This  Registration  Rights Agreement (this "Agreement") is made and entered
                                                 ---------
into  as  of  May  21,  2004  by and between IMAGIN Diagnostic Centres, Inc., an
Ontario,  Canada  corporation  ("IMAGIN"  and  the  "Purchaser"),  and  Positron
                                 ------              ---------
Corporation,  a  Texas  corporation  (the  "Company").
                                            -------


                                R E C I T A L S:
                                ---------------


     WHEREAS,  concurrent  with  the execution of this Agreement the Company and
Purchaser  are  entering  into  a  Note  Purchase  Agreement  (as defined below)
pursuant  to  which  IMAGIN  will  purchase from the Company Secured Convertible
Promissory Notes in the principal amounts of $300,000 and $400,000 (the "Initial
                                                                         -------
Notes");  and
-----

     WHEREAS,  the  Initial  Notes  are convertible at the option of the holders
into  shares  of  the  Company's  Series C Preferred Stock, $1.00 par value (the
"Series C Preferred Stock"), which shares are in turn convertible into shares of
 ------------------------
the  Company's  Common  Stock  (the  "Common  Stock");
                                      -------------

     WHEREAS,  concurrent  with  the  execution of this Agreement the Company is
entering  into  a  Loan  Agreement with Purchaser which will provide the Company
with  advances  of  up  to  a total of $1,300,000 to be evidenced by convertible
notes  (the  "Credit  Notes,"  and  referred  to  herein  with the Initial Notes
              -------------
collectively  as  the  "Notes");
                        -----

     WHEREAS, the Credit Notes are convertible at the option of the holders into
shares of the Company's Series D Preferred Stock, $1.00 par value (the "Series D
                                                                        --------
Preferred  Stock"),  which  shares  are  in  turn convertible into shares of the
----------------
Company's  Common  Stock;

     WHEREAS, the Company is granting warrants (the "Warrants") to the Purchaser
to  acquire  shares  of  the  Company's  Common  Stock  in consideration for the
purchase  by  Purchaser  of  PET  scanners  pursuant  to  the Equipment Purchase
Agreement  (as  defined  below);

     NOW,  THEREFORE,  in consideration of the mutual promises, representations,
warranties  and  conditions  set  forth  in  this Agreement, the parties hereto,
intending  to  be  legally  bound,  hereby  agree  as  follows:

                               A G R E E M E N T :
                               - - - - - - - - -

     1.   Definitions.  For  purposes  of  this  Agreement,  in  addition to the
          -----------
definitions set forth above and elsewhere herein, the following terms shall have
the  following  respective  meanings:

     "Acquisition  Shares"  shall  mean  the shares of Series C Preferred Stock,
      -------------------
Series  D Preferred Stock and Common Stock which the Purchaser will have a right
to  acquire  upon  the  conversion  of  the  Notes.


<PAGE>
     "Commission"  shall  mean  the  United  States  Securities  and  Exchange
      ----------
Commission  and  any  successor  agency.

     "Demand  Date" shall mean the date the Company receives the written request
      ------------
for  registration  of  Registrable  Stock  from  Purchaser pursuant to Section 3
hereof.

     "Equipment  Purchase Agreement" shall mean the Equipment Purchase Agreement
      -----------------------------
between  the  Company  and  Purchaser  dated  May  21,  2004.

     "Exchange  Act" shall mean the Securities Exchange Act of 1934, as amended,
      -------------
or  any similar federal statute, and the rules and regulations of the Commission
thereunder,  all  as  the  same  shall  be  in  effect  at  the  time.

     "Holder"  shall mean the Purchaser and all transferees or assignees thereof
      ------
to  whom  the  rights  under  this Agreement are assigned in accordance with the
provisions  of  Section  8  hereof.

     "Note  Purchase  Agreement"  shall mean the Note Purchase Agreement between
      -------------------------
the  Company  and  the  Purchaser,  dated  May  21,  2004.

     "Person"  shall  mean  an  individual,  corporation,  partnership,  limited
      ------
partnership,  syndicate,  person  (including,  without limitation, a "person" as
defined  in  Section 13(d)(3) of the Exchange Act), trust, association or entity
or government, political subdivision, agency or instrumentality of a government.

