REGISTRATION
      RIGHTS AGREEMENT

     

    This
      Registration Rights Agreement (the
      "Agreement") is entered into as of the 1st day of February, 2006, by and among
      IsoRay,
      Inc.,
      a
      Minnesota corporation (the "Corporation"), Meyers
      Associates, L.P.,
      a New
      York limited partnership (the
      "Selling Agent"), and each of the Corporation's shareholders (collectively,
      the
      "Signing Shareholders") who is a signatory hereto.

     

    Recitals

     

    Whereas,
      the
      Corporation desires to raise between $45,000 and $2,002,000, subject to increase
      to $4,005,000, of equity to fund its working capital requirements.

     

    Whereas,
      the
      Corporation has agreed to provide certain demand and piggyback registration
      rights to the investors who purchase the shares of Common Stock placed by the
      Selling Agent, other members of the selling group, or sold by officers of the
      Corporation.

     

    Now,
      Therefore, in
      consideration of the foregoing and the mutual promises contained herein, and
      for
      other good and valuable consideration, the receipt and sufficiency of which
      are
      hereby acknowledged, the parties hereto agree as follows:

     

    SECTION
      1.  GENERAL.

     

    1.1  Definitions.
      As
      used
      in this Agreement, the following terms shall have the following respective
      meanings:

     

    "Board"
      shall mean the board of directors of the Corporation.

     

    "Common
      Stock" or "Shares" shall mean the Corporation's Common Stock, or any other
      class
      of stock exchanged for Common Stock of the Corporation.

     

    “Conversion
      Shares” shall mean those certain shares of Common Stock issued upon exercise of
      the common stock purchase warrants placed by members of the selling group,
      sold
      by officers of the Corporation, or issued to the members of the selling group
      pursuant to the Memorandum.

     

    "Exchange
      Act" means the Securities Exchange Act of 1934, as amended. 

     

    "GAAP"
      shall mean those generally accepted accounting principles and practices which
      are recognized by the American Institute of Certified Public Accountants and
      which are consistently applied for all periods so as to properly reflect the
      financial condition, and the results of operations and changes in financial
      position, of the Company.

     

    "Holder"
      means any person or entity owning of record Registrable Securities that have
      not
      been sold to the public or any assignee of record of such Registrable Securities
      in accordance with Section 2.7 hereof.

     

    “Memorandum”
      shall mean the Corporation’s Confidential Private Placement Memorandum dated
      February 1, 2006, and all supplements and amendments thereto.

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    "Register,"
      "registered," and "registration" refer to a registration effected by preparing
      and filing a registration statement in compliance with the Securities Act,
      and
      the declaration or ordering of effectiveness of such registration statement
      or
      document.

     

    "Registrable
      Securities" means (a) the Common Stock of the Corporation placed by members
      of
      the selling group or sold by officers of the Corporation; (b) the Conversion
      Shares, and (c) any Common Stock of the Corporation issued as (or issuable
      upon
      the conversion or exercise of any warrant, right or other security which is
      issued as) a dividend or other distribution with respect to, or in exchange
      for
      or in replacement of, such above-described securities. Notwithstanding the
      foregoing, Registrable Securities shall not include any securities sold by
      a
      person or entity to the public either pursuant to a registration statement
      or
      Rule 144 or sold in a private transaction in which the transferor's rights
      under Section 2 of this Agreement are not assigned.

     

    "Registrable
      Securities then outstanding" shall be the number of shares determined by
      calculating the total number of shares of the Corporation's Common Stock that
      are Registrable Securities and either (a) are then issued and outstanding
      or (b) are issuable pursuant to then exercisable or convertible
      securities.

     

    "Registration
      Expenses" shall mean all expenses incurred by the Corporation in complying
      with
      Sections 2.1 and 2.2 hereof, including, without limitation, all registration
      and
      filing fees, printing expenses, fees and disbursements of counsel for the
      Corporation, reasonable fees and disbursements of special counsel for the
      Holders, blue sky fees and expenses and the expense of any special audits
      incident to or required by any such registration (but excluding the compensation
      of regular employees of the Corporation which shall be paid in any event by
      the
      Corporation).

