Document:

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                                                                     EXHIBIT 4.2

                                RADIOLOGIX, INC.

                           10.5% SERIES B SENIOR NOTE
                                    DUE 2008

                                                            CUSIP No.: 75040KAC3
No. 1                                                            $______________

         Radiologix, Inc., a Delaware corporation (hereinafter called the
"Company", which term includes any successors under the Indenture hereinafter
referred to), for value received, hereby promises to pay to Cede & Co., or
registered assigns, the principal sum of _______________________ Dollars, on
December 15, 2008.

         Interest Payment Dates: June 15 and December 15 commencing June 15,
2002.

         Record Dates:  June 1 and December 1.

         Reference is made to the further provisions of this Note on the reverse
side, which will, for all purposes, have the same effect as if set forth at this
place.

<PAGE>

         IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed.

                                   RADIOLOGIX, INC.,
                                   a Delaware corporation

                                   By:
                                      ------------------------------------------
                                   Name:    Mark L. Wagar
                                   Title:   Chairman of the Board and Chief
                                            Executive Officer

                                   By:
                                      ------------------------------------------
                                   Name:    Sami Abbasi
                                   Title:   Chief Financial Officer and
                                            Executive Vice President

Dated:              , 2002
        ------------

                                       2
<PAGE>

         This is one of the Notes described in the within-mentioned Indenture.

                                   U.S. BANK, N.A.

                                   By:
                                      ------------------------------------------
                                       Authorized Signatory

Dated:              , 2002
        ------------

                                       3
<PAGE>

                                 (Back of Note)

                      10.5% Series B Senior Notes due 2008

THIS GLOBAL NOTE IS HELD BY THE DEPOSITARY (AS DEFINED IN THE INDENTURE
GOVERNING THIS NOTE) OR ITS NOMINEE IN CUSTODY FOR THE BENEFIT OF THE BENEFICIAL
OWNERS HEREOF, AND IS NOT TRANSFERABLE TO ANY PERSON UNDER ANY CIRCUMSTANCES
EXCEPT THAT (I) THE TRUSTEE MAY MAKE SUCH NOTATIONS HEREON AS MAY BE REQUIRED
PURSUANT TO SECTION 2.6 OF THE INDENTURE, (II) THIS GLOBAL NOTE MAY BE EXCHANGED
IN WHOLE BUT NOT IN PART PURSUANT TO SECTION 2.6(a) OF THE INDENTURE, (III) THIS
GLOBAL NOTE MAY BE DELIVERED TO THE TRUSTEE FOR CANCELLATION PURSUANT TO SECTION
2.11 OF THE INDENTURE AND (IV) THIS GLOBAL NOTE MAY BE TRANSFERRED TO A
SUCCESSOR DEPOSITARY WITH THE PRIOR WRITTEN CONSENT OF THE COMPANY.

UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR NOTES IN DEFINITIVE
FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE DEPOSITARY TO A
NOMINEE OF THE DEPOSITARY OR BY A NOMINEE OF THE DEPOSITARY TO THE DEPOSITARY OR
ANOTHER NOMINEE OF THE DEPOSITARY OR BY THE DEPOSITARY OR ANY SUCH NOMINEE TO A
SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH SUCCESSOR DEPOSITARY. UNLESS THIS
CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST
COMPANY (55 WATER STREET, NEW YORK, NEW YORK) ("DTC"), TO THE COMPANY OR ITS
AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE
ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS MAY BE
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO
CEDE & CO. OR SUCH OTHER ENTITY AS MAY BE REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

         Capitalized terms used herein shall have the meanings assigned to them
in the Indenture referred to below unless otherwise indicated.

         1. Interest. Radiologix, Inc., a Delaware corporation (the "Company"),
promises to pay interest on the principal amount of this Note at 10.5% per annum
from December 12, 2001 until maturity. The Company will pay interest
semi-annually in arrears on June 15 and December 15 of each year, or if any such
day is not a Business Day, on the next succeeding Business Day (each an
"Interest Payment Date"). Interest on the Notes will accrue from the most recent
date to which interest has been paid or provided for or, if no interest has been
paid, from the Issue Date; provided, that if there is no existing Default in the
payment of interest, and if this Note is authenticated between a Record Date
(defined below) referred to on the face hereof and the next succeeding Interest
Payment Date, interest shall accrue from such next succeeding Interest Payment
Date; provided, further, that the first Interest Payment Date shall be June 15,
2002. The Company shall pay interest on overdue principal and premium, if any,
from time to time on demand at the rate then in effect; it shall pay interest on
overdue installments of interest (without regard to any applicable grace
periods) from time to time on demand at the same rate to the extent lawful.
Interest will be computed on the basis of a 360-day year of twelve 30-day
months.

         2. Method of Payment. The Company will pay interest on the Notes
(except defaulted interest) to the Persons who are registered Holders of Notes
at the close of business on June 1 or December 1 next preceding the Interest
Payment Date (each a "Record Date"), even if such Notes are cancelled after such
Record Date and on or before such Interest Payment Date, except as provided in

                                       4
<PAGE>

Section 2.12 of the Indenture (as defined below) with respect to defaulted
interest. The Notes will be payable as to principal, premium, if any, and
interest at the office or agency of the Company maintained in the Borough of
Manhattan, The City and State of New York for such purpose, or, at the option of
the Company, payment of interest may be made by check mailed to the Holders at
their addresses set forth in the register of Holders, and provided, that payment
by wire transfer of immediately available funds to an account within the United
States will be required with respect to principal of and interest and premium,
if any, on all Global Notes. Such payment shall be in such coin or currency of
the United States of America as at the time of payment is legal tender for
payment of public and private debts.

