Exhibit
2.1






SECURITIES
EXCHANGE AGREEMENT








AMONG








SOLARIS
OPPORTUNITY FUND, L.P.,







IMAGIN
MOLECULAR CORPORATION








AND








POSITRON
CORPORATION








NOVEMBER
18, 2008







THIS SECURITIES EXCHANGE
AGREEMENT (the “Agreement”), is made as of the November 18, 2008, by and
among SOLARIS OPPORTUNITY FUND,
L.P.,a Delaware limited partnership (“Solaris”), IMAGIN MOLECULAR
CORPORATION,  a publicly-owned Delaware corporation (“Imagin”)
and POSITRON
CORPORATION, a publicly-owned Texas corporation (“Positron”)
(collectively, the “Parties”).


WHEREAS, the Parties desire to
provide for the purchase and sale of various securities and the retirement and
satisfaction of various obligations by and among the Parties.





WHEREAS, Imagin is the holder
of a promissory note dated April 10, 2008 in the original principal amount of
One Million Three Hundred Forty-Six Thousand Dollars ($1,346,000) (“Note 1”) and
an additional promissory note dated August 18, 2008 in the original principal
amount of Eight Hundred Thirty-Five Thousand Dollars ($835,000) (“Note 2”),
whereby Note 1 and Note 2 have accrued interest in the amount of Sixty-Seven
Thousand Eight Hundred Seventy- Five Dollars ($67,875) and are secured by a
pledge of One Hundred Million (100,000,000) shares of Positron’s common stock,
par value $0.01 per share (the “Pledged Stock”);





WHEREAS, Solaris is the holder
of advances made to Positron in the aggregate amount of One Million One Hundred
Fifty-Five Thousand Dollars ($1,155,000), together with the sum of Sixty-Eight
Thousand Dollars ($68,000) for which sums no instrument has been negotiated (the
“Solaris Positron Advances”);





WHEREAS, Solaris is the holder
of advances made to Positron in the aggregate amount of One Million One Hundred
Fifty-Five Thousand Dollars ($1,155,000), together with the sum of Sixty-Eight
Thousand Dollars ($68,000) for which sums no instrument has been negotiated (the
“Solaris Positron Advances”);





WHEREAS, Imagin is unable to repay the Solaris
Imagin Advance and Positron is unable to repay Note 1, Note 2. and the Solaris
Positron Advances and Imagin and Positron desire to restructure such obligations
pursuant to the terms and conditions set forth herein;





WHEREAS, the respective Boards
of Directors of the Parties have deemed it advisable and in the best interests
of their respective companies that the Parties consummate the transactions
provided for herein in order to advance their long-term strategic business
interests;





NOW, THEREFORE, in
consideration of the mutual terms, conditions and other agreements set forth
herein and for other good and valuable consideration, the sufficiency and
receipt of which are hereby acknowledged, the Parties hereto hereby agree as
follows:








ARTICLE
I


EXCHANGE
OF SECURITIES








SECTION
1.1.  THE EXCHANGE.  On the Closing Date (as hereinafter
defined) and upon the terms and subject to the conditions set forth in this
Agreement:





(i)     Imagin
shall transfer and assign all of its rights, title and interest to Note 1, Note
2, in the aggregate amount of $2,248,875 with accrued but unpaid interest and
the Pledged Stock to Solaris in consideration for: the delivery by Solaris of
the Imagin Common Stock and the Series A to be retired on the books and records
of Imagin; and the retirement, cancellation and satisfaction by Solaris of the
Solaris Imagin Advance;


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(ii)    Solaris
shall retire, cancel and satisfy the Solaris Positron Advances for the benefit
of Positron and return Note 1 and Note 2, together with any and all accrued but
unpaid interest, but each mark “SATISFIED” and deliver the Pledged Stock, to be
retired  on the books and records of Positron, in exchange for the
issuance and delivery by Positron to Solaris of one
hundred thousand(100,000) shares of Positron’s Series S Convertible
Preferred Stock (the “Series S”);





SECTION
1.2.   CLOSING.  The closing of such Exchange (the
"Closing") shall take place at 10:00 a.m. E.S.T. on November 18, 2008, or at
such other time and date as the parties hereto shall agree in writing (the
"Closing Date"), at the principal offices of Solaris Opportunity Fund, L.P.,
3801 N. Washington Avenue, Oak Brook, Illinois 60523.








