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                                                                  Exhibit 10.2

                              SEPARATION AGREEMENT

          This Separation Agreement ("Agreement") is entered into as of July 29,
2002 by and among the following: Craig Dees, Ph.D. and Dees Family Foundation
(collectively, "Dees"), Eric A. Wachter, Ph.D. and Eric A. Wachter 1998
Charitable Remainder Unitrust (collectively, "Wachter"), Timothy D. Scott, Ph.D.
and Scott Family Investment Limited Partnership (collectively, "Scott"); Walter
Fisher, Ph.D., Fisher Family Investment Limited Partnership, and Walt Fisher
1998 Charitable Remainder Unitrust (collectively, "Fisher"), and John A. Smolik
and Smolik Family LLP (collectively, "Smolik"), Photogen Technologies, Inc.
("Technologies"), Photogen, Inc. ("Photogen"), Robert J. Weinstein, M.D.
("Weinstein"), Stuart P. Levine ("Levine") and Tannebaum, LLC ("Tannebaum,
LLC").

                                    RECITALS

          Dees, Wachter, Scott, Fisher and Smolik are collectively referred to
herein as the "Tennessee Stockholders." The Tennessee Stockholders are the
record and beneficial owners, collectively, of 20,548,435 shares of Technologies
Stock, constituting 52.9% of all of the issued and outstanding common stock of
Technologies. Craig Dees, Walter Fisher and John Smolik are former officers
and/or directors of Technologies and Photogen. Eric Wachter is a current
director and officer, and Timothy Scott is a current officer and former
director, of Technologies and Photogen.

          The Tennessee Stockholders are parties to the Voting Agreement,
pursuant to which they agreed to vote their Technologies Stock for the election
of certain nominees to the Board of Technologies and for certain other matters
as provided in the Voting Agreement. The Tennessee Stockholders are also parties
to the Lock Up Agreement, pursuant to which they agreed to refrain from selling
or otherwise disposing of their Technologies Stock, and to certain other
matters, as provided in the Lock Up Agreement.

          Technologies and its wholly-owned subsidiary Photogen have been
involved in two lines of businesses since May of 1997, namely the Diagnostic
Business and the Therapeutic Business. Photogen's first patents reflect these
two separate and distinct lines of business and its subsequent operations over
the last five years are consistent with, on the one hand, developing
technologies for the treatment of (among other things) cancer, pre-cancerous
conditions, psoriasis and other dermatological conditions ("Therapeutic
Business"); and, on the other hand, the diagnosis of cancer (through
lymphography and other methods) and cardiovascular disease ("Diagnostic
Business").

          Management of Technologies and Photogen believes that the medical need
and economic potential of PH-50 and N-1177 and other diagnostic technologies is
of such significance that management recently determined to focus substantially
all of its development efforts and resources in this area for the foreseeable
future, and to seek to license out, partner or otherwise co-develop PH-10 and
other therapeutic technologies, without significant use of its resources, to or
with other companies for further development and commercialization. Management's
decision to focus principally on the development of PH-50 and diagnostic
technologies is also based on the fact that developing programs for therapeutics
and diagnostic imaging products are significantly different and an attempt to
develop therapeutic and diagnostic

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programs concurrently would require substantial amounts of capital and diverse
management resources not currently available to Technologies or Photogen.

          As a result of the foregoing, certain differences have arisen between
the Tennessee Stockholders, on the one hand, and the current management of
Technologies and Photogen, on the other hand, concerning (among other things)
the management, direction and business plan of Technologies and Photogen and
particularly the resources and development of the Diagnostic Business compared
to the Therapeutic Business (the "Differences"). Such Differences are
increasingly likely to lead to conflicts that may prevent Technologies and
Photogen from devoting the necessary amount of time and resources to developing
the Diagnostic and Therapeutic Businesses, respectively.

          In order to effect the separation contemplated by this Agreement and
allow the Parties to devote full resources to their separate Businesses in a
timely manner, the Parties hereto desire to engage in a separation of the
Businesses, on and subject to the terms of this Agreement.

                                    AGREEMENT

          Now, therefore, in consideration of the promises and representations
herein, and for other good and valuable consideration, the receipt and adequacy
of which are hereby acknowledged, the Parties hereby agree as follows:

                                    ARTICLE I
                                   DEFINITIONS

     1.1  DEFINED TERMS. The following terms are defined for purposes of this
Agreement and any other document delivered in connection with this Agreement:

          (a)  "Claim" means any past, present and future allegations, claims,
actions, causes of action (in law or in equity), suits, debts, agreements,
Liabilities, demands, damages (including actual, consequential, punitive and
exemplary damages), losses, expenses (including attorneys' fees and expenses) or
interest, of any nature whatsoever, whether known or unknown, suspected or
unsuspected, fixed or contingent, other than an Excluded Claim.

          (b)  "Code" means the Internal Revenue Code of 1986, as amended.

          (c)  "Diagnostic Business" means the tangible and intangible assets,
properties, rights and employees associated with the business of research and
development of PH-50 and N-1177 technologies represented by and related to the
inventions listed on Schedule A hereto, and the manufacture, marketing,
licensing, lease and/or sale of products or services relating to such
technologies, together with Liabilities associated with the foregoing (including
those listed on Schedule A), all as more fully set forth in Schedule A hereto.

          (d)  "Excluded Claims" means any Claim (i) to enforce the provisions
of this Agreement, or any document delivered in connection with this Agreement,
including for Technologies to enforce paragraph 4 of Schedule F, (ii) for
indemnification under the bylaws of Technologies or Photogen or any written
indemnification agreement applicable to a Person (except for any act or omission
covered by paragraph 4 of Schedule F which is an Excluded

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Claim), or (iii) relating to a misrepresentation of a material fact related to
the transactions described herein or any omission of a material fact necessary
to make the statements by any Party to another Party not misleading in light of
the circumstances in which such statements were made.

          (e)  "GenNyc Intellectual Property" shall mean all the rights to and
under the General Patent Rights, the Joint Patent Rights and the NC-67722 Patent
Rights (as those terms are defined in the License Agreement dated September 30,
1999 between Massachusetts General Hospital and Photogen) which were initially
licensed to Photogen and thereafter assigned and transferred to Technologies
pursuant to that License Agreement.

          (f)  "Liability" means any liability or obligation of every kind and
nature, whether absolute or contingent, know or unknown, or accrued or
unaccrued.

          (g)  "Lien" means any lien, security interest, pledge, claim,
restriction (other than restrictions on distribution of securities generally
imposed by the securities laws), purchase right, option, or other encumbrance of
any kind.

          (h)  "Lock-Up Agreement" means the Agreement dated as of May 9, 2001
among the Tennessee Stockholders, Technologies and Photogen.

          (i)  "Party" is any Person that executes this Agreement.

          (j)  "Person" means any individual, partnership, corporation,
association, trust, joint venture, limited liability company, unincorporated
organization or group, or any governmental entity (or any department, agency or
political subdivision thereof).

          (k)  "Photogen Stock" means the shares of common stock, $.01 par value
per share, of Photogen, Inc.

          (l)  "Related Person" means, with respect to any Party, any or all of
the following (to the extent applicable): past, present and future stockholders,
partners, principals, controlling Persons, directors, officers, affiliates,
employees, agents, representatives, attorneys, insurers, and each of their
respective estates, trusts, trustees, heirs, predecessors, successors and
assigns, and any Person whose Claim or Liability arises out of or derives from
any relationship with a Party. A Related Person of the Tennessee Stockholders
includes any trust or family partnership that owns Technologies Stock. A Related
Person of Technologies includes Weinstein, Levine and the Tannebaum, LLC, the
Tannebaum Trust and the Tannebaum Estate. After the Closing, the Tennessee
Stockholders and Photogen will not be deemed Related Persons of Technologies.

          (m)  "Technologies Stock" means the shares of common stock, $.001 par
value per share, of Photogen Technologies, Inc.

          (n)  "Therapeutic Business" means the tangible and intangible assets,
properties, rights and employees associated with the business of research and
development of PH-10, laser and biotech technologies represented by and related
to the inventions listed on Schedule B hereto, and the manufacture, marketing,
licensing, lease and/or sale of products or

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services relating to such technologies, together with Liabilities associated
with the foregoing (including those listed on Schedule B), all as more fully set
forth in Schedule B hereto.

          (o)  "Voting Agreement" means the Amended and Restated Voting
Agreement, dated as of September 4, 2001, by and among the Tennessee
Stockholders, Technologies, Photogen and Weinstein.

     1.2  OTHER TERMS. Other capitalized terms in this Agreement and any other
document delivered in association with this Agreement shall have the meaning
given to such terms in this or such other documents. In all events, the singular
includes the plural and vice versa and the masculine includes the neuter and
vice versa. The word "including" or "includes" shall be construed to mean
"including without limitation" or "includes without limitation."

                                   ARTICLE II
                                BASIC TRANSACTION

     2.1  TRANSFER OF BUSINESSES. At the Closing (as hereinafter defined):

          (a)  Photogen will distribute, assign, transfer and deliver to
Technologies all of its right, title and interest in and to the technologies,
properties and Liabilities associated with the Diagnostic Business as set forth
in Schedule A hereto.

          (b)  Technologies will cause to be retained in Photogen and/or
distribute, assign, transfer and deliver to Photogen, to the extent applicable,
all of its right, title and interest in and to the technologies, properties and
Liabilities associated with the Therapeutic Business as set forth in Schedule B
hereto.

          (c)  All retentions, distributions, contributions, assignments and
transfers set forth in Sections 2.1(a) and 2.1(b) are on an "as is" basis and
without recourse and without any representation or warranty (other than those
expressly set forth in Sections 2.3(a) and (b)) or warranty of merchantability,
fitness for any particular purpose, non-infringement or any other express or
implied warranties whatsoever.

     2.2  ASSUMPTION OF LIABILITIES. At and as of the Closing:

          (a)  Technologies will assume and perform, in accordance with their
respective terms, the Liabilities that are part of the Diagnostic Business as
set forth in Schedule A hereto.

          (b)  Photogen will assume and perform, in accordance with their
respective terms, the Liabilities that are part of the Therapeutic Business as
set forth in Schedule B hereto.

          (c)  The obligation to repay the $2,500,000 loan from the Tannebaum,
LLC to Technologies will not be one of the Liabilities assumed by Photogen and
any Lien on the assets of the Therapeutic Business arising from such loan will
be released upon the Closing of the corporate separation.

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     2.3  SPLIT OFF TRANSACTION.

          (a)  At the Closing, Technologies, Photogen, and the Tennessee
Stockholders will engage in the following "split off" transaction in which (i)
each Tennessee Stockholder will transfer and deliver to Technologies all shares
of Technologies Stock he owns, of record or beneficially, directly or
indirectly, free and clear of any Lien, in exchange for (ii) all Photogen Stock,
which Technologies will distribute, assign, transfer and deliver to the
Tennessee Stockholders as jointly directed by them or to an entity controlled by
the Tennessee Stockholders (but in all cases in which Photogen Stock is not
distributed directly to one of the Tennessee Stockholders, the stock will be
distributed to an entity which is wholly owned by the Tennessee Stockholder and
is disregarded for federal income tax purposes), free and clear of all Liens.

          (b)  It is the intentions of the Parties to the split off transaction
to comply with Section 355 of the Code and related Treasury Regulations,
including making such representations to the other parties to the split-off
transaction as are normal and customary in such a transaction except for the
change of control of Technologies. However, notwithstanding the foregoing, each
of the Parties will obtain their own separate tax advice and will be responsible
for any tax associated with or resulting from the split off transaction. Any
Party taking a position on any Internal Revenue Service return or report, other
than consistent with the foregoing, agrees to notify the other Parties prior to
filing such return or report.