         3. Paying Agent and Registrar. Initially, U.S. Bank, N.A., the Trustee
under the Indenture, will act as Paying Agent and Registrar. The Company may
change any Paying Agent or Registrar without notice to any Holder. The Company
or any of its Subsidiaries may act in any such capacity.

         4. Indenture. The Company issued the Notes under an Indenture dated as
of December 12, 2001 ("Indenture") among the Company, the Guarantors party
thereto and the Trustee. The terms of the Notes include those stated in the
Indenture and those made part of the Indenture by reference to the Trust
Indenture Act of 1939, as amended (15 U.S. Code Sections 77aaa-77bbbb). The
Notes are subject to all such terms, and Holders are referred to the Indenture
and such Act for a statement of such terms.

         5. Optional Redemption.

                  (a) Except as set forth in clause (b) of this Section, the
         Company shall not have the option to redeem the Notes pursuant to this
         Section prior to December 15, 2005. The Notes will be redeemable for
         cash at the option of the Company, in whole or in part, at any time on
         or after December 15, 2005, upon not less than 30 days nor more than 60
         days prior notice mailed by first class mail to each Holder at its last
         registered address, at the following redemption prices (expressed as
         percentages of the principal amount) if redeemed during the 12-month
         period commencing December 15 of the years indicated below, in each
         case (subject to the right of Holders of record on a Record Date to
         receive the corresponding interest due on the corresponding Interest
         Payment Date that is on or prior to such Redemption Date), together
         with accrued and unpaid interest thereon to the Redemption Date:

<Table>
<Caption>
        YEAR                                                PERCENTAGE
        ----                                                ----------
<S>                                                 <C>
        2005........................................         105.250%
        2006........................................         102.625%
        2007 and thereafter.........................         100.000%
</Table>

                  (b) Notwithstanding the provisions of clause (a) of this
         Section, at any time or from time to time on or prior to December 15,
         2004, upon any Public Equity Offering, up to 35% of the aggregate
         principal amount of the Notes issued pursuant to the Indenture may be
         redeemed at the option of the Company within 90 days of such Public
         Equity Offering, on not less than 30 days, but not more than 60 days,
         notice to each Holder of the Notes to be redeemed, with cash from the
         Net Cash Proceeds of such Public Equity Offering, at a redemption price
         equal to 110.500% of the principal amount thereof (subject to the right
         of Holders of record on a Record Date to receive the corresponding
         interest due on the Interest Payment Date that is on or prior to such
         Redemption Date), together with accrued and unpaid interest thereon to
         the Redemption Date; provided, however, that immediately following such
         redemption not less than 65% of the aggregate principal amount of the
         Notes originally issued pursuant to the Indenture on the Issue Date
         remain outstanding.

                                       5
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                  (c) Notice of redemption will be mailed by first class mail at
         least 30 days but not more than 60 days before the Redemption Date to
         each Holder whose Notes are to be redeemed at its registered address.
         Notes in denominations larger than $1,000 may be redeemed in part but
         only in integral multiples of $1,000, unless all of the Notes held by a
         Holder are to be redeemed. On and after the Redemption Date, interest
         ceases to accrue on Notes or portions thereof called for redemption
         unless the Company defaults in such payments due on the Redemption
         Date.

         6. Mandatory Redemption. The Company shall not be required to make
mandatory redemption payments with respect to the Notes. The Notes shall not
have the benefit of any sinking fund.

         7. Offers to Purchase.

                  (a) Change of Control. In the event that a Change of Control
         has occurred, each Holder of Notes will have the right, at such
         Holder's option, pursuant to an offer (subject only to conditions
         required by applicable law, if any) by the Company (the "Change of
         Control Offer"), to require the Company to repurchase all or any part
         of such Holder's Notes (provided, that the principal amount of such
         Notes must be $1,000 or an integral multiple thereof) on a date (the
         "Change of Control Purchase Date") that is no later than 60 days after
         the occurrence of such Change of Control, at a cash price equal to 101%
         of the principal amount thereof (the "Change of Control Purchase
         Price"), together with accrued and unpaid interest to the Change of
         Control Purchase Date. The Change of Control Offer shall be made within
         30 days following a Change of Control and shall remain open for 20
         Business Days following its commencement (the "Change of Control Offer
         Period ") or such other period as may be required by applicable law.
         Upon expiration of the Change of Control Offer Period, the Company
         promptly shall purchase all Notes properly tendered in response to the
         Change of Control Offer.

                  On or before the Change of Control Purchase Date, the Company
         shall (i) accept for payment Notes or portions thereof properly
         tendered and not validly withdrawn pursuant to the Change of Control
         Offer, (ii) deposit with the Paying Agent an amount in cash sufficient
         to pay the Change of Control Purchase Price of all Notes so tendered
         and (iii) deliver to the Trustee the Notes so accepted together with an
         Officers' Certificate listing the Notes or portions thereof being
         purchased by the Company. The Paying Agent promptly shall pay the
         Holders of Notes so accepted an amount equal to the Change of Control
         Purchase Price (together with accrued and unpaid interest) and the
         Trustee promptly shall authenticate and deliver to such Holders a new
         Note equal in principal amount to any unpurchased portion of the Note
         surrendered. Any Notes not so accepted will be delivered promptly by
         the Company to the Holder thereof. The Company publicly will announce
         the results of the Change of Control Offer on or as soon as practicable
         after the Change of Control Purchase Date.