ARTICLE
II


REPRESENTATIONS
AND WARRANTIES OF


IMAGIN








Imagin
hereby represents warrants and agrees as follows:





SECTION
2.1.   CORPORATE ORGANIZATION.  Imagin is duly organized,
validly existing and in good standing under the laws of each jurisdiction where
it is required to do so, and has all requisite corporate power and authority to
own its properties and assets and to conduct its business as now conducted and
is duly qualified to do business and in good standing in each jurisdiction in
where the nature of the business conducted or the ownership or leasing of its
properties makes such qualification and being in good standing necessary, except
where the failure to be so qualified and in good standing will not have a
material adverse effect on the business, operations, properties, assets,
condition or results of operation of Imagin (a “Material Adverse
Effect”).




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SECTION
2.2.   TITLE, ENCUMBRANCES.   Imagin is the owner
of Note 1 and Note 2 free and clear of all encumbrances and, on the Closing Date
will transfer all rights, title, and interest to Note 1 and Note 2 and the
Pledged Shares free and clear of all liens, pledges, encumbrances, security
interests or other restrictions.





SECTION
2.3.   AUTHORIZATION AND VALIDITY OF
AGREEMENTS.   Imagin has all corporate power and authority to
execute and deliver this Agreement, to perform its obligations hereunder and to
consummate the transactions contemplated hereby. The execution and delivery of
this Agreement by Imagin and the consummation of the transactions contemplated
hereby have been duly authorized by all necessary corporate action and no other
corporate proceedings on the part of Imagin is necessary to authorize this
Agreement or to consummate the transactions contemplated hereby.





SECTION
2.4.   NO CONFLICT OR VIOLATION. The execution, delivery and
performance of this Agreement by Imagin does not and will not violate or
conflict with any provision of the formation documents or By-laws of Imagin, and
does not and will not violate any provision of law, or any order, judgment or
decree of any court or other governmental or regulatory authority, nor violate
nor will result in a breach of or constitute (with due notice or lapse of time
or both) a default under or give to any other entity any right of termination,
amendment, acceleration or cancellation of any contract, lease, loan agreement,
mortgage, security agreement, trust indenture or other agreement or instrument
to which Imagin is a party or by which any of them is bound or to which any of
its or their respective properties or assets is subject, nor will result in the
creation or imposition of any lien, charge or encumbrance of any kind whatsoever
upon any of the properties or assets of Imagin, nor will result in the
cancellation, modification, revocation or suspension of any of the licenses,
franchises, permits to which Imagin is bound.


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SECTION
2.5.   CONSENTS AND APPROVALS.  No consent, waiver,
authorization or approval of any governmental or regulatory authority, domestic
or foreign, or of any other person, firm or corporation, and each declaration to
or filing or registration with any such governmental or regulatory authority,
that is required in connection with the execution and delivery of this Agreement
by or the performance by Imagin of its obligations hereunder.





SECTION
2.6.   SURVIVAL.  Each of the representations and
warranties set forth in this Article II shall be deemed represented and made by
Imagin at the closing as if made at such time and shall survive the closing for
a period terminating on the second anniversary.








ARTICLE
III


REPRESENTATIONS
AND WARRANTIES OF


POSITRON








Positron
hereby represents warrants and agrees as follows:





SECTION
3.1.   CORPORATE ORGANIZATION.  Positron is duly organized,
validly existing and in good standing under the laws of each jurisdiction where
it is required to do so, and have all requisite corporate power and authority to
own its properties and assets and to conduct its business as now conducted and
is duly qualified to do business and in good standing in each jurisdiction in
where the nature of the business conducted or the ownership or leasing of its
properties makes such qualification and being in good standing necessary, except
where the failure to be so qualified and in good standing will not have a
material adverse effect on the business, operations, properties, assets,
condition or results of operation of Positron (a “ Material Adverse
Effect”).


