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                                                                   Exhibit 10.81

                                                                       EXHIBIT A

                          REGISTRATION RIGHTS AGREEMENT

          This Registration Rights Agreement (this "AGREEMENT") is made and
entered into as of June 17, 2004, by and among Implant Sciences Corporation, a
Massachusetts corporation (the "COMPANY"), and the purchasers signatory hereto
(each such purchaser, a "PURCHASER" and collectively, the "PURCHASERS").

          This Agreement is made pursuant to the Securities Purchase Agreement,
dated as of the date hereof among the Company and the Purchasers (the "PURCHASE
AGREEMENT").

          The Company and the Purchasers hereby agree as follows:

     1.   DEFINITIONS. Capitalized terms used and not otherwise defined herein
that are defined in the Purchase Agreement shall have the meanings given such
terms in the Purchase Agreement. As used in this Agreement, the following terms
shall have the following meanings:

          "ADVICE" shall have the meaning set forth in Section 6(d).

           "EFFECTIVENESS DATE" means, with respect to the Registration
     Statement required to be filed hereunder, the earlier of (a) the 90th
     calendar day following the Closing Date (120th calendar day in the event of
     a "full review" by the SEC) and (b) the fifth Trading Day following the
     date on which the Company is notified by the Commission that the
     Registration Statement will not be reviewed or is no longer subject to
     further review and comments.

           "EFFECTIVENESS PERIOD" shall have the meaning set forth in Section
2(a).

          "EVENT" shall have the meaning set forth in Section 2(b).

          "EVENT DATE" shall have the meaning set forth in Section 2(b).

          "FILING DATE" means, with respect to the Registration Statement
     required to be filed hereunder, the 30th calendar day following the Closing
     Date.

          "HOLDER" or "HOLDERS" means the holder or holders, as the case may be,
     from time to time of Registrable Securities.

          "INDEMNIFIED PARTY" shall have the meaning set forth in Section 5(c).

          "INDEMNIFYING PARTY" shall have the meaning set forth in Section 5(c).

          "LOSSES" shall have the meaning set forth in Section 5(a).

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          "PROCEEDING" means an action, claim, suit, investigation or proceeding
     (including, without limitation, an investigation or partial proceeding,
     such as a deposition), whether commenced or threatened.

          "PROSPECTUS" means the prospectus included in the Registration
     Statement (including, without limitation, a prospectus that includes any
     information previously omitted from a prospectus filed as part of an
     effective registration statement in reliance upon Rule 430A promulgated
     under the Securities Act), as amended or supplemented by any prospectus
     supplement, with respect to the terms of the offering of any portion of the
     Registrable Securities covered by the Registration Statement, and all other
     amendments and supplements to the Prospectus, including post-effective
     amendments, and all material incorporated by reference or deemed to be
     incorporated by reference in such Prospectus.

          "REGISTRABLE SECURITIES" means all of the Shares, the Warrant Shares
     and the Additional Investment Right Shares, together with any shares of
     Common Stock issued or issuable upon any stock split, dividend or other
     distribution, recapitalization or similar event with respect to the
     foregoing.

          "REGISTRATION STATEMENT" means the registration statements required to
     be filed hereunder, including (in each case) the Prospectus, amendments and
     supplements to the registration statement or Prospectus, including pre- and
     post-effective amendments, all exhibits thereto, and all material
     incorporated by reference or deemed to be incorporated by reference in the
     registration statement.

          "RULE 415" means Rule 415 promulgated by the Commission pursuant to
     the Securities Act, as such Rule may be amended from time to time, or any
     similar rule or regulation hereafter adopted by the Commission having
     substantially the same purpose and effect as such Rule.

          "RULE 424" means Rule 424 promulgated by the Commission pursuant to
     the Securities Act, as such Rule may be amended from time to time, or any
     similar rule or regulation hereafter adopted by the Commission having
     substantially the same purpose and effect as such Rule.

     2.   REGISTRATION.

          (a)  On or prior to the Filing Date, the Company shall use its best
     efforts to prepare and file with the Commission the Registration Statement
     covering the resale of all of the Registrable Securities for an offering to
     be made on a continuous basis pursuant to Rule 415. The Registration
     Statement required hereunder shall be on Form S-3 (except if the Company is
     not then eligible to register for resale the Registrable Securities on Form
     S-3, in which case the Registration shall be on another appropriate form in
     accordance herewith). The Registration Statement required hereunder shall
     contain substantially the "PLAN OF DISTRIBUTION" attached hereto as ANNEX
     A. Subject to the terms of this Agreement, the Company shall use its best
     efforts to cause the Registration Statement to be declared effective under
     the Securities Act as promptly as possible after the filing thereof, but in
     any event not later than the Effectiveness Date, and shall use its

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     best efforts to keep the Registration Statement continuously effective
     under the Securities Act until the date when all Registrable Securities
     covered by the Registration Statement have been sold or may be sold without
     volume restrictions pursuant to Rule 144(k) as determined by the counsel to
     the Company pursuant to a written opinion letter to such effect, addressed
     and acceptable to the Company's transfer agent and the affected Holders
     (the "EFFECTIVENESS PERIOD").

