LOAN AGREEMENT
                                 --------------

     THIS  AGREEMENT  is made as of the 29th day of  June,  2001 by and  between
POSITRON CORPORATION ("Borrower"),  a Texas corporation with its principal place
of business at 1304 Langham Creek Drive,  Houston,  Texas 77084 and IMATRON INC.
("Lender"), a New Jersey corporation with its principal place of business at 389
Oyster Point Blvd., So. San Francisco, CA 94080.


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


     WHEREAS, Borrower previously has borrowed certain funds from Lender and has
repaid such funds pursuant to the terms of the applicable loan agreement; and

     WHEREAS,  Borrower has  requested  Lender to make certain  further loans to
Borrower  for working  capital and  certain  other needs as provided  herein and
Lender is agreeable to make such loans upon the terms and conditions hereof;

     NOW THEREFORE,  in consideration of these premises and the mutual covenants
and agreements  herein contained and other valuable  consideration,  the receipt
and adequacy of which the parties hereto acknowledge, the parties have agreed as
follows:

     1. Definitions.
        ------------

     As used in  this  Loan  Agreement,  the  following  terms  shall  have  the
following meanings unless the context requires otherwise:

     Borrower's Obligations means all present and future obligations of Borrower
to  Lender  hereunder,  under  the  Note,  or any  other  document  executed  in
connection herewith.

     Default means any event set forth in Section 6.1 hereof.

     Lender's  Obligations means all present and future obligations of Lender to
Borrower hereunder, or any other document executed in connection herewith.

     Loan  Agreement  means this Loan Agreement and all  attachments,  exhibits,
schedules hereto, all as may be amended from time to time.

     Loan Rate means 10% or, if lower than 10%, the highest rate  permissible by
law.

     Payment Dates means the first day of each calendar month.

     2. LOANS.
        -----

     2.1 Lender agrees, on terms and conditions of this Loan Agreement,  to make
loans (hereinafter called individually a "Loan" and,  collectively "The Loans"),
to Borrower in an aggregate  principal  amount at any one time outstanding up to
but not  exceeding  Two Million  Dollars  ($2,000,000).  Within such limit,  and
subject to the various conditions set forth herein,  Borrower may borrow, repay,
re-borrow  at any  time or from  time to time  from the  date  hereof  up to and
including the earlier of June 30, 2002 and the  termination of the commitment of
Lender, as provided at Section 6.2 below. The obligation of Lender to make Loans
up to but not exceeding such aggregate amount at any one time outstanding herein
is hereinafter called its "Commitment."

     2.2 The  foregoing  notwithstanding,  the  following  shall  be  conditions
precedent each time Borrower  seeks to draw down any portion of the  Commitment:
(a) Within five (5) business days of the effective date of this Loan  Agreement,
Borrower  shall  provide to lender a budget and  estimated  schedule of expenses
("Budget")  reflecting  projected expenses and projected revenue (including Loan
proceeds); (b) Lender shall review the Budget and either approve or revise it in
its sole  judgment;  (c)  Borrower  shall  provide  to Lender at least  three(3)
calendar days' written notice (effective upon receipt) specifying the amount and
date and anticipated use of each requested  borrowing under Section 2.1; and (d)
each requested borrowing must be consistent with the Budget and further shall be
specifically approved by Lender.

     2.3 Repayments. The foregoing further notwithstanding, Borrower shall repay
interest  on a  monthly  basis by the 15th of the month  following  the month in
which it accrues, and shall further repay such portions of the principal amounts
outstanding  as of the  following  dates:  fifty  percent (50%) of all principal
amounts  outstanding  as of December  31,  2001 shall be repaid  within five (5)
business days of December 31, 2001;  seventy-five (75%) of all principal amounts
outstanding  as of March 31, 2002 shall be repaid  within five (5) business days
of  March  31,  2002;  and  100% of all  principal  amounts  plus  all  interest
outstanding as of June 30, 2002 shall be repaid no later than June 30, 2002.