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SECTION
3.2.   DUE ISSUANCE.   The Series S, when issued,
will be legally issued, fully-paid and non assessable, shall not be issued in
violation of any rights of any other person and will be issued free and clear of
all liens, pledges, encumbrances, security interests or other
restrictions.





SECTION
3.3.  AUTHORIZATION AND VALIDITY OF
AGREEMENTS.   Positron has all corporate power and authority to
execute and deliver this Agreement, to perform its obligations hereunder and to
consummate the transactions contemplated hereby. The execution and delivery of
this Agreement by Positron and the consummation of the transactions contemplated
hereby have been duly authorized by all necessary corporate action and no other
corporate proceedings on the part of Positron is necessary to authorize this
Agreement or to consummate the transactions contemplated hereby.





SECTION
3.4.   NO CONFLICT OR VIOLATION. The execution, delivery and
performance of this Agreement by Positron does not and will not violate or
conflict with any provision of the formation documents or By-laws of Positron,
and does not and will not violate any provision of law, or any order, judgment
or decree of any court or other governmental or regulatory authority, not
violate nor will result in a breach of or constitute (with due notice or lapse
of time or both) a default under or give to any other entity any right of
termination, amendment, acceleration or cancellation of any contract, lease,
loan agreement, mortgage, security agreement, trust indenture or other agreement
or instrument to which Positron is a party or by which any of them is bound or
to which any of its or their respective properties or assets is subject, nor
will result in the creation or imposition of any lien, charge or encumbrance of
any kind whatsoever upon any of the properties or assets of Positron, nor will
result in the cancellation, modification, revocation or suspension of any of the
licenses, franchises, permits to which Positron is bound.


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SECTION
3.5.   CONSENTS AND APPROVALS.  No consent, waiver,
authorization or approval of any governmental or regulatory authority, domestic
or foreign, or of any other person, firm or corporation is required in
connection with the execution and delivery of this Agreement or the performance
by Positron of its obligations hereunder.





SECTION
3.6.   SURVIVAL.  Each of the representations and
warranties set forth in this Article III shall be deemed represented and made by
Positron at the closing as if made at such time and shall survive the closing
for a period terminating on the second anniversary.








ARTICLE
IV


REPRESENTATIONS
AND WARRANTIES OF


SOLARIS








Solaris
hereby represents warrants and agrees as follows:





SECTION
4.1.   CORPORATE ORGANIZATION.  Solaris is duly organized,
validly existing and in good standing under the laws of each jurisdiction where
it is required to do so, and have all requisite corporate power and authority to
own its properties and assets and to conduct its business as now conducted and
is duly qualified to do business and in good standing in each jurisdiction in
where the nature of the business conducted or the ownership or leasing of its
properties makes such qualification and being in good standing necessary, except
where the failure to be so qualified and in good standing will not have a
material adverse effect on the business, operations, properties, assets,
condition or results of operation of Solaris (a “Material Adverse
Effect”).


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SECTION
4.2.   TITLE, ENCUMBRANCES.   Solaris is the owner
of the Imagin Common Stock, the Series A and the Solaris Positron Advances, free
and clear of all encumbrances and, on the Closing Date will transfer the Imagin
Common Stock, the Series A and the Solaris Positron Advances free and clear of
all liens, pledges, encumbrances, security interests or other
restrictions.





SECTION
4.3.  AUTHORIZATION AND VALIDITY OF
AGREEMENTS.   Solaris has all corporate power and authority to
execute and deliver this Agreement, to perform its obligations hereunder and to
consummate the transactions contemplated hereby. The execution and delivery of
this Agreement by Solaris and the consummation of the transactions contemplated
hereby have been duly authorized by all necessary corporate action and no other
corporate proceedings on the part of Solaris is necessary to authorize this
Agreement or to consummate the transactions contemplated hereby.