          (b)  If: (i) a Registration Statement is not filed on or prior to the
     Filing Date (if the Company files a Registration Statement without
     affording the Holder the opportunity to review and comment on the same as
     required by Section 3(a), the Company shall not be deemed to have satisfied
     this clause (i)), or (ii) the Company fails to file with the Commission a
     request for acceleration in accordance with Rule 461 promulgated under the
     Securities Act, within five Trading Days of the date that the Company is
     notified (orally or in writing, whichever is earlier) by the Commission
     that a Registration Statement will not be "reviewed," or is not subject to
     further review, or (iii) a Registration Statement filed or required to be
     filed hereunder is not declared effective by the Commission on or before
     the Effectiveness Date, or (iv) after a Registration Statement is first
     declared effective by the Commission, it ceases for any reason to remain
     continuously effective as to all Registrable Securities for which it is
     required to be effective, or the Holders are not permitted to utilize the
     Prospectus therein to resell such Registrable Securities, for in any such
     case 25 calendar consecutive days but no more than an aggregate of 40
     calendar days during any 12 month period (which need not be consecutive
     Trading Days) (subject to tolling extension as provided by Section
     3(k))(any such failure or breach being referred to as an "EVENT," and for
     purposes of clause (i) or (iv) the date on which such Event occurs, or for
     purposes of clause (ii) the date on which such five Trading Day period is
     exceeded, or for purposes of clause (iv) the date on which such 25 or 40
     calendar day period, as applicable, is exceeded being referred to as "EVENT
     DATE"), then in addition to any other rights the Holders may have hereunder
     or under applicable law, on each such Event Date and, on each monthly
     anniversary of each such Event Date (if the applicable Event shall not have
     been cured by such date) until the applicable Event is cured, the Company
     shall pay to each Holder an amount in cash, as partial liquidated damages
     and not as a penalty, equal to 2.0% of the aggregate purchase price paid by
     such Holder pursuant to the Purchase Agreement for any Registrable
     Securities then held by such Holder. If the Company fails to pay any
     partial liquidated damages pursuant to this Section in full within seven
     days after the date payable, the Company will pay interest thereon at a
     rate of 18% per annum (or such lesser maximum amount that is permitted to
     be paid by applicable law) to the Holder, accruing daily from the date such
     partial liquidated damages are due until such amounts, plus all such
     interest thereon, are paid in full. The partial liquidated damages pursuant
     to the terms hereof shall apply on a daily pro-rata basis for any portion
     of a month prior to the cure of an Event.

     3.   REGISTRATION PROCEDURES

          In connection with the Company's registration obligations hereunder,
the Company shall:

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          (a)  Not less than three Trading Days prior to the filing of the
     Registration Statement or any related Prospectus or any amendment or
     supplement thereto, the Company shall, (i) furnish to the Holders copies of
     all such documents proposed to be filed (including documents incorporated
     or deemed incorporated by reference to the extent requested by such Person)
     which documents will be subject to the review of such Holders, and (ii)
     cause its officers and directors, counsel and independent certified public
     accountants to respond to such inquiries as shall be necessary, in the
     reasonable opinion of respective counsel to conduct a reasonable
     investigation within the meaning of the Securities Act. The Company shall
     not file the Registration Statement or any such Prospectus or any
     amendments or supplements thereto to which the Holders of a majority of the
     Registrable Securities shall reasonably object in good faith, provided that
     the Company is notified of such objection in writing no later than 2
     Trading Days after the Holders have been so furnished copies of such
     documents. Each Holder agrees to furnish to the Company a completed
     Questionnaire in the form attached to this Agreement as Annex B (a "SELLING
     HOLDER QUESTIONNAIRE") not less than three Trading Days prior to the Filing
     Date or by the end of the third Trading Day following the date on which
     such Holder receives draft materials in accordance with this Section.

          (b)  (i) Prepare and file with the Commission such amendments,
     including post-effective amendments, to the Registration Statement and the
     Prospectus used in connection therewith as may be necessary to keep the
     Registration Statement continuously effective as to the applicable
     Registrable Securities for the Effectiveness Period and prepare and file
     with the Commission such additional Registration Statements in order to
     register for resale under the Securities Act all of the Registrable
     Securities; (ii) cause the related Prospectus to be amended or supplemented
     by any required Prospectus supplement, and as so supplemented or amended to
     be filed pursuant to Rule 424; (iii) respond as promptly as reasonably
     possible to any comments received from the Commission with respect to the
     Registration Statement or any amendment thereto and, as promptly as
     reasonably possible, upon request, provide the Holders true and complete
     copies of all correspondence from and to the Commission relating to the
     Registration Statement; and (iv) comply in all material respects with the
     provisions of the Securities Act and the Exchange Act with respect to the
     disposition of all Registrable Securities covered by the Registration
     Statement during the applicable period in accordance with the intended
     methods of disposition by the Holders thereof set forth in the Registration
     Statement as so amended or in such Prospectus as so supplemented.

          (c)  Notify the Holders of Registrable Securities to be sold as
     promptly as reasonably possible and (if requested by any such Person)
     confirm such notice in writing promptly following the day (i)(A) when a
     Prospectus or any Prospectus supplement or post-effective amendment to the
     Registration Statement is proposed to be filed; (B) when the Commission
     notifies the Company whether there will be a "review" of the Registration
     Statement and whenever the Commission comments in writing on the
     Registration Statement (the Company shall upon request provide true and
     complete copies thereof and all written responses thereto to each of the
     Holders); and (C) with respect to the Registration Statement or any
     post-effective amendment, when the same has become effective; (ii) of any
     request by the Commission or any other Federal or state governmental
     authority during the period of effectiveness of the Registration Statement

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     for amendments or supplements to the Registration Statement or Prospectus
     or for additional information; (iii) of the issuance by the Commission or
     any other federal or state governmental authority of any stop order
     suspending the effectiveness of the Registration Statement covering any or
     all of the Registrable Securities or the initiation of any Proceedings for
     that purpose; (iv) of the receipt by the Company of any notification with
     respect to the suspension of the qualification or exemption from
     qualification of any of the Registrable Securities for sale in any
     jurisdiction, or the initiation or threatening of any Proceeding for such
     purpose; and (v) of the occurrence of any event or passage of time that
     makes the financial statements included in the Registration Statement
     ineligible for inclusion therein or any statement made in the Registration
     Statement or Prospectus or any document incorporated or deemed to be
     incorporated therein by reference untrue in any material respect or that
     requires any revisions to the Registration Statement, Prospectus or other
     documents so that, in the case of the Registration Statement or the
     Prospectus, as the case may be, it will not contain any untrue statement of
     a material fact or omit to state any material fact required to be stated
     therein or necessary to make the statements therein, in light of the
     circumstances under which they were made, not misleading.