     2.4  Borrower's  obligations  to pay the  principal  of and interest on the
Loans shall be  evidenced by its grid  promissory  note in the form of Exhibit A
hereto (the "Note")  payable to the order of Lender.  The Note shall reflect the
amount of the  Commitment,  with actual Loans,  repayments and balances noted by
Lender on the grid attached to the Note and made a part thereof.  The Note shall
bear interest on the unpaid principal amount thereof until such principal amount
shall be paid in full at a per annum  rate  equal to the Loan  Rate  (based on a
year of 365 or actual number of days elapsed).  The Loan Rate shall apply to the
average  outstanding  principal balance on the Note during any month which shall
be the summation of the daily  balances  during such month divided by the number
of days in the  particular  month.  Unless  accelerated  in accordance  with the
provisions  of this Loan  Agreement,  the  interest on the Note for any calendar
month shall be paid within  fifteen (15) days of each  consecutive  Payment Date
immediately  following  such calendar  month until full payment of the Loan (and
related interest),  with the first Payment Date being the first day of the month
immediately following execution of this Agreement. All principal and interest on
the Note shall be due and payable in full on June 30, 2002.  If any Payment Date
(or other  date for  payment  hereunder)  falls on a day which is not a business
day, such Payment Date (or other date of payment)  shall be the next  succeeding
business day.

     2.5 Mandatory Repayment.  The foregoing  notwithstanding,  beginning on and
after  any date,  from the date of this Loan  Agreement  to the  termination  of
Lender's  Commitment,  that Borrower  receives  third party  financing,  whether
equity or debt  ("Financing"),  in an amount  in  excess  of Five  Million  U.S.
Dollars ($5,000,000) in the aggregate  ("Financing  Threshold"),  Borrower shall
repay,  twenty-five  percent (25%) of each dollar  received  above the Financing
Threshold  from such  Financing,  toward any and all  amounts of  principal  and
interest  outstanding  under this Loan  Agreement  until such  amounts have been
fully  repaid  and  further,  Lender's  Commitment  shall  terminate  and not be
renewed. Solely by way of example, in the event Borrower shall receive Financing
in an  aggregate  amount of  $4,000,000  at any time  during  the first nine (9)
months  of this  Agreement,  and six (6)  months  thereafter  Borrower  receives
additional  Financing in an amount  $1,500,000,  Borrower shall repay to Lender,
promptly following receipt of the $1,500,000,  the sum of $125,000  representing
twenty-five  percent  (25%)  of  all  Financing  received  above  the  Financing
Threshold,  which amount  shall be applied to all interest  accrued on the Loans
and  unpaid to that date  plus,  to the  extent  that  accrued  unpaid  interest
constitutes   less  than   $125,000,   that  amount  of  principal   outstanding
representing  the difference  between the amount of accrued unpaid  interest and
$125,000.  Thereafter,  twenty-five  percent (25%) of every dollar of additional
Financing  provided to Borrower shall be paid over to Lender,  and no more Loans
shall be authorized,  until the full amount of any and all unpaid  principal and
interest on the Loans shall have been paid.

     2.6 All  payments to Lender shall be paid by Borrower to Lender at Lender's
address as follows:  Imatron Inc., 389 Oyster Point Blvd., So. San Francisco, CA
94080, Attn. President.  All amounts paid shall be applied first, to the payment
of all interest accrued and payable with respect to the Note; and second, to the
payment of outstanding  principal of the Loan; and third,  following Default, to
the payment of all expenses and charges,  including reasonable  attorneys' fees,
included  by Lender for the  protection  of its rights or the  pursuance  of its
remedies.