SECTION
4.4.   NO CONFLICT OR VIOLATION. The execution, delivery and
performance of this Agreement by Solaris does not and will not violate or
conflict with any provision of the formation documents or partnership agreement
of Solaris, and does not and will not violate any provision of law, or any
order, judgment or decree of any court or other governmental or regulatory
authority, nor violate nor will result in a breach of or constitute (with due
notice or lapse of time or both) a default under or give to any other entity any
right of termination, amendment, acceleration or cancellation of any contract,
lease, loan agreement, mortgage, security agreement, trust indenture or other
agreement or instrument to which Solaris is a party or by which any of them is
bound or to which any of its or their respective properties or assets is
subject, nor will result in the creation or imposition of any lien, charge or
encumbrance of any kind whatsoever upon any of the properties or assets of
Solaris, nor will result in the cancellation, modification, revocation or
suspension of any of the licenses, franchises, permits to which Solaris is
bound.


8


SECTION
4.5.   CONSENTS AND APPROVALS.  No consent, waiver,
authorization or approval of any governmental or regulatory authority, domestic
or foreign, or of any other person, firm or corporation, and each declaration to
or filing or registration with any such governmental or regulatory authority,
that is required in connection with the execution and delivery of this Agreement
by or the performance by Solaris of its obligations hereunder.





SECTION
4.6.   SURVIVAL.  Each of the representations and
warranties set forth in this Article IV shall be deemed represented and made by
Solaris at the closing as if made at such time and shall survive the closing for
a period terminating on the second anniversary.








ARTICLE
V


COVENANTS








SECTION
5.1.  CERTAIN
CHANGES AND CONDUCT OF BUSINESS.




(a)    From
and after the date of this Agreement and until the Closing Date, the Parties
shall conduct, their business solely in the ordinary course consistent with past
practices and, in a manner consistent with all representations or warranties
herein, and without the prior written consent of each other will not, except as
required or permitted pursuant to the terms hereof:


(i) make
any material change in the conduct of their businesses and operations enter into
any transaction other than in the ordinary course of business consistent with
past practices;





(ii) make
any change in their formation documents; issue any additional shares of capital
stock or equity securities or grant any option, warrant or right to acquire any
capital stock or equity securities or issue any security convertible into or
exchangeable for its capital stock or alter in any material term of any of its
outstanding securities or make any change in its outstanding shares of capital
stock or its capitalization, whether by reason of a reclassification,
recapitalization, stock split or combination, exchange or readjustment of
shares, stock dividend or otherwise;




9




(iii) (A)
incur, assume or guarantee any indebtedness for borrowed money, issue any notes,
bonds, debentures or other corporate securities or grant any option, warrant or
right to purchase any thereof, except pursuant to transactions in the ordinary
course of business consistent with past practices, or (B) issue any securities
convertible or exchangeable for debt securities;





(iv) make
any sale, assignment, transfer, abandonment or other conveyance of any of its
assets or any part thereof;





(v)
subject any of its assets, or any part thereof, to any lien or suffer such to be
imposed other than such liens as may arise in the ordinary course of business
consistent with past practices by operation of law which will not have an
Material Adverse Effect;





(vi)
acquire any assets, raw materials or properties, or enter into any other
transaction, other than in the ordinary course of business consistent with past
practices;


(vii)
enter into any new (or amend any existing) employee benefit plan, program or
arrangement or any new (or amend any existing) employment, severance or
consulting agreement, grant any general increase in the compensation of officers
or employees (including any such increase pursuant to any bonus, pension,
profit-sharing or other plan or commitment) or grant any increase in the
compensation payable or to become payable to any employee, except in accordance
with pre-existing contractual provisions or consistent with past
practices;




(viii)
make or commit to make any material capital expenditure;


10




(ix) pay,
loan or advance any amount to, or sell, transfer or lease any properties or
assets to, or enter into any agreement or arrangement with, any of its
affiliates;





