POSITRON
        CORPORATION

      NOTE
        PURCHASE AGREEMENT

      


      THIS
        NOTE
        PURCHASE AGREEMENT (the "Agreement")
        is
        made as of October 31, 2005 by and between Positron Corporation, a Texas
        corporation (the "Company"),
        and
        Imagin Diagnostic Centers, Inc. ("Investor").
        All
        numbers expressed herein as "$" or "dollars" are in United States
        dollars.

      


      R
        E C
        I T A L S :

      


      WHEREAS,
        the Company desires to issue Convertible Promissory Notes in the aggregate
        principal amount of $400,000, subject to the terms and conditions set forth
        in
        this Agreement.

      


      WHEREAS,
        the Investor desires to purchase the Convertible Promissory Notes, subject
        to
        the terms and conditions set forth in this Agreement.

      


      NOW,
        THEREFORE, in consideration of the respective undertakings, covenants and
        agreements of the parties set forth herein, the parties hereby agree as
        follows:

      


      
        	 	
                SECTION
                  1

              	
                PURCHASE
                  AND SALE OF THE NOTES.

              


      

      


      1.1 Issuance
        of the Notes.
        The
        Company has authorized the issuance and sale to the Investor of, and, subject
        to
        and in reliance upon the representations, warranties, terms and conditions
        of
        this Agreement, the Investor the have agreed to purchase, the Company's
        Convertible Promissory Notes (individually, a "Note,"
        and
        collectively, the "Notes"),
        in
        the aggregate principal amount of $400,000. Each Note shall be substantially
        in
        the form set forth in Exhibit A
        hereto.

      


      1.2 Closing.
        The
        Company agrees to issue and sell to the Investor, and, subject to and in
        reliance upon the representations, warranties, terms and conditions of this
        Agreement, the Investor agrees to purchase, the Notes for the aggregate purchase
        price of $400,000 (the "Aggregate Purchase Price"). Such purchase and sale
        shall
        take place (a) at the initial closing (the "Closing") to be held at the offices
        of the Company on October 31, 2005, at 10:00 A.M., or such other date as
        the
        parties shall agree (the "First
        Closing Date"),
        and
        at subsequent closings ("Subsequent
        Closings")
        which
        shall occur upon 30 days written notice to Investor by the Company. At each
        Subsequent Closing Investor shall purchase a Note in a principal amount
        determined by the Company of not more than $200,000. Subsequent Closings
        shall
        be held not more frequently than every 30 days. At the Closings, the Company
        will issue a Note, dated the such date, payable to the order of Investor,
        in the
        principal amount of $200,000 in the case of the First Closing and in an amount
        specified in the Company's notice in the case of the Subsequent Closings
        in
        exchange for cash. In the event the Company shall not have sold and issued
        to
        Investor pursuant to the notices provided for herein the full amount of the
        Aggregate Purchase Price on or before December 31, 2005, the right of the
        Company to sell any additional Notes and the obligation of the Investor to
        purchase any additional Notes shall terminate. 

      


      
        
           

        

        
           

          
            

          

        

        
           

        

      

      1.3 Payments
        and Endorsements.
        Payments of principal, interest and premium, if any, on the Notes, shall
        be made
        directly by wire transfer or by checks duly mailed or delivered to the Investor
        at address specified in the Notes without any presentment or notation of
        payment, except that prior to any transfer of any Note, the holder of record
        shall endorse on such Note a record of the date to which interest has been
        paid
        and all payments made on account of principal of such Note.

      


      1.4 Payment
        on Non-Business Days.
        Whenever any payment to be made shall be due on a day which is not a Business
        Day, such payment may be made on the next succeeding Business Day, and such
        extension of time shall in such case be included in the computation of payment
        of interest due.

      


      1.5 Registration,
        etc.
        The
        Company shall maintain at its principal office a register of the Notes and
        shall
        record therein the name and address of the registered holder of the Notes,
        the
        address to which notices are to be sent and the address to which payments
        are to
        be made as designated by the registered holder if other than the address
        of the
        holder, and the particulars of all transfers, exchanges and replacements
        of the
        Notes. No transfer of a Note shall be valid unless made on such register
        for the
        registered holder or his executors or administrators or his or their duly
        appointed attorney, upon surrender therefor for exchange as hereinafter
        provided, accompanied by an instrument in writing, in form and execution
        reasonably satisfactory to the Company. Each Note issued hereunder, whether
        originally or upon transfer, exchange or replacement of a Note or Notes,
        shall
        be registered on the date of execution thereof by the Company and shall be
        dated
        the date to which interest has been paid on such Note or Notes. The registered
        holder of the Note shall be that Person in whose name the Note has been so
        registered by the Company. A registered holder shall be deemed the owner
        of a
        Note for all purposes of this Agreement and, subject to the provisions hereof,
        shall be entitled to the principal, premium, if any, and interest evidenced
        by
        such Note free from all equities or rights of set-off or counterclaim among
        the
        Company and the transferor of such registered holder or any previous registered
        holder of such Note.

      


      1.6 Limitations
        on Transferability.
        The
        Investor covenants that in no event will it dispose of any Note or any shares
        of
        capital stock into which such Note is convertible unless and until Investor
        shall have complied with Sections 4.7 and 4.8 hereof and (a) the
        Investor shall have notified the Company of the proposed disposition and
        shall
        have furnished the Company with a statement of the circumstances surrounding
        the
        proposed disposition, and (b) if requested by the Company, the Investor
        shall have furnished the Company with an opinion of counsel satisfactory
        in form
        and substance to the Company and the Company's counsel to the effect that
        (x) such disposition will not require registration under the Securities
        Act
        and (y) appropriate action necessary for compliance with the Securities
        Act
        and any applicable state, local, or foreign law has been taken.