                  (b) Asset Sale. Except as otherwise set forth in Section 4.14
         of the Indenture, the Company and the Guarantors shall not, and neither
         the Company nor the Guarantors shall permit any of their respective
         Subsidiaries to, in one or a series of related transactions, convey,
         sell, transfer, assign or otherwise dispose of, directly or indirectly,
         any of their property, business or assets, including by merger or
         consolidation (in the case of a Guarantor or a Subsidiary of the
         Company), and including any sale or other transfer or issuance of any
         Equity Interests of any Subsidiary of the Company, whether by the
         Company or one of its Subsidiaries or through the issuance, sale or
         transfer of Equity Interests by a Subsidiary of the Company, and
         including any sale and leaseback transaction (any of the foregoing, an
         "Asset Sale "), unless: (1) at least 75% of the total consideration for
         such Asset Sale or series of related Asset Sales consists of cash or
         Cash Equivalents; and (2) the Company receives or such Subsidiary
         receives, as applicable, fair market value for such Asset Sale, such
         determination to be made in good faith by the Company's Board of
         Directors for Asset Sales exceeding $2,000,000. Solely for purposes of
         (1) above, (a) any

                                       6
<PAGE>

         Indebtedness (other than Subordinated Indebtedness) of the Company or
         such Subsidiary that is expressly assumed by the transferee in such
         Asset Sale and with respect to which the Company is and its
         Subsidiaries are fully and unconditionally released from any and all
         obligations in connection therewith, (b) property that within 30 days
         of such Asset Sale is converted into cash or Cash Equivalents;
         provided, that such cash and Cash Equivalents shall be treated as Net
         Cash Proceeds attributable to the original Asset Sale for which such
         property was received, and (c) the fair market value, as determined in
         good faith by the Board of Directors, of any asset (other than
         securities) received by the Company or any Subsidiary that, in the good
         faith reasonable judgment of the Company's Board of Directors, will
         immediately constitute or be a part of a Related Business shall be
         deemed to be cash or Cash Equivalents. Within 360 days following such
         Asset Sale, the Net Cash Proceeds therefrom are: (a) invested in fixed
         assets and property (other than notes, bonds, obligations and other
         securities, except in connection with the acquisition of a Guarantor in
         a Related Business) that in the good faith reasonable judgment of the
         Company's Board of Directors will immediately constitute or be a part
         of a Related Business of the Company or such Subsidiary (if it
         continues to be a Subsidiary) immediately following such transaction;
         or (b) used to retire Purchase Money Indebtedness secured by the asset
         that was the subject of the Asset Sale or to permanently reduce the
         amount of Indebtedness outstanding under the Credit Agreement; or (c)
         applied to the optional redemption of the Notes in accordance with the
         terms of the Indenture and the Company's other Indebtedness ranking on
         a parity with the Notes and with similar provisions requiring the
         Company to redeem such Indebtedness with the proceeds from such Asset
         Sale, pro rata in proportion to the respective principal amounts (or
         accreted values in the case of Indebtedness issued with an original
         issue discount) of the Notes and such other Indebtedness then
         outstanding. Pending the final application of any Net Cash Proceeds,
         the Company may temporarily reduce revolving credit borrowings or
         otherwise invest the Net Cash Proceeds in any manner that is not
         prohibited by the Indenture.

                  The accumulated Net Cash Proceeds from Asset Sales not applied
         as set forth in (a), (b) or (c) of the preceding paragraph shall
         constitute "Excess Proceeds". Within 30 days after the date that the
         amount of Excess Proceeds exceeds $10,000,000, the Company shall apply
         the Excess Proceeds (the "Asset Sale Offer Amount") to the repurchase
         of the Notes and such other Indebtedness ranking on a parity with the
         Notes and with similar provisions requiring the Company to make an
         offer to purchase such Indebtedness with the proceeds from such Asset
         Sale pursuant to a cash offer (subject only to conditions required by
         applicable law, if any) (pro rata in proportion to the respective
         principal amounts (or accreted values in the case of Indebtedness
         issued with an original issue discount) of the Notes and such other
         Indebtedness then outstanding) (the "Asset Sale Offer") at a purchase
         price of 100% of the principal amount (or accreted value in the case of
         Indebtedness issued with an original issue discount) (the "Asset Sale
         Offer Price") together with accrued and unpaid interest to the date of
         payment. Each Asset Sale Offer shall remain open for 20 Business Days
         following its commencement (the "Asset Sale Offer Period"). Upon
         expiration of the Asset Sale Offer Period, the Company shall apply the
         Asset Sale Offer Amount plus an amount equal to accrued and unpaid
         interest, if any, to the purchase of all Indebtedness properly tendered
         in accordance with the provisions hereof (on a pro rata basis if the
         Asset Sale Offer Amount is insufficient to purchase all Indebtedness so
         tendered) at the Asset Sale Offer Price (together with accrued
         interest). To the extent that the aggregate amount of Notes and such
         other pari passu Indebtedness tendered pursuant to an Asset Sale Offer
         is less than the Asset Sale Offer Amount, the Company may use any
         remaining Net Cash Proceeds as otherwise permitted by the Indenture
         (other than for making Restricted Payments that are not Investments)
         and following the consummation of each Asset Sale Offer the Excess
         Proceeds amount shall be reset to zero.