     2.7 The  Loans or any  part  thereof  may be  prepaid  at any time  without
penalty.

     2.8 The interest and other charges  charged with respect to the Loans shall
not exceed the highest rate permissible under any law which a court of competent
jurisdiction  or an  arbitrator  or  panel  of  arbitrators  shall,  in a  final
determination, deem applicable to the Loans. As of the date of execution of this
Loan Agreement, the parties hereto, in good faith, agree that the total interest
and other  charges  payable by Borrower  to Lender  under the terms of this Loan
Agreement do not exceed the maximum legal interest rate applicable to the Loans.
If it is determined  that Lender has received  interest and other  consideration
with respect to the Loans in excess of the highest rate applicable to the Loans,
Lender shall  promptly  refund not more than such excess  amount to Borrower and
the provisions  hereof shall be deemed  amended to provide for such  permissible
rate.

     3. CONDITIONS OF LENDING.
        ---------------------

     The  obligations of Lender to make a Loan is subject to the  fulfillment of
the following conditions:

     3.1 The following  documents shall have been duly authorized,  executed and
delivered  by the  Borrower  to the Lender,  and shall be in form and  substance
satisfactory to the Lender and its counsel and shall be in full force and effect
on the date of the Loan.

         Prior to the first Loan:

     (a)  an executed Loan Agreement,  and all executed documents,  certificates
          and instruments contemplated by this Loan Agreement, including but not
          limited  to  the  Security  Agreement;

     b)   a  certified  copy of the  resolution  of the  Board of  Directors  of
          Borrower, certified by the Secretary or a responsible officer thereof,
          duly  authorizing  execution,  delivery and  performance  of this Loan
          Agreement and the Note contemplated hereby;

     (c)  a certificate  of recent date from the Secretary of State of the state
          of incorporation of Borrower as to its good standing;

     (d)  an incumbency certificate of Borrower dated as of the date of funding,
          as to (i) the person or persons authorized to execute and deliver this
          Loan  Agreement,  the  Note,  the  Security  Agreement,  and any other
          documents  to be  executed  on behalf of them in  connection  with the
          transactions contemplated hereby and (ii) the signature of each person
          or persons;

     (e)  the executed Note;

     (f)  documentary evidence  satisfactory to Lender that any and all liens or
          other security  interests on any of Borrower's  tangible or intangible
          property, including but not limited to accounts, computer hardware and
          software, copyrights,  equipment,  inventory, licenses, patents, trade
          secrets,  trademarks,  general  intangibles,  chattel  paper  or other
          property,  and all  proceeds  thereof,  shall  have been  released  or
          otherwise  subordinated to Lender's  security  interests  contemplated
          herein; and

     (g)  an expense  plan and budget,  including  an  acceptable  cash  control
          system for managing expenditures within the plan and budget, ("Expense
          Plan"), attached hereto as Schedule 3.1(g).

     For  each Loan (including the first):

     (h)  an officer's  certificate in the form of Exhibit B which shall include
          the written request from Borrower  setting forth the requested  amount
          of the Loan and the  proposed  date of  borrowing;

     (i)  for each Loan after the first Loan,  documentary evidence satisfactory
          to Lender,  including  but not limited to Exhibit B, that  Borrower is
          adhering strictly to the Expense Plan; and

     (j)  such other  documents  and evidence with respect to Borrower as Lender
          may reasonably request.

     3.2 On the date of each  borrowing  pursuant to Section  2.1 above,  (i) no
Default  or event  that with the giving of notice or lapse of time or both would
constitute a Default  hereunder  has occurred and is  continuing or would result
from the  performance of this Loan  Agreement,  (ii) no material  adverse change
shall  have  occurred  since the date of this Loan  Agreement  in the  financial
condition or operations  of the Borrower,  and (iii) there shall be no juridical
proceeding or regulatory  action  instituted by or against the Borrower,  or, to
the best of Borrower's knowledge,  any threatened proceeding or action which may
materially  adversely  affect the business,  property,  operation,  or financial
condition of the Borrower.  By acceptance of a Loan,  Borrower  represents as of
such Loan date,  that each of the foregoing  items is true.