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

     "Registrable  Stock" shall mean (a) the Acquisition Shares, (b) the Warrant
      ------------------
Shares,  (c)  any  shares  of  Common  Stock  or other capital stock issued as a
dividend,  or  other  distribution  with  respect  to, or in exchange for, or in
replacement of, any of the Acquisition Shares and/or the Warrant Shares, and (d)
any  shares  of  capital stock issued by way of a stock split of the Acquisition
Shares  and/or  the Warrant Shares referred to in clauses (a) or (b) above.  For
purposes  of this Agreement, any Registrable Stock shall cease to be Registrable
Stock when (i) a registration statement covering such Registrable Stock has been
declared  effective  and such Registrable Stock has been disposed of pursuant to
such  effective registration statement, (ii) such Registrable Stock is sold by a
person  in  a  transaction  in  which  the  rights  under the provisions of this
Agreement  are  not assigned, or (iii) all such Registrable Stock may be sold by
any  and  all  Holders pursuant to Rule 144(k) (or any similar provision then in
force,  but  not  Rule 144A) under the Securities Act without registration under
the  Securities  Act.

     "Securities  Act" shall mean the Securities Act of 1933, as amended, or any
      ---------------
similar  federal  statute,  and  the  rules  and  regulations  of the Commission
thereunder,  all  as  the  same  shall  be  in  effect  at  the  time.

     "Warrant  Shares"  shall  mean  the  shares  of  Common Stock issuable upon
      ---------------
exercise  of  warrants  issued  to  IMAGIN.


                                      -2-
<PAGE>
     2.   Restrictive  Legend.  Each certificate representing Acquisition Shares
          -------------------
and  Warrant  Shares  shall,  except as otherwise provided in this Section 2, be
stamped or otherwise imprinted with a legend substantially in the form set forth
in  the  Note  Purchase  Agreement or the Warrant, as applicable.  A certificate
shall  not  bear  such  legend  if in the opinion of counsel satisfactory to the
Company  or  the  Company shall determine that the securities being sold thereby
may  be  publicly  sold  without  registration  under  the Securities Act or the
transfer  of  such securities is permitted under the provisions of Regulation S,
Rule  144(k)  or  Rule  144A  (or  any  rule  permitting  public  sale  without
registration  under  the  Securities  Act).

     3.   Registration  Rights.  Upon  the  written  request of Purchaser to the
          --------------------
Company,  the  Company shall use its reasonable best efforts to prepare and file
with  the  Commission  a  registration  statement on an applicable form, signed,
pursuant to Section 6(a) of the Securities Act, by the officers and directors of
the  Company,  with respect to the Registrable Stock.  If the Company shall fail
to  register  the  shares  of  Registrable  Stock, the Company shall deliver the
unregistered shares of Registrable Stock to the Purchaser and such shares may be
sold  pursuant  to  and  subject  to  the  requirements  of  Rule  144 under the
Securities  Act.  The Company's delivery of the unregistered shares shall be the
Purchaser's  sole  remedy  for  any  failure  by  the Company to register shares
pursuant  to  this  Section  3.  In  connection with this Section 3, the Company
shall:

          (a)  cause  such  registration  statement  to  become  effective on or
     before  the  three-month  anniversary  of  the  Demand  Date  and to remain
     effective through and including the earlier of (i) the time when all of the
     Registrable  Stock has been sold pursuant to such registration statement or
     (ii) the time when all of the Holders of the Registrable Stock can sell all
     of  the Registrable Stock pursuant to Rule 144(k) (or any similar provision
     then  in  force,  but  not  Rule  144A)  under  the  Securities Act without
     registration  under  the  Securities  Act.

