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                              August 5, 1996



Hologic, Inc.
590 Lincoln Street
Waltham, MA 02154

     RE:  Registration Statement on Form S-4 of Hologic, Inc. filed on July 26,
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          1996
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Ladies and Gentlemen:

     We have acted as counsel to Hologic, Inc., a Delaware corporation (the
"Company"), in connection with the preparation and filing with the Securities
and Exchange Commission of a Registration Statement on Form S-4 (the
"Registration Statement") pursuant to which the Company is registering under the
Securities Act of 1933, as amended (the "Act"), a total of 1,450,000 shares of
common stock, $.01 par value per share (the "Common Stock").  Pursuant to the
Registration Statement and an Agreement and Plan of Merger dated July 18, 1996
(the "Merger Agreement") by and among the Company, FluoroScan Imaging Systems,
Inc. ("FluoroScan") and Fenway Acquisition Corp., in the form filed as Exhibit
2.01 to the Registration Statement, the Company proposes to issue to the holders
of FluoroScan common stock, $.0001 par value per share, up to 1,450,000 shares
of Common Stock (the "Shares").  This opinion is being rendered in connection
with the filing of the Registration Statement.  Unless otherwise indicated,
capitalized terms used herein shall have the meanings ascribed thereto in the
Merger Agreement.

     For purposes of this opinion, we have assumed, without any investigation,
(i) the legal capacity of each natural person, (ii) the full power and authority
of each entity and person other than the Company and Fenway Acquisition Corp. to
execute, deliver and perform each document heretofore executed and delivered or
hereafter to be executed and delivered and to do each other act heretofore done
or hereafter to be done by such entity or person, (iii) the due authorization by
each entity or person other than the Company and Fenway Acquisition Corp. of
each document heretofore executed and delivered or hereafter to be executed and
delivered and to do each other act heretofore done or to be done by such entity
or person, (iv) the due execution and delivery by each entity or person other
than the Company and Fenway Acquisition Corp. of each document heretofore
executed and delivered or hereafter to be executed and delivered by such entity
or person, (v) the legality, validity, binding effect and enforceability as to
each entity or person other than the Company and Fenway Acquisition Corp. of
each document heretofore executed and delivered or hereafter to be executed and
delivered and of each other act heretofore done or

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hereafter to be done by such entity or person, (vi) the genuineness of each
signature on, and the completeness of each document submitted to us as an
original, (vii) the conformity to the original of each document submitted to us
as a copy, (viii) the authenticity of the original of each document submitted to
us as a copy, (ix) the completeness, accuracy and property indexing of all
governmental and judicial records searched and (x) no modification of any
provision of any document, no waiver of any right or remedy and no exercise of
any right or remedy other than in a commercially reasonable and conscionable
manner and in good faith.

     In connection with this opinion, we have examined the following
(collectively, the "Documents"):

     (i) the Certificate of Incorporation of the Company incorporated by
         reference as Exhibit 3.01 to the Registration Statement;
    (ii) the By-laws of the Company incorporated by reference as Exhibit 3.02
         to the Registration Statement;
   (iii) the corporate minute books or other records of the Company;
    (iv) a specimen certificate for the Common Stock incorporated by reference
         as Exhibit 4.01 to the Registration Statement; and
     (v) the Merger Agreement.

     The opinions expressed herein are based solely upon (i) our review of the
Documents, (ii) discussions with S. David Ellenbogen, the Chairman of Board and
Chief Executive Officer of the Company and Glenn P. Muir, the Company's Vice
President of Finance and Treasurer; (iii) the representations and warranties of
the Company, Fenway Acquisition Corp. and FluoroScan contained in the Merger
Agreement and the schedules and exhibits thereto, (iv) discussions with those of
our attorneys who have devoted substantive attention to the matters contained
herein, and (v) such review of published sources of law as we have deemed
necessary.

     Our opinions contained herein are limited to the laws of The Commonwealth
of Massachusetts, the general corporate laws of the State of Delaware and the
federal law of the United States of America.

     Based upon and subject to the foregoing, we are of the opinion that:

     The Shares to be issued by the Company under the circumstances contemplated
in the Registration Statement are duly authorized and, when delivered pursuant
to the Merger Agreement, will be validly issued, fully paid and nonassessable.

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     We understand that this opinion is to be used in connection with the
Registration Statement.  We consent to the filing of this opinion as an Exhibit
to said Registration Statement and to the reference to our firm wherever it
appears in the Registration Statement, including the prospectuses constituting a
part thereof and any amendments thereto.  This opinion may be used in connection
with the offering of the Shares only while the Registration Statement, as it may
be amended from time to time, remains in effect.

                         Very truly yours,

                         BROWN, RUDNICK, FREED & GESMER
                         By:  BROWN, RUDNICK, FREED & GESMER, P.C.


                         By: /s/ Philip J. Flink
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                             Philip J. Flink, A Member
                             Duly Authorized

LML/PJF/CAW

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