     2.4  TERMINATION OF AGREEMENTS; RESIGNATION.

          (a)  As of the Closing, all employment agreements (including any
covenants not to compete other than those set forth in Section 4.2(a), below and
Schedule C-1) to which any of the Tennessee Stockholders are a party with
Technologies will be transferred and assumed by Photogen and no further
compensation, perquisites, bonuses or other benefits will be due from
Technologies, except that accrued but unpaid base salaries as set forth below
will be paid forthwith, subject to normal withholding, after Technologies has
raised funding through an equity financing:

<Table>
<Caption>
                                      AMOUNT OF ACCRUED AND
          NAME OF EMPLOYEE            UNPAID BASE SALARY (1)
          -----------------------     ---------------------
          <S>                         <C>
          Craig Dees                  $25,000.00
          Eric Wachter                $25,000.00
          Tim Scott                   $25,000.00
          Walter Fisher               $62,500.00(2)
          John Smolik                 $78,125.00(2)
</Table>

          (1) through the Closing
          (2) with interest until paid at the rate of 2% per annum

          (b)  Any duties of any Party to Technologies or Photogen (whether
pursuant to agreement, bylaw, statute or otherwise) to (i) maintain the
confidentiality of, and not to use, confidential or proprietary information of,
or (ii) indemnify, another Party shall remain in full force and effect after the
Closing in accordance with the terms thereof.

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          (c)  As of the Closing, the Voting Agreement and the Lock Up Agreement
will be terminated and of no further force or effect.

          (d)  As of the Closing, each of the Tennessee Stockholders will resign
from any offices or other official capacities relating to Technologies,
including as an employee, officer or director of Technologies or trustee of any
employee benefit plan.

          (e)  As of the Closing, all persons associated with Technologies
(including Aidan King) other than a Tennessee Stockholder shall resign as an
officer, director or employee of Photogen.

          (f)  As of the Closing, Photogen's name will be changed to one not
confusingly similar.

     2.5  CERTAIN POST-CLOSING TRANSACTIONS AND ACTIVITIES. Photogen and
Technologies agree that until twelve months after the Closing, they will (i)
maintain their status as companies engaged in the active conduct of the
Therapeutic Business and Diagnostic Business, respectively, and (ii) not engage
in any transaction that would result in their ceasing to be engaged in the
active conduct of a trade or business within the scope of Code Section 355.

                                   ARTICLE III
                                    RELEASES

     3.1  IDENTITY OF RELEASED PERSONS.

          (a)  For purposes of Section 3.3, the Released Persons are
Technologies and each of its Related Persons.

          (b)  For purposes of Section 3.4, the Released Persons are each of the
Tennessee Stockholders, Photogen, and each of their Related Persons.

     3.2  PARTIES FULLY INFORMED.

          (a)  The parties hereto and, in particular, each of the Tennessee
Stockholders acknowledge that they are fully informed regarding all material
facts and information regarding the Therapeutic and Diagnostic Businesses,
including the risks and future prospects associated with those Businesses; in
particular, each Tennessee Stockholder is aware:

               (i)   that Technologies is in the process of attempting to raise
     capital (approximately $16-$20 million) through the sale of its common
     stock or other securities for the purpose of developing the Diagnostic
     Business, but there is no assurance that such a transaction will be
     completed;

               (ii)  that the Diagnostic Business being retained by
     Technologies, in which the Tennessee Stockholders will have no interest as
     a result of the separation of the Businesses under this Agreement, is
     believed to be of substantial potential value in the opinion of management;
     and

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               (iii) that Technologies has provided the Tennessee Stockholders
     with the opportunity to inquire of management regarding all information and
     facts available to management regarding the Diagnostic Business and its
     future prospects.

          (b)  Technologies is aware of and understands that:

               (i)   the Therapeutic Business being retained by the Tennessee
     Stockholders, in which Technologies and its remaining shareholders will
     have no interest as a result of the separation of the Businesses under this
     Agreement, is believed to be of substantial potential value in the opinion
     of the Tennessee Stockholders; and

               (ii)  the Tennessee Stockholders have provided Technologies with
     the opportunity to inquire regarding all information and facts available to
     the Tennessee Stockholders regarding the Therapeutic Business and its
     future prospects.

          (c)  Notwithstanding the foregoing, all Parties desire to proceed with
the separation of the Businesses as contemplated under this Agreement. The
Tennessee Stockholders have full knowledge and understanding that upon the
Closing of this transaction they will have no right to share in future success,
if any, of Technologies unless they should individually decide to purchase stock
of Technologies in the open market at prevailing market prices. Similarly,
Technologies understands that it and its shareholders will have no right to
share in the future success, if any, of the Therapeutic Business, unless they
are able to purchase stock in an entity that ultimately owns the Therapeutic
Business.

     3.3  RELEASE OF TECHNOLOGIES. Effective as of the Closing, each of the
Tennessee Stockholders, on behalf of himself and each of his Related Persons,
hereby fully releases, remises and discharges the Released Persons identified in
Section 3.1(a) of and from, and covenants not to directly or indirectly sue or
otherwise assert in any forum against such Released Persons, any and all Claims
arising out of, based upon or relating to any actual or alleged act or omission
of such Released Persons from the beginning of time through the Closing, whether
asserted before or after the date of this Agreement, whether based upon contract
(written or oral), tort, statute, regulation, course of dealing, contribution,
indemnity, breach of duty, misrepresentation, bad faith, intentional or
negligent acts or omissions, or otherwise, and whether in law or in equity;
provided, however, that the foregoing will not release or impair the Excluded
Claims. Further, none of the Tennessee Stockholders or any of their Related
Persons shall, directly or indirectly, voluntarily assist, encourage, support or
in any way facilitate the prosecution or assertion of any Claims against such
Released Persons.

     3.4  RELEASE OF TENNESSEE STOCKHOLDERS. Effective as of the Closing,
Technologies, on behalf of itself, and its Related Persons, hereby fully
releases, remises and discharges the Released Persons identified in Section
3.1(b) of and from, and covenants not to directly or indirectly sue or otherwise
assert in any forum against such Released Persons, any and all Claims arising
out of, based upon or relating to any actual or alleged act or omission of such
Released Persons from the beginning of time through the Closing, whether
asserted before or after the date of this Agreement, whether based upon contract
(written or oral), tort, statute, regulation, course of dealing, contribution,
indemnity, breach of duty, misrepresentation, bad faith, intentional or
negligent acts or omissions, or otherwise, and whether in law or in equity;
provided, however,

                                        7
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that the foregoing will not release or impair the Excluded Claims. Further,
neither Technologies nor any of its Related Persons shall, directly or
indirectly, voluntarily assist, encourage, support or in any way facilitate the
prosecution or assertion of any Claims against such Released Persons.

     3.5  NO ADMISSIONS. None of the Parties admits any liability or wrongdoing,
or the validity of any claims or defenses in the Differences or otherwise, and
neither this Agreement, the Releases nor any document referred to herein may be
construed as, or may be used as an admission by any Party of any fault,
wrongdoing or liability whatsoever. The Parties have entered into this Agreement
to amicably resolve their Differences.

     3.6  UNKNOWN CLAIMS. The releases in Sections 3.3 and 3.4 include a release
of Claims which, at this time, may be unknown or unsuspected. Each releasing
Party waives any common law or statutory doctrine which limits the release of
unknown or unsuspected Claims.

                                   ARTICLE IV
                         OTHER AGREEMENTS OF THE PARTIES

     4.1  FAIRNESS OPINION. Prior to the Closing, Technologies will obtain a
fairness opinion from a nationally-recognized banking or valuation firm. The
opinion must be satisfactory to Technologies in that it concludes that the
split-off transaction contemplated by this Agreement is fair from a financial
point of view to the remaining stockholders of Technologies after the
separation. If the fairness opinion does not so conclude, the Parties will
cooperate in good faith to agree on modification to the terms of the transaction
so that a fairness opinion can be delivered which concludes that the transaction
is fair from a financial point of review to the remaining stockholders of
Technologies after the separation; but in all events, regardless of any such
modification, all of the Tennessee Stockholders' Technologies Stock will be
transferred to Technologies at the Closing.

     4.2  PH-10 AGREEMENT.

          (a)  Photogen and the Tennessee Stockholders agree not to develop or
sublicense the technologies that are part of the Therapeutic Business for
diagnostic x-ray purposes or to adversely affect the development of N1177 or
PH-50 and will, at the Closing, execute the form of a non-competition agreement
attached as Schedule C-1 to effect the foregoing. Photogen at the Closing will
also grant Technologies a royalty-free, fully paid up, exclusive and worldwide
license in the form attached as Schedule D hereto to fully use and commercialize
the technologies that are necessary to fulfill Technologies' contractual
commitments to Sentigen, Ltd., provided such license does not incur royalties
due to third-party licensees (such as those due to Massachusetts General
Hospital), or impose on Photogen other royalties, fees or penalties to other
third parties, including those for which the licensed technologies may infringe,
or for which an interference may be asserted (any such royalties, fees or
penalties due will be paid by Technologies).

          (b)  Similarly, Technologies agrees not to develop or sublicense
non-nanoparticulate PH-10, or to adversely affect the development of PH-10 and
will, at the Closing, execute the form of a non-competition agreement attached
as Schedule C-2 to effect the foregoing. Moreover, with the exception of the
GenNyc Intellectual Property, Technologies will

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use reasonable efforts to obtain release of all PH-10 technologies from any
contractual commitments to Sentigen, Ltd.

     4.3  INDEMNITY.

          (a)  After the Closing, Photogen shall indemnify, defend, reimburse
and hold harmless each of the Released Persons identified in Section 3.1(a) and
each of their Related Persons against any and all of the following Claims:
Claims arising out of or relating to (i) any Liability assumed by Photogen
pursuant to Section 2.2(b) hereto; (ii) any breach or alleged breach of any
representation, covenant or warranty by Photogen or its Related Persons under
this Agreement; and (iii) any violation by Photogen or its Related Persons of
the release set forth in Section 3.3 hereto. Notwithstanding the foregoing, this
indemnity does not cover or apply to any tax liability to Technologies or any of
its Related Persons resulting from the transactions contemplated by this
Agreement.

          (b)  After the Closing, Technologies shall indemnify, defend,
reimburse and hold harmless each of the Released Persons identified in Section
3.1(b) and each of their Related Persons against any and all of the following
Claims: Claims arising out of or relating to (i) any Liability assumed by
Technologies pursuant to Section 2.1(a) hereto; (ii) any breach or alleged
breach of any representation, covenant or warranty by Technologies or its
Related Persons under this Agreement; and (iv) any violation by Technologies or
its Related Persons of the release set forth in Section 3.4 hereto.
Notwithstanding the foregoing, this indemnity does not cover or apply to any tax
liability to the Tennessee Stockholders or any of their Related Persons
resulting from the transactions contemplated by this Agreement.

          (c)  The indemnity obligations of the Parties set forth in this
Section 4.3 shall be subject to the following conditions: (i) the Party seeking
indemnification and/or defense must promptly notify the indemnifying Party of
the Claim giving rise to the indemnification obligation (provided, that failure
to promptly notify will be a defense to indemnity only to the extent the
indemnifying Party is prejudiced thereby); and (ii) the Party seeking
indemnification shall not settle the lawsuit without the prior consent of the
indemnifying Party (such consent not to be unreasonably withheld, delayed or
conditioned).