          (d)  Use commercially reasonable efforts to avoid the issuance of, or,
     if issued, obtain the withdrawal of (i) any order suspending the
     effectiveness of the Registration Statement, or (ii) any suspension of the
     qualification (or exemption from qualification) of any of the Registrable
     Securities for sale in any jurisdiction, at the earliest practicable
     moment.

          (e)  Furnish to each Holder, without charge, at least one conformed
     copy of the Registration Statement and each amendment thereto, including
     financial statements and schedules, all documents incorporated or deemed to
     be incorporated therein by reference to the extent requested by such
     Person, and all exhibits to the extent requested by such Person (including
     those previously furnished or incorporated by reference) promptly after the
     filing of such documents with the Commission.

          (f)  Promptly deliver to each Holder, without charge, as many copies
     of the Prospectus or Prospectuses (including each form of prospectus) and
     each amendment or supplement thereto as such Persons may reasonably request
     in connection with resales by the Holder of Registrable Securities. Subject
     to the terms of this Agreement, the Company hereby consents to the use of
     such Prospectus and each amendment or supplement thereto by each of the
     selling Holders in connection with the offering and sale of the Registrable
     Securities covered by such Prospectus and any amendment or supplement
     thereto, except after the giving on any notice pursuant to Section 3(c).

          (g) Prior to any resale of Registrable Securities by a Holder, use its
     commercially reasonable efforts to register or qualify or cooperate with
     the selling Holders in connection with the registration or qualification
     (or exemption from the Registration or qualification) of such Registrable
     Securities for the resale by the Holder under the securities or Blue Sky
     laws of such jurisdictions within the United States as any Holder
     reasonably requests in writing, to keep the Registration or qualification
     (or exemption therefrom) effective during the Effectiveness Period and to
     do any and all

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     other acts or things reasonably necessary to enable the disposition in such
     jurisdictions of the Registrable Securities covered by the Registration
     Statement; PROVIDED, that the Company shall not be required to qualify
     generally to do business in any jurisdiction where it is not then so
     qualified, subject the Company to any material tax in any such jurisdiction
     where it is not then so subject or file a general consent to service of
     process in any such jurisdiction.

          (h)  If requested by the Holders, cooperate with the Holders to
     facilitate the timely preparation and delivery of certificates representing
     Registrable Securities to be delivered to a transferee pursuant to the
     Registration Statement, which certificates shall be free, to the extent
     permitted by the Purchase Agreement, of all restrictive legends, and to
     enable such Registrable Securities to be in such denominations and
     registered in such names as any such Holders may request.

          (i)  Upon the occurrence of any event contemplated by Section 3(c)(v),
     as promptly as reasonably possible, prepare a supplement or amendment,
     including a post-effective amendment, to the Registration Statement or a
     supplement to the related Prospectus or any document incorporated or deemed
     to be incorporated therein by reference, and file any other required
     document so that, as thereafter delivered, neither the Registration
     Statement nor such Prospectus will contain an untrue statement of a
     material fact or omit to state a material fact required to be stated
     therein or necessary to make the statements therein, in light of the
     circumstances under which they were made, not misleading. If the Company
     notifies the Holders in accordance with clauses (ii) through (v) of Section
     3(c) above to suspend the use of any Prospectus until the requisite changes
     to such Prospectus have been made, then the Holders shall suspend use of
     such Prospectus. The Company will use its best efforts to ensure that the
     use of the Prospectus may be resumed as promptly as is practicable. The
     Company shall be entitled to exercise its right under this Section 3(i) to
     suspend the availability of a Registration Statement and Prospectus,
     subject to the payment of liquidated damages pursuant to Section 2(b), for
     a period not to exceed 90 days (which need not be consecutive days) in any
     12 month period.

          (j)  Comply with all applicable rules and regulations of the
     Commission.

          (k)  The Company may require each selling Holder to furnish to the
     Company a certified statement as to the number of shares of Common Stock
     beneficially owned by such Holder and, if required by the Commission, the
     person thereof that has voting and dispositive control over the Shares.
     During any periods that the Company is unable to meet its obligations
     hereunder with respect to the registration of the Registrable Securities
     solely because a Holder fails to furnish such information within three
     Trading Days of the Company's request, any liquidated damages that are
     accruing at such time as to all Holders shall be tolled and any Event that
     may otherwise occur solely because of such delay shall be suspended as to
     all Holders, until such information is delivered to the Company.

     4.   REGISTRATION EXPENSES. All fees and expenses incident to the
performance of or compliance with this Agreement by the Company shall be borne
by the Company whether or not

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any Registrable Securities are sold pursuant to the Registration Statement. The
fees and expenses referred to in the foregoing sentence shall include, without
limitation, (i) all registration and filing fees (including, without limitation,
fees and expenses (A) with respect to filings required to be made with the
Trading Market on which the Common Stock is then listed for trading, and (B) in
compliance with applicable state securities or Blue Sky laws), (ii) printing
expenses (including, without limitation, expenses of printing certificates for
Registrable Securities and of printing prospectuses if the printing of
prospectuses is reasonably requested by the holders of a majority of the
Registrable Securities included in the Registration Statement), (iii) messenger,
telephone and delivery expenses, (iv) fees and disbursements of counsel for the
Company, (v) Securities Act liability insurance, if the Company so desires such
insurance, and (vi) fees and expenses of all other Persons retained by the
Company in connection with the consummation of the transactions contemplated by
this Agreement. In addition, the Company shall be responsible for all of its
internal expenses incurred in connection with the consummation of the
transactions contemplated by this Agreement (including, without limitation, all
salaries and expenses of its officers and employees performing legal or
accounting duties), the expense of any annual audit and the fees and expenses
incurred in connection with the listing of the Registrable Securities on any
securities exchange as required hereunder. In no event shall the Company be
responsible for any broker or similar commissions or, except to the extent
provided for in the Transaction Documents, any legal fees or other costs of the
Holders.

