Document:

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                                                                   Exhibit 10.67

                 ACKNOWLEDGEMENT AND CONFIRMATION OF GUARANTIES

         THIS ACKNOWLEDGEMENT AND CONFIRMATION (the "ACKNOWLEDGEMENT") is made
  and entered into as of November 8, 1999, by and between the entities listed
  on EXHIBIT "A" attached hereto (each a "GUARANTOR" and collectively, the
  "GUARANTORS") and DVI BUSINESS CREDIT CORPORATION ("LENDER").

                                   BACKGROUND

         A.  Pursuant to various Unconditional Continuing Guaranties dated
  February 25, 1997, June 29, 1999, or November 8, 1999, as the case may be, by
  and between Guarantors and Lender (each a "Guaranty" and collectively, the
  "GUARANTIES"), each Guarantor has agreed to guaranty and become surety for all
  present and future obligations of US Diagnostic, Inc. ("BORROWER") to Lender,
  including, without limitation, all obligations arising under that certain Loan
  and Security Agreement dated February 25, 1997, by and between Borrower and
  Lender, as amended (the "LOAN AGREEMENT"), the Notes executed thereunder and
  all documents, instruments and agreements related thereto (all of the
  foregoing being collectively, the "LOAN DOCUMENTS").

         B.  Borrower has agreed to divide the Loan, the Notes and the
  Collateral under the Loan Documents into two (2) distinct and separate
  obligations, which obligations may subsequently be merged or
  cross-collateralized.

         C.  All capitalized terms not defined herein shall have the meaning set
  forth in the Loan Agreement.

         NOW, THEREFORE, the parties hereto, intending to be legally bound and
  for good and valuable consideration, agree as follows:

         1.  ACKNOWLEDGEMENT AND CONFIRMATION OF OBLIGATIONS. Each Guarantor
  hereby acknowledges and confirms its unconditional continuing guarantee of the
  due and punctual payment, performance and discharge of any and all present and
  future Obligations (as defined in that Guarantor's Guaranty) of Borrower to
  Lender, including, without limitation, Borrower's obligations under Note A and
  under Note B, whether or not such obligations are divided or subsequently
  merged or cross-collateralized.

         2.  COUNTERPARTS. This Acknowledgement may be executed in counterparts,
  all of which when taken together constitute one and the same instrument.

         3.  GOVERNING LAW. This Acknowledgement is governed by and must be
  interpreted and construed in accordance with the laws of the State of
  California (without giving effect to any principles of conflicts of law).

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         IN WITNESS WHEREOF, the undersigned have executed this Acknowledgement
as of the date first above written.

HE IMAGING PARTNERS, LTD                     PINNACLE IMAGING ASSOCIATES

By: /s/ JOSEPH A. PAUL                       By: /s/ JOSEPH A. PAUL
   -------------------------                    -------------------------

Name: Joseph A. Paul                         Name: Joseph A. Paul
     -----------------------                      -----------------------

Title: President                             Title: President
      ----------------------                       ----------------------

VALLEY PRESBYTERIAN MAGNETIC                 COLUMBUS DIAGNOSTIC CENTER,
RESONANCE CENTER, LP                         INC.

By: /s/ JOSEPH A. PAUL                       By: /s/ JOSEPH A. PAUL
   -------------------------                    -------------------------

Name: Joseph A. Paul                         Name: Joseph A. Paul
     -----------------------                      -----------------------

Title: President                             Title: President
      ----------------------                       ----------------------

MEDITEK - BROWARD, INC.                      MEDITEK - PALM BEACH
                                             GARDENS, INC.

By: /s/ JOSEPH A. PAUL                       By: /s/ JOSEPH A. PAUL
   -------------------------                    -------------------------

Name: Joseph A. Paul                         Name: Joseph A. Paul
     -----------------------                      -----------------------

Title: President                             Title: President
      ----------------------                       ----------------------

ADVANCED MEDICAL IMAGING                     MEDITEK - GREYSTONE, INC.
CENTER, INC.

By: /s/ JOSEPH A. PAUL                       By: /s/ JOSEPH A. PAUL
   -------------------------                    -------------------------

Name: Joseph A. Paul                         Name: Joseph A. Paul
     -----------------------                      -----------------------

Title: President                             Title: President
      ----------------------                       ----------------------

MEDITEK - ICOT, INC.                         KALEY IMAGING, INC.

By: /s/ JOSEPH A. PAUL                       By: /s/ JOSEPH A. PAUL
   -------------------------                    -------------------------

Name: Joseph A. Paul                         Name: Joseph A. Paul
     -----------------------                      -----------------------

Title: President                             Title: President
      ----------------------                       ----------------------

MEDITEK - PALMS, INC.                        MEDITEK - PREMIER NORTH, INC.