          (b)  prepare  and  file  with  the  Commission  such  amendments  and
     supplements  to  such  registration  statement, signed, pursuant to Section
     6(a)  of  the Securities Act, by the officers and directors of the Company,
     and  the  prospectus  used  in  connection therewith as may be necessary to
     comply  with  the  provisions  of  the  Securities  Act with respect to the
     disposition  of  all  Registrable  Stock  covered  by  such  registration
     statement;

          (c)  furnish to the Holders such numbers of copies of the registration
     statement  and  the prospectus included therein (including each preliminary
     prospectus  and  any  amendments or supplements thereto) in conformity with
     the  requirements  of  the  Securities  Act  and  such  other documents and
     information  as  they  may  reasonably  request;

          (d)  use  its  reasonable  best  efforts  to  register  or qualify the
     Registrable  Stock  covered by such registration statement under such other
     securities  or blue sky laws of such jurisdictions within the United States
     and  Puerto Rico as required by law for the distribution of the Registrable
     Stock  covered  by  the registration statement; provided, however, that the
     Company  shall  not  be  required in connection therewith or as a condition
     thereto  to  qualify  to  do  business  in  or to file a general consent to
     service  of  process  in  any jurisdiction wherein it would not but for the
     requirements  of  this  paragraph  (d) be obligated to do so; and provided,
     further, that the Company shall not be required to qualify such Registrable
     Stock  in  any  jurisdiction  in  which  the  securities  regulatory


                                      -3-
<PAGE>
     authority  requires  that  any  Holder submit any shares of its Registrable
     Stock  to  the  terms, provisions and restrictions of any escrow, lockup or
     similar  agreement(s)  for  consent  to  sell  Registrable  Stock  in  such
     jurisdiction  unless  such  Holder  agrees  to  do  so;

          (e)  promptly  notify  each  Holder for whom such Registrable Stock is
     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 any material fact required
     to  be  stated  therein  or  necessary  to  make the statements therein not
     misleading in light of the circumstances under which they were made, and at
     the  request of any such Holder promptly prepare and furnish to such Holder
     a  reasonable  number  of copies of a supplement to or an amendment of such
     prospectus  as may be necessary so that, as thereafter delivered to Holders
     of  such securities, such prospectus shall not 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 light
     of  the  circumstances  under  which  they  were  made;

          (f)  enter  into  customary  agreements and take such other actions as
     are  reasonably required in order to expedite or facilitate the disposition
     of  the  Registrable Stock to be so included in the registration statement;

          (g)  otherwise  use  its  reasonable  best  efforts to comply with all
     applicable  rules  and  regulations  of  the  Commission;

          (h)  use  its  reasonable  best  efforts to list the Registrable Stock
     covered  by  such  registration  statement  with any securities exchange on
     which  Holder  Common  Stock  is  then  listed;  and

          (i)  after  the effectiveness of the registration statement, cooperate
     with  the  Holders  to  facilitate  the  timely preparation and delivery of
     certificates  representing  the  Registrable  Stock  to  be  sold,  which
     certificates  shall not bear any restrictive legends other than restrictive
     legends  still  required  to be imposed by the Warrant or the Note Purchase
     Agreement.

     4.   Suspension  of  Trading.  Notwithstanding  any other provision of this
          -----------------------
Agreement,  the  Company  shall  have  the right at any time to require that all
Holders  suspend  further  open  market  offers  and  sales of Registrable Stock
whenever,  and for so long as, in the reasonable judgment of the Company in good
faith based upon the advice of counsel satisfactory to the Holders of a majority
of the Registrable Stock, there is in existence material undisclosed information
or  events  with  respect  to the Company (the "Suspension Right") such that the
                                                ----------------
registration  statement would contain any untrue statement of a material fact or
omit  to  state  any material fact required to be stated therein or necessary to
make  the  statements therein not misleading in light of the circumstances under
which  they were made.  In the event the Company exercises the Suspension Right,
such  suspension  will continue for such period of time reasonably necessary for
disclosure  to occur at a time that is not materially detrimental to the Company
or  until  such  time  as the registration statement does not include any untrue
statement  of  a  material


                                      -4-
<PAGE>
fact  or  omit  to  state  any  material  fact  required to be stated therein or
necessary  to  make  the  statements  therein  not  misleading  in  light of the
circumstances  under  which  they were made, each as determined in good faith by
the  Company.  The  Company  will promptly give the Holders notice, in a writing
signed by an executive officer of the Company, of any exercise of the Suspension
Right.  The  Company  agrees  to notify the Holders promptly upon termination of
the  Suspension  Right.  Notwithstanding  the  foregoing, under no circumstances
shall  Holder  be  entitled to exercise the Suspension Right for more than sixty
calendar  days  in  any  twelve-month  period.