         8. Denominations, Transfer, Exchange. The Notes are in registered form
without coupons in denominations of $1,000 and integral multiples of $1,000. The
transfer of Notes may be registered and

                                       7
<PAGE>

Notes may be exchanged as provided in the Indenture. The Registrar and the
Trustee may require a Holder, among other things, to furnish appropriate
endorsements and transfer documents and the Company may require a Holder to pay
any taxes and fees required by law or permitted by the Indenture. The Company
need not exchange or register the transfer of any Note or portion of a Note
selected for redemption, except for the unredeemed portion of any Note being
redeemed in part. Also, it need not exchange or register the transfer of any
Notes for a period of 15 days before a selection of Notes to be redeemed or
during the period between a Record Date and the corresponding Interest Payment
Date.

         9. Persons Deemed Owners. The registered Holder of a Note may be
treated as its owner for all purposes.

         10. Amendment, Supplement and Waiver. Subject to certain exceptions,
the Indenture, the Notes or the Guarantees may be amended or supplemented with
the consent of the Holders of not less than a majority in aggregate principal
amount of the then outstanding Notes, and any existing Default or compliance
with any provision of the Indenture, the Notes or the Guarantees may be waived
with the consent of the Holders of a majority in aggregate principal amount of
the then outstanding Notes. Without the consent of any Holder of a Note, the
Indenture, the Notes or the Guarantees may be amended or supplemented (a) to
cure any ambiguity, defect or inconsistency; (b) to add to the covenants of the
Company or the Guarantors for the benefit of the Holders, or to surrender any
right or power conferred upon the Company or the Guarantors by the Indenture or
herein; (c) to provide for collateral for or additional Guarantors of the Notes;
(d) to evidence the succession of another Person to the Company, and the
assumption by any such successor of the obligations of the Company, herein and
in the Indenture in accordance with the terms of the Indenture; (e) to comply
with the TIA; (f) to evidence the succession of another corporation to any
Guarantor and assumption by any such successor of the Guarantee of such
Guarantor pursuant to the Indenture; (g) to evidence the release of any
Guarantor; (h) to evidence and provide for the acceptance of appointment of a
successor Trustee with respect to the Notes; (i) in any other case where a
supplemental indenture is required or permitted to be entered into pursuant to
the provisions of the Indenture without the consent of any Holder; (j) to
provide for the issuance and authorization of the Exchange Notes; or (k) to make
any change that does not adversely affect the rights of any Holder.

         11. Defaults and Remedies. The Indenture provides that each of the
following constitutes an Event of Default:

                  (a) the Company's failure to pay any installment of interest
         on the Notes as and when the same becomes due and payable and the
         continuance of any such failure for 30 days;

                  (b) the Company's failure to pay all or any part of the
         principal of, or premium, if any, on the Notes when and as the same
         becomes due and payable at maturity, redemption, by acceleration or
         otherwise, including, without limitation, payment of the Change of
         Control Purchase Price or the Asset Sale Offer Price on Notes validly
         tendered and not properly withdrawn pursuant to a Change of Control
         Offer or Asset Sale Offer, as applicable;

                  (c) the Company's failure or the failure by any of its
         Subsidiaries to observe or perform any other covenant or agreement
         contained in the Notes or the Indenture and, except for the provisions
         under Section 4.3 and 4.14 and Articles V and X of the Indenture, the
         continuance of such failure for a period of 60 days after written
         notice is given to the Company by the Trustee or to the Company and the
         Trustee by the Holders of at least 25% in aggregate principal amount of
         the Notes outstanding;

                  (d) a decree, judgment, or order by a court of competent
         jurisdiction shall have been entered adjudicating the Company or any of
         its Significant Subsidiaries as bankrupt or insolvent,

                                       8
<PAGE>

         or approving as properly filed a petition seeking reorganization of the
         Company or any of its Significant Subsidiaries under any bankruptcy or
         similar law, and such decree or order shall have continued undischarged
         and unstayed for a period of 60 days; or a decree, judgment or order of
         a court of competent jurisdiction appointing a receiver, liquidator,
         trustee, or assignee in bankruptcy or insolvency for the Company, any
         of its Significant Subsidiaries, or any substantial part of the
         property of any such Person, or for the winding up or liquidation of
         the affairs of any such Person, shall have been entered, and such
         decree, judgment, or order shall have remained in force undischarged
         and unstayed for a period of 60 days;

                  (e) the Company or any of its Significant Subsidiaries shall
         institute proceedings to be adjudicated a voluntary bankrupt, or shall
         consent to the filing of a bankruptcy proceeding against it, or shall
         file a petition or answer or consent seeking reorganization under any
         bankruptcy or similar law or similar statute, or shall consent to the
         filing of any such petition, or shall consent to the appointment of a
         custodian, receiver, liquidator, trustee, or assignee in bankruptcy or
         insolvency of it or any substantial part of its assets or property, or
         shall make a general assignment for the benefit of creditors, or shall
         admit in writing its inability to pay its debts generally as they
         become due, or take any corporate action in furtherance of any of the
         foregoing;

