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                                      AGREEMENT

     THIS AGREEMENT is made effective as of November 1, 1997 by and among
PHOTOGEN, INC., a Tennessee corporation with offices in Knoxville, Tennessee
(hereinafter referred to as "Sponsor"), THE THOMPSON CANCER SURVIVAL CENTER, a
Tennessee not for profit corporation with principal offices in Knoxville,
Tennessee (hereinafter referred to as "Thompson") and MASOUD PANJEHPOUR, Ph.D.,
an employee of Thompson ("Panjehpour").

                                     WITNESSETH:

     WHEREAS, the research project contemplated by this Agreement is of interest
and benefit to all of the parties.

     NOW, THEREFORE, in consideration of the mutual covenants contained herein,
the parties hereto agree as follows:

1.   STATEMENT OF WORK.  Thompson agrees to designate Panjehpour to assist
     Sponsor with the research project which is the subject of that certain
     Agreement dated as of October 1, 1997 between Sponsor and the University of
     Tennessee ("University") (the "Research Contract"), a copy of which is
     attached as Exhibit A hereto and made a part hereof.  Thompson, Panjehpour
     and other Thompson employees have developed substantial experience in laser
     implications in medicine and Thompson and Panjehpour have agreed to consult
     with and advise Sponsor with regard to the matters set forth herein and in
     the Research Contract.

2.   PERIOD OF PERFORMANCE.  The period for the performance of the work shall be
     from November 1, 1997 to October 30, 1998.

3.   PAYMENT.  Sponsor shall pay Thompson $3,068 per month for the satisfactory
     performance of services by Thompson and Panjehpour hereunder, payable on
     the first day of each month.  Checks shall be made payable to THE THOMPSON
     CANCER SURVIVAL CENTER and shall be mailed to the following address:

                          Laser Center
                         1915 White Avenue
                         Knoxville, TN 37916

4.   TERMINATION.  In the event that Thompson, Panjehpour or Sponsor defaults in
     the due performance of its or his respective obligations under this
     Agreement, or in the event that any representation or warranty by any of
     them proves to be false or incorrect and such default or breach is not
     cured within thirty (30) days of written notice thereof, then the
     non-defaulting party may elect to terminate this Agreement by giving
     written notice to the defaulting party, and this Agreement shall terminate
     upon the defaulting party's receipt of said notice; provided, however,
     that this Agreement may not be terminated by either Thompson or Panjehpour
     upon the breach by or false or incorrect representation or warranty of the
     other.  The parties recognize that the results of any particular research
     project cannot be guaranteed

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     even through the use of Thompson's and Panjehpour's best efforts;
     therefore, it is specifically agreed that the failure of the underlying
     research project to achieve specific research results shall not constitute
     a default or breach of this Agreement.

5.   EQUIPMENT.  Thompson will provide certain standard PDT lasers and related
     hardware and such equipment shall remain the property of Thompson.

6.   PROPRIETARY INFORMATION OF THE PARTIES.

     a.     Thompson, Panjehpour and Sponsor each recognizes that the conduct
            of a research project may require the exchange of proprietary
            information among the parties and that each party has ongoing and
            prior knowledge and experience and proprietary information in the
            areas which are the subject of this Agreement and the Research
            Contract.  Accordingly, it is agreed that each party shall retain
            in confidence the proprietary information of each of the other
            parties and shall not disclose any such information to any other
            person, nor use such information, without the written permission
            of the party disclosing such proprietary information, except in
            accordance with the terms of this Agreement.  The term
            "proprietary information" as used herein shall not include any
            information which the recipient clearly shows by appropriate
            documentation:

            (1)    Was at the time of receipt both legally and independently
                   known to the receiving party, its agents, or employees;

            (2)    Without breach of this Agreement by the receiving party has
                   been published or is otherwise within the public knowledge
                   or is generally known to the public at the time of
                   disclosure;

            (3)    Becomes known or available to the receiving party without
                   restriction from a source other than the disclosing party,
                   provided that such source has an unqualified right to
                   disclose such information without restriction;

            (4)    Becomes a part of the public domain after disclosure without
                   breach of this Agreement by the receiving party; or

            (5)    Is required by law to be disclosed, in which case the party
                   required by law to disclose will give the other parties
                   prompt written notice of the required disclosure. Such other
                   parties may, in good faith and at its, his or their own
                   expense, contest disclosure or seek confidential treatment.