     

    "SEC"
      or
      "Commission" means the Securities and Exchange Commission.

     

    "Securities
      Act" shall mean the Securities Act of 1933, as amended.

     

    "Selling
      Expenses" shall mean all underwriting discounts and selling commissions
      applicable to the sale of the Corporation's capital stock.

     

    "Shareholders"
      shall mean all of the holders of the Corporation's capital stock.

     

    "Special
      Registration Statement" shall mean a registration statement relating to any
      employee benefit plan or with respect to any corporate reorganization or other
      transaction under Rule 145 of the Securities Act.

     

    "Termination
      Date" shall mean twenty-four (24) months after the final conclusion of the
      “Offering Period,” as such term is defined in the Memorandum. 

     

    SECTION
      2.  PIGGYBACK
      AND DEMAND REGISTRATION.
      

     

    2.1  Piggyback
      Registration.  The
      Corporation shall promptly notify all Holders of Registrable Securities in
      writing of any proposed filing of any registration statement under the
      Securities Act for purposes of a public offering of securities of the
      Corporation (including, but not limited to, registration statements relating
      to
      secondary offerings of securities of the Corporation, but excluding Special
      Registration Statements), which notice shall be made at least forty-five (45)
      days prior to such filing, and will afford each such Holder an opportunity
      to
      include in such registration statement all or part of such Registrable
      Securities held by such Holder. Each Holder desiring to include in any such
      registration statement all or any part of the Registrable Securities held by
      it
      shall, within twenty (20) days after receipt of the above-described notice
      from
      the Corporation, so notify the Corporation in writing. Such notice shall state
      the intended method of disposition of the Registrable Securities by such Holder.
      If a Holder decides not to include all of its Registrable Securities in any
      registration statement thereafter filed by the Corporation, such Holder shall
      forfeit all future right to include any Registrable Securities in any subsequent
      registration statement or registration statements as may be filed by the
      Corporation with respect to offerings of its securities.

     

    
      
        
        

      

      
        2

        
          

        

      

      
        
        

      

    

    (a)  Underwriting.
      If
      the
      registration statement under which the Corporation gives notice under this
      Section 2.1 is for an underwritten offering, the Corporation shall so
      advise the Holders of Registrable Securities. In such event, the right of any
      such Holder to be included in a registration pursuant to this Section 2.1
      shall be conditioned upon such Holder's participation in such underwriting
      and
      the inclusion of such Holder's Registrable Securities in the underwriting to
      the
      extent provided herein. All Holders proposing to distribute their Registrable
      Securities through such underwriting shall enter into an underwriting agreement
      in customary form with the underwriter or underwriters selected for such
      underwriting by the Corporation. Notwithstanding any other provision of this
      Agreement, if the underwriter determines in good faith that marketing factors
      require a limitation of the number of shares to be underwritten, the number
      of
      shares that may be included in the underwriting shall be allocated, first,
      to
      the Corporation; and second, to the Holders; and thereafter to any other
      Shareholders of the Corporation holding registration rights. If any Holder
      disapproves of the terms of any such underwriting, such Holder may elect to
      withdraw therefrom by written notice to the Corporation and the underwriter,
      delivered on or before the later of (i) five (5) business days after the
      receipt by all Holders and the Placement Agent of the underwriting agreement
      containing the terms thereof and (ii) ten (10) business days prior to the
      effective date of the registration statement. Any Registrable Securities
      excluded or withdrawn from such underwriting shall be excluded and withdrawn
      from the registration. For any Holder which is a partnership or corporation,
      the
      partners, retired partners and shareholders of such Holder, or the estates
      and
      family members of any such partners and retired partners and any trusts for
      the
      benefit of any of the foregoing shall be deemed to be a single "Holder," and
      any
pro
      rata
      reduction with respect to such "Holder" shall be based upon the aggregate amount
      of shares of Corporation capital stock carrying registration rights owned by
      all
      entities and individuals included in such “Holder,” as defined in this
      sentence.