     5.   INDEMNIFICATION

          (a)  INDEMNIFICATION BY THE COMPANY. The Company shall,
     notwithstanding any termination of this Agreement, indemnify and hold
     harmless each Holder, the officers, directors, agents, brokers, investment
     advisors and employees of each of them, each Person who controls any such
     Holder (within the meaning of Section 15 of the Securities Act or Section
     20 of the Exchange Act) and the officers, directors, agents and employees
     of each such controlling Person, to the fullest extent permitted by
     applicable law, from and against any and all losses, claims, damages,
     liabilities, costs (including, without limitation, reasonable attorneys'
     fees) and expenses (collectively, "LOSSES"), as incurred, arising out of or
     relating to any untrue or alleged untrue statement of a material fact
     contained in the Registration Statement, any Prospectus or any form of
     prospectus or in any amendment or supplement thereto or in any preliminary
     prospectus, or arising out of or relating to any omission or alleged
     omission of a material fact required to be stated therein or necessary to
     make the statements therein (in the case of any Prospectus or form of
     prospectus or supplement thereto, in light of the circumstances under which
     they were made) not misleading, except to the extent, but only to the
     extent, that (i) such untrue statements or omissions are based solely upon
     information regarding such Holder furnished in writing to the Company by
     such Holder expressly for use therein, or to the extent that such
     information relates to such Holder or such Holder's proposed method of
     distribution of Registrable Securities and was reviewed and expressly
     approved in writing by such Holder expressly for use in the Registration
     Statement, such Prospectus or such form of Prospectus or in any amendment
     or supplement thereto (it being understood that the Holder has approved
     Annex A hereto for this purpose) or (ii) in the case of an occurrence of an
     event of the type specified in Section 3(c)(ii)-(v), the use by such Holder
     of an outdated or defective Prospectus after the Company has notified such
     Holder in writing that the Prospectus is outdated or defective and prior to
     the receipt by such

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     Holder of the Advice contemplated in Section 6(d). The Company shall notify
     the Holders promptly of the institution, threat or assertion of any
     Proceeding of which the Company is aware in connection with the
     transactions contemplated by this Agreement.

          (b)  INDEMNIFICATION BY HOLDERS. Each Holder shall, severally and not
     jointly, indemnify and hold harmless the Company, its directors, officers,
     agents and employees, each Person who controls the Company (within the
     meaning of Section 15 of the Securities Act and Section 20 of the Exchange
     Act), and the directors, officers, agents or employees of such controlling
     Persons, to the fullest extent permitted by applicable law, from and
     against all Losses, as incurred, to the extent arising out of or based
     solely upon: (x) such Holder's failure to comply with the prospectus
     delivery requirements of the Securities Act or (y) any untrue or alleged
     untrue statement of a material fact contained in any Registration
     Statement, any Prospectus, or any form of prospectus, or in any amendment
     or supplement thereto or in any preliminary prospectus, or arising out of
     or relating to any omission or alleged omission of a material fact required
     to be stated therein or necessary to make the statements therein not
     misleading (i) to the extent, but only to the extent, that such untrue
     statement or omission is contained in any information so furnished in
     writing by such Holder to the Company specifically for inclusion in the
     Registration Statement or such Prospectus or (ii) to the extent that (1)
     such untrue statements or omissions are based solely upon information
     regarding such Holder furnished in writing to the Company by such Holder
     expressly for use therein, or to the extent that such information relates
     to such Holder or such Holder's proposed method of distribution of
     Registrable Securities and was reviewed and expressly approved in writing
     by such Holder expressly for use in the Registration Statement (it being
     understood that the Holder has approved Annex A hereto for this purpose),
     such Prospectus or such form of Prospectus or in any amendment or
     supplement thereto or (2) in the case of an occurrence of an event of the
     type specified in Section 3(c)(ii)-(v), the use by such Holder of an
     outdated or defective Prospectus after the Company has notified such Holder
     in writing that the Prospectus is outdated or defective and prior to the
     receipt by such Holder of the Advice contemplated in Section 6(d). In no
     event shall the liability of any selling Holder hereunder be greater in
     amount than the dollar amount of the net proceeds received by such Holder
     upon the sale of the Registrable Securities giving rise to such
     indemnification obligation.

          (c)  CONDUCT OF INDEMNIFICATION PROCEEDINGS. If any Proceeding shall
     be brought or asserted against any Person entitled to indemnity hereunder
     (an "INDEMNIFIED PARTY"), such Indemnified Party shall promptly notify the
     Person from whom indemnity is sought (the "INDEMNIFYING PARTY") in writing,
     and the Indemnifying Party shall have the right to assume the defense
     thereof, including the employment of counsel reasonably satisfactory to the
     Indemnified Party and the payment of all fees and expenses incurred in
     connection with defense thereof; provided, that the failure of any
     Indemnified Party to give such notice shall not relieve the Indemnifying
     Party of its obligations or liabilities pursuant to this Agreement, except
     (and only) to the extent that it shall be finally determined by a court of
     competent jurisdiction (which determination is not subject to appeal or
     further review) that such failure shall have prejudiced the Indemnifying
     Party.