      


      1.7 Replacement
        of Notes.
        Upon
        receipt of evidence satisfactory to the Company of the loss, theft, destruction
        or mutilation of any Note and, if requested in the case of any such loss,
        theft
        or destruction, upon delivery of an indemnity bond or other agreement or
        security reasonably satisfactory to the Company, or, in the case of any such
        mutilation, upon surrender and cancellation of such Note, the Company will
        issue
        a new Note, of like tenor and amount and dated the date to which interest
        has
        been paid, in lieu of such lost, stolen, destroyed or mutilated Note;
provided,
        however,
        if any
        Note of which an Investor, its nominee, or any of its partners or affiliates
        is
        the registered holder is lost, stolen or destroyed, the affidavit of the
        registered holder setting forth the circumstances with respect to such loss,
        theft or destruction shall be accepted as satisfactory evidence thereof,
        and no
        indemnification bond or other security shall be required as a condition to
        the
        execution and delivery by the Company of a new Note in replacement of such
        lost,
        stolen or destroyed Note other
        than
        the
        registered holder's written agreement to indemnify the Company.

      


      
        
           

        

        
          -2-

          
            

          

        

        
           

        

      

      1.8 Conversion
        of Note.
        All or
        any portion of the principal amounts of the Notes, may be converted at the
        option of the Investor, into shares of Common Stock (as defined herein) at
        a
        conversion price and on such terms as are provided in the Notes.

      


      
        	 	
                SECTION
                  2

              	
                DEFINITIONS.

              


      

      


      For
        purposes of this Agreement the following terms shall have the following
        meanings:

      


      2.1 "Articles"
        shall
        mean the Company's Articles of Incorporation, as amended, as of the First
        Closing, and including the Series A Statement, Series C Statement,
        Series D Statement, Series E Statement and Series F Statement
        thereto.

      


      2.2 "Business
        Day"
        shall
        mean a day other than Saturday, Sunday or a public holiday under the laws
        of the
        State of Texas.

      


      2.3 "Commission"
        shall
        mean the Securities and Exchange Commission.

      


      2.4 "Common
        Stock"
        shall
        mean the Common Stock of the Company, par value $0.01 per share.

      


      2.5 "GAAP"
        shall
        mean United States generally accepted accounting principles.

      


      2.6 "Intellectual
        Property"
        shall
        mean patents, patent applications, trademarks, service marks, mask works,
        trade
        names, copyrights, trade secrets, information, proprietary rights and
        processes.

      


      2.7 "Material
        Adverse Event"
        shall
        mean any change, event or effect that is materially adverse to the general
        affairs, business, operations, assets, condition (financial or otherwise)
        or
        results of operations of the Company and its subsidiaries taken as a whole;
        provided, however, that the following shall not be taken into account in
        determining a "Material
        Adverse Event":
        (a) any adverse change, event or effect that is directly attributable
        to
        conditions affecting the United States economy generally unless such conditions
        adversely affect the Company in a materially disproportionate manner, and
        (b) any adverse change, event or effect that is directly attributable
        to
        conditions affecting the Company's industry generally, unless such conditions
        adversely affect the Company in a materially disproportionate manner.


      


      2.8 "Person"
        shall
        mean an individual, corporation, partnership, joint venture, limited liability
        company, trust, or unincorporated organization, or a government or any agency
        or
        political subdivision thereof, or any other entity or business
        form.

      


      
        
           

        

        
          -3-

          
            

          

        

        
           

        

      

      2.9 "Preferred
        Stock"
        shall
        mean the Company's Series A Preferred Stock, Series C Preferred Stock,
        Series D Preferred Stock, Series E Preferred Stock and Series
        F
        Preferred Stock.

      


      2.10 "Registration
        Rights Agreement"
        shall
        mean the Registration Rights Agreement dated as of the First Closing by and
        between the Company and the Investor in the form attached hereto as Exhibit B.

      


      2.11 "Securities
        Act"
        shall
        mean the Securities Act of 1933, as amended and the rules and regulations
        of the
        Commission promulgated thereunder.

      


      2.12 "Series
        A Preferred Stock"
        shall
        mean the Series A Preferred Stock of the Company, par value $1.00
        per
        share.

      


      2.13 "Series
        A Statement"
        shall
        mean the Statement of Designation Establishing Series A 8% Cumulative
        Convertible Redeemable Preferred Stock of Position Corporation, filed with
        the
        Texas Secretary of State on February 29, 1996.

      


      2.14 "Series
        C Preferred Stock"
        shall
        mean the Series C Preferred Stock of the Company, par value $1.00
        per
        share.

      


      2.15 "Series
        C Statement"
        shall
        mean the Statement of Designation Establishing Series C Preferred
        Stock of
        Positron Corporation, filed with the Texas Secretary of State on May 21,
        2004.

      


      2.16 "Series
        D Preferred Stock"
        shall
        mean the Series D Preferred Stock of the Company, par value $1.00
        per
        share.

      


      2.17 "Series
        D Statement"
        shall
        mean the Statement of Designation Establishing Series D Preferred
        Stock of
        Positron Corporation, filed with the Texas Secretary of State on May 21,
        2004.

      


      2.18 "Series
        E Preferred Stock"
        shall
        mean the Series E Preferred Stock of the Company, par value $1.00
        per
        share.

      


      2.19 "Series
        E Statement"
        shall
        mean the Statement of Designation Establishing Series E Preferred
        Stock of
        Positron Corporation, to be filed with the Texas Secretary of State following
        the Closing. 

      


      2.20 "Series
        F Preferred Stock"
        shall
        mean the Series F Preferred Stock of the Company, par value $1.00 per
        share.

