the institution of, or any such determination or development in, any
     proceeding in the United States Patent and Trademark Office, the United
     States Copyright Office or any foreign counterpart thereof or any court)
     regarding the Guarantor's ownership of any of the Intellectual Property
     Collateral, its right to register the same or to keep and maintain and
     enforce the same;

          (b)       in no event will the Guarantor or any of its agents,
     employees, designees or licensees file an application for the registration
     of any Intellectual Property Collateral of the Guarantor with the United
     States Patent and Trademark Office, the United States Copyright Office or
     any similar office or agency in any other country or any political
     subdivision thereof, unless it promptly informs the Agent, and upon request
     of the Agent, executes and delivers all agreements, instruments and
     documents as the Agent may reasonably request to evidence the Agent's
     security interest in such Intellectual Property Collateral;

          (c)       the Guarantor will take all necessary steps, including in
     any proceeding before the United States Patent and Trademark Office, the
     United States Copyright Office or any similar office or agency in any other
     country or any political subdivision thereof, to maintain and pursue any
     application (and to obtain the relevant registration after application)
     filed with respect to, and to maintain any registration of, all material
     items of the Intellectual Property Collateral, including the filing of
     applications for renewal, affidavits of use, affidavits of incontestability
     and opposition, interference and cancellation proceedings and the payment
     of fees and taxes (except to the extent that (i) dedication, abandonment or
     invalidation is permitted under the foregoing clause (b) or (ii) the
                                                   ----------
     Guarantor shall either (a) reasonably and in good faith determine that any
     of such

                                       9
<PAGE>

     Intellectual Property Collateral is of negligible economic value to the
     Guarantor, or (b) have a valid business purpose to do otherwise;); and

          (d)       the Guarantor will promptly (but no less than quarterly)
     execute and deliver to the Agent (as applicable) a Patent Security
     Agreement, Trademark Security Agreement and/or Copyright Security
     Agreement, as the case may be, substantially in the form of the Patent
     Security Agreement, the Trademark Security Agreement and the Copyright
     Security Agreement following its obtaining an interest in any patents,
     trademarks or copyrights, and shall execute and deliver to the Agent any
     other document required to acknowledge or register or perfect the Agent's
     interest in any part of such item of Intellectual Property Collateral, in
     each case at the request of the Agent.

     SECTION 5.2.   Further Assurances, etc.  Guarantor, from time to time and
                    ------------------------
at its own expense, will promptly execute and deliver all further documents and
instruments, and take all further action, that may be necessary to protect,
preserve and perfect any security interest granted or purported to be granted
hereby.  Without limiting the generality of the foregoing, Guarantor will:

          (a)       enter into control agreements, and otherwise cause the Agent
     to obtain control over such items of Collateral as the Agent may reasonably
     request;

          (b)       furnish to the Agent, from time to time at the Agent's
     request, statements and schedules further identifying and describing the
     Collateral and such other reports in connection with the Collateral as the
     Agent may reasonably request, all in reasonable detail.

With respect to the foregoing and the grant of the security interest hereunder,
the Guarantor hereby authorizes the Agent to file one or more financing or
continuation statements, and amendments thereto, relative to all or any part of
the Collateral without the signature of the Guarantor where permitted by law.

                                  ARTICLE VI
                                   THE AGENT

     SECTION 6.1.   Agent Appointed Attorney-in-Fact.  The Guarantor hereby
                    --------------------------------
irrevocably appoints the Agent its attorney-in-fact, with full authority in the
place and stead of the Guarantor and in the name of the Guarantor or otherwise,
from time to time in the Agent's discretion, following the occurrence and during
the continuance of an Event of Default, to take any action and to execute any
instrument which the Agent may deem necessary or advisable to accomplish the
purposes of this Guaranty and Security Agreement, including:

          (a)       to ask, demand, collect, sue for, recover, compromise,
     receive and give acquittance and receipts for moneys due and to become due
     under or in respect of any of the Collateral;

                                       10
<PAGE>

          (b)       to receive, endorse, and collect any drafts or other
     instruments, documents and chattel paper, in connection with clause (a)
                                                                  ----------
     above;

          (c)       to file any claims or take any action or institute any
     proceedings which the Agent may deem necessary or desirable for the
     collection of any of the Collateral or otherwise to enforce the rights of
     the Agent with respect to any of the Collateral; and

          (d)       to perform the affirmative obligations of the Guarantor
     hereunder (including all obligations of the Guarantor pursuant to Section
                                                                       -------
     5.6).
     ----

The Guarantor hereby acknowledges, consents and agrees that the power of
attorney granted pursuant to this Section is irrevocable and coupled with an
                                  -------
interest.