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          An Indemnified Party shall have the right to employ separate counsel
     in any such Proceeding and to participate in the defense thereof, but the
     fees and expenses of such counsel shall be at the expense of such
     Indemnified Party or Parties unless: (1) the Indemnifying Party has agreed
     in writing to pay such fees and expenses; (2) the Indemnifying Party shall
     have failed promptly to assume the defense of such Proceeding and to employ
     counsel reasonably satisfactory to such Indemnified Party in any such
     Proceeding; or (3) the named parties to any such Proceeding (including any
     impleaded parties) include both such Indemnified Party and the Indemnifying
     Party, and such Indemnified Party shall reasonably believe that a material
     conflict of interest is likely to exist if the same counsel were to
     represent such Indemnified Party and the Indemnifying Party (in which case,
     if such Indemnified Party notifies the Indemnifying Party in writing that
     it elects to employ separate counsel at the expense of the Indemnifying
     Party, the Indemnifying Party shall not have the right to assume the
     defense thereof and the reasonable fees and expenses of one separate
     counsel shall be at the expense of the Indemnifying Party). The
     Indemnifying Party shall not be liable for any settlement of any such
     Proceeding effected without its written consent, which consent shall not be
     unreasonably withheld. No Indemnifying Party shall, without the prior
     written consent of the Indemnified Party, effect any settlement of any
     pending Proceeding in respect of which any Indemnified Party is a party,
     unless such settlement includes an unconditional release of such
     Indemnified Party from all liability on claims that are the subject matter
     of such Proceeding.

          Subject to the terms of this Agreement, all reasonable fees and
     expenses of the Indemnified Party (including reasonable fees and expenses
     to the extent incurred in connection with investigating or preparing to
     defend such Proceeding in a manner not inconsistent with this Section)
     shall be paid to the Indemnified Party, as incurred, within ten Trading
     Days of written notice thereof to the Indemnifying Party; PROVIDED, that
     the Indemnified Party shall promptly reimburse the Indemnifying Party for
     that portion of such fees and expenses applicable to such actions for which
     such Indemnified Party is not entitled to indemnification hereunder,
     determined based upon the relative faults of the parties.

          (d)  CONTRIBUTION. If a claim for indemnification under Section 5(a)
     or 5(b) is unavailable to an Indemnified Party (by reason of public policy
     or otherwise), then each Indemnifying Party, in lieu of indemnifying such
     Indemnified Party, shall contribute to the amount paid or payable by such
     Indemnified Party as a result of such Losses, in such proportion as is
     appropriate to reflect the relative fault of the Indemnifying Party and
     Indemnified Party in connection with the actions, statements or omissions
     that resulted in such Losses as well as any other relevant equitable
     considerations. The relative fault of such Indemnifying Party and
     Indemnified Party shall be determined by reference to, among other things,
     whether any action in question, including any untrue or alleged untrue
     statement of a material fact or omission or alleged omission of a material
     fact, has been taken or made by, or relates to information supplied by,
     such Indemnifying Party or Indemnified Party, and the parties' relative
     intent, knowledge, access to information and opportunity to correct or
     prevent such action, statement or omission. The amount paid or payable by a
     party as a result of any Losses shall be deemed to include, subject to the
     limitations set forth in this Agreement, any reasonable attorneys' or other
     reasonable fees

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     or expenses incurred by such party in connection with any Proceeding to the
     extent such party would have been indemnified for such fees or expenses if
     the indemnification provided for in this Section was available to such
     party in accordance with its terms.

          The parties hereto agree that it would not be just and equitable if
     contribution pursuant to this Section 5(d) were determined by pro rata
     allocation or by any other method of allocation that does not take into
     account the equitable considerations referred to in the immediately
     preceding paragraph. Notwithstanding the provisions of this Section 5(d),
     no Holder shall be required to contribute, in the aggregate, any amount in
     excess of the amount by which the proceeds actually received by such Holder
     from the sale of the Registrable Securities subject to the Proceeding
     exceeds the amount of any damages that such Holder has otherwise been
     required to pay by reason of such untrue or alleged untrue statement or
     omission or alleged omission, except in the case of fraud by such Holder.

          The indemnity and contribution agreements contained in this Section
     are in addition to any liability that the Indemnifying Parties may have to
     the Indemnified Parties.

     6.   MISCELLANEOUS

          (a)  REMEDIES. In the event of a breach by the Company or by a Holder,
     of any of their obligations under this Agreement, each Holder or the
     Company, as the case may be, in addition to being entitled to exercise all
     rights granted by law and under this Agreement, including recovery of
     damages, will be entitled to specific performance of its rights under this
     Agreement. The Company and each Holder agree that monetary damages would
     not provide adequate compensation for any losses incurred by reason of a
     breach by it of any of the provisions of this Agreement and hereby further
     agrees that, in the event of any action for specific performance in respect
     of such breach, it shall waive the defense that a remedy at law would be
     adequate.

          (b)  NO PIGGYBACK ON REGISTRATIONS. Except as set forth on SCHEDULE
     6(b) attached hereto, neither the Company nor any of its security holders
     (other than the Holders in such capacity pursuant hereto) may include
     securities of the Company in a Registration Statement other than the
     Registrable Securities. No Person has any right to cause the Company to
     effect the registration under the Securities Act of any securities of the
     Company. The Company shall not file any other registration statement until
     after the Effective Date.

          (c)  COMPLIANCE. Each Holder covenants and agrees that it will comply
     with the prospectus delivery requirements of the Securities Act as
     applicable to it in connection with sales of Registrable Securities
     pursuant to the Registration Statement.