     3.3  Borrower  shall have  entered  issued to Imatron a Warrant to Purchase
Common  Stock,  materially in the form of Exhibit D, covering the purchase of up
to six million  (6,000,000)  shares of  Borrower's  common  stock at an exercise
price of $ 0.30 for the period  beginning on the date of issuance of the Warrant
and ending June 30, 2006.

     3.4 Borrower and Imatron  shall have  entered  into a  Registration  Rights
Agreement materially in the form of Exhibit E, pursuant to which Borrower agrees
to register the common shares  underlying the Warrant  pursuant to certain terms
and conditions.

     4. REPRESENTATIONS AND WARRANTIES.
        ------------------------------

     4.1 Borrower is a corporation  duly organized and validly  existing in good
standing under the laws of the state of Texas.

     4.2 Borrower has full corporate  power to own its  properties,  to carry on
its business as now being  conducted  and has full  corporate  power to execute,
deliver and perform all of its  obligations  under this Loan  Agreement  and the
Note.

     4.3 The  execution,  delivery  and  performance  by  Borrower  of this Loan
Agreement,   the  Note,  the  Security   Agreement  and  all  related  documents
contemplated  by this  transaction  have been duly  authorized  by all necessary
corporate  action of Borrower and do not violate any provision of law,  statute,
rule or regulation,  applicable to Borrower, or any judgment, franchise, permit,
order,  decree,  ruling, writ or injunction of any court or administrative body,
applicable to Borrower, or of Borrower's  certificate of incorporation,  by-laws
or the terms of any of its  securities or result in the breach of, or constitute
a Default under, or require any consent under, any indenture,  bank loan, credit
agreement or other  agreement or instrument  to which  Borrower is a party or by
which Borrower or any of its property may be bound or affected.

     4.4 No filings, recordations, notifications,  registrations, notarizations,
authentications  or other  formalities  or property,  stamp or similar  taxes or
duties  and  no  approvals,  licenses,  orders,   authorizations,   consents  or
undertakings of any governmental bodies or regulatory,  supervisory  authorities
are necessary in connection  with the  execution,  delivery and  performance  by
Borrower of this Loan Agreement or the Note, or for the payment to Lender of all
sums hereunder or under the Note or for the legality,  validity,  binding effect
or enforceability hereof or thereof.

     4.5 Except as disclosed and described in Schedule 4.5 hereto,  Borrower has
good and  marketable  title to, or a valid  leasehold  interest in, the tangible
personal  property or other  properties  and assets  used by it,  located on its
premises, or shown on the most recent balance sheet, free and clear of all liens
or other security interests.

     4.6 This Loan Agreement and the Note, have been duly executed and delivered
by  Borrower  and  are  legal,  valid  and  binding   obligations  of  Borrower,
enforceable in accordance with their respective terms, subject to (i) the effect
of any applicable bankruptcy,  insolvency,  reorganization,  moratorium or other
similar laws affecting the enforcement of creditors' rights generally,  (ii) the
availability  of the remedies of specific  performance  or injunctive  relief as
subject  to the  discretion  of the court  before  which a  proceeding  for such
remedies  may be brought,  and (iii) the  exercise by any court before which any
proceeding may be brought of equitable judicial discretion.

     4.7 Borrower has  delivered to Lender its  unaudited  balance  sheet of the
Borrower and the related  statements of income,  retained earnings and cash flow
of Borrower  (collectively  "Financial  Statements")  for the three month period
ending March 31, 2001, and further has updated the Financial  Statements through
May 31, 2001 so that the financial  status of Borrower as of that date is fairly
represented.  Such balance  sheet and  statement  fairly  present the  financial
condition of the  Borrower as of such date(s) and the results of the  operations
of the  Borrower  for the  period  ended on such  date(s),  and such  statements
through March 31, 2001 have been prepared in accordance with generally  accepted
accounting  principles  consistently  applied,  and contain any disclosure  that
would normally be required by financial  statements  prepared in accordance with
generally accepted accounting principles.  Since the end of the period reflected
in such financial  statements  there has been no material adverse change in such
condition or operations.