     4.4  VOTING; WAIVER. Each Tennessee Stockholder, Tannebaum, LLC, Weinstein
and Levine agrees to approve (i) the separation transactions in this Agreement,
in all capacities as holders of Technologies Stock, directors, officers or
otherwise, and (ii) a financing transaction approved by a majority of the Board
of Directors of Technologies ("Financing Transaction"). Each Tennessee
Stockholder irrevocably waives the right to participate in any offering by
Technologies of Technologies Stock to its stockholders (even if the Tennessee
Stockholders are stockholders of record and otherwise would have been eligible
to participate in such offering). The Parties represent that there is no known
bar to their voting for the transactions in this Agreement or the proposed
Financing Transaction, will take all reasonable measures to avoid the creation
of any such bar, will not dispose, transfer, assign or otherwise affect
ownership or voting rights of their shares, and will cause all shares under
their direct or indirect control, as listed in Schedules E-1 and E-2 opposite
his or its name as appropriate, to be voted in favor of this Agreement and the
proposed Financing Transaction.

                                        9
<Page>

     4.5  FURTHER ACTS. If, at any time hereafter, any further assignments or
assurances or any other acts are necessary, desirable or proper to: (a) vest,
perfect or confirm ownership of and title to any of the assets to be transferred
and/or retained as contemplated by this Agreement including, in particular, to
provide Technologies with all intellectual and other property related to PH-50
(including N1177); (b) ensure proper and complete compliance with federal, state
and local administrative or regulatory laws; or (c) otherwise carry out the
purposes of this Agreement, each Party shall execute and deliver all such
assignments and assurances and do all such acts as such other Party shall
reasonably request.

     4.6  NON-INTERFERENCE.

          (a)  None of the Tennessee Stockholders, Photogen, nor any Person
acting on their behalf or any of them, will take any action before and after the
Closing intended or having the effect in any way to disparage Technologies
(including its products or technology), Weinstein, Levine, the Tannebaum, LLC or
any of their respective Related Persons, or make or solicit any comments or
statements to the media or other Persons that may reasonably be considered to be
derogatory or detrimental to their professional or personal reputation.

          (b)  None of Technologies, Weinstein, Levine, the Tannebaum, LLC, nor
any Person acting on behalf of any of them, will take any action before and
after the Closing intended or having the effect in any way to disparage any of
the Tennessee Stockholders, Photogen, (including its products or technology), or
any of their respective Related Persons, or make or solicit any comments or
statements to the media or other Persons that may reasonably be considered to be
derogatory or detrimental to their professional or personal reputation.

     4.7  USE OF THE NAME PHOTOGEN. The Parties agree that upon the Closing,
Photogen will have changed its corporate name to a name not confusingly similar
to "Photogen" and will not thereafter use "Photogen" or similar words as its
name or in any other materials or products.

                                    ARTICLE V
                                 REPRESENTATIONS

     5.1  REPRESENTATION OF TENNESSEE STOCKHOLDERS. Each Tennessee Stockholder
represents and warrants to Technologies as follows:

          (a)  He is the record and beneficial owner of the Technologies Stock
set forth opposite his name on Schedule E-1 hereto.

          (b)  The transfer contemplated by Section 2.3(a) above will vest in
Technologies all right, title and interest in and to all Technologies Stock
owned beneficially by such Tennessee Stockholder, free and clear of all Liens.

          (c)  He does not own (beneficially or of record) or control, directly
or indirectly, any Technologies Stock (or rights to acquire, or instruments
convertible into or exercisable for, Technologies Stock) except as set forth in
Schedule E-1 hereto.

                                       10
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          (d)  He has not conveyed to any other Person any interest or right in
the Differences or any Claim against Technologies, Weinstein, Levine, the
Tannebaum, LLC or any Related Person.

          (e)  He is receiving the Photogen Stock solely for his Technologies
Stock and no part of the consideration received is for accrued but unpaid
salary.

          (f)  He is acquiring the Photogen Stock for his own account and not
with a view to the resale or distribution thereof except in compliance with
applicable securities laws.

          (g)  His "Statement of Facts" set forth in Schedule F-1 does not
contain any untrue statement of a material fact or omit to state a material fact
required to be stated therein or necessary in order to make the statements made
therein, in the light of the circumstances under which they were made, not
misleading.

     5.2  REPRESENTATION OF WEINSTEIN, LEVINE AND THE TANNEBAUM LLC ("CHICAGO
STOCKHOLDERS"). Each Chicago Stockholder represents and warrants to the
Tennessee Stockholders as follows:

          (a)  He is the record and beneficial owner of the Technologies Stock
set forth opposite his name on Schedule E-2 hereto.

          (b)  He does not own (beneficially or of record) or control, directly
or indirectly, any Technologies Stock (or rights to acquire, or instruments
convertible into or exercisable for, Technologies Stock) except as set forth in
Schedule E-2 hereto.

          (c)  He has not conveyed to any other Person any interest or right in
the Differences of any Claim against Photogen, the Tennessee Stockholders or any
Related Person.

     5.3  Technologies represents and warrants to the Tennessee Stockholders
that Technologies is acquiring the Technologies Stock from the Tennessee
Stockholders for its own account for the purpose of cancellation.

     5.4  Each Party (a "Representing Party") hereby represents and warrants, as
to himself or itself only, to each other Party as follows:

          (a)  The Representing Party has full power and authority to execute
and deliver this Agreement and all of the other documents contemplated hereby to
be executed and delivered in connection with this Agreement, and this Agreement
and such other documents constitute the valid and legally binding obligation of
the Representing Party, enforceable in accordance with their respective terms
and conditions.

          (b)  The Representing Party has been represented by counsel of his or
its choice in negotiating and concluding this Separation Agreement, has entered
into this Agreement as his or its free and voluntary act, and has discussed this
Agreement (including the releases herein) with his or its counsel.

                                       11
<Page>

          (c)  Except for matters expressly covered by Article V of this
Agreement, the Representing Party is relying on his or its own due diligence on
all matters concerning the transactions contemplated by this Agreement. The
Representing Party understands that if the facts (other than facts expressly
covered by this Article V) upon which he or it relied on in entering into this
Agreement are later found to be different from the facts he or it now believes
to be true, that Representing Party accepts the risk of those possible
differences, waives the benefit of any statute or common law that limits or
restricts the effectiveness of a release of unknown claims and agrees that this
Agreement (including the releases) will nonetheless be effective. Without
limiting the generality of the foregoing, each Representing Party acknowledges
that Technologies and Photogen are continuously planning and achieving
scientific developments and strategic, collaborative and financing transactions
which Technologies and Photogen believe are not appropriate for public
disclosure at this time but which may be material and may come to fruition
during the next 12 months or thereafter. Each Representing Party represents and
warrants that he or it is entering into this Agreement with awareness of the
foregoing.

                                   ARTICLE VI
                               CLOSING CONDITIONS

     6.1  AT THE CLOSING. The consummation of the transactions contemplated in
Article II and the other transactions contemplated hereby to be consummated by
the Closing (the "Closing") shall take place as soon as practicable after all of
the conditions in Section 6.2 below have been fulfilled or waived by the
appropriate Party. At the Closing, the Parties shall each deliver or cause to be
delivered such documents and other items consisted with this Agreement that
would customarily be necessary to Close.

     6.2  CONDITIONS TO CLOSING. The Closing shall by subject to the following
conditions:

          (a)  That the Parties have executed mutually acceptable definitive
agreements, instruments of transfer or assignment, and closing documents
containing commercially reasonable representations, warranties and covenants
customary for transactions of this type;

          (b)  That all representations and warranties in this Agreement and the
other agreements to be executed in connection with this Agreement are true,
correct and complete, at and as of the Closing;

          (c)  That all covenants and agreements required to be performed by the
Parties before the Closing have been performed;

          (d)  That there is no litigation or proceeding filed by a Person
seeking damages as a result of the transactions herein or seeking to enjoin such
transactions;

          (e)  That the fairness opinion contemplated by Section 4.1 above has
been obtained and is satisfactory to Technologies;

          (f)  That all requisite Technologies stockholder and Board consents
and approvals have been obtained, including that the holders of a majority of
Technologies Stock, (other than the Tennessee Stockholders), approve the
transactions in this Agreement;

                                       12
<Page>

          (g)  That all requisite third party and governmental filings have been
made and all necessary consents and approvals have been obtained;

          (h)  That Technologies shall be permitted to consummate the
transactions contemplated by this Agreement under Section 78.288 of the Nevada
General Corporation Law; and

          (i)  That Photogen shall, immediately following the closing (but
contemporaneous with the closing of the Financing Transaction) reimburse
Technologies in the amount of $60,000 out of its post-closing assets.

          (j)  That Technologies shall receive written advice from BDO Seidman
that, if the Corporate Separation is not tax free to Technologies under Sec. 355
of the Code, that the resulting tax would not exceed the amount of its current
NOL's (Net Operating Losses) (whether such NOL's are currently on the books of
Photogen or Technologies) which would be eligible to offset such tax. Any NOL's
remaining after offsetting any such tax shall be allocated between Technologies
and Photogen in accordance with the Code pursuant to written advice from BDO
Seidman.

          (k)  The closing of the Corporate Separation and its related
transactions under this Agreement shall be contemporaneous with the closing of
the proposed Financing Transaction with Mi3 and others pursuant to the Agreement
dated July 29, 2002, in accordance with a time sequence and agenda mutually
agreeable to the parties hereto.

                                   ARTICLE VII
                               DISPUTE RESOLUTION

     7.1  If the parties are unable to resolve any dispute or claim relating to
this Agreement, then such dispute or claim shall be resolved by final and
binding arbitration conducted by the American Arbitration Association ("AAA")
pursuant to its commercial arbitration rules. If the parties cannot otherwise
agree, the arbitration shall be conducted at a time and place selected by the
AAA. Each party to the dispute shall select one arbitrator and the two so chosen
shall choose a third (however, the parties to the dispute may by mutual
agreement elect to jointly select only one arbitrator). Each arbitrator shall be
qualified by education and training to pass upon the particular matter to be
decided. The arbitration shall be kept confidential. The arbitration shall be
conducted as expeditiously as possible with due consideration for the complexity
of the dispute in question, and the arbitration panel shall render its award or
decision within 30 days after any final arguments of the parties. Each party to
the dispute shall pay its own fees and expenses of the arbitration (including
legal fees) and the parties to the dispute shall share equally the costs of the
arbitrator(s). The decision of the arbitrator(s) may be enforced in any court
having jurisdiction over the parties to the dispute. Notwithstanding the
foregoing, any party shall be entitled to seek injunctive or other equitable
relief from any court having jurisdiction over the parties before, during or
after the arbitration procedures described above. Seeking such relief shall not
operate to waive the right or obligation to compel the parties to arbitration.

                                       13



<Page>

                                  ARTICLE VIII
                                  MISCELLANEOUS

     8.1  GENERAL. This Agreement:

          (a)  Shall be binding upon and inure to the benefit of the Parties,
their respective successors and assigns and the other Related Persons subject to
the releases set forth above, but may not be assigned without the written
consent of the other Parties hereto;

          (b)  May be executed in one or more counterparts, each of which shall
be deemed an original but all of which together will constitute one and the same
instrument and shall be binding upon the Party executing the same;

          (c)  May be executed by a signature page delivered by telecopier, in
which case the Party so executing this Agreement shall promptly thereafter
deliver its originally executed signature page (but the failure to deliver an
original shall not affect the binding nature of such Party's signature);

          (d)  Shall be governed by the internal laws of the State of Nevada
without regard to its conflict of laws provisions;

          (e)  May only be amended by a writing dated after the date hereof and
signed by or on behalf of all the Parties; and

          (f)  Together with the Recitals set forth above and the Schedules (all
of which are incorporated into this Agreement by reference), constitutes the
full and entire understanding and agreement among the Parties with regard to the
subject matter hereof and thereof, and supersedes any prior negotiations,
representations or agreements, written or oral, with respect to such subject
matter (none of which prior matters shall be binding upon the Parties).