          (d)  DISCONTINUED DISPOSITION. Each Holder agrees by its acquisition
     of such Registrable Securities that, upon receipt of a notice from the
     Company of the occurrence of any event of the kind described in Section
     3(c), such Holder will forthwith discontinue disposition of such
     Registrable Securities under the Registration Statement until such

                                      -- 10
<Page>

     Holder's receipt of the copies of the supplemented Prospectus and/or
     amended Registration Statement or until it is advised in writing (the
     "ADVICE") by the Company that the use of the applicable Prospectus may be
     resumed, and, in either case, has received copies of any additional or
     supplemental filings that are incorporated or deemed to be incorporated by
     reference in such Prospectus or Registration Statement. The Company will
     use its best efforts to ensure that the use of the Prospectus may be
     resumed as promptly as it practicable. The Company agrees and acknowledges
     that any periods during which the Holder is required to discontinue the
     disposition of the Registrable Securities hereunder shall be subject to the
     provisions of Section 2(b).

          (e)  PIGGY-BACK REGISTRATIONS. If at any time during the Effectiveness
     Period there is not an effective Registration Statement covering all of the
     Registrable Securities and the Company shall determine to prepare and file
     with the Commission a registration statement relating to an offering for
     its own account or the account of others under the Securities Act of any of
     its equity securities, other than on Form S-4 or Form S-8 (each as
     promulgated under the Securities Act) or their then equivalents relating to
     equity securities to be issued solely in connection with any acquisition of
     any entity or business or equity securities issuable in connection with the
     stock option or other employee benefit plans, then the Company shall send
     to each Holder a written notice of such determination and, if within
     fifteen days after the date of such notice, any such Holder shall so
     request in writing, the Company shall include in such registration
     statement all or any part of such Registrable Securities such Holder
     requests to be registered, subject to customary underwriter cutbacks
     applicable to all holders of registration rights.

          (f)  AMENDMENTS AND WAIVERS. The provisions of this Agreement,
     including the provisions of this sentence, may not be amended, modified or
     supplemented, and waivers or consents to departures from the provisions
     hereof may not be given, unless the same shall be in writing and signed by
     the Company and each Holder of the then outstanding Registrable Securities.

          (g)  NOTICES. Any and all notices or other communications or
     deliveries required or permitted to be provided hereunder shall be made in
     accordance with the provisions of the Purchase Agreement.

          (h)  SUCCESSORS AND ASSIGNS. This Agreement shall inure to the benefit
     of and be binding upon the successors and permitted assigns of each of the
     parties and shall inure to the benefit of each Holder. Each Holder may
     assign their respective rights hereunder in the manner and to the Persons
     as permitted under the Purchase Agreement.

          (i)  EXECUTION AND COUNTERPARTS. This Agreement may be executed in any
     number of counterparts, each of which when so executed shall be deemed to
     be an original and, all of which taken together shall constitute one and
     the same Agreement. In the event that any signature is delivered by
     facsimile transmission, such signature shall create a valid binding
     obligation of the party executing (or on whose behalf such signature is
     executed) the same with the same force and effect as if such facsimile
     signature were the original thereof.

                                      -- 11
<Page>

          (j)  GOVERNING LAW. All questions concerning the construction,
     validity, enforcement and interpretation of this Agreement shall be
     determined with the provisions of the Purchase Agreement.

          (k)  CUMULATIVE REMEDIES. The remedies provided herein are cumulative
     and not exclusive of any remedies provided by law.

          (l)  SEVERABILITY. If any term, provision, covenant or restriction of
     this Agreement is held by a court of competent jurisdiction to be invalid,
     illegal, void or unenforceable, the remainder of the terms, provisions,
     covenants and restrictions set forth herein shall remain in full force and
     effect and shall in no way be affected, impaired or invalidated, and the
     parties hereto shall use their commercially reasonable efforts to find and
     employ an alternative means to achieve the same or substantially the same
     result as that contemplated by such term, provision, covenant or
     restriction. It is hereby stipulated and declared to be the intention of
     the parties that they would have executed the remaining terms, provisions,
     covenants and restrictions without including any of such that may be
     hereafter declared invalid, illegal, void or unenforceable.

          (m)  HEADINGS. The headings in this Agreement are for convenience of
     reference only and shall not limit or otherwise affect the meaning hereof.

          (n)  INDEPENDENT NATURE OF PURCHASERS' OBLIGATIONS AND RIGHTS. The
     obligations of each Holder hereunder are several and not joint with the
     obligations of any other Holder hereunder, and no Holder shall be
     responsible in any way for the performance of the obligations of any other
     Holder hereunder. Nothing contained herein or in any other agreement or
     document delivered at any closing, and no action taken by any Holder
     pursuant hereto or thereto, shall be deemed to constitute the Holders as a
     partnership, an association, a joint venture or any other kind of entity,
     or create a presumption that the Holders are in any way acting in concert
     with respect to such obligations or the transactions contemplated by this
     Agreement. Each Holder shall be entitled to protect and enforce its rights,
     including without limitation the rights arising out of this Agreement, and
     it shall not be necessary for any other Holder to be joined as an
     additional party in any proceeding for such purpose.

                            *************************

                                     -- 12
<Page>

          IN WITNESS WHEREOF, the parties have executed this Registration Rights
Agreement as of the date first written above.