     

    (b)  Right
      to Terminate Registration. The
      Corporation shall have the right to terminate or withdraw any registration
      initiated by it under this Section 2.1 prior to the effectiveness of such
      registration whether or not any Holder has elected to include securities in
      such
      registration. The Registration Expenses of such withdrawn registration shall
      be
      borne by the Corporation in accordance with Section 2.3 hereof.


     

    2.2  Demand
      Registration. At
      any
      time on or after October 1, 2006, Holders
      shall have a "onetime" demand right to make a written request ("Demand Request")
      that the Corporation register the Registrable Securities. Within thirty (30)
      days after receipt of Demand Requests from Holders of at least a majority of
      the
      Registrable Securities, the Corporation shall prepare and file under the Act,
      one registration statement to permit a public offering of all of the Registrable
      Securities ("Demand Registration"). 

     

    
      
        
        

      

      
        3

        
          

        

      

      
        
        

      

    

    2.3  Expenses
      of Registration. Except
      as
      specifically provided herein, all Registration Expenses incurred in connection
      with any registration pursuant to Sections 2.1 and 2.2 herein shall be borne
      by
      the Corporation. All Selling Expenses incurred in connection with any
      registrations hereunder shall be borne by the holders of the securities so
      registered pro
      rata
      on the
      basis of the number of Shares so registered. 

     

    2.4     
      Obligations
      of the Corporation.  Whenever
      required to effect the registration of any Registrable Securities, the
      Corporation shall, as expeditiously as reasonably possible (and, with respect
      to
      any registration statement required to be filed pursuant to Section 2.2, in
      any
      event within thirty (30) days): 

     

    (a)  With
      respect to any registration statement required to be filed under
      Section 2.2, prepare and file with the SEC a registration statement with
      respect to such Registrable Securities and use all reasonable efforts to cause
      such registration statement to become effective, and, upon the request of the
      Holders of a majority of the Registrable Securities registered thereunder,
      keep
      such registration statement effective for up to two (2) years or, if earlier,
      until the Holders have completed the distribution related thereto.

     

    (b)  Prepare
      and file with the SEC such amendments and supplements to such registration
      statement and the prospectus used in connection with such registration statement
      as may be necessary to comply with the provisions of the Securities Act with
      respect to the disposition of all securities covered by such registration
      statement for the period set forth in paragraph (a) above.

     

    (c)  Furnish
      to the Holders such number of copies of a prospectus, including a preliminary
      prospectus, in conformity with the requirements of the Securities Act, and
      such
      other documents as they may reasonably request in order to facilitate the
      disposition of Registrable Securities owned by them.

     

    (d)  Use
      its
      reasonable efforts to register and qualify the securities covered by such
      registration statement under such other securities or Blue Sky laws of such
      jurisdictions as shall be reasonably requested by the Holders; provided
      that
      the
      Company shall not be required in connection therewith or as a condition thereto
      to qualify to do business or to file a general consent to service of process
      in
      any such states or jurisdictions.

     

    (e)  In
      the
      event of any underwritten public offering, enter into and perform its
      obligations under an underwriting agreement, in usual and customary form, with
      the managing underwriter(s) of such offering. Each Holder participating in
      such
      underwriting shall also enter into and perform its obligations under such an
      agreement.

     

    (f)  Notify
      each Holder of Registrable Securities covered by such registration statement
      at
      any time when a prospectus relating thereto is required to be delivered under
      the Securities Act of the happening of any event as a result of which the
      prospectus included in such registration statement, as then in effect, includes
      an untrue statement of a material fact or omits to state a material fact
      required to be stated therein or necessary to make the statements therein not
      misleading in the light of the circumstances then existing. The Corporation
      will
      use reasonable efforts to amend or supplement such prospectus in order to cause
      such prospectus not to include any untrue statement of a material fact or omit
      to state a material fact required to be stated therein or necessary to make
      the
      statements therein not misleading in the light of the circumstances then
      existing.