     8.2  SEVERABILITY. If any term or provision of this Agreement is held by a
court of competent jurisdiction to be invalid, illegal or contrary to public
policy, such term or provision shall be modified to the extent necessary to be
valid and enforceable and shall be enforced as modified; provided, however, that
if no modification is possible such provision shall be deemed stricken from this
Agreement. In any case, the remaining provisions of this Agreement shall not be
affected thereby.

     8.3  NOTICES. All notices and other communications hereunder shall be in
writing and addressed to the Party to be notified at the address set forth in
Schedule 0 (which address may be changed by like notice); and shall be deemed
effective and duly given (i) three days after being mailed by certified or
registered mail, postage prepaid, return receipt requested, (ii) upon receipt if
delivered by personal delivery, expedited courier or messenger service, or (iii)
upon the transmitting Party obtaining a confirmation of receipt of a facsimile
transmission.

                            [Signature pages follow]

                                       14
<Page>

          IN WITNESS WHEREOF, the Parties have executed this Agreement effective
as of the date first set forth above.

                                  Photogen Technologies, Inc.

                                  By:
                                      ------------------------------------------
                                  Its:   President


                                  Photogen, Inc.

                                  By:
                                      ------------------------------------------
                                  Its:   President


                                  ----------------------------------------------
                                  Craig Dees, Ph.D.


                                  Dees Family Foundation

                                  By:
                                      ------------------------------------------


                                  ----------------------------------------------
                                  Eric A. Wachter, Ph.D.


                                  Eric A. Wachter 1998 Charitable Remainder
                                  Unitrust

                                  By:
                                      ------------------------------------------


                                  ----------------------------------------------
                                  Timothy D. Scott, Ph.D.


                                  Scott Family Investment Limited Partnership

                                  By:
                                      ------------------------------------------


                    [SIGNATURE PAGE TO SEPARATION AGREEMENT]

<Page>

                                  ----------------------------------------------
                                  Walter Fisher, Ph.D.


                                  Fisher Family Investment Limited Partnership

                                  By:
                                      ------------------------------------------


                                  Walt Fisher 1998 Charitable Remainder Unitrust

                                  By:
                                      ------------------------------------------


                                  ----------------------------------------------
                                  John A. Smolik


                                  Smolik Family LLP

                                  By:
                                      ------------------------------------------


                                  ----------------------------------------------
                                  Robert J. Weinstein, M.D.


                                  ----------------------------------------------
                                  W.F. Investments Enterprises, LP


                                  ----------------------------------------------
                                  Robert and Lois Weinstein
                                  Family Foundation, Inc.


                                  ----------------------------------------------
                                  Lois B. and Robert J. Weinstein
                                  Joint Revocable Trust


                    [SIGNATURE PAGE TO SEPARATION AGREEMENT]

<Page>


                                  ----------------------------------------------
                                  Stuart P. Levine


                                  ----------------------------------------------
                                  SL Enterprises, LP


                                  ----------------------------------------------
                                  Stuart and Sherri Levine
                                  Family Foundation, Inc.


                                  Tannebaum, LLC,
                                  By: STRO, LLC (its manager)


                                  By:
                                      ------------------------------------------
                                  Its:
                                      ------------------------------------------


                    [SIGNATURE PAGE TO SEPARATION AGREEMENT]

<Page>

                                    SCHEDULES

A    Diagnostic Line of Business

B    Therapeutic Line of Business

C-1  Form of Non-Competition Agreement
     (Photogen, Inc., Tennessee Stockholders to Photogen Technologies)

C-2  Form of Non-Compensation Agreement
     (Photogen Technologies to Photogen, Inc.)

D    Form of License Agreement

E-1  Stock Holdings of Tennessee Group

E-2  Stock Holdings of Certain Chicago Stockholders

F    Statement of Facts

G    Addresses for Notices

<Page>

                                                                      Schedule A

                DIAGNOSTIC LINE OF BUSINESS (AS OF JULY 29, 2002)

I.   SPECIFIC INTELLECTUAL PROPERTY (INCLUDING ALL RELATED INTERNATIONAL PATENTS
     AND APPLICATIONS):

-    Photogen/Alliance Patents:

     U.S. 5,114,703  Percutaneous Lymphography using Particulate Fluorocarbon
                     Emulsions (Wolf and Long)
     U.S. 5,496,536  Percutaneous Lymphography (Wolf)

-    GENNYC Intellectual Property:

     PHO-112   Enhanced Radiation Therapy (Wolf, McIntire, Bacon and Illig)
     SEN-104   Radiodense Compositions (McIntire, Bacon, Illig and Wolf)

-    Photogen Intellectual Property:

     PHO-125   Medicaments and Methods for deliveries pharmalogic active
               substances using nanoparticulates
     PHO-124   Method for Vascular Imaging using Nanoparticulate Contrast Agents
               (Koenig)
     PHO-111   Photogen(R) trademark (issued)
     SEN-101   Sentagen(TM) trademark (pending)
     SEN-102   Nanolymph(TM) trademark (pending)
     SEN-107   Sentigen(TM) trademark (pending)

     License:  License Agreement as of September 30, 1999 between The General
               Hospital Corporation d/b/a Massachusetts General Hospital and
               Photogen, Inc. (Recently assigned to Photogen Technologies,
               Inc.), including all technology, intellectual property, know how
               and patents covered thereby from MGH and Nycomed Imaging, AS

II.  OTHER ASSETS:

(a)  Except as set forth in Schedule B and to the extent related to the
     Diagnostic Business, all of Technologies' and Photogen's right, title and
     interest in and to all of their respective property and assets, real,
     personal or mixed, tangible and intangible, of every kind and description,
     wherever located, including the following to the extent related to the
     Diagnostic Business:

-    all real property, and leases for real property;

-    all tangible personal property, including all machinery, equipment, tools,
     furniture, office equipment, computer hardware, supplies, materials, and
     other items of tangible personal property of every kind owned or leased by
     Technologies or Photogen (wherever located and whether or not carried on
     their books), together with any express or implied warranty by the
     manufacturers or sellers or lessors of any item or component part thereof
     and all maintenance records and other documents relating thereto;

                                        1
<Page>

                                                                      Schedule A

-    all inventories, wherever located, including all finished goods, work in
     process, raw materials, spare parts, samples and all other materials and
     supplies to be used or consumed by Technologies or Photogen in the eventual
     production of finished goods or services;

-    all accounts receivable, notes and other rights to payment from third
     parties and the full benefit of all security for such accounts or rights to
     payment;

-    all cash, cash equivalents and securities (other than the Photogen Stock);

-    all contracts, agreements and similar arrangements, whether written or
     oral, and all outstanding offers or solicitations made by or to
     Technologies or Photogen to enter into any of the foregoing, including the
     following:

          -    Picker lease
          -    Elan JV documents
          -    lease for New Hope space
          -    research contracts relating to the Diagnostic Business
          -    consulting or other service providers relating to the Diagnostic
               Business

-    all governmental permits and authorizations and all pending applications
     therefor or renewals thereof;

-    all data and records related to the operations of Technologies or Photogen,
     including research and development reports and records, records relating to
     clinical or pre-clinical studies, trials or experiments and financial
     records;

-    all intellectual property not specifically identified above, including the
     following to the extent related to the Diagnostic Business:

     -    all inventions (whether patentable or unpatentable and whether or not
          reduced to practice), all improvements thereto, and all patents,
          patent applications, and patent disclosures, together with all
          reissuances, continuations, continuations-in-part, revisions,
          extensions and reexaminations thereof,

     -    the name "Photogen," and all trade names, trade marks, service marks,
          logos, and all translations, adaptations, derivations and combinations
          thereof and all goodwill associated therewith, and all applications,
          registrations and renewals in connection therewith,

     -    all copyrightable works, all copyrights and all applications,
          registrations and renewals in connection therewith,

     -    all trade secrets and confidential information, including ideas,
          research and development, know how, formulas, compositions, processes
          and techniques, technical data, specifications, business and marketing
          plans,

     -    all computer software and licenses to use computer software, and

                                        2
<Page>

                                                                      Schedule A

     -    all copies and tangible embodiments thereof (in whatever form or
          medium)

-    all intangible rights and property not otherwise listed herein, including
     going concern value, goodwill, telephone, telecopy and e-mail addresses,
     URLs, and web sites and listings;

-    all insurance policies and benefits, including rights to defense and
     indemnity, and proceeds;

-    all claims against third parties, whether inchoate, known or unknown,
     contingent or non-contingent; and

-    all rights relating to deposits and prepaid expenses, claims for refunds
     and rights to offset in respect thereof.

(b)  All of the assets and properties listed on Schedule B to this Agreement are
     not part of the Diagnostic Business and are excluded from the assets and
     properties transferred to Technologies and shall remain the property of
     Photogen after the Closing.

(c)  Photogen and Technologies will cooperate after the closing to effect a
     transfer of all Knoxville-based employees' 401(k) contributions to another
     plan or investment vehicle of their selection.

III. LIABILITIES ASSUMED:

-    Picker lease: 60 month lease at $32,776 / mo, 25 payments remaining,
     totaling $554,894

-    All accounts payable of Photogen Technologies, Inc. (and of Photogen, Inc.
     as set forth in the attachment hereto dated July __ 2002 and from July __,
     2002 to Closing with the approval of Technologies.

-    Accrued but unpaid base salaries as set forth in Section 2.4(a), upon
     receipt of equity financing.

-    Loan from Tannebaum, LLC to Photogen Technologies, Inc.

-    Loan from Elan to Photogen Technologies, Inc.

-    Normal 1/2 salary of Dan Hamilton until closing and then payment of back
     salary; unpaid severance of Jay Harkins at closing; normal full salary of
     Heather Long until closing.

                                        3
<Page>

                                                                      Schedule B

               THERAPEUTIC LINE OF BUSINESS (AS OF JULY 29, 2002)

I.   SPECIFIC INTELLECTUAL PROPERTY (INCLUDING ALL RELATED INTERNATIONAL PATENTS
     AND APPLICATIONS):

     The following Patents patent applications, drafts, and disclosures, U.S.
and international:*

PHO-0001  Method for Improved Selectivity in Photo-Activation of Molecular
          Agents (Fisher, Wachter, and Dees) - including U.S. 5,829,448;
          5,998,597; and 6,042,603.
PHO-0002  Method for Improved Selectivity in Photo-Activation and Detection of
          Molecular Diagnostic Agents (Wachter, Fisher, and Dees) - including
          U.S. 5,832,931.
PHO-102   Treatment of Pigmented Tissues Using Optical Energy (Dees and
          Wachter).
PHO-104   Improved Methods and Apparatus For Multi-Photon Photo-Activation of
          Therapeutic Agents (Wachter, Fisher and Smolik).
PHO-105   Improved Method for Targeted Topical Treatment of Disease (Dees,
          Scott, Smolik, Wachter and Fisher).
PHO-106   Method for Improved Imaging and Photodynamic Therapy (Dees and Scott).
PHO-107   High Energy Phototherapeutic Agents (Dees, Scott, Smolik and Wachter)
          - including U.S. 6,331,286.
PHO-108   Method and Agents for Improved Radiation Therapy (Wachter, Smolik and
          Dees) - ABANDONED 15 April 2002.
PHO-109   Improved Methods and Apparatus for Multi-photon Photo-activation and
          Detection of Molecular Agents (Fisher, Wachter, Smolik and Dees).
PHO-110   Method for Enhanced Protein Stabilization and for Production of Cell
          Lines Useful for Production of such Stabilized Proteins (Dees and
          Smolik).
PHO-113   Improved Topical Medicaments and Methods for Photodynamic Treatment of
          Disease (Dees, Scott, Smolik, Wachter and Fisher).
PHO-118   PulseView(R) trademark (issued).
PHO-119   Improved Intracorporeal Medicaments for Photodynamic Treatment of
          Disease (Dees, Scott, Wachter, Fisher, and Smolik).
PHO-120   Improved Intracorporeal Medicaments for High Energy Phototherapeutic
          Treatment of Disease (Dees, Scott, Wachter, Fisher, and Smolik).
PHO-121   Improved Methods and Apparatus for Optical Imaging (Fisher and
          Wachter).
PHO-122   Improved Medicaments for Chemotherapeutic Treatment of Disease (Scott
          and Dees).
PHO-123   Phototherapeutic Vaccination and Immunotherapy Against Tumors (Dees,
          Scott and Wachter).