                                            IMPLANT SCIENCES CORPORATION


                                            By:
                                               --------------------------------
                                               Name:
                                               Title:


                       [SIGNATURE PAGE OF HOLDERS FOLLOWS]

<Page>

                     [PURCHASER'S SIGNATURE PAGE TO IMX RRA]

Name of Investing Entity: __________________________
SIGNATURE OF AUTHORIZED SIGNATORY OF INVESTING ENTITY: _________________________
Name of Authorized Signatory: _________________________
Title of Authorized Signatory: __________________________


                           [SIGNATURE PAGES CONTINUE]


                                      -- 14
<Page>

                                     ANNEX A

                              PLAN OF DISTRIBUTION

     The Selling Stockholders (the "SELLING STOCKHOLDERS") of the common stock
("COMMON STOCK") of Implant Sciences Corporation (the "COMPANY") and any of
their pledgees, assignees and successors-in-interest may, from time to time,
sell any or all of their shares of Common Stock on any stock exchange, market or
trading facility on which the shares are traded or in private transactions.
These sales may be at fixed or negotiated prices. The Selling Stockholders may
use any one or more of the following methods when selling shares:

          -    ordinary brokerage transactions and transactions in which the
               broker-dealer solicits purchasers;

          -    block trades in which the broker-dealer will attempt to sell the
               shares as agent but may position and resell a portion of the
               block as principal to facilitate the transaction;

          -    purchases by a broker-dealer as principal and resale by the
               broker-dealer for its account;

          -    an exchange distribution in accordance with the rules of the
               applicable exchange;

          -    privately negotiated transactions;

          -    settlement of short sales entered into after the date of this
               prospectus;

          -    broker-dealers may agree with the Selling Stockholders to sell a
               specified number of such shares at a stipulated price per share;

          -    a combination of any such methods of sale;

          -    through the writing or settlement of options or other hedging
               transactions, whether through an options exchange or otherwise;
               or

          -    any other method permitted pursuant to applicable law.

     The Selling Stockholders may also sell shares under Rule 144 under the
Securities Act of 1933, as amended (the "SECURITIES ACT"), if available, rather
than under this prospectus.

     Broker-dealers engaged by the Selling Stockholders may arrange for other
brokers-dealers to participate in sales. Broker-dealers may receive commissions
or discounts from the Selling Stockholders (or, if any broker-dealer acts as
agent for the purchaser of shares, from the purchaser) in amounts to be
negotiated. Each Selling Stockholder does not expect these commissions and
discounts relating to its sales of shares to exceed what is customary in the
types of transactions involved.

                                      -- 15
<Page>

     In connection with the sale of our common stock or interests therein, the
Selling Stockholders may enter into hedging transactions with broker-dealers or
other financial institutions, which may in turn engage in short sales of the
common stock in the course of hedging the positions they assume. The Selling
Stockholders may also sell shares of our common stock short and deliver these
securities to close out their short positions, or loan or pledge the common
stock to broker-dealers that in turn may sell these securities. The Selling
Stockholders may also enter into option or other transactions with
broker-dealers or other financial institutions or the creation of one or more
derivative securities which require the delivery to such broker-dealer or other
financial institution of shares offered by this prospectus, which shares such
broker-dealer or other financial institution may resell pursuant to this
prospectus (as supplemented or amended to reflect such transaction).

     The Selling Stockholders and any broker-dealers or agents that are involved
in selling the shares may be deemed to be "underwriters" within the meaning of
the Securities Act in connection with such sales. In such event, any commissions
received by such broker-dealers or agents and any profit on the resale of the
shares purchased by them may be deemed to be underwriting commissions or
discounts under the Securities Act. Each Selling Stockholder has informed the
Company that it does not have any agreement or understanding, directly or
indirectly, with any person to distribute the Common Stock.

     The Company is required to pay certain fees and expenses incurred by the
Company incident to the registration of the shares. The Company has agreed to
indemnify the Selling Stockholders against certain losses, claims, damages and
liabilities, including liabilities under the Securities Act.

     Because Selling Stockholders may be deemed to be "underwriters" within the
meaning of the Securities Act, they will be subject to the prospectus delivery
requirements of the Securities Act. In addition, any securities covered by this
prospectus which qualify for sale pursuant to Rule 144 under the Securities Act
may be sold under Rule 144 rather than under this prospectus. Each Selling
Stockholder has advised us that they have not entered into any agreements,
understandings or arrangements with any underwriter or broker-dealer regarding
the sale of the resale shares. There is no underwriter or coordinating broker
acting in connection with the proposed sale of the resale shares by the Selling
Stockholders.

     We agreed to keep this prospectus effective until the earlier of (i) the
date on which the shares may be resold by the Selling Stockholders without
registration and without regard to any volume limitations by reason of Rule
144(k) under the Securities Act or any other rule of similar effect or (ii) all
of the shares have been sold pursuant to the prospectus or Rule 144 under the
Securities Act or any other rule of similar effect. The resale shares will be
sold only through registered or licensed brokers or dealers if required under
applicable state securities laws. In addition, in certain states, the resale
shares may not be sold unless they have been registered or qualified for sale in
the applicable state or an exemption from the registration or qualification
requirement is available and is complied with.

     Under applicable rules and regulations under the Exchange Act, any person
engaged in the distribution of the resale shares may not simultaneously engage
in market making activities with respect to our common stock for a period of two
business days prior to the commencement

                                      -- 16
<Page>

of the distribution. In addition, the Selling Stockholders will be subject to
applicable provisions of the Exchange Act and the rules and regulations
thereunder, including Regulation M, which may limit the timing of purchases and
sales of shares of our common stock by the Selling Stockholders or any other
person. We will make copies of this prospectus available to the Selling
Stockholders and have informed them of the need to deliver a copy of this
prospectus to each purchaser at or prior to the time of the sale.