     

    
      
        
        

      

      
        4

        
          

        

      

      
        
        

      

    

    (g)  Use
      its
      reasonable efforts to furnish, on the date that such Registrable Securities
      are
      delivered to the underwriters for sale, if such securities are being sold
      through underwriters, (i) an opinion, dated as of such date, of the counsel
      representing the Corporation for the purposes of such registration, in form
      and
      substance as is customarily given to underwriters in an underwritten public
      offering, addressed to the underwriters, if any, and (ii) a letter dated as
      of such date, from the independent certified public accountants of the
      Corporation, in form and substance as is customarily given by independent
      certified public accountants to underwriters in an underwritten public offering
      addressed to the underwriters. 

     

    2.5  Furnishing
      Information. It
      shall
      be a condition precedent to the obligations of the Corporation to take any
      action pursuant to Sections 2.1 and 2.2 that the selling Holders shall furnish
      to the Corporation such information regarding themselves and warrant the
      accuracy thereof, the Registrable Securities held by them and the intended
      method of disposition of such securities as shall be required to effect the
      registration of their Registrable Securities.

     

    2.6  Indemnification.
      In
      the
      event any Registrable Securities are included in a registration statement under
      Sections 2.1 and 2.2:

     

    (a)  To
      the
      extent permitted by law, the Corporation will indemnify and hold harmless each
      Holder, the partners, officers and directors of each Holder, any underwriter
      (as
      defined in the Securities Act) for such Holder and each person, if any, who
      controls such Holder or underwriter within the meaning of the Securities Act
      or
      the Exchange Act, against any losses, claims, damages, or liabilities (joint
      or
      several) to which they may become subject under the Securities Act, the Exchange
      Act or other federal or state law, insofar as such losses, claims, damages
      or
      liabilities (or actions in respect thereof) arise out of or are based upon
      any
      of the following statements, omissions or violations (collectively a
      "Violation") by the Corporation: (i) any untrue statement or alleged untrue
      statement of a material fact contained in such registration statement, including
      any preliminary prospectus or final prospectus contained therein or any
      amendments or supplements thereto, (ii) the omission or alleged omission to
      state therein a material fact required to be stated therein, or necessary to
      make the statements therein not misleading, or (iii) any violation or
      alleged violation by the Corporation of the Securities Act, the Exchange Act,
      any state securities law or any rule or regulation promulgated under the
      Securities Act, the Exchange Act or any state securities law in connection
      with
      the offering covered by such registration statement; and the Corporation will
      pay as incurred to each such Holder, partner, officer, director, underwriter
      or
      controlling person for any legal or other expenses reasonably incurred by them
      in connection with investigating or defending any such loss, claim, damage,
      liability or action; provided
      however,
      that
      the indemnity agreement contained in this Section 2.6(a) shall not apply to
      amounts paid in settlement of any such loss, claim, damage, liability or action
      if such settlement is effected without the consent of the Corporation, which
      consent shall not be unreasonably withheld, nor shall the Corporation be liable
      in any such case for any such loss, claim, damage, liability or action to the
      extent that it arises out of or is based upon a Violation which occurs in
      reliance upon and in conformity with written information furnished expressly
      for
      use in connection with such registration by such Holder, partner, officer,
      director, underwriter or controlling person of such Holder.

