Exhibit 4.5
                                  -----------


                  ASSIGNMENT, ASSUMPTION AND RELEASE AGREEMENT


THIS AGREEMENT made as of the 30th day of April, 2004 (the "EFFECTIVE DATE").


B E T W E E N:

                                 HEMOSOL INC., a corporation incorporated
                                 pursuant to the laws of the Province of Ontario

                                 (the "ASSIGNOR")

                                                              OF THE FIRST PART

                                 - AND -

                                 HEMOSOL LP, a limited partnership constated
                                 pursuant to the laws of the Province of Ontario

                                 (the "ASSIGNEE")

                                                             OF THE SECOND PART

                                 - AND -

                                 MDS INC., a corporation incorporated pursuant
                                 to the laws of Canada

                                 (the "GUARANTOR")

                                                              OF THE THIRD PART

                                 - AND -

                                 THE BANK OF NOVA SCOTIA

                                 ("BNS")

                                                             OF THE FOURTH PART

WHEREAS pursuant to the terms of a commitment letter dated October 25, 2002, as
amended and supplemented by a supplemental agreement dated as of November 22,
2002 and as further amended by amending agreements dated April 29, 2003 and
December 29, 2003 (collectively, the "COMMITMENT LETTER"), BNS agreed to extend
to the Assignor the credit facilities specifically described therein (the
"CREDIT FACILITIES") including that credit facility designated as Credit No: 01
in the principal amount of $20,000,000 (the "$20,000,000 CREDIT FACILITY");

AND WHEREAS in accordance with the terms of the Commitment Letter, the Assignor
issued to BNS a promissory note in the principal amount of $20,000,000 dated
November 22, 2002 evidencing the indebtedness under the $20,000,000 Credit

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Facility (the "PROMISSORY Note") and the security and other instruments in
support of the Credit Facilities listed in Schedule "A" hereto (the Promissory
Note and such security and other instruments, collectively, the "EXISTING
SECURITY");

AND WHEREAS the Guarantor issued to BNS a guarantee in support of the
$20,000,000 Credit Facility dated November 22, 2002, amended by way of letter
agreement dated December 29, 2003 (collectively, the "GUARANTEE");

AND WHEREAS pursuant to the contribution agreement (the "CONTRIBUTION
AGREEMENT") dated the "Effective Date" as defined in the Arrangement Agreement
made as of February 11, 2004 between the Assignor and the Assignee, the Assignor
has agreed to transfer to the Assignee all of the Purchased Assets and the
Assumed Liabilities (each as defined in the Contribution Agreement) and the
Assignor has agreed to assign to the Assignee, and the Assignee has agreed to
assume, each of the Assumed Contracts (as defined in the Contribution
Agreement).

AND WHEREAS BNS has approved the assignment of the Credit Facilities to the
Assignee and the assumption of the Credit Facilities by the Assignee on the
terms and conditions contained herein;

AND WHEREAS BNS has agreed to release the Assignor from all liability and
obligations in connection with the Credit Facilities on the terms and conditions
contained herein;

AND WHEREAS the Guarantor and BNS desire that the Guarantee remain in place in
support of the $20,000,000 Credit Facility subsequent to the completion of the
transactions referred to and provided for herein;

AND WHEREAS the parties hereto have agreed to execute this Agreement.

NOW THEREFORE IN CONSIDERATION of $10.00, the mutual covenants contained herein
and other good and valuable consideration (the receipt and adequacy whereof are
hereby acknowledged), the parties hereto covenant, agree and acknowledge as
follows:

1.         Each of the parties severally acknowledges to and agrees with each
           other party that the recitals contained herein to the extent they
           relate to it and each agreement to which it is party are true and
           correct as of the Effective Date and form part of this Agreement.

2.         Each of the Assignor and the Assignee represents and warrants to BNS
           that the Contribution Agreement in the form attached hereto as
           Schedule "B" constitutes the entire Contribution Agreement as of the
           Effective Date and that the Contribution Agreement has not been
           otherwise amended or supplemented.