     SECTION 6.2.   Agent May Perform.  If the Guarantor fails to perform any
                    -----------------
agreement contained herein, the Agent may itself perform, or cause performance
of, such agreement, and the expenses of the Agent incurred in connection
therewith shall be payable by the Guarantor pursuant to Section 7.4.
                                                        -----------

     SECTION 6.3.   Agent Has No Duty.  The powers conferred on the Agent
                    -----------------
hereunder are solely to protect its interest (on behalf of the Secured Parties)
in the Collateral and shall not impose any duty on it to exercise any such
powers. Except for reasonable care of any Collateral in its possession and the
accounting for moneys actually received by it hereunder, the Agent shall have no
duty as to any Collateral or responsibility for

          (a)       ascertaining or taking action with respect to calls,
     conversions, exchanges, maturities, tenders or other matters relative to
     any investment property, whether or not the Agent has or is deemed to have
     knowledge of such matters, or

          (b)       taking any necessary steps to preserve rights against prior
     parties or any other rights pertaining to any Collateral.

     SECTION 6.4.   Reasonable Care.  The Agent is required to exercise
                    ---------------
reasonable care in the custody and preservation of any of the Collateral in its
possession; provided, however, that the Agent shall be deemed to have exercised
            --------  -------
reasonable care in the custody and preservation of any of the Collateral, if it
takes such action for that purpose as the Guarantor reasonably requests in
writing at times other than upon the occurrence and during the continuance of
any Event of Default, but failure of the Agent to comply with any such request
at any time shall not in itself be deemed a failure to exercise reasonable care.

                                  ARTICLE VII
                                   REMEDIES

     SECTION 7.1.   Certain Remedies.  If any Event of Default shall have
                    ----------------
occurred and be continuing:

                                       11
<PAGE>

          (a)       The Agent may exercise in respect of the Collateral, in
     addition to other rights and remedies provided for herein or otherwise
     available to it, all the rights and remedies of a secured party on default
     under the Code (whether or not the Code applies to the affected Collateral)
     and also may

                    (i)    require the Guarantor to, and the Guarantor hereby
          agrees that it will, at its expense and upon request of the Agent
          forthwith, assemble all or part of the Collateral as directed by the
          Agent and make it available to the Agent at a place to be designated
          by the Agent which is reasonably convenient to both parties, and

                    (ii)   without notice except as specified below, sell the
          Collateral or any part thereof in one or more parcels at public or
          private sale, at any of the Agent's offices or elsewhere, for cash, on
          credit or for future delivery, and upon such other terms as the Agent
          may deem commercially reasonable. The Guarantor agrees that, to the
          extent notice of sale shall be required by law, at least ten days
          prior notice to the Guarantor of the time and place of any public sale
          or the time after which any private sale is to be made shall
          constitute reasonable notification. The Agent shall not be obligated
          to make any sale of Collateral regardless of notice of sale having
          been given. The Agent may adjourn any public or private sale from time
          to time by announcement at the time and place fixed therefor, and such
          sale may, without further notice, be made at the time and place to
          which it was so adjourned.

