Exhibit10.56

SECONDAMENDMENT TOFIRST AMENDED AND RESTATED CREDIT AGREEMENT

               THIS SECOND AMENDMENT TO FIRST AMENDED AND RESTATED CREDITAGREEMENT (this “Amendment”) is made and dated as ofthe 21st day of December, 2001 by and among the Lenders currentlyparty to the Credit Agreement referred to below, BANK ONE, NA, asadministrative agent for the Lenders (in such capacity, the“Administrative Agent”), THE BANK OF NOVA SCOTIA, asdocumentation agent (in such capacity, the “DocumentationAgent”), SYNCOR INTERNATIONAL CORPORATION, a Delawarecorporation (the “Parent”), and SYNCOR MANAGEMENTCORPORATION, a Delaware corporation (the“Borrower”). 

RECITALS

               A.           Pursuant to that certain First Amended and Restated CreditAgreement dated as of May 10, 2001, by and among theAdministrative Agent, the Documentation Agent, the Lenders, theParent and the Borrower (as amended, extended and replaced fromtime to time, the “Credit Agreement”), the Lendersagreed to extend credit to the Borrower on the terms and subject tothe conditions set forth therein.  All capitalized terms nototherwise defined herein are used with the meanings given suchterms in the Credit Agreement.

               B.           The parties to the Credit Agreement have agreed to amend the samein certain respects and desire to set forth the terms andconditions of such amendment pursuant hereto.

               NOW, THEREFORE, in consideration of the foregoing Recitals and forother valuable consideration, the receipt and adequacy of which arehereby acknowledged, the parties hereto hereby agree asfollows:

AGREEMENT

               1.            Limited Recourse Sales of Assets.  To reflect certainagreements of the parties hereto with respect to securitizationtransactions which may be entered into from time to time by theParent and the Borrower, effective as of the Second AmendmentEffective Date (as defined in Paragraph 4 below):

                               (a)          Subsection (iii) of Section 6.13 of the Credit Agreement is herebyamended to read in its entirety as follows:
|            |                            “(iii) Any transfer of an interest in accounts or notes receivable on alimited recourse basis, provided that such transfer qualifies as asale under Agreement Accounting Principles and, notwithstandingthat such transaction may not qualify as such a sale, the InitialPermitted Accounts Receivable Financing Facility; provided,however, that the aggregate dollar amount owing by the obligorsunder the assets which are the subject of such sales or secure theInitial Permitted Accounts Receivable Financing Facility does notexceed at any time $100,000,000.” |
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                               (b)           Anew subsection (viii) is hereby added in correct numerical order toSection 6.15 of the Credit Agreement to read in its entirety asfollows:
|           |                           “(viii) Liens granted in connection with transfers of interests in accountsor notes receivable permitted pursuant to Section 6.13(iii) of thisAgreement, including, without limitation, pursuant to the InitialPermitted Accounts Receivable Financing Facility; provided,however, that:  (1) such Liens secure only the obligations ofthe Parent and its Subsidiaries, as applicable, arising under suchtransactions, (2) such obligations remain non-recourse to theParent and its Subsidiaries, as applicable, except to the extent ofsuch Person’s interest in the assets transferred, theproceeds thereof and rights associated therewith arising inconnection with such transactions (the “SecuritizationAssets”) and with respect to customary indemnificationprovisions provided in connection with such transactions, and (3)such Liens attach only to the SecuritizationAssets.” |
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                               (c)           Thedefinition of “Indebtedness” set forth in Article I ofthe Credit Agreement is hereby amended to read in its entirety asfollows:
|              |                          “’Indebtedness’of a Person means, without duplication, such Person's (i)obligations for borrowed money, (ii) obligations representing thedeferred purchase price of Property or services (other thanaccounts payable arising in the ordinary course of such Person'sbusiness payable on terms customary in the trade), (iii)obligations, whether or not assumed, secured by Liens or payableout of the proceeds or production from Property now or hereafterowned or acquired by such Person, (iv) obligations which areevidenced by notes, acceptances, or other instruments, (v)Capitalized Lease Obligations, (vi) Contingent Obligations, and(vii) to the extent not otherwise included in subsections (i)through (vi) hereof, obligations arising under transactionspermitted pursuant to Section 6.13(iii). |
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                               (d)           Anew definition of “Initial Permitted Accounts ReceivableFinancing Facility” is hereby added to Article I of theCredit Agreement in correct alphabetical order to read in itsentirety as follows:
|             |                        "’InitialPermitted Accounts Receivable Financing Facility’ means thatcertain accounts receivable financing facility which will beconsummated in or around January 2002 evidenced by:  (i) thatcertain Receivables Financing Agreement among Syncor FinancingCorporation, as seller, the Borrower, as servicer, JupiterSecuritization Corporation and the other financial institutionsparty thereto, as purchasers, and Bank One, as agent, (ii) thatcertain Receivables Sale Agreement between the Borrower, as sellingsubsidiary, and Syncor Financing Corporation, as buyer, and (c)that certain Receivables Sale Agreement between the Parent, asoriginator, and the Borrower, as buyer, as each such agreement maybe amended, restated, supplemented or otherwise modified from timeto time.” |
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               2.            Reaffirmation of Loan Documents.  The Parent andBorrower hereby affirm and agree that except to the extentexpressly provided herein, the Credit Agreement, the Notes and theother Loan Documents remain in full force and effect.