3.         The Assignor hereby sells, transfers and assigns unto the Assignee,
           and the Assignee hereby agrees to assume, all of the Assignor's
           right, title and interest in, as well as its corresponding
           responsibilities and obligations in connection with, the Credit
           Facilities, the indebtedness and obligations arising thereunder
           regardless of whether such indebtedness and obligations arose prior
           or subsequent to the date hereof (collectively, the "INDEBTEDNESS"),
           the Commitment Letter and the Existing Security.


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<PAGE>
4.         The Assignee hereby accepts the assignment of the Credit Facilities,
           the Indebtedness, the Commitment Letter and the Existing Security
           upon the terms set out herein and assumes, and agrees to observe,
           perform, fulfill and be bound by all terms, covenants, conditions,
           obligations and responsibilities relating to the Credit Facilities,
           the Indebtedness, the Commitment Letter and the Existing Security
           which are to be observed, performed and fulfilled by the Assignor
           pursuant to the said instruments in the same manner and to the same
           extent as if the Assignee were the borrower named therein.

5.         The Assignee acknowledges that the Purchased Assets assigned to it
           pursuant to the Contribution Agreement are subject to the terms,
           conditions, security interests, charges and provisions of the
           Existing Security. The Assignee agrees to be bound by the Existing
           Security to the same extent as if the Assignee was named as the
           entity issuing the security therein and acknowledges receipt of same.
           The Assignee acknowledges and agrees that the Existing Security is in
           full force and effect, that the security interests created thereunder
           have remained continuously attached at all times before, at the time
           of and subsequent to the sale, transfer and assignment referred to
           herein and that the Existing Security creates a security interest in
           property and assets the Assignee acquires an interest in subsequent
           to the sale, transfer and assignment referred to herein.

6.         The Guarantor acknowledges having received a copy of the Contribution
           Agreement and agrees the Assignee shall be substituted for the
           Assignor as "Customer" under the Guarantee such that subsequent to
           the Effective Date the Assignee shall be the "Customer" under the
           Guarantee. The Guarantor agrees with BNS that the Guarantee remains
           in full force and effect, is hereby confirmed and continues to
           guarantee the $20,000,000 Credit Facility in accordance with its
           terms notwithstanding that the Assignee rather than the Assignor is,
           subsequent to the Effective Date, the borrower under the $20,000,000
           Credit Facility. The definition of "Security" in the Guarantee shall
           include the security instruments issued by the Assignee referred to
           in Section 7 herein.

7.         In consideration of BNS agreeing to consent to the assignment and
           assumption referred to herein, the Assignee agrees to provide the
           following additional security or other documentation to BNS:

           (a)        General Security Agreement;

           (b)        General Assignment of Contracts;

           (c)        Specific Assignment of Contract with SNC Lavalin Inc.;

           (d)        Debenture in the amount of $25,000,000, inter alia,
                      mortgaging and charging the lands known municipally as
                      2585 Meadowpine Blvd., Mississauga, Ontario;

           (e)        Documentation substituting warrants to purchase 45,000
                      common shares of Hemosol Inc. held by BNS with an exercise
                      price of $6.31 with warrants to purchase 45,000 common
                      shares of Hemosol Corp. held by BNS with an exercise price
                      of $6.27.

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<PAGE>
8.         Each of the Guarantor, the Assignee and BNS severally confirm to each
           other that the balance of the indebtedness owing under the
           $20,000,000 Credit Facility as of the Effective Date is $20,000,000
           plus accrued interest. Each of the Assignee and the Bank severally
           confirm that there is a letter of credit to the City of Mississauga
           in the revised amount of $20,000 outstanding under Credit No. 3 in
           the Commitment Letter. BNS confirms to the other parties hereto that
           all payments of principal and interest due and owing in connection
           with the said indebtedness are current and in good standing to date.

9.         Each of BNS and the Guarantor hereby consents to the assignment of
           Purchased Assets and Assumed Liabilities from the Assignor to the
           Assignee provided for in the Contribution Agreement, the within
           assignment and assumption of the Credit Facilities, the Indebtedness,
           the Commitment Letter and the Existing Security from the Assignor to
           the Assignee and BNS acknowledges that the Guarantor has affirmed the
           continuation of the Guarantee.