     5.   Furnish  Information.  It  shall  be  a  condition  precedent  to  the
          --------------------
obligations  of  the  Company to take any action pursuant to this Agreement that
the  Holders shall furnish to the Company such information regarding themselves,
the  Registrable  Stock  held by them, and the intended method of disposition of
such securities as the Company shall reasonably request and as shall be required
in  connection  with  the  action  to  be  taken  by  the  Company.

     6.   Expenses  of Registration.  So long as the Company shall have received
          -------------------------
at least $700,000 in principal under the Initial Notes, all expenses incurred in
connection  with  the registration pursuant to this Agreement, including without
limitation  all  registration,  filing  and qualification fees, word processing,
duplicating,  printers'  and  accounting  fees  (including  the  expenses of any
special  audits  or  comfort letters required by or incident to such performance
and compliance), fees of the National Association of Securities Dealers, Inc. or
listing  fees,  messenger  and  delivery  expenses,  all  fees  and  expenses of
complying  with  state  securities  or  blue  sky  laws,  reasonable  fees  and
disbursements  of  counsel for the Company (collectively, the "Expenses"), shall
                                                               --------
be  paid  by  the Company.  If the Company has not received at least $700,000 in
principal  under  the  Initial  Notes  and  Purchaser has requested registration
pursuant  to  this  Agreement,  all Expenses shall be paid by Purchaser.  In the
event  Expenses  are  to be paid by Purchaser, such Expenses shall be prepaid by
Purchaser  to the Company upon receipt of a reasonable estimate from the Company
(the  "Expenses  Estimate").  To  extent  the  Expenses  Estimate exceeds actual
       ------------------
Expenses,  Purchaser  shall  be  reimbursed  within  30  days  of  the effective
registration  of  the  Registrable  Stock.  To  extent  the Expenses Estimate is
insufficient  to  cover  total  actual  Expenses,  Purchaser shall reimburse the
Company  for such excess within 30 days of receipt of an invoice for such excess
Expenses.  The  parties  agree  that  all underwriting discounts and commissions
shall  be  the  responsibility  of  the  Holders.

     7.   Indemnification.
          ---------------

          (a)  To  the  extent  permitted  by  applicable law, the Company shall
     indemnify  and  hold  harmless  each  Holder,  such  Holder's directors and
     officers,  any  underwriter  (as  defined  in the Securities Act), and each
     person,  if any, who controls such Holder or underwriter within the meaning
     of  the Securities Act, against any losses, claims, damages or liabilities,
     joint or several, to which they may become subject under the Securities Act
     or  any  other  applicable  state  or  federal law, insofar as such losses,
     claims,  damages  or  liabilities (or proceedings in respect thereof) arise
     out  of  or  are  based  on  any  untrue or alleged untrue statement of any
     material  fact  contained  in  such registration statement on the effective
     date  thereof  (including  any  prospectus  filed  under Rule 424 under the
     Securities Act or any amendments or supplements thereto) or arise out of or
     are based upon the omission or alleged omission to state therein a material
     fact  required  to  be  stated