*Note:    Applications for PHO-114 and PHO-115 were filed as provisionals and
          never pursued as utility applications within the one-year deadline,
          and were therefore abandoned and the rights reverted to Mary Hendrix.
          PHO-116 was never prepared or filed.

                                        1
<Page>

                                                                      Schedule B

     The following other intellectual property:

     To the extent related to the Therapeutic Business, all ideas and inventions
(whether patentable or unpatentable, tangible or intangible, and whether or not
reduced to practice, including patent disclosures and other forms of invention
disclosures, draft patent applications, patent applications, patents, other
patent files or records, disclosures, draft patent applications, patent
applications, patents, other patent files or records, and all improvements
thereto, together with all reissuances, continuations, continuations-in-part,
divisionals, revisions, extensions, and reexaminations thereof, and all data,
manuscripts and draft manuscripts, reports, records, notes and notebooks,
analyses, and all similar works and all other intellectual properties produced
or conceived by the Tennessee Stockholders, under the auspices of their
respective Employment Agreements with, or resulting from any other duties to,
Photogen, Inc. or Photogen Technologies, Inc., including that intellectual
property identified in writing by E. Wachter to Technologies on July __. 2002.

II.  OTHER ASSETS

     To the extent related to the Therapeutic Business and except as set forth
on Schedule A:

          (a)  All right, title and interest in and to all property and assets,
real, personal or mixed, tangible and intangible, of every kind and description,
located anywhere in the state of Tennessee, at the Massachusetts Eye and Ear
Infirmary, or in any way part of or otherwise associated with the Laserscope
Aura XP laser believed to be located in New Hope, PA, together with any express
or implied warranty by the manufacturers or sellers or lessors of any item or
component part thereof and all maintenance records and other documents relating
thereto;

          (b)  All other data, reports, market studies, and similar properties;

          (c)  All inventories, wherever located, including all finished goods,
work in process, raw materials, spare parts, samples and all other materials and
supplies;

          (d)  All contracts, agreements and similar arrangements, whether
written or oral, and all outstanding offers or solicitations made by or to
Technologies or Photogen to enter into any of the foregoing, including the
following:

     -    lease and utility contracts for the Knoxville facility;
     -    research contracts;
     -    consulting or other service providers;

          (e)  All governmental permits and authorizations and all pending
applications therefore or renewals thereof, along with all supporting documents
and other records thereof, relating in any way to any use of PH-10;

          (f)  All data and records related to the operations of Technologies or
Photogen, including research and development reports and records, records
relating to clinical or pre-clinical studies, trials or experiments and
financial records;

          (g)  All intellectual property not specifically identified above,
including the following to the extent related to the Therapeutic Business:

                                        2
<Page>

                                                                      Schedule B

     -    all copyrightable works, all copyrights and all applications,
          registrations and renewals in connection therewith,

     -    all trade secrets and confidential information, including ideas,
          research and development, know how, formulas, substances, compositions
          of matter, formulations, processes and techniques, technical data,
          specifications, protocols, designs and commercial information relating
          to design, development, manufacture, assembly, use, or sale, and all
          business and marketing plans,

     -    all computer software and licenses to use computer software, and

     -    all copies and tangible embodiments thereof (in whatever form or
          medium);

          (h)  All goodwill and all telephone and telecopy addresses in the
state of Tennessee;

          (i)  All claims against third parties, whether inchoate, known or
unknown, contingent or non-contingent; and

          (j)  All rights relating to deposits and prepaid expenses, claims for
refunds and rights to offset in respect thereof

III. LIABILITIES ASSUMED:

          (a)  All liabilities associated with the Therapeutic Business,
excluding accounts payable accrued on the books of Photogen, Inc. prior to the
Corporate Separation as provided on Schedule A(III) (which will be retired by
Technologies using its available capital) but including the following:

     -    All costs of maintaining and operating the Knoxville, TN facility
          including but not limited to lease expense (including any costs or
          penalties that may be incurred should the lease be terminated
          including early termination charges or penalties), utilities, costs,
          including residual value payments, of any leased equipment.

     -    Costs, if any, of any environmental violations or remediation, if any.

     -    Costs for salary, insurance, benefits and other compensation items for
          employees based in Knoxville.

          (b)  Photogen shall be liable after the Closing for:

               (1)  all maintenance costs relating to the above-referenced U.S.
     and foreign patent and patent application filings, accruing after the
     Corporate Separation;

               (2)  the royalty payable to Dr. Wolf pursuant to Section 4.1 of
     the Settlement Agreement regarding PH-10 dated June 13, 2002;

               (3)  IMRA FCPA-2 Laser: PO PHGN--6091 (replaces PHGN-5625; due
     January 2003), $20,000; and

                                        3
<Page>

                                                                      Schedule B

               (4)  Laserscope Aura XP Laser: Leased through HPSC, Inc.; 26
     months remaining at $63,203, $2,180.89/month with 10% residual value
     ($6499.50) due at completion.

                                        4
<Page>

                                                                    Schedule C-1

                        FORM OF NON-COMPETITION AGREEMENT

          THIS NON-COMPETITION AGREEMENT (this "Noncompetition Agreement"), is
entered into as of ________, 2002, by and between Photogen, Inc., a Tennessee
corporation ("Photogen"), Craig Dees, Ph. D., Eric A. Wachter, Ph.D., Timothy D.
Scott, Ph.D., Walter Fisher, Ph.D., and John A. Smolik (Dees, Wachter, Scott,
Fisher and Smolik are, collectively, the "Tennessee Stockholders," each of
Photogen and the Tennessee Stockholders shall be referred to individually as a
"Restricted Party" and collectively as the "Restricted Parties"), and Photogen
Technologies, a Nevada corporation ("Photogen Technologies").

                                    RECITALS

A.   Pursuant to that certain Separation Agreement of even date herewith by and
     among Photogen, Photogen Technologies, each of the Tennessee Stockholders,
     the Dees Family Foundation, the Eric A. Wachter 1998 Charitable Remainder
     Trust, the Scott Family Investment Limited Partnership, the Fisher Family
     Investment Limited Partnership, the Walt Fisher 1998 Charitable Remainder
     Trust, the Smolik Family LLP, Robert J. Weinstein, M.D., Stuart P. Levine
     and Tannebaum, LLC (the "Separation Agreement"), Photogen and the Tennessee
     Stockholders, on the one hand, and Photogen Technologies, on the other
     hand, have separated their business interests in order to devote their full
     resources to the Therapeutic Business and Diagnostic Business,
     respectively.

B.   In order to induce Photogen Technologies to enter into the Separation
     Agreement, and as a condition to the closing of the transactions
     contemplated by the Separation Agreement, Photogen and the Tennessee
     Stockholders have to enter into this Noncompetition Agreement with Photogen
     Technologies.

                              TERMS AND CONDITIONS

          NOW THEREFORE, in consideration of (i) the execution and delivery of
the Separation Agreement and the consummation of the transactions associated
therewith, (ii) the mutual covenants, agreements and promises set forth in this
Noncompetition Agreement and (iii) other good and valuable consideration, the
receipt and adequacy of which is hereby acknowledged, each of the parties hereto
agree as follows:

     2.   DEFINITIONS. The following terms are defined for purposes of this
Noncompetition Agreement (capitalized terms used but not defined in this
Noncompetition Agreement shall have the meaning given such terms in the
Separation Agreement):

          (a)  "Competitive Business" means engaging in the research,
development, sale, lease, license (or sub-license) marketing, financing or
distribution of technology, products or services that are part of the
Therapeutic Business for diagnostic x-ray purposes or otherwise adversely affect
the development of PH-50 or N-1177 or any analog of PH-50 or N-1177.

          (b)  "Confidential Information" means any and all information that has
or could have value or utility to Photogen Technologies, whether or not reduced
to written or other tangible form and all copies thereof, relating to Photogen
Technologies' private or proprietary

                                        1
<Page>

                                                                    Schedule C-1

matters, confidential matters or trade secrets. Confidential Information
includes, but is not limited to, the following:

          i.   technical information (whether or not subject to patent
     registration or protection), such as research and development, methods,
     trade secrets, Know-How, formulas, compositions, protocols, processes and
     techniques, discoveries, machines, inventions, ideas, computer programs
     (including software and data used in all such programs), drawings,
     specifications;

          ii.  except to the extent publicly disclosed by Photogen Technologies
     without any fault by any Restricted Party or any other person or entity,
     information relating to Photogen Technologies' patents, patent
     applications, and patent disclosures, together with all reissuances,
     continuations, continuations-in-part, revisions, extensions, and
     reexaminations thereof, and all improvements and inventions related
     thereto;

          iii. business information, such as information concerning any
     products, customers, suppliers, production, developments, costs,
     purchasing, pricing, profits, markets, sales, accounts, customers,
     financing, acquisitions, strategic alliances or collaborations, expansions;
     and

          iv.  other information relating to Photogen Technologies' business
     practices, strategies or policies.

          (c)  "Know-How" means information and know-how, whether patentable or
not, including but not limited to any and all discoveries, inventions,
substances, compositions of matter, data, techniques, processes, systems,
formulations, designs and commercial information relating to design,
development, manufacture, assembly, use or sale.

          (d)  "Restricted Period" means a period starting on the date of this
Noncompetition Agreement and ending on the fifth anniversary of such date.

          (e)  "Restricted Territory" means the entire world.

     3.   NONCOMPETITION.

          (a)  Each of the Restricted Parties, during the Restricted Period and
in the Restricted Territory, shall not, directly or indirectly through any other
person or entity:

          i.   own, manage, control, participate in, consult with, be employed
     by, or render services for, any person or entity engaged in a Competitive
     Business or in any other manner or in any other capacity (except as owner
     of 2% or less of stock of a publicly registered and traded entity) engage
     in any Competitive Business;

          ii.  solicit, induce or attempt to influence any other person or
     entity to engage in any Competitive Business or to curtail or cease any
     business or business relationship with Photogen Technologies, its
     affiliates, employees or independent contractors;

                                        2
<Page>

                                                                    Schedule C-1

          iii. solicit any other employee or independent contractor to terminate
     any employment or engagement with Photogen Technologies and engage in a
     Competitive Business; or

          iv.  disparage Photogen Technologies, its affiliates, employees,
     independent contractors or their services or products.

     4.   CONFIDENTIAL INFORMATION. The Restricted Parties above have knowledge
of Photogen Technologies' Confidential Information. Each Restricted Party agrees
that, during the term of this Agreement and at all times thereafter, such
Restricted Party will hold in trust, keep confidential and not disclose,
directly or indirectly, to any third parties or make any use of the Photogen
Technologies' Confidential Information. Confidential Information of Photogen
Technologies will not be subject to these restrictions if it becomes generally
known to the public or in the industry without any fault by the Restricted Party
or any other person or entity, or if Technologies ceases to have a legally
protectable interest in it. If a Restricted Party is required by valid subpoena
or similar legal requirement to disclose Confidential Information, such
Restricted Party will promptly notify Photogen Technologies in writing and
cooperate with Photogen Technologies' efforts to obtain a protective order or
similar relief, and such Restricted Party will disclose only the minimum amount
of Confidential Information necessary.