     b.     Thompson and Panjehpour each will make full and prompt disclosure to
            Sponsor of all "Developments" which are  created, made, conceived,
            or reduced to practice in whole or in part by Thompson and/or
            Panjehpour during the term of this Agreement and for a period of
            three years thereafter.  "Developments" means all copyright, patent,
            and trademark rights, and all improvements, inventions,
            technologies,

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            methods, applications, discoveries, drawings, and other know-how
            and developments resulting from the project described in Article 1
            of the Research Contract, whether or not subject to U.S. or foreign
            Patent and Trademark Office, U.S. Copyright Office or other
            registration, which are unique to two photon excitation,
            two photon continuous fast pulsed lasers, cellular targeting
            involving proprietary compounds that Photogen can demonstrate it
            developed during the term of this Agreement, imaging using two
            photon lasers, or the interrelationship of two photon lasers and
            photophrin.  Sponsor recognizes and acknowledges that Thompson has
            prior proprietary rights in laser photo-dynamics and related heat
            and light applications.

     c.     Subject only to Thompson's and Panjehpour's respective rights set
            forth in this Article 6 and in Articles 7 and 14.a. hereof (which
            remain subject to the confidentiality provisions hereof), all
            Developments and all U.S. and foreign copyright, patent and
            trademark rights, and any other proprietary rights pertaining to any
            Developments, and all renewals and extensions thereof, shall vest
            in and be owned exclusively by Sponsor; and Thompson and Panjehpour
            each hereby transfers and assigns all of its or his respective
            right, title and interest in and to the Developments to Sponsor.
            Sponsor shall have the right to use and sell any Developments or
            any product incorporating any Developments free of any royalty to
            Thompson and/or Panjehpour and Thompson and Panjehpour each agrees
            to execute and deliver to Sponsor any and all assignments,
            applications and other instruments that may be necessary to secure
            such rights to Sponsor.

     d.     Thompson and Panjehpour each agrees not to, directly or indirectly,
            disclose any proprietary information constituting a Development to
            others or to make use of it for any purpose except to perform the
            services hereunder, during the term hereof and for a period of
            five (5) years after termination or expiration of this Agreement.

     e.     Upon termination hereof, Thompson and Panjehpour each shall promptly
            deliver all memoranda, books, papers, letters, formulas, drawings,
            manuals, notes, reports, computer disks or tapes, all copies of the
            foregoing, and all other materials (whether or not reduced to
            written or tangible form) which are unique to the work and/or
            project (including the Developments) requested in writing by
            Sponsor, which are in Thompson's or Panjehpour's respective
            possession or under its or his respective control. Thompson may
            retain one copy of the foregoing for its records, which shall in
            all events be subject to the provisions hereof.

     f.     Except as expressly set forth in this Agreement, each party's
            obligations hereunder shall survive the termination or expiration
            of this Agreement.  This Agreement shall be binding upon the parties
            and their respective affiliates, officers, employees and

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            independent contractors and shall inure to the benefit of the
            parties and their respective successors and assigns, heirs and
            legal representatives.

     g.     Each party reserves any available remedies to enforce this
            Agreement.

7.   PUBLICATION. Thompson or Panjehpour may publish interim and/or final
     results of the investigation/research described in Article 1 hereof, upon
     receipt of prior written approval from Sponsor, and provided the results
     to be published do not contain or divulge proprietary information as
     reasonably determined by Sponsor. Sponsor shall have 30 days from receipt
     of publication manuscripts to review the same for content.  If Sponsor
     fails to respond within 30 days, and Thompson and/or Panjehpour has
     obtained written approval from Sponsor to publish, it and/or he, as
     applicable, has the right to publish and shall incur no liability to
     Sponsor therefor.

8.   INDEPENDENT CONTRACTOR. Thompson's relationship to Sponsor in the
     performance of this Agreement is that of an independent contractor.
     Panjehpour's relationship hereunder is that of employee of Thompson.

9.   INDEMNIFICATION BY SPONSOR. Sponsor shall indemnify, defend and hold
     Thompson and Panjehpour harmless from any and all claims and suits which
     are based on any injury or damage arising out of the research conducted
     hereunder (including, but not limited to, the clinical evaluation or
     testing of any drug or device included in this study if applicable) for
     any act or omission of Sponsor involving the use, manufacture or
     distribution of any product or process arising out of or involved with
     this Agreement.