By: /s/ JOSEPH A. PAUL                       By: /s/ JOSEPH A. PAUL
   -------------------------                    -------------------------

Name: Joseph A. Paul                         Name: Joseph A. Paul
     -----------------------                      -----------------------

Title: President                             Title: President
      ----------------------                       ----------------------

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MEDITEK -- SUN COAST, INC.              COMPUTERIZED MEDICAL
                                        IMAGING CENTER, INC.

By: /s/ JOSEPH A. PAUL                  By: /s/ JOSEPH A. PAUL
   -----------------------                 ------------------------
Name: Joseph A. Paul                    Name: Joseph A. Paul
     ---------------------                   ----------------------
Title: President                        Title: President
      --------------------                    ---------------------

SAN FRANCISCO MAGNETIC                  MODESTO IMAGING CENTER, INC.
RESONANCE CENTER, INC.

By: /s/ JOSEPH A. PAUL                  By: /s/ JOSEPH A. PAUL
   -----------------------                 ------------------------
Name: Joseph A. Paul                    Name: Joseph A. Paul
     ---------------------                   ----------------------
Title: President                        Title: President
      --------------------                    ---------------------

SOUTH COAST RADIOLOGISTS,               AH IMAGING CENTER, INC.
A CORPORATION

By: /s/ JOSEPH A. PAUL                  By: /s/ JOSEPH A. PAUL
   -----------------------                 ------------------------
Name: Joseph A. Paul                    Name: Joseph A. Paul
     ---------------------                   ----------------------
Title: President                        Title: President
      --------------------                    ---------------------

DI IMAGING CENTER, INC.                 LB IMAGING, INC.

By: /s/ JOSEPH A. PAUL                  By: /s/ JOSEPH A. PAUL
   -----------------------                 ------------------------
Name: Joseph A. Paul                    Name: Joseph A. Paul
     ---------------------                   ----------------------
Title: President                        Title: President
      --------------------                    ---------------------

MEDITEK PREMIER, INC.                   ORANGE PARK DIAGNOSTIC
                                        CENTER, INC.

By: /s/ JOSEPH A. PAUL                  By: /s/ JOSEPH A. PAUL
   -----------------------                 ------------------------
Name: Joseph A. Paul                    Name: Joseph A. Paul
     ---------------------                   ----------------------
Title: President                        Title: President
      --------------------                    ---------------------

SALISBURY IMAGING, INC.                 BRIDGETON MRI CENTER, INC.

By: /s/ JOSEPH A. PAUL                  By: /s/ JOSEPH A. PAUL
   -----------------------                 ------------------------
Name: Joseph A. Paul                    Name: Joseph A. Paul
     ---------------------                   ----------------------
Title: President                        Title: President
      --------------------                    ---------------------

JEFFERSON MAGNETIC RESONANCE            KIRKWOOD MRI CENTER, INC.
IMAGING, LLC

By: /s/ JOSEPH A. PAUL                  By: /s/ JOSEPH A. PAUL
   -----------------------                 ------------------------
Name: Joseph A. Paul                    Name: Joseph A. Paul
     ---------------------                   ----------------------
Title: President                        Title: President
      --------------------                    ---------------------

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MR OF KANSAS CITY, L.P.                 OUTPATIENT RADIOLOGY CENTER

By: /s/ JOSEPH A. PAUL                  By: /s/ JOSEPH A. PAUL
   -----------------------                 ------------------------
Name: Joseph A. Paul                    Name: Joseph A. Paul
     ---------------------                   ----------------------
Title: President                        Title: President
      --------------------                    ---------------------

COMMUNITY RADIOLOGY OF                   USDL PITTSBURGH, INC.
VIRGINIA, INC.

By: /s/ JOSEPH A. PAUL                  By: /s/ JOSEPH A. PAUL
   -----------------------                 ------------------------
Name: Joseph A. Paul                    Name: Joseph A. Paul
     ---------------------                   ----------------------
Title: President                        Title: President
      --------------------                    ---------------------

MEDITEK -- CHATHAM                      HEIGHTS IMAGING CENTER, INC.
INDUSTRIES, INC.

By: /s/ JOSEPH A. PAUL                  By: /s/ JOSEPH A. PAUL
   -----------------------                 ------------------------
Name: Joseph A. Paul                    Name: Joseph A. Paul
     ---------------------                   ----------------------
Title: President                        Title: President
      --------------------                    ---------------------

MEDICAL MARKETING                       SANTA FE IMAGING CENTER, INC.
DEVELOPMENT, INC.