                  (f) a default in the Company's Indebtedness or the
         Indebtedness of any of its Subsidiaries with an aggregate amount
         outstanding in excess of $10,000,000 (i) resulting from the failure to
         pay principal at maturity or (ii) as a result of which the maturity of
         such Indebtedness has been accelerated prior to its stated maturity;

                  (g) unsatisfied judgments not covered by insurance aggregating
         in excess of $5,000,000 at any one time rendered against the Company or
         any of its Subsidiaries and not stayed, bonded or discharged within 60
         days after such judgment became final and nonappealable; and

                  (h) any Guarantee of a Guarantor that is a Significant
         Subsidiary ceases to be in full force and effect or becomes
         unenforceable or invalid or is declared null and void (other than in
         accordance with the terms of the Guarantee and the Indenture) or any
         Guarantor denies or disaffirms its obligations under its Guarantee.

         12. Trustee Dealings with Company. The Trustee, in its individual or
any other capacity, may make loans to, accept deposits from, and perform
services for the Company or its Affiliates, and may otherwise deal with the
Company or its Affiliates, as if it were not the Trustee.

         13. No Recourse Against Others. No direct or indirect incorporator,
stockholder, employee, officer or director, as such, past, present or future, of
the Company or any Guarantor, or any successor entity, shall have any personal
liability in respect of the obligations of the Company or the Guarantors under
the Notes or the Indenture solely by reason of his or its status as such
incorporator, stockholder, employee, officer or director; provided, that this
Section 13 shall in no way limit the obligation of any Guarantor pursuant to any
Guarantee of the Notes. Each Securityholder by accepting a Note waives and
releases all such liability. The waiver and release are part of the
consideration for the issuance of the Notes.

         14. Authentication. This Note shall not be valid until authenticated by
the manual signature of the Trustee or an authenticating agent.

         15. Abbreviations. Customary abbreviations may be used in the name of a
Holder or an assignee, such as: TEN COM (= tenants in common), TEN ENT (=
tenants by the entireties), JT TEN

                                       9
<PAGE>

(= joint tenants with right of survivorship and not as tenants in common), CUST
(= Custodian), and U/G/M/A (= Uniform Gifts to Minors Act).

         16. CUSIP Numbers. Pursuant to a recommendation promulgated by the
Committee on Uniform Security Identification Procedures, the Company has caused
CUSIP numbers to be printed on the Notes, and the Trustee may use CUSIP numbers
in notices of redemption as a convenience to Holders. No representation is made
as to the accuracy of such numbers either as printed on the Notes or as
contained in any notice of redemption and reliance may be placed only on the
other identification numbers placed thereon, and any such redemption shall not
be affected by any defect in or omission of such numbers.

         17. Notation of Guarantee. As more fully set forth in the Indenture,
each of the Guarantors from time to time, in accordance with the provisions of
the Indenture, shall irrevocably and unconditionally and jointly and severally
guarantee, on a senior basis, in accordance with Article XI of the Indenture, to
each Holder of a Note authenticated and delivered by the Trustee and to the
Trustee and its successors and assigns, that: (a) the principal of, and premium,
if any, and interest on the Notes will be paid in full when due, whether at the
Maturity Date or Interest Payment Date, by acceleration, call for redemption,
upon a Change of Control Offer, upon an Asset Sale Offer or otherwise; (b) all
other obligations of the Company to the Holders or the Trustee under the
Indenture or under the Notes will be promptly paid in full or performed, all in
accordance with the terms of the Indenture and the Notes; and (c) in case of any
extension of time of payment or renewal of any Notes or any of such other
obligations, the same will be promptly paid in full when due or performed in
accordance with the terms of the extension or renewal, whether at maturity, by
acceleration, call for redemption, upon a Change of Control Offer, upon an Asset
Sale Offer or otherwise. Such Guarantees shall cease to apply, and shall be null
and void, with respect to any Guarantor who, pursuant to Article XI of the
Indenture, is released from its Guarantee or whose Guarantee otherwise ceases to
be applicable pursuant to the terms of the Indenture.

         When a successor assumes all the obligations of its predecessor under
the Notes and the Indenture, the predecessor will be released from those
obligations.

         18. Governing Law. THE INDENTURE AND THE NOTES SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, INCLUDING,
WITHOUT LIMITATION, SECTIONS 5-1401 AND 5-1402 OF THE NEW YORK GENERAL
OBLIGATIONS LAW AND RULE 327(b) OF THE NEW YORK CIVIL PRACTICE LAWS AND RULES.

         The Company will furnish to any Holder upon written request and without
charge a copy of the Indenture. Requests may be made to:

                                Radiologix, Inc.
                           3600 JP Morgan Chase Tower
                                2200 Ross Avenue
                               Dallas, Texas 75201
                       Attention: Chief Financial Officer
                          Telephone No.: (214) 303-2777

                                       10
<PAGE>

                                 ASSIGNMENT FORM

To assign this Note, fill in the form below: (I) or (we) assign and transfer
this Note to

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                  (Insert assignee's soc. sec. or tax I.D. no.)