     5.   NO CONFLICTS. Each Restricted Party represents and warrants, and
agrees with, Photogen Technologies that such Restricted Party is under no
contractual or other obligation or restriction which is inconsistent with his or
its obligations under this Noncompetition Agreement.

     6.   SEVERABILITY; CHOICE OF LAW; INJUNCTION. If any provision of this
Noncompetition Agreement is deemed by a court of competent jurisdiction to be
unenforceable or invalid, the enforceability and validity of all other
provisions shall not be affected and that court shall modify the unenforceable
or invalid provision to the extent necessary to render it enforceable and valid
and that provision shall be enforced as modified. Each Restricted Party agrees
that the time period, geographic scope and other terms of the covenants and
restrictions in this Noncompetition Agreement are reasonable and appropriate
under the circumstances of Photogen Technologies' business. This Noncompetition
Agreement shall be governed and interpreted in accordance with the laws of the
State of Nevada without regard to its provisions on conflicts of law. Without
limiting any other available remedies at law or in equity, Photogen Technologies
will be entitled to injunctive relief restraining any individual or entity from
participating in any breach or threatened breach of this Noncompetition
Agreement without having to post a bond or security.

     7.   MISCELLANEOUS. This Noncompetition Agreement may not be amended or
modified except by a written instrument signed by all parties hereto after the
date of this Noncompetition Agreement. This Noncompetition Agreement may be
assigned by Photogen Technologies and shall inure to the benefit of Photogen
Technologies, its successors and assigns, but may not be assigned or delegated
by any of the Restricted Parties. This Noncompetition Agreement supersedes all
prior agreements, negotiations and representations, written or oral, between or
among the parties hereto with respect to the subject matter contained herein.
Any waiver of any breach of, or failure to enforce, any of the provisions of
this Noncompetition

                                        3
<Page>

                                                                    Schedule C-1

Agreement shall not operate as a waiver of any other breach or waiver of
performance of such provisions or any other provisions. Any waiver must be in
writing signed by Photogen Technologies.


                            (SIGNATURE PAGE FOLLOWS)

                                        4
<Page>

                                                                    Schedule C-1

     IN WITNESS WHEREOF, the parties hereto have executed this Noncompetition
Agreement effective as of the first date set forth above.


                                        Photogen Technologies, Inc.

                                        By:
                                            ------------------------------------
                                        Its:     President


                                        Photogen, Inc.

                                        By:
                                            ------------------------------------
                                        Its:     President


                                        ----------------------------------------
                                        Craig Dees, Ph.D.


                                        ----------------------------------------
                                        Eric A. Wachter, Ph.D.


                                        ----------------------------------------
                                        Timothy D. Scott, Ph.D.


                                        ----------------------------------------
                                        Walter Fischer, Ph.D.


                                        ----------------------------------------
                                        John A. Smolik

                                        5
<Page>

                                                                    Schedule C-2

                        FORM OF NON-COMPETITION AGREEMENT

          THIS NON-COMPETITION AGREEMENT (this "Noncompetition Agreement"), is
entered into as of ________, 2002, by and between Photogen, Inc., a Tennessee
corporation ("Photogen"), Craig Dees, Ph. D., Eric A. Wachter, Ph.D., Timothy D.
Scott, Ph.D., Walter Fisher, Ph.D., and John A. Smolik (Dees, Wachter, Scott,
Fisher and Smolik are, collectively, the "Tennessee Stockholders") and Photogen
Technologies, a Nevada corporation ("Photogen Technologies" and shall also be
referred to as the "Restricted Party").

                                    RECITALS

A.   Pursuant to that certain Separation Agreement of even date herewith by and
     among Photogen, Photogen Technologies, each of the Tennessee Stockholders,
     the Dees Family Foundation, the Eric A. Wachter 1998 Charitable Remainder
     Trust, the Scott Family Investment Limited Partnership, the Fisher Family
     Investment Limited Partnership, the Walt Fisher 1998 Charitable Remainder
     Trust, the Smolik Family LLP, Robert J. Weinstein, M.D., Stuart P. Levine
     and Tannebaum, LLC (the "Separation Agreement"), Photogen and the Tennessee
     Stockholders, on the one hand, and Photogen Technologies, on the other
     hand, have separated their business interests in order to devote their full
     resources to the Therapeutic Business and Diagnostic Business,
     respectively.

B.   In order to induce Photogen and the Tennessee Stockholders to enter into
     the Separation Agreement, and as a condition to the closing of the
     transactions contemplated by the Separation Agreement, Photogen
     Technologies has to enter into this Noncompetition Agreement with Photogen
     and the Tennessee Stockholders.

                              TERMS AND CONDITIONS

          NOW THEREFORE, in consideration of (i) the execution and delivery of
the Separation Agreement and the consummation of the transactions associated
therewith, (ii) the mutual covenants, agreements and promises set forth in this
Noncompetition Agreement and (iii) other good and valuable consideration, the
receipt and adequacy of which is hereby acknowledged, each of the parties hereto
agree as follows:

     8.   DEFINITIONS. The following terms are defined for purposes of this
Noncompetition Agreement (capitalized terms used but not defined in this
Noncompetition Agreement shall have the meaning given such terms in the
Separation Agreement):

          (a)  "Competitive Business" means engaging in the research,
development, sale, lease, license (or sub-license) marketing, financing or
distribution of technology, products or services involving non-nanoparticulate
PH-10 or any non-nanoparticulate analog of PH-10, or otherwise adversely affect
the development of PH-10 or any non-nanoparticulate analog of PH-10.

          (b)  "Confidential Information" means any and all information that has
or could have value or utility to Photogen, whether or not reduced to written or
other tangible form and all

                                        1
<Page>

                                                                    Schedule C-2

copies thereof, relating to Photogen's private or proprietary matters,
confidential matters or trade secrets. Confidential Information includes, but is
not limited to, the following:

          i.   technical information (whether or not subject to patent
     registration or protection), such as research and development, methods,
     trade secrets, Know-How, formulas, compositions, protocols, processes and
     techniques, discoveries, machines, inventions, ideas, computer programs
     (including software and data used in all such programs), drawings,
     specifications;

          ii.  except to the extent publicly disclosed by Photogen without any
     fault by the Restricted Party or any other person or entity, information
     relating to Photogen's patents, patent applications, and patent
     disclosures, together with all reissuances, continuations,
     continuations-in-part, revisions, extensions, and reexaminations thereof,
     and all improvements and inventions related thereto;

          iii. business information, such as information concerning any
     products, customers, suppliers, production, developments, costs,
     purchasing, pricing, profits, markets, sales, accounts, customers,
     financing, acquisitions, strategic alliances or collaborations, expansions;
     and

          iv.  other information relating to Photogen's business practices,
     strategies or policies.

          (c)  "Know-How" means information and know-how, whether patentable or
not, including but not limited to any and all discoveries, inventions,
substances, compositions of matter, data, techniques, processes, systems,
formulations, designs and commercial information relating to design,
development, manufacture, assembly, use or sale.

          (d)  "Restricted Period" means a period starting on the date of this
Noncompetition Agreement and ending on the fifth anniversary of such date.

          (e)  "Restricted Territory" means the entire world.

     9.   NONCOMPETITION.

          (a)  The Restricted Party, during the Restricted Period and in the
Restricted Territory, shall not, directly or indirectly through any other person
or entity:

          i.   own, manage, control, participate in, consult with, be employed
     by, or render services for, any person or entity engaged in a Competitive
     Business or in any other manner or in any other capacity (except as owner
     of 2% or less of stock of a publicly registered and traded entity) engage
     in any Competitive Business;

          ii.  solicit, induce or attempt to influence any other person or
     entity to engage in any Competitive Business or to curtail or cease any
     business or business relationship with Photogen, its affiliates, employees
     or independent contractors;

          iii. solicit any other employee or independent contractor to terminate
     any employment or engagement with Photogen and engage in a Competitive
     Business; or

                                        2
<Page>

                                                                    Schedule C-2

          iv.  disparage Photogen, its affiliates, employees, independent
     contractors or their services or products.

     10.  CONFIDENTIAL INFORMATION. The Restricted Party has knowledge of
Photogen's Confidential Information. The Restricted Party agrees that, during
the term of this Agreement and at all times thereafter, such Restricted Party
will hold in trust, keep confidential and not disclose, directly or indirectly,
to any third parties or make any use of the Photogen's Confidential Information.
Confidential Information of Photogen will not be subject to these restrictions
if it becomes generally known to the public or in the industry without any fault
by the Restricted Party or any other person or entity, or if Photogen ceases to
have a legally protectable interest in it. If the Restricted Party is required
by valid subpoena or similar legal requirement to disclose Confidential
Information, such Restricted Party will promptly notify Photogen in writing and
cooperate with Photogen's efforts to obtain a protective order or similar
relief, and the Restricted Party will disclose only the minimum amount of
Confidential Information necessary.

     11.  NO CONFLICTS. The Restricted Party represents and warrants, and agrees
with, Photogen that such Restricted Party is under no contractual or other
obligation or restriction which is inconsistent with his or its obligations
under this Noncompetition Agreement.

     12.  SEVERABILITY; CHOICE OF LAW; INJUNCTION. If any provision of this
Noncompetition Agreement is deemed by a court of competent jurisdiction to be
unenforceable or invalid, the enforceability and validity of all other
provisions shall not be affected and that court shall modify the unenforceable
or invalid provision to the extent necessary to render it enforceable and valid
and that provision shall be enforced as modified. The Restricted Party agrees
that the time period, geographic scope and other terms of the covenants and
restrictions in this Noncompetition Agreement are reasonable and appropriate
under the circumstances of Photogen's business. This Noncompetition Agreement
shall be governed and interpreted in accordance with the laws of the State of
Nevada without regard to its provisions on conflicts of law. Without limiting
any other available remedies at law or in equity, Photogen will be entitled to
injunctive relief restraining any individual or entity from participating in any
breach or threatened breach of this Noncompetition Agreement without having to
post a bond or security.

     13.  MISCELLANEOUS. This Noncompetition Agreement may not be amended or
modified except by a written instrument signed by all parties hereto after the
date of this Noncompetition Agreement. This Noncompetition Agreement may be
assigned by Photogen and shall inure to the benefit of Photogen, its successors
and assigns, but may not be assigned or delegated by the Restricted Party. This
Noncompetition Agreement supersedes all prior agreements, negotiations and
representations, written or oral, between or among the parties hereto with
respect to the subject matter contained herein. Any waiver of any breach of, or
failure to enforce, any of the provisions of this Noncompetition Agreement shall
not operate as a waiver of any other breach or waiver of performance of such
provisions or any other provisions. Any waiver must be in writing signed by
Photogen.

                            (SIGNATURE PAGE FOLLOWS)

                                        3
<Page>

                                                                    Schedule C-2

     IN WITNESS WHEREOF, the parties hereto have executed this Noncompetition
Agreement effective as of the first date set forth above.


                                        Photogen Technologies, Inc.

                                        By:
                                            ------------------------------------
                                        Its:  President


                                        Photogen, Inc.

                                        By:
                                            ------------------------------------
                                        Its:  President


                                        ----------------------------------------
                                        Craig Dees, Ph.D.


                                        ----------------------------------------
                                        Eric A. Wachter, Ph.D.


                                        ----------------------------------------
                                        Timothy D. Scott, Ph.D.


                                        ----------------------------------------
                                        Walter Fischer, Ph.D.


                                        ----------------------------------------
                                        John A. Smolik

                                        4


<Page>

                                                                      Schedule D

                            FORM OF LICENSE AGREEMENT

                      PATENT AND KNOW HOW-LICENSE AGREEMENT

          This Agreement (the "Agreement"), is entered into as of _________,
2002, by Photogen Technologies, Inc., a Nevada corporation ("Technologies"), and
Photogen, Inc., a Tennessee corporation ("Photogen"). Capitalized terms not
otherwise defined in this Agreement shall have the meaning ascribed to such
terms in the Existing License Agreement (as defined below).