     

    
      
        
        

      

      
        5

        
          

        

      

      
        
        

      

    

    (b)  To
      the
      extent permitted by law, each Holder will, if Registrable Securities held by
      such Holder are included in the securities as to which such registration
      qualifications or compliance is being effected, indemnify and hold harmless
      the
      Corporation, each of its directors, its officers and each person, if any, who
      controls the Corporation within the meaning of the Securities Act, any
      underwriter and any other Holder selling securities under such registration
      statement or any of such other Holder's partners, directors or officers or
      any
      person who controls such Holder, against any losses, claims, damages or
      liabilities (joint or several) to which the Corporation or any such director,
      officer, controlling person, underwriter or other such Holder, or partner,
      director, officer or controlling person of such other Holder may become subject
      under the Securities Act, the Exchange Act or other federal or state law,
      insofar as such losses, claims, damages or liabilities (or actions in respect
      thereto) arise out of or are based upon any Violation, in each case to the
      extent (and only to the extent) that such Violation occurs in reliance upon
      and
      in conformity with written information furnished by such Holder under an
      instrument duly executed by such Holder and stated to be specifically for use
      in
      connection with such registration; and each such Holder will pay as incurred
      any
      legal or other expenses reasonably incurred by the Corporation or any such
      director, officer, controlling person, underwriter or other Holder, or partner,
      officer, director or controlling person of such other Holder in connection
      with
      investigating or defending any such loss, claim, damage, liability or action
      if
      it is judicially determined that there was such a Violation; provided,
      however,
      that the
      indemnity agreement contained in this Section 2.6(b) shall not apply to
      amounts paid in settlement of any such loss, claim, damage, liability or action
      if such settlement is effected without the consent of the Holder, which consent
      shall not be unreasonably withheld; provided
      further,
      that in
      no event shall any indemnity under this Section 2.6 exceed the net proceeds
      from the offering received by such Holder.

     

    (c)  Promptly
      after receipt by an indemnified party under this Section 2.6 of notice of
      the commencement of any action (including any governmental action), such
      indemnified party will, if a claim in respect thereof is to be made against
      any
      indemnifying party under this Section 2.6, deliver to the indemnifying
      party a written notice of the commencement thereof and the indemnifying party
      shall have the right to participate in, and, to the extent the indemnifying
      party so desires, jointly with any other indemnifying party similarly noticed,
      to assume the defense thereof with counsel mutually satisfactory to the parties;
      provided,
      however,
      that an
      indemnified party shall have the right to retain its own counsel, with the
      fees
      and expenses to be paid by the indemnifying party, if representation of such
      indemnified party by the counsel retained by the indemnifying party would be
      inappropriate due to actual or potential differing interests between such
      indemnified party and any other party represented by such counsel in such
      proceeding. The failure to deliver written notice to the indemnifying party
      within a reasonable time of the commencement of any such action, if materially
      prejudicial to its ability to defend such action, shall relieve such
      indemnifying party of any liability to the indemnified party under this
      Section 2.6, but the omission so to deliver written notice to the
      indemnifying party will not relieve it of any liability that it may have to
      any
      indemnified party otherwise than under this Section 2.6.

     

    
      
        
        

      

      
        6

        
          

        

      

      
        
        

      

    

    (d)  If
      the
      indemnification provided for in this Section 2.6 is held by a court of
      competent jurisdiction to be unavailable to an indemnified party with respect
      to
      any losses, claims, damages or liabilities referred to herein, the indemnifying
      party, in lieu of indemnifying such indemnified party thereunder, shall to
      the
      extent permitted by applicable law contribute to the amount paid or payable
      by
      such indemnified party as a result of such loss, claim, damage or liability
      in
      such proportion as is appropriate to reflect the relative fault of the
      indemnifying party on the one hand and of the indemnified party on the other
      in
      connection with the Violation(s) that resulted in such loss, claim, damage
      or
      liability, as well as any other relevant equitable considerations. The relative
      fault of the indemnifying party and of the indemnified party shall be determined
      by a court of law by reference to, among other things, whether the untrue or
      alleged untrue statement of a material fact or the omission to state a material
      fact relates to information supplied by the indemnifying party or by the
      indemnified party and the parties' relative intent, knowledge, access to
      information and opportunity to correct or prevent such statement or omission;
      provided,
      that in
      no event shall any contribution by a Holder hereunder exceed the net proceeds
      from the offering received by such Holder.