      


      2.21 "Series
        F Statement"
        shall
        mean the Statement of Designation Establishing Series F Preferred Stock of
        Positron corporation to be filed with the Texas Secretary of State following
        the
        Closing.

      


      2.22 "Subsidiary"
        shall
        mean any corporation, partnership or other entity, more than 50% of whose
        equity
        interests (measured by virtue of voting rights) in the aggregate is owned
        by the
        Company.

      


      
        
           

        

        
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      2.23 "Transactional
        Agreements"
        shall
        mean this Agreement, the Notes, and the Registration Rights
        Agreement.

      


      
        	 	
                SECTION
                  3

              	
                REPRESENTATIONS
                  AND WARRANTIES OF THE COMPANY.

              


      

      


      The
        Company hereby represents and warrants to the Investor that:

      


      3.1 Corporate
        Organization and Authority.
        The
        Company:

      


      3.1.1 is
        a
        corporation duly organized, validly existing, authorized to exercise all
        its
        corporate powers, rights and privileges, and in good standing in the State
        of
        Texas;

      


      3.1.2 has
        the
        corporate power and corporate authority to own and operate its properties
        and to
        carry on its business as now conducted and as proposed to be
        conducted;

      


      3.1.3 has
        made
        available to the Investor or their counsel a copy of the minute books of
        the
        Company, and said copies are true, correct, and complete and contain all
        amendments and all minutes of meetings and actions taken by the shareholders
        and
        directors of the Company through the date of this Agreement.

      


      3.2 Subsidiaries.
        The
        Company does not presently own, have any equity interest or investment in,
        or
        control, directly or indirectly, any other corporation, partnership or entity.
        The Company is not a participant in any joint venture or
        partnership.

      


      3.3 SEC
        Filings; Financial Statements.
        The
        Company has filed (i) its Annual Report on Form 10-K for the
        fiscal
        year ended December 31, 2004 (the "Company
        Current 10-K"),
        and
        (ii) its Quarterly Reports on Form 10-Q for the fiscal quarters ended
        March 31, 2005 and June 30, 2005, (the "Company
        Current 10-Qs"
        and,
        together with the Company Current 10-K and the "Company
        SEC Reports"),
        all
        of which complied when filed in all material respects with all applicable
        requirements of the Securities Act and the Exchange Act of 1934, as amended.
        The
        audited financial statements and unaudited interim financial statements
        of the Company included or incorporated by reference in such Company SEC
        Reports
        were prepared in accordance with GAAP applied on a consistent basis during
        the
        periods involved (except as may be indicated in the notes thereto) and present
        fairly, in all material respects, the financial position and results of
        operations and cash flows of the Company at the respective dates and for
        the
        respective periods indicated (and in the case of all such financial statements
        that are interim financial statements, contain all adjustments so to present
        fairly). Except to the extent that information contained in any Company SEC
        Report was revised or superseded by a later filed report, none of the Company
        SEC Reports contained any untrue statement of a material fact or omitted
        to
        state any material fact required to be stated therein or necessary in order
        to
        make the statements therein, in light of the circumstances under which they
        were
        made, not misleading.

      


      3.4 Corporate
        Power.
        The
        Company will have at the Closing Date all requisite legal and corporate power
        and authority to execute and deliver the Transactional Agreements, to sell
        and
        issue the Notes hereunder, to issue the Common Stock upon conversion of the
        Notes (subject to stockholder approval as set forth in Section 7.1
        hereof),
        and to carry out and perform its obligations under the terms of the
        Transactional Agreements.

      


      
        
           

        

        
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      3.5 Authorization.
        All
        corporate action on the part of the Company, its officers, directors, and
        stockholders necessary for the authorization, execution, delivery, and
        performance of all obligations under the Transactional Agreements, and for
        the
        authorization, issuance, and delivery of the Notes, and of the Common Stock
        (subject to stockholder approval as set forth in Section 7.1 hereof)
        issuable upon conversion of the Notes has been taken. The Transactional
        Agreements constitute legally binding and valid obligations of the Company
        enforceable in accordance with their respective terms, except to the extent
        that
        such enforcement may be subject to applicable bankruptcy, insolvency,
        reorganization, moratorium, or other laws of general application relating
        to or
        affecting enforcement of creditors' rights and laws concerning equitable
        remedies.

      


      3.6 Validity
        of Shares.
        Subject
        to stockholder approval, as set forth in Section 7.1 hereof, the Common
        Stock issuable upon conversion of the Notes has been duly and validly reserved
        and, assuming such Common Stock is issued in accordance with the Articles,
        will
        be duly and validly issued (including, without limitation, issued in compliance
        with applicable federal and state securities laws) and non-assessable and
        will
        be free of any liens or encumbrances other than any liens or encumbrances
        created by or imposed thereon by the holders; provided, however, that the
        Common
        Stock shall be subject to restrictions on transfer under state and/or federal
        securities laws. Except as set forth in the Articles and the Notes, the Common
        Stock issuable upon conversion of the Notes is not subject to any preemptive
        or
        other similar statutory or contractual rights and will not conflict with
        any
        provisions of any agreement or instrument to which the Company is a party
        or by
        which it is bound. 

      


      
        	 	
                SECTION
                  4

              	
                REPRESENTATIONS
                  AND WARRANTIES OF THE INVESTOR.

              


      

      


      The
        Investor represents and warrants to the Company as follows:

      


      4.1 Authorization.
        When
        executed and delivered by the Investor, and assuming execution and delivery
        by
        the Company, the Transactional Agreements will each constitute a valid
        obligation of the Investor, enforceable in accordance with its terms, except
        to
        the extent that such enforcement may be subject to applicable bankruptcy,
        insolvency, reorganization, moratorium, or other laws of general application
        relating to or affecting enforcement of creditors' rights and laws concerning
        equitable remedies.