                                   WITNESSETH:

          WHEREAS, Photogen has certain patents and know-how relating to the
Field of Use and Technologies wishes to license such patents and know-how from
Photogen;

          WHEREAS, Technologies is party to the Existing License Agreement (as
defined below) and has certain contractual commitments to Sentigen (as defined
below) under the Existing License Agreement involving such patents and know-how;
and

          WHEREAS, Photogen and Technologies are parties to the Separation
Agreement (as defined below), and Section 4.2 of the Separation Agreement calls
for Photogen and Technologies to enter into this Agreement in order that
Technologies may fulfill its contractual commitments to Sentigen under the
Existing License Agreement.

          NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which is hereby
acknowledged, the parties do hereby agree as follows:

                                    ARTICLE I
                          DEFINITIONS AND GENERAL TERMS

     1.1  The effectiveness of this Agreement is conditioned upon the parties
executing the Separation Agreement and closing the transactions that are the
subject of the Separation Agreement.

     1.2  Terms not otherwise defined herein shall have the meaning indicated in
the Separation Agreement.

     1.3  The following terms shall have the following meanings:

          "Affiliate" means, with respect to any specified Person, any other
Person which, directly or indirectly, through one or more intermediaries, owns
or controls, is under common ownership or control with, or is owned or
controlled by, such specified Person. A Person shall be deemed to "own" or
"control" another Person if it owns more than 50% of the capital stock or other
equity interest, or has the power to direct the management, policies or
operations, of such other Person.

                                        1
<Page>

                                                                      Schedule D

          "Confidential Information" means any and all information that has or
could have value or utility to either party, whether or not reduced to written
or other tangible form and all copies thereof, relating to either party's
private or proprietary matters, confidential matters or trade secrets.
Confidential Information includes, but is not limited to, the following:

          (a)  technical information (whether or not subject to patent
registration or protection), such as research and development, methods, trade
secrets, Know-How, formulas, compositions, protocols, processes and techniques,
discoveries, machines, inventions, ideas, computer programs (including software
and data used in all such programs), drawings, specifications;

          (b)  except to the extent publicly disclosed by either party without
any fault by the other party or any other person or entity, information relating
to such party's patents, patent applications, and patent disclosures, together
with all reissuances, continuations, continuations-in-part, revisions,
extensions, and reexaminations thereof, and all improvements and inventions
related thereto;

          (c)  business information, such as information concerning any
products, customers, suppliers, production, developments, costs, purchasing,
pricing, profits, markets, sales, accounts, customers, financing, acquisitions,
strategic alliances or collaborations, expansions; and

          (d)  other information relating to either party's business practices,
strategies or policies.

          "Elan" means Elan Pharma International Limited, incorporated under the
laws of Ireland and having its registered office at WIL House, Shannon Business
Park, Shannon, County Clare, Ireland, and its Affiliates and/or its successor in
interest.

          "Existing License Agreement" means that certain License Agreement
dated October 20, 1999, by and between Technologies and Sentigen (as defined
below).

          "Field of Use" means research, development, manufacture and
commercialization of nanoparticulate x-ray, CT and/or MRI diagnostic imaging
agents using radio-opaque molecules containing Iodine that passively target to
lymphnodes involved in a disease state following parenteral administration to a
mammal to locate, diagnose and/or treat cancer and/or other diseases.

          "Improvement" means any modification, review, or variation of the
Photogen Patents or Photogen Know-How that improves the underlying intellectual
property, improves the performance of a Product, increases the marketability or
consumer acceptance of a Product expands the application of any intellectual
property or would, if implemented, replace or displace any intellectual
property.

          "Photogen Know-How" means information and know-how relating to the
field of use, whether patentable or not, including but not limited to any and
all discoveries, inventions, substances, compositions of matter, data,
techniques, processes, systems, formulations, designs and commercial information
relating to design, development, manufacture, assembly, use or sale.

                                        2
<Page>

                                                                      Schedule D

          "Photogen Patents" means any and all patents and patent applications
as set forth in Appendix 1 to this Agreement, including all divisionals,
continuations, continuations-in-part, reissues, re-examinations, substitutions,
renewals, divisions, extensions, patents-of-additions, re-examinations,
re-issues, supplementary protection certificates and foreign counterparts of
such patents and patent applications and any patents issuing thereon and
extensions thereon.

          "Product" means any article, device, composition, method, good or
service the manufacture, sale or use of which but for this License, would
infringe on a claim in the Photogen Patents or on any Photogen Know-How.

          "Project" means all activities undertaken by Elan, Technologies and
Sentigen in order to develop the Products.

          "Sentigen" means Sentigen, Ltd., an exempted limited liability company
incorporated under the laws of Bermuda, defined as "Newco" in the Existing
License Agreement, and having its registered office at Clarendon House, 2 Church
Street, Hamilton, Bermuda, or any successor.

          "Sentigen Release" shall have the meaning provided in Section 6.1
INFRA.

          "Separation Agreement" means that certain Separation Agreement dated
of even date herewith and entered into by and among Craig Dees, Ph.D., Dees
Family Foundation, Eric A. Wachter, Ph.D., Eric A. Wachter 1998 Charitable
Remainder Unitrust, Timothy D. Scott, Ph.D., Scott Family Investment Limited
Partnership, Walter Fisher, Ph.D., Fisher Family Investment Limited Partnership,
Walt Fisher 1998 Charitable Remainder Unitrust, and John A. Smolik, Smolik
Family LLP, Technologies, Photogen, Robert J. Weinstein, M.D., Stuart P. Levine
and Tannebaum, LLC.

          "Settlement Agreement" means that certain Settlement Agreement and
Mutual Release of Claims dated as of June 13, 2002, by and among Technologies,
Photogen, The General Hospital Corporation d/b/a Massachusetts General Hospital
and Gerald L. Wolf, Ph.D., M.D.

                                   ARTICLE II
                                  LICENSE GRANT

     2.1  Photogen hereby grants to Technologies a royalty-free, fully paid-up,
worldwide, exclusive license to the Photogen Patents and necessary, related
Confidential Information and Photogen Know-How to the extent required to make,
have made, use, sell, lease, market, export, import or otherwise commercialize
Products solely in the Field of Use, with the right to sublicense. Such license
and sub-license shall each be irrevocable except as hereinafter expressly
provided.

     2.2  Any Improvement or development to the Photogen Patents, Photogen
Know-How or related Confidential Information within the Field of Use shall be
subject to the license and sub-license in Section 2.1 above. Any Improvement or
development to the Photogen Patents or Photogen Know-How outside the Field of
Use shall, if conceived of or otherwise developed by Photogen, be owned by
Photogen and not subject to the foregoing license or sub-license. Technologies
hereby grants Photogen a paid-up, worldwide, exclusive license under any

                                        3
<Page>

                                                                      Schedule D

Improvement or development to the Photogen Patents or Photogen Know-How
conceived or otherwise developed or owned by Technologies, to make, have made,
use, sell and import any products outside the Field of Use.

     2.3  All rights not expressly granted to Technologies in this Agreement are
hereby reserved to Photogen.

                                   ARTICLE III
                  REPRESENTATIONS AND DISCLAIMER OF WARRANTIES

     3.1  Nothing in this Agreement shall be deemed to be a representation or
warranty by Photogen of the validity of the Photogen Patents, Confidential
Information or Photogen Know-How. TECHNOLOGIES IS LICENSING THE PHOTOGEN
PATENTS, CONFIDENTIAL INFORMATION AND PHOTOGEN KNOW-HOW ON AN "AS IS, WHERE IS"
BASIS AND WITHOUT RECOURSE AND WITHOUT ANY REPRESENTATION AND WARRANTY
WHATSOEVER, AND WITHOUT THE WARRANTIES OF MERCHANTABIILITY, FITNESS FOR ANY
PARTICULAR PURPOSE, NON-INFRINGEMENT OR ANY OTHER IMPLIED OR EXPRESS WARRANTIES
WHATSOEVER, EACH OF WHICH WARRANTIES IS HEREBY DISCLAIMED. Except to the extent
set forth in either the Separation Agreement or the Settlement Agreement,
Photogen shall have no liability whatsoever to Technologies or any other person
for or on account of any injury, loss, or damage, of any kind or nature
sustained by, or any damage assessed or asserted against, or any other liability
incurred by or imposed upon Technologies or any other person, including any such
liability arising out of or in connection with or resulting from (a) the
production, use, or sale of any Products, or the practice of the Photogen
Patents, Photogen Know-How, or Confidential Information; or (b) any advertising
or other promotional activities with respect to any of the foregoing.
Technologies shall hold Photogen, and its officers, agents, or employees,
harmless in the event Photogen, or its officers, agents, or employees, is held
so liable.

     3.2  Photogen shall have the right to file, prosecute and maintain all of
the Photogen Patents under this Agreement and shall have the right to determine
whether or not, and where, to file a patent application, to abandon the
prosecution of any patent or patent application, or to discontinue the
maintenance of any patent or patent application; PROVIDED, HOWEVER, that
Photogen shall keep Technologies advised on a regular basis with its prosecution
and maintenance activities and shall cooperate on a good faith basis with
Technologies' suggestions and recommendations regarding such matters.

     3.3  In the event that Photogen elects to abandon the prosecution of any
licensed patent application or discontinue the maintenance of any licensed
patent or licensed patent application, Photogen shall promptly provide written
notice of such election to Technologies. If Technologies elects to continue the
prosecution or maintenance of the licensed patent application or patent,
Technologies shall notify Photogen within thirty (30) days or receipt of such
notice, whereupon Technologies shall continue with the prosecution or
maintenance of the licensed patent or patent application at its sole expense.

                                        4
<Page>

                                                                      Schedule D

     3.4  In the event that Technologies elects to continue with the prosecution
or maintenance of the licensed patent or patent application, the licensed right
to practice such Patent in the Field of Use shall revert to Technologies.

                                   ARTICLE IV
                                   LITIGATION

     4.1  Each party shall notify the other party in writing of any suspected
infringement(s) of the Photogen Patents and shall inform the other party of the
evidence of such infringement(s).

     4.2  Technologies shall have the first right to institute suit for
infringement of Photogen Patents in the Field of Use. Photogen agrees to join as
a party plaintiff in any such lawsuit initiated by Technologies, if requested by
Technologies, with all reasonable costs, attorney's fees and expenses to be paid
by Technologies.

     4.3  If Technologies does not institute suit for infringement within ninety
(90) days of receipt of written notice from Photogen of Photogen's desire to
bring suit for infringement in its own name and on its own behalf, then Photogen
may, at its own expense, bring suit or take any other appropriate action.

     4.4  Technologies shall be entitled to any recovery of damages resulting
from a lawsuit brought by it pursuant to Section 4.2. Photogen shall be entitled
to recovery of damages resulting from any lawsuit brought by Photogen to enforce
any Photogen Patent pursuant to Section 4.3.

     4.5  Neither party may settle with an alleged infringer without the prior
approval of the other party, such approval not to be unreasonably withheld,
delayed or conditioned.