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--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
              (Print or type assignee's name, address and zip code)

and irrevocably appoint ________________________________________________________
to transfer this Note on the books of the Company. The agent may substitute
another to act for him.

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Date:                   Your Signature:
     ---------------                   -----------------------------------------
                                             (Sign exactly as your name appears
                                                  on the face of this Note)

Signature Guarantee*

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*NOTICE: The Signature must be guaranteed by an Institution which is a member of
one of the following recognized signature Guarantee Programs: (i) The Securities
Transfer Agent Medallion Program (STAMP); (ii) The New York Stock Exchange
Medallion Program (MNSP); (iii) The Stock Exchange Medallion Program (SEMP); or
(iv) in such other guarantee program acceptable to the Trustee.

                                       11
<PAGE>

                       OPTION OF HOLDER TO ELECT PURCHASE

         If you want to elect to have this Note purchased by the Company
pursuant to Section 4.14 or 10.1 of the Indenture, check the box below:

                      [ ] Section 4.14    [ ] Section 10.1

         If you want to elect to have only part of the Note purchased by the
Company pursuant to Section 4.14 or Section 10.1 of the Indenture, state the
amount you elect to have purchased (in denominations of $1,000 only, except if
you have elected to have all of your Notes purchased): $___________

Date:                   Your Signature:
     ---------------                   -----------------------------------------
                                             (Sign exactly as your name appears
                                                  on the face of this Note)

Signature Guarantee*

--------------------------------------------------------------------------------

*NOTICE: The Signature must be guaranteed by an Institution which is a member of
one of the following recognized signature Guarantee Programs: (i) The Securities
Transfer Agent Medallion Program (STAMP); (ii) The New York Stock Exchange
Medallion Program (MNSP); (iii) The Stock Exchange Medallion Program (SEMP); or
(iv) in such other guarantee program acceptable to the Trustee.

                                       12
<PAGE>

              SCHEDULE OF EXCHANGES OF INTERESTS IN THE GLOBAL NOTE

         The following exchanges of a part of this Global Note for an interest
in another Global Note or for a Definitive Note, or exchanges of a part of
another Global Note or Definitive Note for an interest in this Global Note, have
been made:

<Table>
<Caption>
                                                                        Principal Amount of       Signature of
                        Amount of decrease in  Amount of increase in     this Global Note      authorized officer
                         Principal Amount of    Principal Amount of       following such       of Trustee or Note
   Date of Exchange       this Global Note        this Global Note    decrease (or increase)        Custodian
   ----------------     ---------------------  ---------------------  ----------------------   ------------------
<S>                     <C>                    <C>                    <C>                      <C>
</Table>

                                       13
<PAGE>

                                    GUARANTEE

         The Guarantors listed below (hereinafter referred to as the
"Guarantors," which term includes any successors or assigns under the Indenture,
dated the date hereof, among the Guarantors, the Company (defined below) and
U.S. Bank, N.A., as trustee (the "Indenture") and any additional Guarantors),
jointly and severally, irrevocably and unconditionally guarantee, in accordance
with Article XI of the Indenture: (i) the due and punctual payment of the
principal of, premium, if any, and interest on the 10.5% Senior Notes due 2008
(the "Notes") of Radiologix, Inc., a Delaware corporation (the "Company"),
whether at the Maturity Date, or Interest Payment Date, by acceleration, call
for redemption, upon a Change of Control Offer, upon an Asset Sale Offer or
otherwise; (ii) the due and punctual payment or performance of all other
obligations of the Company to the Holders or the Trustee under the Indenture and
the Notes, all in accordance with the terms set forth in Article XI of the
Indenture; (iii) in case of any extension of time of payment or renewal of any
Notes or any of such other obligations, that the same will be promptly paid in
full when due or performed in accordance with the terms of the extension or
renewal, whether at maturity, by acceleration, call for redemption, upon a
Change of Control Offer, upon an Asset Sale Offer or otherwise; and (iv) the
payment of any and all costs and expenses (including attorneys' fees) incurred
by the Trustee in enforcing any rights under this Guarantee.

         The obligations of each Guarantor to the Holders and to the Trustee
pursuant to this Guarantee and the Indenture are expressly set forth in Article
XI of the Indenture and reference is hereby made to such Indenture for the
precise terms of this Guarantee.

         No direct or indirect stockholder, employee, officer or director, as
such, past, present or future, of any of the Guarantors, or any successor
entity, shall have any personal liability in respect of the obligations of any
of the Guarantors under the Guarantees or the Indenture solely by reason of his
or its status as such stockholder, employee, officer or director; provided, that
this provision shall in no way limit the obligation of any Guarantor pursuant to
this Guarantee.

         This is a continuing Guarantee and shall remain in full force and
effect and shall be binding upon each Guarantor and its successors and assigns
until full and final payment of all of the Company's obligations under the Notes
and Indenture or until released or legally defeased in accordance with the
Indenture and shall inure to the benefit of the successors and assigns of the
Trustee and the Holders, and, in the event of any transfer or assignment of
rights by any Holder or the Trustee, the rights and privileges herein conferred
upon that party shall automatically extend to and be vested in such transferee
or assignee, all subject to the terms and conditions hereof. This is a Guarantee
of payment and not of collectibility.

         This Guarantee shall not be valid or obligatory for any purpose until
the certificate of authentication on the Note upon which this Guarantee is noted
shall have been executed by the Trustee under the Indenture by the manual
signature of one of its authorized officers.