(x)
guarantee any indebtedness for borrowed money or any other obligation of any
other person;





(xi) take
any other action that would cause any of the representations and warranties made
by it in this Agreement not to remain true and correct in all
material;





(xii)
make any loan, advance or capital contribution to or investment in any
person;





(xiii)
make any change in any method of accounting or accounting principle, method,
estimate or practice;





(xiv)
settle, release or forgive any claim or litigation or waive any
right;





(xv)
commit itself to do any of the foregoing;





(xvi)
file, when due or required, federal, state, foreign and other tax returns and
other reports required to be filed and pay when due all taxes, assessments, fees
and other charges lawfully levied or assessed against it, unless the validity
thereof is contested in good faith and by appropriate proceedings diligently
conducted; and





(xvii)
continue to conduct its business in the ordinary course consistent with past
practices.


SECTION
5.2.  ACCESS TO PROPERTIES AND RECORDS. The Parties shall afford to
each other’s accountants, counsel and representatives full access during normal
business hours throughout the period prior to the Closing Date (or the earlier
termination of this Agreement) to all of such parties properties, books,
contracts, commitments and records and, during such period, shall furnish
promptly to the requesting party all other information concerning the other
party's business, properties and personnel as the requesting party may
reasonably request, provided that no investigation or receipt of information
pursuant to this Section 5.2 shall affect any representation or warranty of, or
the conditions to, the obligations of any party.




11




SECTION
5.3.  NEGOTIATIONS. From and after the date hereof until the earlier
of the Closing or the termination of this Agreement, no party to this Agreement
nor its officers or directors (subject to such director's fiduciary duties) nor
anyone acting on behalf of party or persons shall, directly or indirectly,
encourage, solicit, engage in discussions or negotiations with, or provide any
information to, any person, firm, or other entity or group concerning any
merger, sale of substantial assets, purchase or sale of shares of common stock
or similar transaction involving any party thereof except as permitted
herein.  A party shall promptly communicate to any other party any
inquiries or communications concerning any such transaction which they may
receive or of which they may become aware of.


SECTION
5.4.   CONSENTS AND APPROVALS. The Parties, (i) shall use their
reasonable commercial efforts to obtain all necessary consents, waivers,
authorizations and approvals of all governmental and regulatory authorities,
domestic and foreign, and of all other persons, firms or corporations required
in connection with the execution, delivery and performance by them of this
Agreement, and (ii) shall diligently assist and cooperate with each party in
preparing and filing all documents required to be submitted by a party to any
governmental or regulatory authority, domestic or foreign, in connection with
such  transactions and in obtaining any governmental consents,
waivers, authorizations or approvals which may be required to be obtained
connection with such transactions.




12





SECTION
5.5.   PUBLIC ANNOUNCEMENT. Unless otherwise required by
applicable law, the parties hereto shall consult with each other before issuing
any press release or otherwise making any public statements with respect to this
Agreement and shall not issue any such press release or make any such public
statement prior to such consultation.






ARTICLE
VII


MISCELLANEOUS
PROVISIONS






SECTION
6.1.   SURVIVAL
OF PROVISIONS. The respective representations, warranties, covenants and
agreements of each of the parties to this Agreement (except covenants and
agreements which are expressly required to be performed and are performed in
full on or before the Closing Date) shall survive the Closing Date and the
consummation of the transactions contemplated by this Agreement, subject to
Sections 2.6, 3.6 and 4.6.  In the event of a breach of any of such
representations, warranties or covenants, the party to whom such
representations, warranties or covenants have been made shall have all rights
and remedies for such breach available to it under the provisions of this
Agreement or otherwise, whether at law or in equity, regardless of any
disclosure to, or investigation made by or on behalf of such party on or before
the Closing Date.