      


      4.2 Brokers
        and Finders.
        The
        Investor has not retained any investment banker, broker, or finder in connection
        with the transactions contemplated by this Agreement.

      


      4.3 Investment.
        This
        Agreement is made with the Investor in reliance upon the Investor's
        representation to the Company, which by the Investor's execution of this
        Agreement the Investor hereby confirms, that the Notes (including capital
        stock
        issuable upon conversion thereof) to be received by the Investor will be
        acquired for investment for the Investor's own account, not as a nominee
        or
        agent, and not with a view to the sale or distribution of any part thereof,
        and
        that the Investor has no present intention of selling, granting any
        participation in, or otherwise distributing any of the Notes (including capital
        stock issuable upon conversion thereof). By executing this Agreement, the
        Investor further represents that it has no contract, undertaking, agreement,
        or
        arrangement with any person to sell, transfer, or grant participation to
        such
        person or to any third person, with respect to any of the Notes (including
        capital stock issuable upon conversion thereof).

      


      
        
           

        

        
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      4.4 No
        Public Market.
        The
        Investor understands that no public market now exists for the Notes and that
        the
        Company has given no assurances that a public market will ever exist for
        the
        Notes. The investor understands that the Company's Common Stock is currently
        quoted by the Nasdaq OTC Bulletin Board and that although the Company will
        use
        its best efforts to obtain listing on the Nasdaq SmallCap Market and Toronto
        Street Exchange, no assurance can be given that the Company's securities
        will be
        approved for listing on such exchanges. 

      


      4.5 Experience.
        The
        Investor represents that: (a) it has such knowledge and experience
        in
        financial and business matters as to be capable of evaluating the merits
        and
        risks of its prospective investment in the Notes; (b) it believes
        it has
        received all the information it has requested from the Company and considers
        necessary or appropriate for deciding whether to obtain the Notes; (c) it
        has had the opportunity to discuss the Company's business, management, and
        financial affairs with the Company's management; (d) it understands the economic
        implications of the transactions contemplated by this Agreement and confronting
        the Company; (e) it has had the full opportunity to seek advice of counsel
        and
        any other appropriate advice with respect to the transactions contemplated
        by
        this Agreement; (f) it has the ability to bear the economic risks
        of its
        prospective investment; and (g) it is able, without materially impairing
        its financial condition, to hold the Notes for an indefinite period of time
        and
        to suffer a complete loss on its investment.

      


      4.6 Accredited
        Investor.
        The
        Investor presently qualifies and will as of the Closing qualify as an
        "accredited investor" within the meaning of Regulation D of the rules and
        regulations promulgated under the Securities Act.

       

      4.7 Limitations
        on Transferability.
        The
        Investor covenants that in no event will it dispose of the Notes (other than
        pursuant to Rule 144 promulgated by Securities and Exchange Commission under
        the
        Securities Act ("Rule
        144")
        or any
        similar or analogous rule) unless and until (a) the Investor shall
        have
        notified the Company of the proposed disposition and shall have furnished
        the
        Company with a statement of the circumstances surrounding the proposed
        disposition, and (b) if requested by the Company, the Investor shall
        have
        furnished the Company with an opinion of counsel satisfactory in form and
        substance to the Company and the Company's counsel to the effect that
        (x) such disposition will not require registration under the Securities
        Act
        and (y) appropriate action necessary for compliance with the Securities
        Act
        and any applicable state, local, or foreign law has been taken. Notwithstanding
        the limitations set forth in the foregoing sentence, if the Investor is a
        partnership or limited liability company it may transfer Notes (or portions
        thereof) to its constituent partners or a retired partner of such partnership
        who retires after the date hereof, or its constituent members or retired
        members
        of such limited liability company who retires after the date hereof, as the
        case
        may be, or to the estate of any such partner, member or retired partner or
        member or transfer by gift, will, or intestate succession to any such partner's
        or member's spouse or lineal descendants or ancestors without the necessity
        of
        registration or opinion of counsel if the transferee agrees in writing to
        be
        subject to the terms of this Agreement to the same extent if such transferee
        were an Investor; provided, however, that Investor hereby covenants not to
        effect such transfer if such transfer either would invalidate the securities
        laws exemptions pursuant to which the Notes were originally offered and sold
        or
        would itself require registration and/or qualification under the Securities
        Act
        or applicable state securities laws. Each Note transferred as above provided
        shall bear the appropriate restrictive legend set forth in Section 5
        below,
        except that such Note shall not bear such legend if the transfer was made
        in
        compliance with subsection (k) of Rule 144 or if the opinion of counsel
        referred to above is to the further effect that such legend is not required
        in
        order to establish compliance with any provisions of the Securities
        Act.

      


      
        
           

        

        
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      4.8 Ownership
        Change Under Section 382 of the Internal Revenue Code; Special Restrictions
        Upon
        Transfer.
        

      


      4.8.1 Special
        Restrictions Upon Transfer.
        The
        following restrictions shall apply to the transfer of shares of Common Stock,
        issuable directly or indirectly upon the conversion of any Note.

      


      4.8.2 Definitions.
        For
        purposes of this Section 4.8 the following terms shall have the following
        meanings:

      


      "Board"
        means
        the Company's Board of Directors.

      


      "Common
        Stock"
        shall
        mean the Common Stock of the Company, par value $0.01 per share.

      


      "Section
        382"
        means
        Section 382 of the Internal Revenue Code of 1986, as amended, and the
        regulations thereunder.