          (b)       All cash proceeds received by the Agent in respect of any
     sale of, collection from, or other realization upon, all or any part of the
     Collateral shall be applied by the Agent against all or any part of the
     Obligations as set forth in Section 3.7.
                                 -----------

          (c)       The Agent may

                    (i)    transfer all or any part of the Collateral into the
          name of the Agent or its nominee, with or without disclosing that such
          Collateral is subject to the Lien hereunder,

                    (ii)   notify the parties obligated on any of the Collateral
          to make payment to the Agent of any amount due or to become due
          thereunder,

                    (iii)  enforce collection of any of the Collateral by suit
          or otherwise, and surrender, release or exchange all or any part
          thereof, or compromise or extend or renew for any period (whether or
          not longer than the original period) any obligations of any nature of
          any party with respect thereto,

                    (iv)   endorse any checks, drafts, or other writings in the
          Guarantor's name to allow collection of the Collateral,

                    (v)    take control of any proceeds of the Collateral, and

                                       12
<PAGE>

                    (vi)   execute (in the name, place and stead of the
          Guarantor) endorsements, assignments, stock powers and other
          instruments of conveyance or transfer with respect to all or any of
          the Collateral.

     SECTION 7.2.   Waiver.  The Guarantor agrees, to the full extent that it
                    ------
may lawfully so agree, that neither it nor anyone claiming through or under it
will set up, claim or seek to take advantage of any appraisement, valuation,
stay, extension or redemption law now or hereafter in force in any locality
where any property subject to the Lien hereof may be situated, in order to
prevent, hinder or delay the enforcement or foreclosure of this Agreement, or
the absolute sale of the Collateral or any part thereof, or the final and
absolute putting into possession thereof, immediately after such sale, of the
purchaser thereof and the Guarantor, for itself and all who may at any time
claim through or under it, hereby waives, to the full extent that it may be
lawful so to do, the benefit of all such laws, and any and all right to have any
of the properties or assets comprising the Collateral marshaled upon any such
sale, and agrees that, subject to the terms of this Agreement, the Agent, or any
court having jurisdiction to foreclose the Lien hereof, may sell the Collateral
as an entirety or in such parcels as it may determine.

     SECTION 7.3.   Compliance with Restrictions.  The Guarantor agrees that
                    ----------------------------

          (a)       in any sale of any of the Collateral whenever an Event of
     Default shall have occurred and be continuing, the Agent is hereby
     authorized to comply with any limitation or restriction in connection with
     such sale as it may be advised by counsel is necessary in order to

                    (i)    avoid any violation of applicable law (including
          compliance with such procedures as may restrict the number of
          prospective bidders and purchasers, require that such prospective
          bidders and purchasers have certain qualifications, and restrict such
          prospective bidders and purchasers to Persons who will represent and
          agree that they are purchasing for their own account for investment
          and not with a view to the distribution or resale of such Collateral),
          or

                    (ii)   obtain any required approval of the sale or of the
          purchaser by any Governmental Authority or official, and

          (b)       such compliance shall not result in such sale being
     considered or deemed not to have been made in a commercially reasonable
     manner, nor shall the Agent be liable nor accountable to the Guarantor for
     any discount allowed by the reason of the fact that such Collateral is sold
     in compliance with any such limitation or restriction.

     SECTION 7.4.   Protection of Collateral.  The Agent may from time to time,
                    ------------------------
at its option, perform any act which the Guarantor fails to perform after being
requested in writing so to perform (it being understood that no such request
need be given after the occurrence and during the continuance of an Event of
Default) and the Agent may from time to time take any other action which the
Agent reasonably deems necessary for the maintenance, preservation or protection
of any of the Collateral or of its security interest therein.

                                       13
<PAGE>

                                 ARTICLE VIII
                           MISCELLANEOUS PROVISIONS

     SECTION 8.1.   Loan Document.  This Guaranty and Security Agreement is a
                    -------------
Loan Document executed pursuant to the Loan Agreement and shall (unless
otherwise expressly indicated herein) be construed, administered and applied in
accordance with the terms and provisions thereof.

     SECTION 8.2.   Binding on Successors, Transferees and Assigns; Assignment.
                    ----------------------------------------------------------
This Guaranty and Security Agreement shall remain in full force and effect until
the Final Payment Date has occurred, shall be binding upon the Guarantor and its
successors, transferees and assigns and shall inure to the benefit of and be
enforceable by each Secured Party and its successors, transferees and assigns,
in each case as permitted by the Loan Agreement; provided, however, that the
                                                 --------  -------
Guarantor may not assign any of its obligations hereunder without the prior
written consent of all Lenders.