     

    (e)  The
      obligations of the Corporation and Holders under this Section 2.6 shall
      survive completion of any offering of Registrable Securities in a registration
      statement and the termination of this agreement. No Indemnifying Party, in
      the
      defense of any such claim or litigation, shall, except with the consent of
      each
      Indemnified Party, consent to entry of any judgment or enter into any settlement
      which does not include as an unconditional term thereof the giving by the
      claimant or plaintiff to such Indemnified Party of a release from all liability
      in respect to such claim or litigation.

     

    2.7  Assignment
      of Registration Rights.  The
      registration rights of the Holders under this Agreement may be transferred
      to
      any transferee if the Corporation is given written notice by the Holder at
      the
      time of such transfer stating the name and address of the transferee and
      identifying the securities with respect to which the rights under this Agreement
      are being assigned.

     

    2.8  Amendment
      of Registration Rights.  Any
      provision of this Section 2 may be amended and the observance thereof may
      be waived (either generally or in a particular instance and either retroactively
      or prospectively), only with the written consent of the Corporation and the
      holders of at least a majority of the Registrable Securities then outstanding.
      Any amendment or waiver effected in accordance with this Section 2.8 shall
      be binding upon each Holder and the Corporation. By acceptance of any benefits
      under this Section 2, Holders of Registrable Securities hereby agree to be
      bound by the provisions hereunder.

     

    2.9  Rule
      144 Reporting.  With
      a
      view to making available to the Holders the benefits of certain rules and
      regulations of the SEC which may permit the sale of the Registrable Securities
      to the public without registration, the Corporation agrees to use its best
      efforts to:

     

    (a)  Make
      and
      keep public information available, as those terms are understood and defined
      in
      SEC Rule 144 or any similar or analogous rule promulgated under the
      Securities Act, at all times after the effective date of the first registration
      filed by the Corporation for an offering of its securities to the general
      public;

     

    
      
        
        

      

      
        7

        
          

        

      

      
        
        

      

    

    (b)  File
      with
      the SEC, in a timely manner, all reports and other documents required of the
      Corporation under the Exchange Act; and

     

    (c)  So
      long
      as a Holder owns any Registrable Securities, furnish to such Holder forthwith
      upon request: a written statement by the Corporation as to its compliance with
      the reporting requirements of said Rule 144 of the Securities Act, and of the
      Exchange Act (at any time after it has become subject to such reporting
      requirements); a copy of the most recent annual or quarterly report of the
      Corporation; and such other reports and documents as a Holder may reasonably
      request in availing itself of any rule or regulation of the SEC allowing it
      to
      sell any such securities without registration.

     

    SECTION
      3.  MISCELLANEOUS.

     

    3.1  Governing
      Law.  This
      Agreement and
      the
      rights and obligations of the parties hereto, shall be governed, construed
      and
      interpreted according to the laws of the State of Washington. The parties agree
      that any final judgment after exhaustion of all appeals or the expiration of
      time to appeal in any such action or proceeding shall be conclusive and binding,
      and may be enforced in any federal or state court in the United States by suit
      on the judgment or in any other manner provided by law. Nothing contained in
      this Agreement shall affect or limit the right of a party to serve any process
      or notice or motion or other application in any other manner permitted by law,
      or limit or affect the right of a party to bring any action or proceeding
      against the other parties or any of their respective property in the courts
      of
      any other jurisdiction. All parties hereby consent to the jurisdiction of the
      federal courts whose districts encompass any part of the City of Phoenix or
      the
      state courts of the State of Arizona sitting in the City of Phoenix in
      connection with any dispute arising under this Agreement, and hereby waives,
      to
      the maximum extent permitted by law, any objection, including any objections
      based on forum non
      conveniens, to
      the
      bringing of any such proceeding in such jurisdictions.