      


      "Special
        Board Approval"
        shall
        mean the approval by the Board of Directors of the Company acting in accordance
        with applicable law.

      


      4.8.3 Purported
        Transfers Not Effective.
        Unless
        such transfer shall have been preceded by Special Board Approval, any purported
        transfer of Common Stock into which any Note is directly or indirectly
        convertible in excess of the number of shares that can be transferred without
        increasing the transferee's ownership interest percentage above 4.5% is not
        effective to transfer ownership of such excess shares (the "Prohibited
        Shares")
        from
        the transferor (the "Initial
        Transferor")
        to the
        purported acquiror (the "Purported
        Acquiror").
        For
        this purpose a transferee's ownership interest percentage shall be calculated
        pursuant to Section 382. By way of explanation, a transferees ownership interest
        is generally the sum of the transferee's direct ownership interest percentage
        as
        calculated pursuant to Section 382 and the transferee's indirect ownership
        interest as calculated pursuant to Section 382, with adjustments made to
        include
        ownership interests that, under ordinary circumstances, are not included
        in
        measuring ownership interests. In the event a Initial Transferor seeks a
        Special
        Board Approval, to the extent that the transaction reflected in the proposed
        request for a Special Board Approval does not result in an "ownership shift"
        in
        excess of 40% and does not result in an "ownership change" as those terms
        are
        used in Section 382, the approval of the Board will not be unreasonably
        withheld. Moreover, to the extent that the proceeds of any "ownership shift"
        of
        up to 40% results directly or indirectly in the receipt of cash by the Company,
        the transaction will be presumed to be in the interest of the Company unless
        it
        results in an "ownership change".

      


      
        
           

        

        
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      4.8.4 Transfer
        to Agent of Prohibited Shares; Sale by Agent; Payment of
        Proceeds.
        On
        demand by the Company (which demand must be made within 30 days of the time
        Company learns of the transfer of Prohibited Shares), a Purported Acquiror
        must
        transfer any certificate or other evidence of ownership of the Prohibited
        Shares
        within the Purported Acquiror's possession or control, together with any
        dividends or other distributions that were received by the Purported Acquiror
        from Company with respect to the Prohibited Shares ("Prohibited
        Distributions"),
        to an
        agent designated by Company (the "Agent").
        The
        Agent will sell the Prohibited Shares in an arms-length transaction (over
        a
        public exchange, if reasonable possible), and the Purported Acquiror will
        receive an amount of sales proceeds not in excess of the price paid or
        consideration surrendered by the Purported Acquiror for the Prohibited Shares
        (or the fair market value of the Prohibited Shares at the time of an attempted
        transfer to the Purported Acquiror by gift, inheritance, or a similar transfer).
        If the Purported Acquiror has resold the Prohibited Shares prior to receiving
        the Company's demand to surrender the Prohibited Shares to the Agent, the
        Purported Acquiror shall be deemed to have sold the Prohibited Shares as
        agent
        for the Initial Transferor and shall be required to transfer to the Agent
        any
        Prohibited Distributions and the proceeds of such sale, except to the extent
        that the Agent grants written permission to the Purported Acquiror to retain
        a
        portion of such sales proceeds not exceeding the amount that the Purported
        Acquiror would have received from the Agent if the Agent rather than the
        Purported Acquiror had resold the Prohibited Shares. If the Initial Transferor
        can be identified, the Agent will pay to the Initial Transferor any sales
        proceeds in excess of those due to the Purported Acquiror, together with
        any
        amounts received by the Agent from the Purported Acquiror that are attributable
        to Prohibited Distributions. If the Initial Transferor cannot be identified
        within 90 days, the Agent may pay any amounts due to the Initial Transferor
        into
        a court or governmental agency, if applicable law permits, and otherwise
        must
        transfer such amounts to a charity designated by Company. In no event shall
        amounts due to the Initial Transferor pursuant to Article inure to the benefit
        of Company or the Agent, but such amounts may be used to cover expenses incurred
        by Agent in attempting to identify the initial Transferor. If the Purported
        Acquiror fails to surrender the Prohibited Shares within the next 30 business
        days from demand by Company, then the Company will institute legal proceedings
        to compel the surrender.

      


      4.8.5 Legend.
        The
        Investor understands and agrees that each certificate held by the Investor
        representing the Notes and the Common Stock issuable upon conversion thereof,
        or
        any other securities issued in respect of the Notes and Common Stock issuable
        upon conversion thereof upon any stock split, stock dividend, recapitalization,
        merger, consolidation or similar event, shall bear the following legend (in
        addition to any legend required by this Agreement, the other Agreements or
        under
        applicable state securities laws):

      


      "THE
        SHARES REPRESENTED BY THIS CERTIFICATE ARE RESTRICTED BY THE TERMS OF, AND
        ARE
        SUBJECT TO RESTRICTIONS ON TRANSFER AND RIGHTS OF SALE AS PROVIDED IN A NOTE
        PURCHASE AGREEMENT BETWEEN THE COMPANY AND THE HOLDER HEREOF, OR ITS SUCCESSOR,
        A COPY OF WHICH IS AVAILABLE FROM THE COMPANY."

      


      
        
           

        

        
          -9-

          
            

          

        

        
           

        

      

      
        	 	
                SECTION
                  5

              	
                CONDITIONS
                  OF INVESTOR'S OBLIGATIONS AT
                  CLOSING.

              


      

      


      The
        obligations of the Investor under Section 1 of this Agreement are
        subject
        to the fulfillment at or before each of the Closings of the following
        conditions, any of which may be waived in writing by such Investor:

      


      5.1 Representations
        and Warranties.
        The
        representations and warranties of the Company contained in Section 3
        shall
        be true in all respects on and as of the Closing with the same effect as
        if made
        on and as of the Closing.