10.        BNS hereby remises, releases and forever discharges the Assignor from
           any and all indebtedness, obligations, liabilities, claims and
           demands of any nature or kind whatsoever which BNS may now or
           hereafter have against the Assignor arising under, by reason of
           otherwise in connection with the Assumed Liabilities, including
           without limitation those arising under, by reason of or otherwise in
           respect of the Credit Facilities, the Indebtedness owing thereunder,
           the Commitment Letter and the Existing Security.

11.        This Agreement may be executed in any number of counterparts each of
           which when so executed shall be deemed to be an original and all of
           such counterparts taken together shall be deemed to constitute one
           and the same instrument.

12.        This Agreement shall be binding upon and enure to the benefit of the
           parties and their respective successors and assigns.

13.        This Agreement shall be governed by and construed in accordance with
           the laws of the Province of Ontario.

14.        This Agreement shall become effective on the Effective Date.




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<PAGE>
IN WITNESS WHEREOF the parties hereto have executed this Agreement as of the
Effective Date.

                                  HEMOSOL INC.


                                  Per: /s/ Jonathan Wolch                   c/s
                                       -------------------------------------
                                       Name: Jonathan Wolch
                                       Title: Assistant Secretary


                                  HEMOSOL LP
                                  BY ITS GENERAL PARTNER HEMOSOL CORP.


                                  Per: /s/ Jonathan Wolch
                                       -------------------------------------
                                       Name: Jonathan Wolch
                                       Title: Assistant Secretary


                                  MDS INC.


                                  Per: /s/ John Rogers                      c/s
                                       -------------------------------------
                                       Name: John Rogers
                                       Title: CEO


                                  Per: /s/ Alan Torrie                      c/s
                                       -------------------------------------
                                       Name: Alan Torrie
                                       Title: Executive Vice-President,
                                              Global Markets


                                  THE BANK OF NOVA SCOTIA


                                  Per: /s/ Byron Kwan
                                       -------------------------------------
                                       Name: Byron Kwan
                                       Title: Director


                                  Per: /s/ Jason Fielden
                                       -------------------------------------
                                       Name: Jason Fielden
                                       Title: Associate


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<PAGE>
                                   SCHEDULE A

1. General Security Agreement over all present and future personal property
granted by the Assignor in favour of BNS on November 22, 2002;

2. Assignment of Contracts dated November 22, 2002 between the Assignor and BNS
with respect to certain contracts listed in a schedule thereto;

3. Specific Assignment of Contract dated November 22, 2002 between the Assignor
and BNS with respect to relating to the Assignor's interest in an EPC contract
between the Assignor and SNC Lavalin Inc. dated August 8, 2000, as amended;

4. Assignments of security over patents, patent applications, trademarks and
trademark applications (Canada) owned, licensed or applied for by the Assignor,
each dated November 22, 2002, in favour of BNS;

5. Assignments of security over patents, patent applications, trademarks and
trademark applications (U.S.) owned, licensed or applied for by the Assignor,
each dated November 22, 2002, in favour of BNS;

6. Debenture in the principal amount of $25,000,000 dated November 22, 2002
executed by the Assignor in favour of BNS;

7. Charge/mortgage of the of the property municipally known as 2585 Meadowpine
Boulevard, Mississauga, Ontario (the "Meadowpine Property") registered against
title to the Meadowpine Property on November 22, 2002 as Instrument No. PR
351375 granted by the Assignor in favour of BNS, in the original principal
amount of $25,000,000;

8. Notice of intention to give security under section 427 of the Bank Act
executed by the Assignor;

9. Application for credit and promise to give security under Section 427 of the
Bank Act executed by the Assignor;

10. Agreement as to security under section 427 of the Bank Act by the Assignor
in favour of BNS dated November 22, 2002;

11. Special security in respect of specified property or classes of property
described in section 427 of the Bank Act by the Assignor in favour of BNS dated
November 22, 2002; and

12. Application and Agreement for Irrevocable Standby Letter of Credit/Letter of
Guarantee executed by the Assignor (Bank Reference Number S18572/165586).