     

    3.2  Successors
      and Assigns.  Except
      as
      otherwise expressly provided herein, the provisions hereof shall inure to the
      benefit of, and be binding upon, the successors, assigns, heirs, executors,
      and
      administrators of the parties hereto and shall inure to the benefit of and
      be
      enforceable by each person who shall be a holder of Registrable Securities;
      provided,
      however,
      that
      prior to the receipt by the Corporation of adequate written notice of the
      transfer of any Registrable Securities or any rights hereunder specifying the
      full name and address of the transferee, the Corporation may deem and treat
      the
      person listed as the holder of such shares in its records as the absolute owner
      and holder of such shares for all purposes, including the payment of dividends
      or any redemption price.

     

    3.3  Severability.  In
      the
      event one or more of the provisions of this Agreement should, for any reason,
      be
      held to be invalid, illegal or unenforceable in any respect, such invalidity,
      illegality, or unenforceability shall not affect any other provisions of this
      Agreement, and this Agreement shall be construed as if such invalid, illegal
      or
      unenforceable provision had never been contained herein.

     

    
      
        
        

      

      
        8

        
          

        

      

      
        
        

      

    

    3.4  Amendment
      and Waiver.

     

    (a)  Except
      as
      otherwise expressly provided, this Agreement may be amended or modified only
      upon the written consent of the Corporation and the holders of at least a
      majority of the Registrable Securities.

     

    (b)  Except
      as
      otherwise expressly provided herein, the obligations of the Corporation and
      the
      rights of the Holders under this Agreement may be waived only with the written
      consent of the Holders of at least a majority of the Registrable
      Securities.

     

    3.5  Delays
      or Omissions.  It
      is
      agreed that no delay or omission to exercise any right, power, or remedy
      accruing to any Holder, upon any breach, default or noncompliance of the
      Corporation under this Agreement shall impair any such right, power, or remedy,
      nor shall it be construed to be a waiver of any such breach, default or
      noncompliance, or any acquiescence therein, or of any similar breach, default
      or
      noncompliance thereafter occurring. It is further agreed that any waiver,
      permit, consent, or approval of any kind or character on any Holder's part
      of
      any breach, default or noncompliance under the Agreement or any waiver on such
      Holder's part of any provisions or conditions of this Agreement must be in
      writing and shall be effective only to the extent specifically set forth in
      such
      writing. All remedies, either under this Agreement, by law, or otherwise
      afforded to Holders, shall be cumulative and not alternative. 

     

    3.6  Notices.
      All
      notices required or permitted hereunder shall be in writing and shall be deemed
      effectively given: (a) upon personal delivery to the party to be notified,
      (b) three (3) days after having been sent by registered or certified mail,
      return receipt requested, postage prepaid, or (c) one (1) day after deposit
      with a nationally recognized overnight courier, specifying next day delivery,
      with written verification of receipt. All communications shall be sent to the
      party to be notified at the address as set forth on either the signature pages
      hereof or at such other address as such party may designate by ten (10) days
      advance written notice to the other parties hereto. 

     

    3.7  Attorneys'
      Fees.  In
      the
      event that any suit or action is instituted to enforce any provision in this
      Agreement, the prevailing party in such dispute shall be entitled to recover
      from the losing party all fees, costs and expenses of enforcing any right of
      such prevailing party under or with respect to this Agreement, including without
      limitation, such reasonable fees and expenses of attorneys and accountants,
      which shall include, without limitation, all fees, costs and expenses of
      appeals.

     

    3.8  Construction.
      The
      terms of this Agreement constitute the written expression of the mutual
      agreement of the parties and shall be construed neutrally and not for or against
      either party. Whenever a noun or pronoun is used in this Agreement in the
      singular and when required by the context, the same shall include the plural,
      and the masculine gender shall include the feminine and neuter genders and
      vice
      versa. As used in this Agreement, the term "party" or "parties" shall mean
      the
      parties to this Agreement. The term "person" shall include any individual,
      entity, trust or association. The headings in this Agreement are inserted for
      convenience; the provisions of this Agreement shall control in determining
      the
      intent hereof.