      


      5.2 Performance.
        The
        Company shall have performed or fulfilled in all material respects all
        agreements, obligations, and conditions contained herein required to be
        performed or fulfilled by the Company before the Closing.

      


      5.3 Qualifications.
        All
        authorizations, approvals, or permits, if any, of any governmental authority
        or
        regulatory body of the United States or any state that are required in
        connection with the lawful issuance and sale of the Notes pursuant to this
        Agreement shall be duly obtained effective as of the Closing.

      


      3.4 Compliance
        Certificate.
        Upon
        request by the Investor the Company shall deliver to the Investor a certificate
        dated as of the Closing, signed by the Company's Secretary, certifying as
        to
        (a) the Company's Articles, (b) the Company's Bylaws, (c) the
        resolutions adopted by, and other consents and approvals of, the Company's
        Board
        of Directors and stockholders in connection with the Transactional Agreements
        and the transactions contemplated hereby and thereby, and (d) the
        names of
        the officers of the Company authorized to sign the Transactional Agreements
        and
        the other documents or certificates to be delivered pursuant to this Agreement
        by the Company, or any of its officers, together with the true signatures
        of
        such officers. Upon request by the Investor, the Company shall deliver to
        the
        Investor a certificate dated as of the Closing, signed by the Company's
        President, certifying that the conditions set forth in Sections 5.1,
        5.2
        and 5.3 have been satisfied.

      


      5.5 Notes.
        The
        Company shall have executed and delivered to Investor the original
        Notes.

      


      5.6 Registration
        Rights Agreement.
        The
        Company shall have executed and delivered to Investor the Registration Rights
        Agreement.

      


      
        	 	
                SECTION
                  6

              	
                CONDITIONS
                  OF THE COMPANY'S OBLIGATIONS AT
                  CLOSING.

              


      

      


      The
        obligations of the Company under Section 1 of this Agreement are subject
        to
        the fulfillment at or before the Closing of the following conditions, any
        of
        which may be waived in writing by the Company:

      


      6.1 Representations
        and Warranties.
        The
        representations and warranties of the Investor contained in Section 4
        shall
        be true in all respects on and as of the Closing with the same effect as
        though
        said representations and warranties had been made on and as of the
        Closing.

      


      
        
           

        

        
          -10-

          
            

          

        

        
           

        

      

      6.2 Blue
        Sky Compliance.
        The
        Company shall have complied with the securities laws of the State of Texas
        and
        any other applicable states as necessary to offer and sell the Notes to the
        Investor.

      


      6.3 Legal
        Matters.
        All
        material matters of a legal nature which pertain to the Transactional Agreements
        and the transactions contemplated hereby and thereby shall have been reasonably
        approved by counsel to the Company.

      


      6.4 Registration
        Rights Agreement.
        Investor shall have executed and delivered to the Company the Registration
        Rights Agreement.

      


      
        	 	
                SECTION
                  7

              	
                POST-CLOSING
                  COVENANTS OF THE COMPANY.

              


      

      


      7.1 Stockholder
        Approval.
        The
        Company shall use reasonable efforts to obtain all required stockholder approval
        of the transactions contemplated by the Transactional Agreements, including
        amending the Articles to increase the number of shares of authorized Common
        Stock to account for conversion of the Notes and all other series of Preferred
        Stock.

      


      7.2 Securities
        Laws Compliance.
        Within
        15 days after the Closing the Company shall make any filings necessary under
        the
        securities or blue sky laws of any applicable jurisdiction.

      


      7.3 Private
        Offering.
        The
        Company agrees that neither the Company nor anyone acting on its behalf will
        offer the Notes or any similar securities for issuance or sale to, or solicit
        any offer to acquire any of the same from, anyone or take any other action
        so as
        to make the issuance and sale of the Notes subject to the registration
        requirements of Section 5 of the Securities Act.

      


      7.4 Properties,
        Business, Insurance.
        The
        Company shall maintain, and cause each of its subsidiaries to maintain, as
        to
        their respective properties and business, insurance against such casualties
        and
        contingencies and of such types and in such amounts as is customary for
        companies similarly situated, of similar size, scope and financial condition,
        which insurance shall be deemed by the Company to be sufficient. 

      


      7.5 Restrictive
        Agreements Prohibited.
        Neither
        the Company nor any of its subsidiaries shall become a party to any agreement
        which by its terms restricts the Company's performance of the Transactional
        Agreements or the Articles.

      


      7.6 Use
        of
        Proceeds.
        The
        Company agrees to use the proceeds from the sale of the Notes for (i) payment
        of
        expenses related to the transactions contemplated by the Transactional
        Agreements, (ii) payment of outstanding accounts payable, and (iii) current
        operating, capital and investment expenses.

      


      7.7 Material
        Changes and Litigation.
        The
        Company shall promptly notify the Investor of any Material Adverse Event
        and of
        any litigation or governmental proceeding or investigation brought or, to
        the
        Company's knowledge, threatened in writing against the Company, officer,
        director, key employee or principal stockholder of the Company which, if
        adversely determined, would result in a Material Adverse Event.

      


      
        
           

        

        
          -11-

          
            

          

        

        
           

        

      

      7.8 Punctual
        Payment.
        The
        Company shall pay the principal of, premium, if any, and interest on the
        Notes
        at the times and place and in the manner provided in the Notes and
        herein.