                                      -- 17
<Page>

                                                                         ANNEX B

                          IMPLANT SCIENCES CORPORATION

                 SELLING SECURITYHOLDER NOTICE AND QUESTIONNAIRE

     The undersigned beneficial owner of common stock, par value $0.10 per share
(the "COMMON STOCK"), of Implant Sciences Corporation, a Massachusetts
corporation (the "COMPANY"), (the "REGISTRABLE SECURITIES") understands that the
Company has filed or intends to file with the Securities and Exchange Commission
(the "COMMISSION") a registration statement on Form S-3 (the "REGISTRATION
STATEMENT") for the registration and resale under Rule 415 of the Securities Act
of 1933, as amended (the "SECURITIES ACT"), of the Registrable Securities, in
accordance with the terms of the Registration Rights Agreement, dated as of June
___, 2004 (the "REGISTRATION RIGHTS AGREEMENT"), among the Company and the
Purchasers named therein. A copy of the Registration Rights Agreement is
available from the Company upon request at the address set forth below. All
capitalized terms not otherwise defined herein shall have the meanings ascribed
thereto in the Registration Rights Agreement.

     Certain legal consequences arise from being named as a selling
securityholder in the Registration Statement and the related prospectus.
Accordingly, holders and beneficial owners of Registrable Securities are advised
to consult their own securities law counsel regarding the consequences of being
named or not being named as a selling securityholder in the Registration
Statement and the related prospectus.

                                     NOTICE

     The undersigned beneficial owner (the "SELLING SECURITYHOLDER") of
Registrable Securities hereby elects to include the Registrable Securities owned
by it and listed below in Item 3 (unless otherwise specified under such Item 3)
in the Registration Statement.

                                      -- 18
<Page>

The undersigned hereby provides the following information to the Company and
represents and warrants that such information is accurate:

                                  QUESTIONNAIRE

1.   NAME.

     (a)    Full Legal Name of Selling Securityholder

            ____________________________________________________________________

     (b)    Full Legal Name of Registered Holder (if not the same as (a) above)
            through which Registrable Securities Listed in Item 3 below are
            held:

            ____________________________________________________________________

     (c)    Full Legal Name of Natural Control Person (which means a natural
            person who directly you indirectly alone or with others has power to
            vote or dispose of the securities covered by the questionnaire):

            ____________________________________________________________________


2. ADDRESS FOR NOTICES TO SELLING SECURITYHOLDER:

________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
 Telephone:_____________________________________________________________________
 Fax:___________________________________________________________________________
 Contact Person:________________________________________________________________

3. BENEFICIAL OWNERSHIP OF REGISTRABLE SECURITIES:

     (a)    Type and Principal Amount of Registrable Securities beneficially
            owned:

            ____________________________________________________________________

            ____________________________________________________________________

            ____________________________________________________________________

                                      -- 19
<Page>

4. BROKER-DEALER STATUS:

     (a)    Are you a broker-dealer?

                               Yes / /     No / /

     Note:  If yes, the Commission's staff has indicated that you should be
            identified as an underwriter in the Registration Statement.

     (b)    Are you an affiliate of a broker-dealer?

                               Yes / /     No / /

     (c)    If you are an affiliate of a broker-dealer, do you certify that you
            bought the Registrable Securities in the ordinary course of
            business, and at the time of the purchase of the Registrable
            Securities to be resold, you had no agreements or understandings,
            directly or indirectly, with any person to distribute the
            Registrable Securities?

                               Yes / /     No / /

     Note:  If no, the Commission's staff has indicated that you should be
            identified as an underwriter in the Registration Statement.

5. BENEFICIAL OWNERSHIP OF OTHER SECURITIES OF THE COMPANY OWNED BY THE SELLING
            SECURITYHOLDER.

     EXCEPT AS SET FORTH BELOW IN THIS ITEM 5, THE UNDERSIGNED IS NOT THE
     BENEFICIAL OR REGISTERED OWNER OF ANY SECURITIES OF THE COMPANY OTHER THAN
     THE REGISTRABLE SECURITIES LISTED ABOVE IN ITEM 3.

     (a)    Type and Amount of Other Securities beneficially owned by the
            Selling Securityholder:

            ____________________________________________________________________

            ____________________________________________________________________

                                      -- 20
<Page>

6. RELATIONSHIPS WITH THE COMPANY:

     EXCEPT AS SET FORTH BELOW, NEITHER THE UNDERSIGNED NOR ANY OF ITS
     AFFILIATES, OFFICERS, DIRECTORS OR PRINCIPAL EQUITY HOLDERS (OWNERS OF 5%
     OF MORE OF THE EQUITY SECURITIES OF THE UNDERSIGNED) HAS HELD ANY POSITION
     OR OFFICE OR HAS HAD ANY OTHER MATERIAL RELATIONSHIP WITH THE COMPANY (OR
     ITS PREDECESSORS OR AFFILIATES) DURING THE PAST THREE YEARS.

     State any exceptions here:

     ___________________________________________________________________________

     ___________________________________________________________________________


     The undersigned agrees to promptly notify the Company of any inaccuracies
or changes in the information provided herein that may occur subsequent to the
date hereof at any time while the Registration Statement remains effective.

     By signing below, the undersigned consents to the disclosure of the
information contained herein in its answers to Items 1 through 6 and the
inclusion of such information in the Registration Statement and the related
prospectus. The undersigned understands that such information will be relied
upon by the Company in connection with the preparation or amendment of the
Registration Statement and the related prospectus.

     IN WITNESS WHEREOF the undersigned, by authority duly given, has caused
this Notice and Questionnaire to be executed and delivered either in person or
by its duly authorized agent.

Dated:                                     Beneficial Owner:
      -------------------------                             --------------------

                                           By:
                                              ----------------------------------
                                              Name:
                                              Title:

PLEASE FAX A COPY OF THE COMPLETED AND EXECUTED NOTICE AND QUESTIONNAIRE, AND
RETURN THE ORIGINAL BY OVERNIGHT MAIL, TO:

                                      -- 21