     4.8 Except as disclosed and  described on Schedule 4.8,  Borrower has filed
all  applicable  tax  returns  required  to be filed by it, and has paid or made
provisions  for the payment of all taxes which have become due  pursuant to said
returns or pursuant to any assessment received by Borrower except such taxes, if
any, as are being contested in good faith and as to which adequate reserves have
been provided in accordance with generally accepted accounting  principles,  and
warrants that such returns properly  reflect the United States,  state and local
income and tax liability of the Borrower for the period covered thereby.

     4.9 Except as disclosed and fully  described on Schedule  4.9,  there is no
action,  suit  or  proceeding  pending  or,  to the  knowledge  of the  Borrower
threatened,  against  the  Borrower  or any of its  property  before  any court,
governmental department, administrative agency or instrumentality which, if such
action,  suit or proceeding were adversely  determined,  would materially affect
the  financial  condition  or the results of  operations  of the Borrower or its
business or the ability of the  Borrower to perform its  obligations  hereunder.
4.10 Except as disclosed and described on Schedule

     4.10  hereto,  Borrower  is not in default on or has  otherwise  delayed or
postponed  payment of any  accounts  payable or other  liabilities  in excess of
$25,000 outside the ordinary course of business.

     4.11 Each Loan shall be fully  applied by  Borrower  solely for its working
capital  needs or for the  purchase  of  equipment  or  leasehold  improvements,
consistent with Schedule  3.1(g) and the cash control  system,  and for no other
purpose.

     4.12 No broker or finder  acting on behalf of  Borrower  brought  about the
obtaining,  making  or  closing  of this  Loan  Agreement  and  Borrower  has no
obligation  to pay any  finder's  or  brokerage  fees  in  connection  with  the
transactions contemplated herein.

     4.13 As of the date of  execution  of this Loan  Agreement,  the  aggregate
interest and other charges payable by Borrower to Lender under the terms of this
Loan Agreement do not exceed the maximum legal  interest rate  applicable to the
Loans.

     5. COVENANTS.
        ---------

     Borrower  hereby  covenants and agrees that until  satisfaction  of all its
obligations, it shall:

     5.1 Preserve and maintain its  corporate  existence  and all of its rights,
privileges and franchises,  and continue the conduct of its present  business in
an orderly,  efficient and regular manner;  comply in all material respects with
all  applicable  laws,  rules,   regulations  and  orders  of  any  governmental
authority,  non-compliance  with which  would  materially  affect the ability of
Borrower to perform its obligations.

     5.2 Make payments or  commitments  for payments  only in strict  compliance
with the Budget,  the Expense Plan and the cash control system,  or otherwise as
authorized by Lender.

     5.3 Furnish Lender  promptly with any financial  information or statements,
and other current information  regarding or relating to Borrower,  as reasonably
requested by Lender, other than information  relating to Borrower's  proprietary
know-how and technology information.

     5.4 Timely file any and all tax returns and tax filings  required under any
governmental  statute or regulation and timely pay and discharge,  when due, all
tax  obligations,  and  material  obligations  to third  parties,  except  those
obligations  being  contested in good faith,  and for which  Borrower shall have
maintained,   in  accordance  with  generally  accepted  accounting  principles,
adequate reserves for the payment of the same.

     5.5  Notify  Lender  immediately  upon  receipt  of  notice  of  any  lien,
attachment,  administrative or judicial proceeding, pending or threatened claim,
dispute,  litigation  or  governmental  proceedings,  material to the  financial
condition or operations of Borrower,  which for this purpose shall be any amount
in excess of $ 10,000; provide immediate written notice to Lender of any Default
or event  which  with the  lapse  of time or  giving  of  notice  or both  would
constitute a Default.