By: /s/ JOSEPH A. PAUL                  By: /s/ JOSEPH A. PAUL
   -----------------------                 ------------------------
Name: Joseph A. Paul                    Name: Joseph A. Paul
     ---------------------                   ----------------------
Title: President                        Title: President
      --------------------                    ---------------------

AFFILIATED MEDICAL IMAGING              USD DAYTON, INC.
NETWORK, INC.

By: /s/ JOSEPH A. PAUL                  By: /s/ JOSEPH A. PAUL
   -----------------------                 ------------------------
Name: Joseph A. Paul                    Name: Joseph A. Paul
     ---------------------                   ----------------------
Title: President                        Title: President
      --------------------                    ---------------------

WESTLAKE DIAGNOSTIC CENTER
INC.

By: /s/ JOSEPH A. PAUL
   -----------------------
Name: Joseph A. Paul
     ---------------------
Title: President
      --------------------

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                                   GUARANTORS

HE Imaging Partners, Ltd.
Pinnacle Imaging Associates
Valley Presbyterian Magnetic Resonance Center, LP
Columbus Diagnostic Center, Inc.
MediTek -- Broward, Inc.
MediTek -- Palm Beach Gardens, Inc.
ADvanced Medical Imaging Center, Inc.
MediTek -- Greystone, Inc.
MediTek -- ICOT, Inc.
Kaley Imaging, Inc.
MediTek -- Palms, Inc.
MediTek -- Premier North, Inc.
MediTek -- Sun Coast, Inc.
Computerized Medical Imaging Center, Inc.
San Francisco Magnetic Resonance Center, Inc.
Modesto Imaging Center, Inc.
South Coast Radiologists, a Corporation
AH Imaging, Inc.
DI Imaging Center, Inc.
LB Imaging, Inc.
MediTek Premier, Inc.
Orange Park Diagnostic Center, Inc.
Salisbury Imaging, Inc.
Jefferson Magnetic Resonance Imaging, LLC
MR of Kansas City, L.P.
Outpatient Radiology Center
Community Radiology of Virginia, Inc.
USDL Pittsburgh, Inc.
MediTek -- Chatham Industries, Inc.
Heights Imaging Center, Inc.
Medical Marketing Development, Inc.
Santa Fe Imaging Center, Inc.
Affiliated Medical Imaging Network, Inc.
USD Dayton, Inc.

                                  EXHIBIT "A"
                                       TO
                        ACKNOWLEDGMENT AND CONFIRMATION
                                 OF GUARANTIES

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Westlake Diagnostic Center, Inc.
MICA Imaging, Inc.
Bridgeton MRI Center, Inc.
Kirkwood MRI Center, Inc.

                            EXHIBIT "A" (continued)
                                       to
                        ACKNOWLEDGMENT AND CONFIRMATION
                                 OF GUARANTORS

                                       6<PAGE>   1
                                                                   Exhibit 10.68

                                AMENDMENT NO. 6
                                      TO
                          LOAN AND SECURITY AGREEMENT
                     DATED FEBRUARY 25, 1997 ("AGREEMENT")
                                    BETWEEN
                       U.S. DIAGNOSTIC INC. ("BORROWER")
                                      AND
                  DVI BUSINESS CREDIT CORPORATION ("LENDER")

         This Amendment No. 6 ("Amendment") to the Loan and Security Agreement
is made and entered into as of January 18, 2000, by and between U.S. Diagnostic
Inc. ("Borrower") and DVI Business Credit Corporation ("Lender").

                                   RECITALS

         A.  Borrower and Lender entered into a Loan and Security Agreement
             dated February 25, 1997, and all amendments thereto (collectively
             referred to as the "Agreement") pursuant to which Borrower
             obtained a revolving loan in the amount of Thirty Five Million
             Dollars ($35,000,000).

         B.  The parties now desire to amend certain terms of the Agreement on
             and subject to the terms hereof.

         NOW, THEREFORE, in consideration of the mutual covenants and
agreements set forth herein, and for other good and valuable consideration, the
receipt and sufficiency of which are being acknowledged and affirmed, the
parties hereto agree as follows:

         1.  A new Section 2.13 is hereby inserted in the Agreement:

                  "2.13 Loan B Additional Facility. Subject to the terms of
         this Agreement, Lender agrees, for so long as no Event of Default
         exists, to provide Borrower, and Borrower agrees to accept,
         overadvance financing for the purposes described herein (each advance
         being a "Loan B Additional Advance"), up to an aggregate unpaid
         principal amount not to exceed at any time Two Million Dollars
         ($2,000,000), subject to the provisions of item (e) below, and
         otherwise on and subject to the following terms and conditions (the
         "Loan B Additional Facility"):

                  (a) A Loan B Additional Advance may be made to satisfy
         Borrower's working capital needs to the extent they exceed the
         formula-determined Borrowing Base B.