         The obligations of each Guarantor under its Guarantee shall be limited
to the extent necessary to insure that it does not constitute a fraudulent
conveyance under applicable law.

         THE TERMS OF ARTICLE XI OF THE INDENTURE IS INCORPORATED HEREIN BY
REFERENCE.

         Capitalized terms used herein have the same meanings given in the
Indenture unless otherwise indicated.

                                       14
<PAGE>

         IN WITNESS WHEREOF, each of the Guarantors has caused this instrument
to be duly executed.

Dated:                , 2002
       ---------------
                                        IDE IMAGING PARTNERS, INC.
                                        PACIFIC IMAGING PARTNERS, INC.
                                        QUESTAR IMAGING, INC.
                                        WB&A IMAGING PARTNERS, INC.
                                        TREASURE COAST IMAGING PARTNERS, INC.
                                        RADIOLOGIX SERVICES, INC.
                                        ADVANCED IMAGING PARTNERS, INC.
                                        MID ROCKLAND IMAGING PARTNERS, INC.
                                        RADIOLOGY AND NUCLEAR MEDICINE
                                            IMAGING PARTNERS, INC.
                                        COMMUNITY IMAGING PARTNERS, INC.
                                        VALLEY IMAGING PARTNERS, INC.
                                        ADVANCED RADIOLOGY, LLC
                                        ADVANCED MEDICAL IMAGING, INC.
                                        M&S IMAGING PARTNERS I, INC.
                                        M&S IMAGING PARTNERS, L.P. (BY M&S
                                            IMAGING PARTNERS, INC., ITS GENERAL
                                            PARTNER)
                                        QUESTAR CLEVELAND, INC.
                                        QUESTAR TAMPA, INC.
                                        QUESTAR ORLANDO, INC.
                                        ROCKY MOUNTAIN OPENSCAN MRI, LLC
                                        PREMIER ADVANCED IMAGING NETWORK,
                                            LTD. (BY QUESTAR ORLANDO, INC., ITS
                                            GENERAL PARTNER)
                                        QUESTAR KANSAS, INC.
                                        QUESTAR PVH, INC.
                                        QUESTAR SAN FRANCISCO, INC.
                                        QUESTAR HENDERSON, INC.
                                        QUESTAR TRISTATES, INC.
                                        QUESTAR DULUTH, INC.
                                        QUESTAR LINCOLN, INC.
                                        QUESTAR PALM SPRINGS, INC.
                                        QUESTAR LOWER BUCKS, INC.
                                        QUESTAR TOLEDO, INC.
                                        QUESTAR LOS ALAMITOS, INC.
                                        QUESTAR VICTORVILLE, INC.
                                        QUESTAR COLUMBUS, INC.
                                        QUESTAR NAPERVILLE, INC.
                                        QUESTAR QUAKERTOWN, INC.
                                        QUESTAR TUCSON, INC.

                                        By:
                                           -------------------------------------
                                           Mark L. Wagar
                                           Chairman of the Board and Chief
                                           Executive Officer

                                       15
<PAGE>

                                        M&S IMAGING INVESTMENTS, INC.

                                        By:
                                           -------------------------------------
                                           Mark L. Wagar
                                           Chairman of the Board and Chief
                                           Executive Officer

                                       16<PAGE>
                                                                     EXHIBIT 4.3

                                RADIOLOGIX, INC.

                    $160,000,000 10.5% SENIOR NOTES DUE 2008

                          REGISTRATION RIGHTS AGREEMENT

                                                               December 12, 2001

JEFFERIES & COMPANY, INC.
DEUTSCHE BANC ALEX. BROWN INC.
c/o Jefferies & Company, Inc.
11100 Santa Monica Boulevard
10th Floor
Los Angeles, California  90025

Ladies and Gentlemen:

                  Radiologix, Inc., a Delaware corporation (the "ISSUER"), is
issuing and selling to Jefferies & Company, Inc. and Deutsche Banc Alex. Brown
Inc. (the "INITIAL PURCHASERS"), upon the terms set forth in a purchase
agreement, dated as of December 7, 2001 (the "PURCHASE AGREEMENT"), $160,000,000
aggregate principal amount at maturity of the Issuer's 10.5% Senior Notes due
2008, Series A, including the Guarantees (as defined below) endorsed thereon
(the "NOTES"). As an inducement to the Initial Purchasers to enter into the
Purchase Agreement, the Issuer and each of the guarantors signatory to the
Purchase Agreement (the "GUARANTORS") jointly and severally agree with the
Initial Purchasers, for the benefit of the holders of the Securities (as defined
below) (including, without limitation, the Initial Purchasers), as follows:

1.       DEFINITIONS.

                  Capitalized terms used herein without definition shall have
the respective meanings set forth in the Purchase Agreement. As used in this
Agreement, the following terms shall have the following meanings:

                  ADVICE: See the last paragraph of Section 5.

                  AGREEMENT: This Registration Rights Agreement.

                  APPLICABLE PERIOD: See Section 2(f).

                                       1
<PAGE>

                  BUSINESS DAY: Any day, other than a Saturday, a Sunday or a
day on which banking institutions in The City of New York or at a place of
payment are authorized by law, regulation or executive order to remained closed.