               3.            Reaffirmation of Guaranties.  By acknowledging andagreeing to this Amendment as provided below, each of theGuarantors affirms and agrees that:  (a) the executionand delivery by the Borrower and the Parent and the performance oftheir obligations under this Amendment shall not in any manner orto any extent affect any of the obligations of the Guarantors orthe rights of the Lenders and the Administrative Agent under theGuaranties or any other document, instrument or agreement made orgiven by the Guarantors in connection therewith, (b) the term“Obligations” as used in the Guaranties includes,without limitation, the Obligations under the Credit Agreement asamended hereby, and (c) the Guaranties remain in full forceand effect.

               4.            Second Amendment Effective Date.  This Amendment shallbe effective as of the date (the “Second Amendment EffectiveDate”) the Administrative Agent shall have received each ofthe following:

                               (a)           Acopy of this Amendment duly executed by the Borrower, the Parentand Lenders constituting not less than the Required Lenders underthe Credit Agreement; and

                               (b)          Such other documents, instruments, agreements, corporateauthorizations and opinions of legal counsel as the AdministrativeAgent or the Lenders may reasonably request.

               5.            Representations and Warranties.  The Borrower and theParent hereby represent and warrant to the Administrative Agent andthe Lenders that as of the date hereof and at and as of the SecondAmendment Effective Date and both before and after giving effecthereto:

                               (a)          Each of the Borrower and the Parent has the corporate power andauthority and the legal right to execute, deliver and perform theAmendment and has taken all necessary corporate action to authorizesuch execution, delivery and performance.

                               (b)           TheAmendment has been duly executed and delivered on behalf of suchPerson and constitutes the legal, valid and binding obligation ofsuch Person, enforceable against such Person in accordance with itsterms, subject to the effect of applicable bankruptcy, insolvency,reorganization, moratorium and other similar laws affecting therights of creditors generally and the effect of equitableprinciples whether applied in an action at law or a suit inequity.

                               (c)           Therepresentations and warranties of the Borrower and the Parentcontained in the Credit Agreement as amended hereby are accurateand complete in all material respects.

                               (d)          There has not occurred a Default or UnmaturedDefault. 

               6.            No Other Amendment.  Except as expressly amendedhereby, the Loan Documents shall remain in full force and effect aswritten and amended to date.

               7.            Counterparts.  This Amendment may be executed in anynumber of counterparts, each of which when so executed shall bedeemed to be an original and all of which when taken together shallconstitute one and the same agreement.

[Signaturepages following]

               IN WITNESS WHEREOF, theparties hereto have caused this Amendment to be executed as of theday and year first above written. 

                                                               SYNCOR MANAGEMENT CORPORATION, as the Borrower

                                                               By: /s/William P.Forster                                                                        Name: William P. Forster                                                               Title: Vice President

                                                               SYNCOR INTERNATIONAL CORPORATION, as the Parent

                                                               By: /s/William P.Forster                                                                         Name: William P. Forster                                                               Title: Chief Financial Officer

                                                               BANK ONE, NA, as Administrative Agent and as a Lender

                                                               By: /s/Joseph R.Perdenza                                                                        Name: Joseph R. Perdenza                                                               Title: Associate Director

                                                               THE BANK OF NOVA SCOTIA, as Documentation Agent and as aLender

                                                               By:/s/R.P.Reynolds                                                                                 Name: R.P. Reynolds                                                               Title: Director

                                                               FLEET NATIONAL BANK, as a Lender

                                                               By:                                                                                                             Name:                                                                                                       Title:                                          

                                                               MELLON BANK, N.A., as a Lender

                                                               By:                                                                                                             Name:                                                                                                       Title:                                          

                                                               THE NORTHERN TRUST COMPANY, as a Lender

                                                               By: /s/Steven W.Ryan                                                                               Name: Steven W. Ryan                                                               Title: Vice President

                                                               UNITED CALIFORNIA BANK (formerly Sanwa Bank California), as aLender

                                                               By:                                                                                                               Name:                                                                                                         Title:                                            

                                                               UNION BANK OF CALIFORNIA, N.A., as a Lender

                                                               By: /s/P MRoesner                                                                                       Name: Philip M. Roesner                                                               Title: Vice President

                                                               KEY CORPORATE CAPITAL INC., as a Lender

                                                               By:                                                                                                                  Name:                                                                                                             Title:                                               

Acknowledged and agreedto as of the __ day of December, 2001:

COMPREHENSIVE MEDICALIMAGING, INC.,as a Guarantor

By: /s/DavidWard                        Name: David WardTitle: President

SYNCOR OVERSEASLTD.,as a Guarantor

By: /s/William P.Forster           Name: William P. ForsterTitle: Chief Financial Officer

SYNCOR INTERNATIONALCORPORATION,as a Guarantor

By: /s/William P.Forster           Name: William P. ForsterTitle: Chief Financial Officer