                  (b) Each Loan B Additional Advance shall be due and payable in
         accordance with the terms of this Agreement and shall constitute
         Obligations.

                  (c) No Guaranty shall be in default and each shall be in full
         force and effect at the time any Loan B Additional Advance is made.

                  (d) Borrower will pay Lender interest on the principal amount
         of any Loan B Additional Advance outstanding at the rates provided for
         Loans herein.

                  (e) The Loan B Additional Facility, shall be repaid in whole
         on or before May 20, 2000, and to achieve such limitation, the Loan B
         Additional Facility shall be reduced by $180,000 per week

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         commencing on March 1, 2000. If the foregoing provisions for repayment,
         or any of them, are not satisfied by Borrower, it shall constitute an
         Event of Default. To the extent that the Loan B Additional Facility is
         not repaid by the final maturity date described above, all cash
         receipts and other monies received on Loan B will immediately serve to
         repay the Loan B Additional Facility.

                  (f) Except as provided to the contrary in the provisions
         above, the Loan B Additional Facility pursuant to this Section 2.13
         shall be subject to all other terms and conditions of this Agreement.
         In no event shall any amount of the Loan B Additional Facility be
         available under Loan A.

         Notwithstanding anything else herein, the total outstanding principal
         amount of all Loans under Loan B shall at no time exceed $11,000,000.

         2.  The definition of "Loan Availability" in Section 1.1 of the
Agreement is deleted in its entirety and replaced with the following:

         "'Loan Availability A' shall mean the lesser of (a) the Commitment
         Amount A or (b) the sum of (i) the Borrowing Base A, plus (ii) the then
         existing maximum amount of the Overadvance Facility, minus the
         aggregate Advances under Loan A and other monetary Obligations
         outstanding under this Agreement allocable to Loan A.

         "'Loan Availability B' shall mean the lesser of (a) the Commitment
         Amount B or (b) the sum of (i) the Borrowing Base B, plus (ii) the then
         existing maximum amount of the Loan B Additional Facility, minus the
         aggregate Advances under Loan B and other monetary Obligations
         outstanding under this Agreement allocable to Loan B."

         For purposes of the Agreement any reference to the term Loan
         Availability in the Loan Documents shall be interpreted with the
         foregoing amendment, as the context so requires.

         3.  The Agreement shall be amended to provide that on or before the
first day of each month following the date hereof, Borrower shall pay Lender a
monthly maintenance fee of Eight Thousand Five Hundred Dollars ($8,500).
Increases to the Loan Availability during the term will be charged an
incremental increase in the monthly maintenance fee proportionate to the
percentage increase in the Loan Availability.

         4.  The term "Borrowing Base" in Section 1 of the Agreement, is hereby
amended by deleting the reference therein to "eighty percent (80%)" and
replacing it with "eighty-five percent (85%)".

         5.  Wilkes Barre Imaging is hereby added as a Loan B Guarantor under
the Agreement.

         6.  Except as expressly amended by this Amendment, the Agreement
remains in full force and effect. References to the Agreement are deemed to mean
the Agreement as amended by this Amendment.

         7.  This Amendment may be executed in counterparts, all of which when
taken together constitute one and the same instrument.

         8.  This Amendment is governed by and must be interpreted and construed
in accordance with the laws of the State of California.

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Lender is entering into this Amendment without any forbearance, and without
waiver or prejudice of defaults, events of default, and any rights or remedies
Lender has or may have under the Agreement and applicable law. Lender hereby
expressly reserves the right to declare a default in accordance with the
Agreement and exercise all of Lender's rights and remedies thereunder.

All capitalized terms used herein and not otherwise defined herein shall have
the same meaning as in the Agreement. Any provision in the Amendment hereof
that may be contrary to any provision of the Agreement shall prevail and
override the Agreement. Except as expressly set forth herein, all other
provisions of the Agreement shall remain in full force and effect. Borrower and
Lender warrant to each other that this Amendment has been authorized and duly
executed and is binding on all parties hereto as of the date first above
written.

BORROWER                                     LENDER

U.S. DIAGNOSTIC INC.                         DVI BUSINESS CREDIT CORPORATION

By:                                          By:
   ----------------------------                 ----------------------------

Name: Paul Andrew Shaw                       Name: Cynthia J. Cohen
     --------------------------                   --------------------------

Title: Executive Vice President              Title: Executive Vice President
      -------------------------                    -------------------------

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