                                      -5-
<PAGE>
     therein  or  necessary  to  make the statements therein not misleading, and
     shall  reimburse  each  such  Holder, such Holder's directors and officers,
     such  underwriter  or  controlling  person  for any legal or other expenses
     reasonably  incurred  by  them  (but  not in excess of expenses incurred in
     respect of one counsel and one local counsel for all of them unless, in the
     reasonable  judgment of an indemnified party there is potential conflict of
     interest  between any indemnified parties, which indemnified parties may be
     represented  by  separate  counsel  and  local  counsel) in connection with
     investigating  or  defending  any  such  loss,  claim, damage, liability or
     action;  provided,  however, that the indemnity agreement contained in this
     Section  7(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 Company (which consent shall not be unreasonably
     withheld);  provided,  further, that the Company shall not be liable to any
     Holder,  such  Holder's  directors and officers, underwriter or controlling
     person  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 an untrue
     statement  or alleged untrue statement or omission or alleged omission made
     in  connection  with  such  registration statement, preliminary prospectus,
     final prospectus or amendments or supplements thereto, in reliance upon and
     in  conformity  with  written  information  furnished  expressly for use in
     connection  with  such  registration  by  any  such  Holder,  such Holder's
     directors  and  officers, underwriter or controlling person. Such indemnity
     shall  remain in full force and effect regardless of any investigation made
     by  or  on behalf of any such Holder, such Holder's directors and officers,
     underwriter  or  controlling person, and shall survive the transfer of such
     securities  by  such  Holder.

          (b)  To  the  extent  permitted  by  applicable law, each Holder shall
     indemnify  and  hold  harmless  the  Company,  each  of  its  directors and
     officers,  each person, if any, who controls the Company within the meaning
     of  the  Securities  Act,  and  any  underwriter (within the meaning of the
     Securities  Act)  for  the  Company  against any losses, claims, damages or
     liabilities,  joint  or several, to which the Company or any such director,
     officer,  controlling  person  or underwriter may become subject, under the
     Securities  Act  or  any  other applicable state or federal law, insofar as
     such  losses,  claims,  damages  or  liabilities (or proceedings in respect
     thereof)  arise  out  of  or are based upon any untrue statement or alleged
     untrue  statement  of  any  material  fact  contained  in such registration
     statement  on  the  effective  date thereof (including any prospectus filed
     under  Rule  424  under the Securities Act or any amendments or supplements
     thereto) or arise out of or are based upon 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, in each case to the extent,
     but  only  to  the  extent,  that  such  untrue statement or alleged untrue
     statement  or  omission  or  alleged omission was made in such registration
     statement  in  reliance  upon  and  in  conformity with written information
     furnished  expressly  by  or on behalf of such Holder for use in connection
     with  such  registration; and each such Holder shall reimburse any legal or
     other  expenses  reasonably  incurred  by the Company or any such director,
     officer,  controlling  person,  agent  or underwriter (but not in excess of
     expenses  incurred  in respect of one counsel and one local counsel for all
     of  them  unless,  in  the  reasonable judgment to of an indemnified party,
     there  is  a  conflict  of  interest between any indemnified parties, which
     indemnified  parties  may  be  represented  by  separate  counsel and local
     counsel)  in  connection  with  investigating  or  defending any such loss,
     claim,  damage,  liability or action; provided, however, that the indemnity
     agreement  contained  in


                                      -6-
<PAGE>
     this Section 7(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 such Holder (which consent shall not be unreasonably
     withheld),  and  provided,  further,  that  the  liability  of  each Holder
     hereunder  shall  be  limited  to  the  proportion of any such loss, claim,
     damage,  liability or expense which is equal to the proportion that the net
     proceeds  from  the  sale  of the shares sold by such Holder under any such
     registration statement bears to the total net proceeds from the sale of all
     securities sold thereunder, but not in any event to exceed the net proceeds
     received  by such Holder from the sale of Registrable Stock covered by such
     registration  statement.

          (c)  Promptly after receipt by an indemnified party under this Section
     of  notice of the commencement of any action, such indemnified party shall,
     if  a claim in respect thereof is to be made against any indemnifying party
     under  this  Section,  notify  the  indemnifying  party  in  writing of the
     commencement  thereof  and  the  indemnifying party shall have the right to
     participate  in and assume the defense thereof with counsel selected by the
     indemnifying  party  and  reasonably satisfactory to the indemnified party;
     provided,  however,  that  the  exercise  of  the  foregoing right shall be
     conditioned  upon  the  written acknowledgment of the indemnifying party to
     the  indemnified  party of the indemnifying party's obligation hereunder to
     indemnify  the  indemnified  party for any losses arising from such action;
     and  provided further, that in such event, the indemnified party shall have
     the  right  to  retain its own counsel and local counsel, with all fees and
     expenses  thereof  to be paid by such indemnified party, and to be apprised
     of  all progress in any proceeding the defense of which has been assumed by
     the  indemnifying  party.  The  failure  to  notify  an  indemnifying party
     promptly  of  the  commencement  of any such action, shall only release the
     indemnifying  party from any of its obligations under this Section 7(c) if,
     and  only  to  the  extent  that,  such  indemnifying  party  is materially
     prejudiced  by such failure, but the omission to so notify the indemnifying
     party  will  not  relieve  it  of  any  liability  that  it may have to any
     indemnified  party  otherwise  than  under  this  Section.