      


      7.9 Preservation
        of Corporate Existence.
        The
        Company shall preserve and maintain its corporate existence and all rights,
        franchises and privileges in the jurisdiction of its organization, and qualify
        and remain qualified as a foreign corporation in each jurisdiction in which
        such
        qualification is necessary or desirable in view of its business and operations
        or the ownership of its properties, except where the failure to qualify would
        not constitute a Material Adverse Event. The Company shall preserve and maintain
        all licenses and other rights to use patents, processes, licenses, trademarks,
        trade names, inventions, Intellectual Property rights or copyrights owned
        or
        possessed by it, and material to the conduct of its business.

      


      7.10 Compliance
        with Laws.
        The
        Company shall comply, and cause each Subsidiary to comply, with all applicable
        laws, rules, regulations and orders of any governmental authority, noncompliance
        with which could materially adversely affect its business or condition,
        financial or other.

      


      7.11 Keeping
        of Records and Books of Account.
        The
        Company shall keep adequate records and books of account, in which complete
        entries will be made in accordance with GAAP consistently applied, reflecting
        all material financial transactions of the Company and in which, for each
        fiscal
        year, are proper reserves for depreciation, depletion, obsolescence,
        amortization, taxes, bad debts and other purposes in connection with its
        business shall be made.

      


      7.12 Compliance
        with ERISA.
        The
        Company shall comply with all minimum funding requirements applicable to
        any
        pension or other employee benefit or employee contribution plans which are
        subject to ERISA or to the Code, and comply in all material respects with
        the
        provisions of ERISA and the Code, and the rules and regulations thereunder,
        which are applicable to any such plan. The Company will not permit any event
        or
        condition to exist which could permit any such plan to be terminated under
        circumstances which would cause the lien provided for in Section 4068
        of
        ERISA to attach to the assets of the Company.

      


      7.13 Foreign
        Corrupt Practices Act.
        The
        Company shall comply and cause each officer, director, partner, employee
        and
        agent of the Company, each Subsidiary to comply, at all times with the
        prohibitions on certain acts and practices set forth in the Foreign Corrupt
        Practices Act of 1977, and any rules or regulations promulgated
        thereunder.

      


      7.14 Exchange
        Relisting.
        The
        Company shall use its best efforts to obtain listing of its Common Stock
        on the
        Nasdaq SmallCap Market and the Toronto Stock Exchange.

      


      
        	 	
                SECTION
                  8

              	
                MISCELLANEOUS.

              


      

      


      8.1 Governing
        Law.
        This
        Agreement shall be governed by, and construed in accordance with, the laws
        of
        the State of Texas, excluding those laws that direct the application of the
        laws
        of another jurisdiction.

      


      8.2 Counterparts.
        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.

      


      
        
           

        

        
          -12-

          
            

          

        

        
           

        

      

      8.3 Headings.
        The
        headings of the sections of this Agreement are for convenience and shall
        not by
        themselves determine the interpretation of this Agreement.

      


      8.4 Notices.
        Any
        notice required or permitted hereunder shall be given in writing and shall
        be
        conclusively deemed effectively given upon personal delivery or delivery
        by
        courier, or on the first business day after transmission if sent by confirmed
        facsimile transmission or electronic mail transmission, or five days after
        deposit in the United States mail, by registered or certified mail, postage
        prepaid, addressed (i) if to the Company, as set forth below the Company's
        name on the signature page of this Agreement, and (ii) if to an Investor,
        at such Investor's address as set forth on the Signature page of this Agreement,
        or at such other address as the Company or such Investor may designate by
        10
        days' advance written notice to the other parties hereto.

      


      8.5 Survival
        of Warranties.
        The
        warranties and representations of the parties contained in or made pursuant
        to
        this Agreement shall survive for two years after the execution and delivery
        of
        this Agreement and the First Closing; provided, however, that such
        representations and warranties need only be accurate as of the date of such
        execution and delivery and as of the Closing.

      


      8.6 Amendments,
        Waivers and Consent.
        Any
        provision in this Agreement or the Notes to the contrary notwithstanding,
        changes in or additions to this Agreement may be made, and compliance with
        any
        covenant or provision herein or therein set forth may be omitted or waived,
        if
        the Company shall obtain consent thereto in writing from the holder of the
        Notes; provided
        that no
        such consent shall be effective to reduce or to postpone the date fixed for
        the
        payment of the principal (including any required redemption) or interest
        payable
        on the Notes, without the consent of the holder thereof. Any waiver or consent
        may be given subject to satisfaction of conditions stated therein and any
        waiver
        or consent shall be effective only in the specific instance and for the specific
        purpose for which given. Written notice of any waiver or consent effected
        under
        this subsection shall promptly be delivered by the Company to any holder
        who did
        not execute the same. No failure or delay on the part of the Investor, or
        any
        other holder of the Notes in exercising any right, power or remedy hereunder
        shall operate as a waiver thereof, nor shall any single or partial exercise
        of
        any such right, power or remedy preclude any other or further exercise thereof
        or the exercise of any other right, power or remedy hereunder. The remedies
        herein provided are cumulative and not exclusive of any remedies provided
        by
        law.

      


      8.7 Finders'
        Fees.
        The
        Company and the Investor will indemnify the other against all liabilities
        incurred by the indemnifying party with respect to claims related to investment
        banking or finders' fees in connection with the transactions contemplated
        by
        this Agreement, arising out of arrangements between the party asserting such
        claims and the indemnifying party, and all costs and expenses (including
        reasonable fees of counsel) of investigating and defending such
        claims.

      


      8.8 Expenses.
        The
        Company and the Investor will bear their respective legal and other fees
        and
        expenses with respect to this Agreement and the transactions contemplated
        hereby.