     5.6 Promptly and duly execute and deliver to Lender such further documents,
instruments  and assurances and take such further action as Lender may from time
to time reasonably  request in order to carry out the intent and purpose of this
Loan  Agreement and to establish and protect the rights and remedies  created or
intended to be created in favor of Lender hereunder.

     5.7  Reimburse  Borrower  for its  costs  and  reasonable  attorneys'  fees
incurred in enforcing its rights pursuant to the provisions of this Agreement.

     6. DEFAULTS AND REMEDIES.
        ---------------------

     6.1 Any of the following shall  constitute a default by Borrower  hereunder
("Default"):  (a) failure by Borrower to pay any amounts  hereunder or under any
Note when due and such remains unremedied for a period of fifteen (15) days from
the due date;  or (b)  failure of  Borrower  to comply  with any  provisions  or
perform any of its  obligations  arising under this Loan  Agreement  (other than
those  referred  to in clause (a) above),  or if, but only if,  such  failure to
comply is remediable, it remains unremedied by Borrower for a period of ten (10)
days from notice to Borrower;  or (c) any  representations or warranties made or
given  by  Borrower  in  connection  with  this  Loan  Agreement  were  false or
misleading  when made,  in any  material  way; or (d)  subjection  of any of the
assets in an amount in excess of  $10,000.00  of Borrower to  attachment,  levy,
execution,  forfeiture  or  cancellation  or other  administrative  or  judicial
process which is not or cannot be removed with reasonable diligence within sixty
(60) days from the subjection  thereof,  or (e)  commencement of any insolvency,
bankruptcy  or  similar  proceedings,  by or  against  Borrower,  including  any
assignment  by  Borrower  for the benefit of  creditors,  and in the case of any
involuntary  proceedings,  such is not  dismissed  within  ninety  (90)  days of
institution;  or the  inability of Borrower to pay its debts as they become due;
or (f) the  liquidation or dissolution  of Borrower or the  commencement  of any
acts relative thereto,  or without the prior written consent of Lender, any sale
or other disposition of all or substantially  all of the assets of Borrower,  or
any merger or  consolidation  of  Borrower,  or the  cessation  of  business  by
Borrower; or (g) a default by Borrower under any agreement for borrowed money or
under any lease,  except with  regard to the lease of premises  located at 16350
Park Ten Place,  Houston,  Texas 77084, whereby the holder of the obligation has
accelerated it prior to its stated maturity and such accelerated  amount exceeds
$100,000.00,  except as otherwise disclosed on Schedule 4.10; or (h) there shall
be a money judgment,  in excess of $25,000.00  entered against Borrower which is
not fully  covered by  insurance  or remains  unvacated,  unbonded,  unstayed or
undischarged for more than sixty (60) days.

     6.2 Upon any default, Lender, upon written notice to Borrower, may exercise
any one or more of the following remedies (which remedies shall be cumulative to
the extent  permitted by law):  (a) terminate  any further  obligation of Lender
hereunder  (including  any  obligation to make further  loans);  (b) declare the
remaining  unpaid  principal  balances of the Note,  plus all accrued but unpaid
interest  thereon,   plus  all  other  amounts  due  from  Borrower   hereunder,
immediately  due and payable in full without  notice or demand,  whereupon  such
shall  become due and  payable;  or (c) exercise any other right or remedy which
may be  available  to it under  applicable  law.  Upon a  default  any  proceeds
received from  Borrower  shall be applied by Lender to the  obligations,  in the
order of application as Lender shall elect.

     7. NOTICES; CHANGES.
        ----------------

         Notices, requests or other communications required hereunder to be sent
to either party shall be in writing and shall be by: (a) United States first
class mail, postage prepaid, and addressed to the other party at the address set
forth above (or to such other address as such party shall have designated by
proper notice), effective five days after deposit; (b) by personal or overnight
delivery, effective upon receipt.