          (d)  To  the  extent  any  indemnification by an indemnifying party is
     prohibited  or  limited  by  law,  the  indemnifying  party,  in  lieu  of
     indemnifying such indemnified party, shall contribute to the amount paid or
     payable  by  such  indemnified  party  as  a result of such losses, claims,
     damages  or liabilities in such proportion as is appropriate to reflect the
     relative  fault  of  the  indemnifying  party  and  indemnified  party  in
     connection  with the actions which resulted in such losses, claims, damages
     or liabilities, as well as any other relevant equitable considerations. The
     relative  fault  of  such indemnifying party and indemnified party shall be
     determined  by  reference  to,  among  other  things, whether any action in
     question, including any untrue or alleged untrue statement of material fact
     or omission or alleged omission to state a material fact, has been made by,
     or  relates  to  information  supplied  by,  such  indemnifying  party  or
     indemnified  party,  and the parties' relative intent, knowledge, access to
     information  and  opportunity to correct or prevent such action. The amount
     paid  or  payable  by a party as a result of the losses, claims, damages or
     liabilities referred to above shall be deemed to include any legal or other
     fees  or  expenses reasonably incurred by such party in connection with any
     investigation  or  proceeding.


                                      -7-
<PAGE>
     The  parties  hereto  agree  that  it  would  not  be just and equitable if
     contribution  pursuant  to  this  Section  7(d) were determined by pro rata
     allocation or by any other method of allocation which does not take account
     of  the  equitable  considerations referred to in the immediately preceding
     paragraph.  No  person  guilty  of fraudulent misrepresentation (within the
     meaning  of  Section  11(f)  of  the  Securities  Act) shall be entitled to
     contribution  from  any  person  who  was  not  guilty  of  such fraudulent
     misrepresentation.

     8.   Transfer of Registration Rights.  Subject to any transfer restrictions
          -------------------------------
set forth in the Note Purchase Agreement, the Notes, or the Warrants, the rights
of  any Holder under this Agreement with respect to any Registrable Stock may be
transferred to any transferee of such Registrable Stock; provided, however, that
(i) the transferring Holder shall give the Company written notice at or prior to
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 transferred; (ii) such transferee shall agree in writing, in form and
substance reasonably satisfactory to the Company, to be bound as a Holder by the
provisions  of this Agreement; and (iii) immediately following such transfer the
further  disposition  of  such securities by such transferee is restricted under
the  Securities  Act.  Except  as  set  forth  in this Section 8, no transfer of
Registrable  Stock  shall  cause  such  Registrable  Stock  to lose such status.

     9.   Successors  and  Assigns.  Except  as  otherwise  expressly  provided
          ------------------------
herein, the terms and conditions of this Agreement shall inure to the benefit of
and be binding upon the respective successors and assigns of the parties hereto.
Except  as  expressly  provided  in  this  Agreement, nothing in this Agreement,
express or implied, is intended to confer upon any person other than the parties
hereto  or  their  respective  successors  and  assigns  any  rights,  remedies,
obligations,  or  liabilities  under  or  by  reason  of  this  Agreement.

     10.  Counterparts;  Titles.  This  Agreement  may be executed and delivered
          ---------------------
(including  by  facsimile  transmission) in one or more counterparts, and by the
different parties hereto in separate counterparts, each of which shall be deemed
to  be an original, but all of which taken together shall constitute one and the
same  agreement.  The  titles  of  the  Sections  of this Agreement are used for
convenience only and are not to be considered in construing or interpreting this
Agreement.