10.  INDEMNIFICATION BY THOMPSON AND PANJEHPOUR. Thompson and Panjehpour,
     jointly and severally, shall indemnify, defend and hold Sponsor harmless
     from any and all claims and suits which arise out of or are related to any
     negligent act or omission or the wilful misconduct of Thompson and/or
     Panjehpour.

11.  NEGATION OF WARRANTIES BY THOMPSON. Although Thompson and Panjehpour will
     use its and his respective best efforts in providing services hereunder,
     neither of them makes any warranties, either expressed or implied, as to
     the results of the underlying research or the merchantability or fitness
     for a particular purpose of such research or any Development arising out
     of the research.  Thompson and Panjehpour shall not be liable for any
     direct, consequential, or other damages suffered by the Sponsor or others
     which may result from the use of the research result or any Development
     arising out of the research.

12.  KEY PERSONNEL. MASOUD PANJEHPOUR, PH.D. is considered to be essential to
     the work performed by Thompson under this Agreement. Substitutions for or
     substantial changes in his level of effort will not be made without the
     prior written approval of Sponsor.

13.  PRE-EXISTING INTELLECTUAL PROPERTY RIGHTS OF THE PARTIES. None of the
     parties claims by virtue of this Agreement any right, title, or interest in
     (a) any issued or pending patents or copyrights owned or controlled by
     another party or (b) any previous

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     invention, process, software, or product of another party, whether or not
     protected under the intellectual property laws of the United States or any
     other country.

14.  INVENTIONS AND DATA.

     a.    Developments directly resulting from the performance of the work
           described herein and in the Research Contract shall be the property
           of Sponsor. However, Thompson and Panjehpour shall have the right to
           use such Developments for internal education, research and academic
           purposes.

     b.    The original data generated as a result of the performance of the
           work described herein and in the Research Contract shall be provided
           to Sponsor, and Sponsor may use such data as it deems advisable.
           However, this provision shall not be interpreted to restrict
           Thompson's and Panjehpour's publication rights under Article 7 of
           this Agreement.

15.  USE OF PARTIES' NAMES. None of the parties to this Agreement shall use the
     name of any other party in any form of publicity without the written
     permission of such other party.

16.  MODIFICATION. This Agreement constitutes the sole, full, and complete
     agreement by and among the parties, and no amendments, changes, additions,
     deletions, or modifications to or of this Agreement shall be valid unless
     reduced to writing, and signed by all of the parties.

17.  NOTICES AND OTHER COMMUNICATIONS.  With the exception the payments made by
     Sponsor under the provision of Paragraph 3, all notices and other
     communications between the parties shall be deemed sufficiently given when
     hand delivered or sent by prepaid United States mail or other recognized
     carrier, addressed as follows:

     a.    If to Sponsor:

           John Smolik
           President, CEO
           Photogen, Inc.
           7327 Oak Ridge Highway
           Knoxville, TN 37931

     b.    If to Thompson:

           Phillip B. Johnson
           Vice President
           The Thompson Cancer Survival Center
           1915 White Avenue
           Knoxville, TN 37916

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     c.    If to Panjehpour:

           Masoud Panjehpour, Ph.D.
           _____________________________
           _____________________________


     A party may change its or his address by written notice given to the other
     parties.  It is specifically provided that this notice provision shall not
     be construed in such a manner as to abrogate the provisions of Section 16
     regarding modification for this Agreement.

18.  GOVERNING LAW.  This Agreement is made and entered into in the State of
     Tennessee and its validity and interpretation and the legal relations of
     the parties to it shall be governed by the law of the State of Tennessee.

THIS AGREEMENT shall not be considered accepted, approved, or otherwise
effective until the signature of each party is affixed in the space provided
below.

IN WITNESS WHEREOF, signifying their acceptance of and agreement to be bound
by the terms and conditions of this Agreement, the signatures of the parties
are affixed hereto:

PHOTOGEN, INC.                         THE THOMPSON CANCER SURVIVAL
                                       CENTER

By: /s/ John Smolik                    By: /s/ Phillip B. Johnson
   ---------------------------            -----------------------------
   John Smolik                            Phillip B. Johnson
   President, CEO                         Vice President

Date: February 2, 1998                 DATE: January 12, 1998




                                        /s/ Masoud Panjehpour
                                       --------------------------------
                                       Masoud Panjehpour, Ph.D.

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