      


      
        
           

        

        
          -13-

          
            

          

        

        
           

        

      

      8.9 Confidentiality.
        Each
        party hereto agrees that, except with the prior written permission of the
        Company, it shall at all times keep confidential and not divulge or furnish
        or
        make accessible to anyone any confidential information concerning or relating
        to
        the business or financial affairs of the Company to which such party has
        become
        privy by reason of this Agreement, discussions or negotiations relating to
        this
        Agreement or the exhibits to this Agreement, provided that an Investor may
        disclose confidential information if (i) the information is publicly
        known
        through publication or otherwise through no wrongful act of the Investor;
        (ii) the information is received from a third party who rightfully
        discloses it to the Investor without restriction on its subsequent disclosure;
        (iii) the information is disclosed pursuant to the lawful requirement
        of a
        governmental agency or by order of court of competent jurisdiction, provided
        that in such event, Investor will provide prior written notice of such proposed
        disclosure to the Company; or (iv) the information is reasonably required
        to be disclosed in order for the Investor or their transferee to market an
        interest in the capital stock of the Company, provided that in such instance
        the
        person to whom the information is provided shall be required to hold such
        information in confidence.

      


      8.10 Further
        Assurances.
        From
        and after the date of this Agreement, upon the request of the Investor, the
        Company and each Subsidiary shall execute and deliver such instruments,
        documents and other writings as may be necessary or desirable to confirm
        and
        carry out and to effectuate fully the intent and purposes of this Agreement
        and
        the Notes.

      


      8.11 Jury
        Waiver.
        THE
        COMPANY AND THE INVESTOR AGREE THAT NEITHER OF THEM NOR ANY ASSIGNEE OR
        SUCCESSOR SHALL (A) SEEK A JURY TRIAL IN ANY LAWSUIT, PROCEEDING,
        COUNTERCLAIM, OR ANY OTHER ACTION BASED UPON, OR ARISING OUT OF, THIS AGREEMENT
        OR ANY OF THE OTHER TRANSACTIONAL AGREEMENTS, ANY RELATED INSTRUMENTS, ANY
        COLLATERAL OR THE DEALINGS OR THE RELATIONSHIP BETWEEN OR AMONG ANY OF THEM,
        OR
        (B) SEEK TO CONSOLIDATE ANY SUCH ACTION WITH ANY OTHER ACTION IN WHICH
        A
        JURY TRIAL CANNOT BE OR HAS NOT BEEN WAIVED; PROVIDED, HOWEVER, THAT THE
        FOREGOING SHALL NOT PRECLUDE ANY PARTY OR ITS SUCCESSORS FROM ASSERTING ANY
        COUNTERCLAIM WHICH WOULD OTHERWISE BE BARRED OR FORFEITED. EXCEPT AS STATED
        IN
        THE PRECEDING SENTENCE, THE PROVISIONS OF THIS SECTION SHALL BE SUBJECT TO
        NO
        EXCEPTIONS. NEITHER THE COMPANY NOR ANY OF THE INVESTOR HAS AGREED WITH OR
        REPRESENTED TO THE OTHER THAT THE PROVISIONS OF THIS SECTION WILL NOT BE
        FULLY
        ENFORCED IN ALL INSTANCES.

      


      8.12 Entire
        Agreement; Successors and Assigns.
        This
        Agreement (and the exhibits hereto) constitutes the entire contract between
        the
        Company and the Investor relative to the subject matter hereof. Any prior
        and
        contemporaneous agreement, discussion, understanding or correspondence between
        the Company and the Investor regarding the purchase of the Notes is superseded
        by this Agreement. Subject to the exceptions specifically set forth in this
        Agreement, the terms and conditions of this Agreement shall inure to the
        benefit
        of and be binding upon the respective executors, administrators, heirs,
        successors, and assigns of the parties. All subsequent transferees or assigns
        of
        the Notes shall be deemed a party to this Agreement and bound by the obligations
        imposed upon Investor herein.


      
        
           

        

        
          -14-

          
            

          

        

        
           

        

      

      


      IN
        WITNESS WHEREOF, the parties hereto have executed this Note Purchase Agreement
        as of the date first above written.

      


      
        
          	COMPANY:	
                  POSITRON
                    CORPORATION

                   

                   

                  By:                                                                              
                    

                  Patrick
                    G. Rooney, Chairman of the Board

                  


                  Address:    1304
                    Langham Creek Drive, #300, 

                                       Houston,
                    Texas 77084

                


        

      

       

      
        	INVESTOR:	
                IMAGIN
                  DIAGNOSTIC CENTRES, INC.

                 

                 

                By:                                                                              
                  

                Name:
                  

                Its:
                  

                


                Address:     1835
                  Yonge St., Suite 500

                                     
                  Toronto, Ontario, Canada M4S

              


      

       

       


      
        
           

        

        
          -15-

          
            

          

        

        
           

        

      

      


      SCHEDULES
        AND EXHIBITS

      


      
        	Exhibit
                A	
                Convertible
                  Promissory Note

              


      

      


      
        	Exhibit
                B	
                Registration
                  Rights Agreement

              


      

      



      
        
           

        

        
          -16-

          
            

          

        

        
           

          
          

        

      


      EXHIBIT
        A

      


      CONVERTIBLE
        PROMISSORY NOTE

       

      
 

      

EXHIBIT
      A

      
        
           

        

        
          -1-

          
            

          

        

        
           

        

      


      EXHIBIT
        B

      


      REGISTRATION
        RIGHTS AGREEMENT

      


       

      
 
EXHIBIT
      B

      
        
           

        

        
          -1-

          
            

          

        

        
           

        

      



      


      
        
          

        

      

      


      
        

         


      


      


      POSITRON
        CORPORATION

      


      NOTE
        PURCHASE AGREEMENT

       

      


      
        

         


      
        

         


      
 

      October
        31, 2005