     SECTION 8.3.   Amendments, etc.  No amendment to or waiver of any provision
                    ----------------
of this Guaranty and Security Agreement, nor consent to any departure by the
Guarantor from its obligations under this Guaranty and Security Agreement, shall
in any event be effective unless the same shall be in writing and signed by the
Agent (on behalf of the Lenders or the Required Lenders, as the case may be,
pursuant to the Loan Agreement) and then such waiver or consent shall be
effective only in the specific instance and for the specific purpose for which
given.

     SECTION 8.4.   Notices.  All notices and other communications provided for
                    -------
hereunder shall be given and effective as set forth in the Loan Agreement.

     SECTION 8.5.   Release of Liens.  On the Final Payment Date, the security
                    ----------------
interests granted herein shall automatically terminate with respect to all
Collateral.  At such time, the Agent will, at the Guarantor's expense, deliver
to the Guarantor, without any representations, warranties or recourse of any
kind whatsoever, all Collateral held by the Agent hereunder, and execute and
deliver to the Guarantor such documents as the Guarantor shall reasonably
request to evidence such termination.

     SECTION 8.6.   No Waiver; Remedies.  No failure on the part of any Secured
                    -------------------
Party to exercise, and no delay in exercising, any right hereunder shall operate
as a waiver thereof, nor shall any single or partial exercise of any right
hereunder preclude any other or further exercise thereof or the exercise of any
other right.  The remedies herein provided are cumulative and not exclusive of
any remedies provided by law.

     SECTION 8.7.   Section Captions.  Section captions used in this Guaranty
                    ----------------
and Security Agreement are for convenience of reference only, and shall not
affect the construction of this Guaranty and Security Agreement.

     SECTION 8.8.   Severability.  Wherever possible each provision of this
                    ------------
Guaranty and Security Agreement shall be interpreted in such manner as to be
effective and valid under applicable law, but if any provision of this Guaranty
and Security Agreement shall be prohibited

                                       14
<PAGE>

by or invalid under such law, such provision shall be ineffective to the extent
of such prohibition or invalidity, without invalidating the remainder of such
provision or the remaining provisions of this Guaranty and Security Agreement.

     SECTION 8.9.   Governing Law, Entire Agreement, etc.  THIS GUARANTY AND
                    -------------------------------------
SECURITY AGREEMENT WILL BE DEEMED TO BE A CONTRACT MADE UNDER AND GOVERNED BY
THE LAWS OF THE COMMONWEALTH OF MASSACHUSETTS, EXCEPT TO THE EXTENT THAT THE
VALIDITY OR PERFECTION OF THE SECURITY INTEREST HEREUNDER, OR REMEDIES
HEREUNDER, IN RESPECT OF ANY PARTICULAR COLLATERAL ARE GOVERNED BY THE LAWS OF A
JURISDICTION OTHER THAN THE COMMONWEALTH OF MASSACHUSETTS.  This Guaranty and
Security Agreement and the other Loan Documents constitute the entire
understanding among the parties hereto with respect to the subject matter hereof
and thereof and supersede any prior agreements, written or oral, with respect
thereto.

     SECTION 8.10.  Counterparts.  This Guaranty and Security Agreement may be
                    ------------
executed by the parties hereto in several counterparts, each of which shall be
deemed to be an original and all of which shall constitute together but one and
the same agreement.

                                       15
<PAGE>

     IN WITNESS WHEREOF, each of the parties hereto has caused this Guaranty and
Security Agreement to be duly executed and delivered by its officer thereunto
duly authorized as a document under seal as of the date first above written.


                                    X-RAY TECHNOLOGY CORP.



                                    By: /s/ Glenn P. Muir
                                        -------------------------------------
                                        Glenn P. Muir, Vice President-Finance


                                    FOOTHILL CAPITAL CORPORATION



                                    By: /s/ Scott Ryan
                                        -------------------------------------
                                        Scott Ryan, Vice President

                                      D-1