     8. GOVERNING LAW.
        -------------

     This Loan Agreement  shall be governed and construed in accordance with the
laws of the State of  California  without  giving  effect to the  principles  of
conflict of laws thereof.

     9. DISPUTE  RESOLUTION.
        -------------------

     9.1 Any controversy or claim between or among the parties arising out of or
relating  to this  Loan  Agreement  or any  related  agreements  or  instruments
("Subject  Documents"),  including any claim based on or arising from an alleged
tort,  shall be  submitted  to and  determined  by  arbitration  before  one (1)
arbitrator  who shall be an attorney  admitted  to practice  law in the state of
California,  in  accordance  with  Title 9 of the U.S.  Code and the  Commercial
Arbitration  Rules  of the  American  Arbitration  Association  ("AAA")  then in
effect,  and shall be held in the county of San  Francisco,  CA. All statutes of
limitations  which would otherwise be applicable  shall apply to any arbitration
proceeding under this  subparagraph 9.1. Judgment upon the award rendered may be
entered in any court having jurisdiction. This subparagraph 9.1 shall apply only
if, at the time of the proposed  submission to AAA, none of the  obligations  to
Lender  described in or covered by any of the Subject  Documents  are secured by
real  property  collateral  or,  if so  secured,  all  parties  consent  to such
submission.

     9.2 If the controversy or claim is not submitted to arbitration as provided
and limited in Section  9.1, but becomes the subject of a judicial  action,  any
party may elect to have all decisions of fact and law determined by a referee in
accordance with  applicable  state law. If such an election is made, the parties
shall  designate to the court a referee or referees  selected under the auspices
of the AAA in the same  manner as  arbitrators  are  selected  in  AAA-sponsored
proceedings.  The referee, or presiding referee of the panel, shall be an active
attorney or retired judge.  Judgment upon the award rendered shall be entered in
the court in which such proceeding was commenced.

     9.3 Except as provided  herein,  no  provision  of, or the  exercise of any
rights under,  Section 9.1,  shall limit the right of any party to exercise self
help remedies such as setoff,  or to obtain  provisional  or ancillary  remedies
such as injunctive  relief or the  appointment of a receiver from a court having
jurisdiction  before,  during  or after the  pendency  of any  arbitration.  The
institution  and  maintenance  of an action  for  judicial  relief or pursuit of
provisional  or ancillary  remedies or exercise of self help remedies  shall not
constitute  a waiver of the right of any  party,  including  the  plaintiff,  to
submit the controversy or claim to arbitrators.

     9.4 The  parties  understand  and  agree  the  arbitration  will  be  their
exclusive form of resolving  disputes  between them regarding the issues covered
by this Agreement.  BOTH PARTIES EXPRESSLY WAIVE THEIR  ENTITLEMENT,  IF ANY, TO
HAVE CONTROVERSIES BETWEEN THEM DECIDED BY A JURY OR COURT OF LAW.