     

    3.9  Enforcement;
      Specific Performance; Remedies Cumulative.
      

     

    
      
        
        

      

      
        9

        
          

        

      

      
        
        

      

    

    (a)  In
      case
      any one or more defaults shall occur and be continuing, a party may proceed
      to
      protect and enforce its rights by an action at law, suit in equity or other
      appropriate proceeding, whether for the specific performance of any agreement
      contained herein or for an injunction against a violation of any of the terms
      hereof or thereof, or in aid of the exercise of any power granted hereby or
      thereby or by law.

     

    (b)  The
      parties expressly agree that each party may not have adequate remedies at law
      if
      the other parties do not perform its obligations under this Agreement. Upon
      a
      party's breach of the terms or covenants of this Agreement, the other parties
      shall, each in addition to all other remedies, be entitled to obtain injunctive
      relief, and an order for specific performance of the breaching party's
      obligations hereunder. 

     

    3.10  Other
      Registration Rights.
      Each
      signing Security Holder understands and acknowledges that (i) certain
      shareholders of the Corporation who purchased debentures convertible into common
      stock at $4.15 per share as part of the Corporation’s subsidiary’s private
      offering in the Spring of 2005 and (ii) certain shareholders of the Corporation
      who purchased shares of common stock at $4.00 per share and warrants to purchase
      shares of common stock exercisable at $6.00 per share as part of the
      Corporation’s private offering in the Fall and Winter of 2005 have piggyback
      registration rights that may be triggered by the Holders’ exercise of their
      demand right pursuant to this Agreement. 

     

    3.11  Counterparts.  This
      Agreement may be executed in any number of counterparts, each of which shall
      be
      an original, but all of which together shall constitute one
      instrument.

     

    [Signature
      page to follow]

     

    
      
        
        

      

      
        10

        
          

        

      

      
        
        

      

    

    In
      Witness Whereof, the
      parties hereto have executed this Registration
      Rights Agreement as
      of the
      date set forth in the first paragraph hereof.

     

    
      	
              Meyers
                Associates, L.P.

               

               

              By:
                __________________________________________

              Name:
                ________________________________________

              Title:  
                ________________________________________

            	 	
              IsoRay,
                Inc.

               

               

              By:
                __________________________________________

              Name:
                ________________________________________

              Title:  
                ________________________________________

            	 
	 	 	 	 
	
              Address: 45
                Broadway Avenue, 2nd
                Floor 

              New
                York, NY 10006

            	 	
              Address: 350
                Hills Street, Suite 106 

              Richland,
                WA 99354

            	 
	
              Shareholders

               

               

              By:
                __________________________________________

              Name: 
                ____________________________________

              Address:
                __________________________________

               

               

               

              By:
                __________________________________________

              Name: 
                ____________________________________

              Address:
                __________________________________

               

               

               

              By:
                __________________________________________

              Name: 
                ____________________________________

              Address:
                __________________________________

               

               

               

              By:
                __________________________________________

              Name: 
                ____________________________________

              Address:
                __________________________________

               

               

               

              By:
                __________________________________________

              Name: 
                ____________________________________

              Address:
                __________________________________

               

            	 	
              Shareholders

               

               

              By:
                __________________________________________

              Name: 
                ____________________________________

              Address:
                __________________________________

               

               

               

              By:
                __________________________________________

              Name:
                 ____________________________________

              Address:
                __________________________________

               

               

               

              By:
                __________________________________________

              Name: 
                ____________________________________

              Address:
                __________________________________

               

               

               

              By:
                __________________________________________

              Name:
                 ____________________________________

              Address:
                __________________________________

               

               

               

              By:
                __________________________________________

              Name:
                 ____________________________________

              Address:
                __________________________________

               

            	 
	 	 	 	 


    

     

    
 

    
      
        
        

      

      
        11