     11.  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.

     12.  Amendments  and  Waivers.  Any  provision  of  this  Agreement  may be
          ------------------------
amended  and  the  observance  of  any provision of this Agreement may be waived
(either  generally  or  in  a  particular  instance  and either retroactively or
prospectively),  only with the written consent of the Company and the Holders of
at  least  50%  of  the  Registrable  Stock  then  outstanding.  Any


                                      -8-
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amendment or waiver effected in accordance with this Section 12 shall be binding
upon  each  Holder  of  any  securities  subject  to  this Agreement at the time
outstanding  (including  securities into which such securities are convertible),
each  future  Holder  and  all  such securities, and the Company.  No failure or
delay  by  any party in exercising any right, power or privilege hereunder shall
operate  as  a  waiver  thereof nor shall any single or partial exercise thereof
preclude  any  other  or  further  exercise thereof or the exercise of any other
right,  power  or  privilege.

     13.  Severability;  Entire  Agreement.  If  one  or more provisions of this
          --------------------------------
Agreement  are  held  to  be unenforceable under applicable law, such provisions
shall be excluded from this Agreement and the balance of this Agreement shall be
interpreted  as  if such provisions were so excluded and shall be enforceable in
accordance  with  its terms.  All prior agreements of the parties concerning the
subject  matter  of  this  Agreement are expressly superseded by this Agreement.
This  Agreement  contains  the  entire  Agreement  of the parties concerning the
subject  matter  hereof.  Any  oral  representations  or  modifications  of this
Agreement  shall  be  of  no  effect.

     14.  Governing  Law.  This  Agreement shall be governed by and construed in
          --------------
accordance  with  the  laws of the State of Texas without regard to conflicts of
law  principles.

     15.  Forum;  Waiver  of  Jury  Trial.
          -------------------------------

          (a)  All  actions  and  proceedings arising out of or relating to this
     Agreement  shall be heard and determined in the Texas Superior Court or the
     United  States  Superior  Court  located in the City of Houston, Texas. The
     parties hereto hereby (i) submit to the exclusive jurisdiction of the Texas
     Superior  Court  or the United States Superior Court located in the City of
     Houston,  Texas  for the purpose of any action or proceeding arising out of
     or  relating to this Agreement brought by any party hereto, and (ii) waive,
     and  agree  not  to  assert by way of motion, defense, or otherwise, in any
     such  action,  any  claim  that  it  is  not  subject  personally  to  the
     jurisdiction  of  the  above-named  courts,  that its property is exempt or
     immune  from  attachment  or  execution,  that  the action or proceeding is
     brought  in  an  inconvenient  forum,  that  the  venue  of  the  action or
     proceeding is improper, or that this Agreement may not be enforced in or by
     any  of  the  above-named  courts.

          (b)  EACH  OF  THE  PARTIES HERETO HEREBY WAIVES TO THE FULLEST EXTENT
     PERMITTED  BY  APPLICABLE LAW ANY RIGHT IT MAY HAVE TO A TRIAL BY JURY WITH
     RESPECT  TO  ANY  ACTIONS OR PROCEEDINGS DIRECTLY OR INDIRECTLY ARISING OUT
     OF,  UNDER  OR  IN  CONNECTION  WITH  THIS  AGREEMENT  OR  THE TRANSACTIONS
     CONTEMPLATED  HEREBY.


                  [Remainder of page intentionally left blank]


                                      -9-
<PAGE>
     IN  WITNESS  WHEREOF, the parties hereto have executed this Agreement as of
the  date  first  above  written.


Positron Corporation,                      IMAGIN Diagnostic Centres, Inc.,
a Texas corporation                        an Ontario, Canada corporation


By:  /s/ Gary H. Brooks                    By:  /s/ Cynthia R. Jordan
     Gary H. Brooks, President                  Name:  Cynthia R. Jordan
                                                Title: Chief Executive Officer


Address:  1304 Langham Creek Drive, #300,  Address: 1835 Yonge St., Suite 500
          Houston, Texas 77084                      Toronto, Ontario, Canada M4S
                                                    1XB


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