     10. MISCELLANEOUS.
         -------------

     This Loan  Agreement  or any part  hereof,  may not be assigned by Borrower
without the written consent of Lender and shall be binding upon and inure to the
benefit of the parties hereto, their legal representatives, permitted successors
and  assigns.  This Loan  Agreement  and/or the note or any part  thereof may be
assigned by Lender without the consent of Borrower. No amendment hereunder shall
be  effective  unless in  writing  signed by the  parties  hereto  and no waiver
hereunder  shall be  effective  unless  in  writing,  signed  by the party to be
charged.  No  failure  to  exercise,  no delay in  exercising,  and no single or
partial exercise on the part of Lender of any right, remedy, or power hereunder,
shall operate as a waiver thereof or preclude  Lender from  exercising any other
right,  remedy or power  hereunder.  Any provision of this Loan Agreement or the
Note which is unenforceable in any jurisdiction  shall, as to such jurisdiction,
be ineffective to the extent of such  prohibition or  unenforceability,  without
invalidating   the   remaining   provisions   hereof   or  of  the   note.   The
representations,  warranties,  obligations  and  indemnities of Borrower  herein
shall survive the  termination of this Loan Agreement to the extent required for
their full observance and  performance.  The obligation of each comaker (if any)
of this Loan Agreement or the Note shall be primary,  joint and several and each
such comaker  hereby  irrevocably  consents to any extension of time of payments
and/or the execution of any refinancing or restructuring  agreements relative to
this  Loan  Agreement  or the  Note.  In the  event  Borrower  fails to meet any
obligation of it hereunder, Lender may at its option satisfy such obligation and
Borrower shall reimburse  Lender on demand  therefor.  The captions in this Loan
Agreement  are for  convenience  only and shall  not  define or limit any of the
terms hereof.  This Loan Agreement may be executed in counterparts  and all said
counterparts  taken  together  shall be  deemed to  constitute  one and the same
instrument.

     THIS LOAN IS SECURED BY THE TERMS OF THAT  CERTAIN  SECURITY  AGREEMENT  OF
EVEN DATE BY AND  BETWEEN  BORROWER  AND LENDER  HEREUNDER,  ATTACHED  HERETO AS
EXHIBIT C.

<PAGE>


     IN  WITNESS  WHEREOF,  the  parties  hereto  have duly  executed  this Loan
Agreement as of the date first above written.  Borrower  acknowledges  that this
Loan  Agreement  shall not be effective  until accepted by Lender at its address
above.

LENDER:                                    BORROWER:

IMATRON INC.                               POSITRON CORPORATION

By: _____________________________          By: _____________________________

Its: _____________________________         Its: ______________________________

Attest:                                    Attest:

By: ______________________________         By: ______________________________

Its: _____________________________         Its: ______________________________




<PAGE>




                                 Schedule 3.1(g)

                                  Expense Plan


                      (Attach ProForma's for 2001 and 2002)



<PAGE>


                                  Schedule 4.5


                       Exceptions to Good Title to Assets

None



<PAGE>



                                  Schedule 4.5

                       Current Outstanding Loan agreements

None



<PAGE>



                                  Schedule 4.8

                  Overdue tax returns and provisions for taxes

None



<PAGE>



                                  Schedule 4.9

                          Pending or threatened actions

Currently Pending
-----------------

ProFutures Bridge Capital Fund, L.P. v. Positron Corporation, Case No. 00CV7146,
District Court, City and County of Denver,  Colorado.  Complaint for Declaratory
and Other Relief



<PAGE>



                                  Schedule 4.10

        Defaults or delays in payments in excess of $25,000 (a/o 6/29/01)



Payable to                                             Amount Due
-----------                                            ----------

Allen Matkins Leck Gable & Mallory LLP               $  34,267.92

Future Electronics                                   $ 127,778.00

GE Access                                            $ 123,104.59

LFJ Associates                                       $  29,018.11

Photonis                                             $ 126,700.00

Polymer Corporation                                  $ 182,217.26

Primary Sourcing                                     $  45,511.74

Saint-Gobain                                         $ 327,085.44

Sigma Electronics                                    $  34,048.46

Special Products (Invoice 00032969)                  $  29,186.96

Tristar                                              $  95,574.00



TOTAL AP OUTSTANDING (including above)   $1,554,890.46



<PAGE>




                                    EXHIBIT A


                                 PROMISSORY NOTE





<PAGE>



                                    EXHIBIT B

                              OFFICER'S CERTIFICATE





<PAGE>



                                    EXHIBIT C

                               SECURITY AGREEMENT





<PAGE>



                                    EXHIBIT D

                             STOCK PURCHASE WARRANT





<PAGE>



                                    EXHIBIT E

                          REGISTRATION RIGHTS AGREEMENT