                                    ARTICLE V
                            CONFIDENTIAL INFORMATION

     5.1  It is contemplated that in the course of the performance of this
Agreement each party may (each in such instance a "Disclosing Party"), from time
to time, have disclosed or will disclose Confidential Information to the other
(each in such instance a "Receiving Party"). Each Receiving Party agrees that,
during the term of this Agreement and at all times thereafter, such Receiving
Party will hold in trust, keep confidential and not disclose, directly or
indirectly, to any third parties or make any use of the Disclosing Party's
Confidential Information (except under the terms of this Agreement); PROVIDED,
HOWEVER, no provision of this Agreement shall be construed to preclude
disclosure of Confidential Information as may be inherent in or reasonably
necessary for marketing or sublicensing a Product pursuant to this Agreement,
for securing from any governmental agency any necessary approval or license, or
for obtaining patents by either party relating to the subject or performance of
this Agreement. Confidential Information of either Disclosing Party will not be
subject to these restrictions if it becomes generally known to the public or in
the industry without any fault by the Receiving Party or any other person or
entity, or if the Disclosing Party ceases to have a legally protectable interest
in it. If a Receiving Party is required by valid subpoena or similar legal
requirement to disclose Confidential Information, such Receiving Party will
promptly notify the Disclosing Party in writing and cooperate with the
Disclosing Party's efforts to obtain a protective order or similar relief, and

                                        5
<Page>

                                                                      Schedule D

such Receiving Party will disclose only the minimum amount of Confidential
Information necessary.

                                   ARTICLE VI
                              TERM AND TERMINATION

     6.1  Unless otherwise terminated as herein provided, this Agreement shall
terminate upon the earlier of (i) the date of and Sentigen's written waiver and
release, and Elan's written approval of such waiver and release, of all of
Sentigen's rights to all Photogen Intellectual Property (as defined in the
Existing License Agreement) and the GenNyc Intellectual Property (as defined in
the Existing License Agreement) under the Existing License Agreement (the
"Sentigen Release"), or (ii) the expiration of the last to expire patent of the
Photogen Patents licensed or sub-licensed hereunder. Technologies shall use
commercially reasonable efforts to seek, but Sentigen shall be under no
obligation to grant, the Sentigen Release. At any time that Technologies or an
entity wholly-owned by Technologies shall become fully vested with the
technology that is the subject of this License, with no obligations to any third
party, this License shall terminate.

     6.2  Technologies may surrender and thereby terminate the license or
sub-license granted hereunder, in any country, at any time upon sixty (60) days
prior written notice to Photogen, and such termination shall terminate all
sublicenses granted under such license.

     6.3  This Agreement is not terminable by either party for any reason other
than those set forth in Section 6.1 hereof.

     6.4  In the event of a breach by either party of any representation,
warranty or any other material term or provision of this Agreement, the parties
shall cooperate in good faith to cure such breach as promptly as practicable.

     6.5  Termination, expiration, cancellation or abandonment of this Agreement
through any means and for any reason shall not relieve the parties of any
obligation accruing prior thereto and shall be without prejudice to the rights
and remedies of either party with respect to any antecedent breach of any of the
provisions of this Agreement.

                                   ARTICLE VII
                                  MISCELLANEOUS

     7.1  Consistently with Section 4.2(a) of the Separation Agreement,
Technologies shall pay (i) all fees or penalties incurred by Photogen as a
result of a defense against or assertion of any third party infringement,
interference, or similar proceeding, or otherwise, due to Technologies' use or
ownership of the license or sub-license granted to it hereunder, and (ii) all
liability for royalty payments to third parties incurred by Photogen due to
Technologies' use or ownership of such license or sub-license.

     7.2  This Agreement is provided for in the Separation Agreement and shall
be subject to Sections 7.1, 7.2 and 7.3 of the Separation Agreement, which
provisions are incorporated herein by reference.

                                        6
<Page>

                                                                      Schedule D

     7.3  Nothing in this Agreement shall render Photogen and Technologies as
partners or joint venturers or in an agency/principal relationship.

     7.4  This Agreement, the Separation Agreement and the Settlement Agreement
set forth the entire agreement and understanding of the parties with respect to
the transactions contemplated hereby and supersede any and all prior agreements,
arrangements and understandings among the parties relating to the subject matter
hereof.

     7.5  This Agreement may be executed in two or more counterparts, each of
which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

     7.6  Technologies may assign its rights and delegate its duties under this
Agreement to a third party without the consent of Photogen. Photogen may assign
its rights and delegate its duties under this Agreement to a third party with
the advance written consent of Technologies, such consent not to be unreasonably
withheld, delayed or conditioned.

                            (SIGNATURE PAGE FOLLOWS)

                                        7
<Page>

                                                                      Schedule D

          IN WITNESS WHEREOF, each of the parties hereto has caused this
Agreement to be executed in duplicate originals by its duly authorized officers
or representatives.


PHOTOGEN TECHNOLOGIES, INC.             PHOTOGEN, INC.

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

                                        8
<Page>

                                   APPENDIX 1
                                       TO
             PHOTOGEN PATENT AND PHOTOGEN KNOW-HOW-LICENSE AGREEMENT

     The following Photogen Patents and patent applications, U.S. and
international, and all Photogen Know-How related thereto:

PHO-106   Method for Improved Imaging and Photodynamic Therapy (Dees and Scott).

PHO-107   High Energy Phototherapeutic Agents (Dees, Scott, Smolik and Wachter)
          - including U.S. 6,331,286.

PHO-108   Method and Agents for Improved Radiation Therapy (Wachter, Smolik and
          Dees) - ABANDONED 15 April 2002.

PHO-120   Improved Intracorporeal Medicaments for High Energy Phototherapeutic
          Treatment of Disease (Dees, Scott, Wachter, Fisher, and Smolik).

<Page>

                                                                    Schedule E-1

                                 STOCK HOLDINGS

<Table>
          <S>                                                             <C>
          Craig Dees, Ph.D.                                                3,999,667
          Dees Family Foundation                                              22,000
                                                                          ----------
                                                          TOTAL DEES       4,021,667

          Eric A. Wachter, Ph.D.                                           4,324,667
          Eric A. Wachter 1998 Charitable Remainder Unitrust                 200,000
                                                                          ----------
                                                       TOTAL WACHTER       4,524,667

          Walter Fisher, Ph.D.                                             1,310,167
          Fisher Family Investment Limited Partnership                     2,284,000
          Walt Fisher 1998 Charitable Remainder Unitrust                     400,000
                                                                          ----------
                                                        TOTAL FISHER       3,994,167

          Timothy D. Scott, Ph.D.                                          1,707,667
          Scott Family Investment Limited Partnership                      2,300,000
                                                                          ----------
                                                         TOTAL SCOTT       4,007,667

          John A. Smolik                                                   2,000,267
          Smolik Family LLP                                                2,000,000
                                                                          ----------
                                                        TOTAL SMOLIK       4,000,267

                                                         GRAND TOTAL      20,548,435
                                                                          ==========
</Table>

<Page>

                                                                    Schedule E-2

                                 STOCK HOLDINGS

<Table>
          <S>                                                             <C>
          Tannebaum, LLC                                                   4,116,921
          WEINSTEIN GROUP
            W. F. Investments Enterprises L.P.                             1,400,170
            Robert and Lois Weinstein Family Foundation, Inc.                100,000
            Louis B. and Robert J. Weinstein Joint
              Revocable Trust                                              1,499,251
            Robert J. Weinstein, M.D. and Lois Weinstein                     450,000
                                                                          ----------
                                                     TOTAL WEINSTEIN       3,449,421

          LEVINE GROUP
            Stuart P. Levine                                               2,049,621
            S L Investment Enterprise, L.P.                                1,000,000
            Stuart and Sherri Levine Family Foundation, Inc.                 100,000
            Harris Bank                                                      140,000
                                                                          ----------
                                                        TOTAL LEVINE       3,289,621

                                                         GRAND TOTAL      10,855,963
                                                                          ==========
</Table>

<Page>

                                                                      Schedule F

                               STATEMENT OF FACTS

1.   Disclose all inventions, discoveries, improvements, know-how, works or
     other intellectual property relating to Photogen's Diagnostic or
     Therapeutic Business conceived, reduced to practice, discovered or made by
     any of the founders (i.e., Dees, Wachter, Fisher, Scott or Smolik) while
     subject to their employment agreements which are not disclosed on either
     Schedule A or B. If "None," state that specifically.

     ANSWER:   None

2.   Disclose any corporate opportunity that came to the attention of any of the
     founders while subject to their employment agreements which was not
     disclosed to the Board of Directors and which any of the founders took for
     themselves. If "None," state that specifically.

     ANSWER:   None

3.   Since February 1, 2002, have Dees, Wachter and Scott indicate what
     percentage of their time they spent on Company Business versus the
     percentage of their time they spent developing their new business venture.

ANSWER:   Prior to this query in June 2002, Dees, Wachter and Scott were not
requested to record or track their time spent or percentage of time spent on
tasks assigned to them by Photogen.

     Since February 1, 2002, Dees, Wachter and Scott have made themselves
available full-time to Photogen, and during the last year of their Employment
Agreements (May 17, 2001 through May 16, 2002), as well as all years of the
Employment Agreements since May 16, 1997, Dees, Wachter and Scott have worked to
whatever extent made necessary by their responsibilities, and have "competently
and faithfully promoted [Photogen's] interests and performed the duties assigned
to them" by Photogen in a timely and professional manner as required by their
Employment Agreements.

     However, in September 2001, Dr. Williams instructed Dees, Wachter and Scott
to place "experimentation not critical to lead product development ... on hold,"
and in December 2001, Dr. Williams instructed them to discontinue all R&D
activities, purchase no more supplies, and avoid any other expenditures
unrelated to PH-50. Similar directives have been made since that time.

     Since February 1, 2002, Dees, Wachter and Scott have devoted a portion of
their non-work time to a company called Provectus Pharmaceuticals, which was
formed in order to have an entity in which to place all, or a portion of, the
entity and/or assets to be received by the Tennessee stockholders as part of the
Separation Agreement.

<Page>



4.   Dees, Wachter and Scott (and Fisher and Smolik if they are part of
     Provectus) hereby indemnify and hold Technologies harmless from any claim,
     or liabilities resulting from their acts or omission relating to Provectus
     (and any other none Photogen activities), including the issuance of press
     releases, statements, fund raising, sale of securities or related
     activities.

     ANSWER:   Agreed

5.   Any other material facts regarding the foregoing, if "none," state that
     specifically.

     ANSWER:   None.

                                                     Please initial:

                                                     Dees: _______________
                                                     Fisher: _____________
                                                     Scott: ______________
                                                     Wachter: ____________
                                                     Smolik: _____________




<Page>

                                                                      Schedule G

                              ADDRESSES FOR NOTICES

          Photogen, Inc.
          7327 Oak Ridge Highway
          Knoxville, TN 37931

          Dees Family Foundation
          c/o:  Craig Dees, Ph.D.
          1006 Wyndham Way #1517
          Knoxville, TN 37923

          Fisher Family Investment Limited Partnership,
          Walt Fisher 1998 Charitable Remainder Unitrust
          c/o:  Walter Fisher, Ph.D.
          2009 Still Water Lane
          Knoxville, TN 37922

          Scott Family Investment Limited Partnership
          c/o:  Timothy D. Scott, Ph.D.
          10225 Bob Gray Road
          Knoxville, TN 37932

          Smolik Family LLP
          c/o:  John A. Smolik
          119 Tanasi Court
          Loudon, TN 37774

          Eric A. Wachter 1998 Charitable Remainder Unitrust
          c/o:  Eric A. Wachter, Ph.D.
          138 Bay Path Drive
          Oak Ridge, TN 37830

          Photogen Technologies, Inc.
          140 Union Square Drive
          New Hope, PA 18938

          Tannebaum, LLC
          875 N. Michigan Avenue
          Suite 2930
          Chicago, IL 60611-1901

          Robert J. Weinstein, M.D.
          875 N. Michigan Avenue
          Suite 2930
          Chicago, IL 60611-1901

          Stuart P. Levine
          875 N. Michigan Avenue
          Suite 2930
          Chicago, IL 60611-1901