SECTION
6.2.   SUCCESSORS AND ASSIGNS; NO THIRD-PARTY
BENEFICIARIES.  This Agreement shall inure to the benefit of, and be
binding upon, the parties hereto and their respective successors and assigns;
provided, however, that no party shall assign or delegate any of the obligations
created under this Agreement without the prior written consent of the other
party.




13





SECTION
6.3.   FEES AND EXPENSES. Except as otherwise expressly provided
in this Agreement, all legal and other fees, costs and expenses incurred in
connection with this Agreement and the transactions contemplated hereby shall be
paid by the party incurring such fees, costs or expenses.





SECTION
6.4.   NOTICES. All notices and other communications given or
made pursuant hereto shall be in writing and shall be deemed to have been given
or made if in writing and delivered personally, transmitted facsimile with proof
of transmission, or sent by registered or certified mail (postage prepaid,
return receipt requested) to the Parties.





SECTION
6.5.   ENTIRE AGREEMENT. This Agreement, together with the
exhibits hereto, represents the entire agreement and understanding of the
parties with reference to the transactions set forth herein and no
representations or warranties have been made in connection with this Agreement
other than those expressly set forth herein or in the exhibits, certificates and
other documents delivered in accordance herewith. This Agreement supersedes all
prior negotiations, discussions, correspondence, communications, understandings
and agreements between the parties relating to the subject matter of this
Agreement and all prior drafts of this Agreement, all of which are merged into
this Agreement. No prior drafts of this Agreement and no words or phrases from
any such prior drafts shall be admissible into evidence in any action or suit
involving this Agreement.


SECTION
6.6.   SEVERABILITY. This Agreement shall be deemed severable,
and the invalidity or unenforceability of any term or provision hereof shall not
affect the validity or enforceability of this Agreement or of any other term or
provision hereof. Furthermore, in lieu of any such invalid or unenforceable term
or provision, the parties hereto intend that there shall be added as a part of
this Agreement a provision as similar in terms to such invalid or unenforceable
provision as may be possible and be valid and enforceable.




14




SECTION
6.7.   TITLES AND HEADINGS. The Article and Section headings
contained in this Agreement are solely for convenience of reference and shall
not affect the meaning or interpretation of this Agreement or of any term or
provision hereof.





SECTION
6.8.   COUNTERPARTS. This Agreement may be executed in two or
more counterparts, each of which shall be deemed an original and all of which
together shall be considered one and the same agreement.





SECTION
6.9.   ARBITRATION. The Parties to this Agreement, acting for
themselves and for their respective successors and assigns, without regard to
domicile, citizenship or residence, hereby expressly and irrevocably agree that
any controversy or claim, arising out of or relating to this Agreement or the
breach thereof, shall be settled by arbitration administered by the American
Arbitration Association, in accordance with its Commercial Arbitration Rules,
including the Optional Rules for Emergency Measures of Protection, and judgment
rendered by award of the arbitrator(s) may be entered in any court having
jurisdiction thereof.


SECTION
6.10. ENFORCEMENT OF THE AGREEMENT. The Parties hereto agree that
irreparable damage would occur if any of the provisions of this Agreement were
not performed in accordance with their specific terms or were otherwise
breached. It is accordingly agreed that the parties shall be entitled to an
injunction or injunctions to prevent breaches of this Agreement and to enforce
specifically the terms and provisions hereto, this being in addition to any
other remedy to which they are entitled at law or in equity in accordance with
Section 6.9 herein.




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SECTION
6.11. GOVERNING LAW. This Agreement shall be governed by and interpreted
and enforced in accordance with the laws of the State of Delaware, without
giving effect to the choice-of-law provisions thereof.






Remainder
of page intentionally left blank.


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








SOLARIS
      OPPORTUNITY FUND L.P.BY:PATRICK
      G. ROONEY,MANAGING
      DIRECTORIMAGIN
      MOLECULAR CORORATIONBY:JOSEPH
      G. OLIVERIO,CHIEF
      EXECUTIVE OFFICERPOSITRON
      CORPORATIONBY:COREY
      CONN,CHIEF
      FINANCIAL
OFFICER







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