                  CLOSING DATE: December 12, 2001.

                  CONTROLLING PERSON: See Section 7(a).

                  DTC: See Section 5(i).

                  EFFECTIVENESS DATE: The 180th day following the Closing Date.

                  EFFECTIVENESS PERIOD: See Section 3(a).

                  EVENT: See Section 4(a).

                  EVENT DATE: See Section 4(a).

                  EXCHANGE ACT: The Securities Exchange Act of 1934, as amended,
and the rules and regulations of the SEC promulgated thereunder.

                  EXCHANGE OFFER: See Section 2(a).

                  EXCHANGE OFFER REGISTRATION STATEMENT: See Section 2(a).

                  EXCHANGE SECURITIES: 10.5% Senior Notes due 2008, Series B, of
the Issuer, including the guarantees endorsed thereon, identical in all respects
to the Notes and the Guarantees, except for references to series and restrictive
legends.

                  FILING DATE: The 120th day following the Closing Date.

                  GUARANTEES: The full and unconditional guarantee, on a senior
basis by the Guarantors, as to payment of principal, interest, premium, if any,
and the Weekly Liquidated Damages Amount, if any, with respect to the Notes.

                  HOLDER: Each holder of Transfer Restricted Securities.

                  HOLDER INDEMNIFIED PARTIES: See Section 7(a).

                  INDEMNIFIED PARTY: See Section 7(c).

                  INDEMNIFYING PARTIES: See Section 7(c).

                                       2
<PAGE>

                  INDENTURE: The Indenture, dated as of the date hereof, by and
among the Issuer, the Guarantors and U.S. Bank, N.A., as trustee, pursuant to
which the Notes are being issued, as amended or supplemented from time to time,
in accordance with the terms thereof.

                  INITIAL SHELF REGISTRATION: See Section 3(a).

                  LOSSES: See Section 7(a).

                  MAXIMUM CONTRIBUTION AMOUNT: See Section 7(d).

                  NASD: The National Association of Securities Dealers, Inc.

                  PARTICIPATING BROKER-DEALER: See Section 2(f).

                  PERSON: An individual, trustee, corporation, limited liability
company, partnership, limited liability partnership, joint stock company, joint
venture, trust, unincorporated organization or association, government or any
agency or political subdivision thereof, union, business association, firm or
other entity.

                  PRIVATE EXCHANGE: See Section 2(g).

                  PRIVATE EXCHANGE SECURITIES: See Section 2(g).

                  PROSPECTUS: The prospectus included in a Registration
Statement at the time that such Registration Statement is declared effective
(including, without limitation, a prospectus that discloses information
previously omitted from a prospectus filed as part of an effective registration
statement in reliance upon Rule 430A under the Securities Act), as amended or
supplemented by any prospectus supplement with respect to the terms of the
offering of any portion of the Securities covered by such Registration
Statement, and all other amendments and supplements to such prospectus,
including post-effective amendments, and all material incorporated by reference
or deemed to be incorporated by reference in such prospectus.

                  REGISTRATION STATEMENT: Any registration statement of the
Issuer that covers any of the Securities and that is filed pursuant to the
provisions of this Agreement, including the Prospectus included therein, all
amendments and supplements to such registration statement and Prospectus
(including post-effective amendments), all exhibits thereto and all material
incorporated by reference or deemed to be incorporated by reference therein.

                                       3
<PAGE>

                  RULE 144: Rule 144 under the Securities Act, as such rule may
be amended from time to time, or any similar rule (other than Rule 144A) or
regulation hereafter adopted by the SEC.

                  RULE 144A: Rule 144A under the Securities Act, as such rule
may be amended from time to time, or any similar rule (other than Rule 144) or
regulation hereafter adopted by the SEC.

                  RULE 415: Rule 415 under the Securities Act, as such rule may
be amended from time to time, or any similar rule or regulation hereafter
adopted by the SEC.

                  SEC: The Securities and Exchange Commission.

                  SECURITIES: The Notes, the Private Exchange Securities and the
Exchange Securities, collectively.

                  SECURITIES ACT: The Securities Act of 1933, as amended, and
the rules and regulations of the SEC promulgated thereunder.

                  SHELF EFFECTIVENESS DATE: With respect to a Shelf
Registration, the 90th day after the filing of such Shelf Registration.

                  SHELF FILING DATE: With respect to a Shelf Registration, the
30th day following delivery of the Shelf Notice triggering the obligation to
file such Shelf Registration.

                  SHELF NOTICE: See Section 2(i).

                  SHELF REGISTRATION: The Initial Shelf Registration and any
Subsequent Shelf Registration.

                  SPECIAL COUNSEL: Counsel chosen by the holders of a majority
in aggregate principal amount of Securities.

                  SUBSEQUENT SHELF REGISTRATION: See Section 3(b).

                  TIA: The Trust Indenture Act of 1939, as amended.

                  TRANSFER RESTRICTED SECURITIES: Each Security until (i) the
date on which such Security has been exchanged by a person other than a
Participating Broker-Dealer for an Exchange Security in the Exchange Offer; (ii)
following receipt of an Exchange Security by a Participating Broker-Dealer in
the Exchange Offer, the

                                       4
<PAGE>
date on which such Exchange Security is sold to a purchaser who receives from
such Participating Broker-Dealer on or prior to the date of such sale a copy of
the Prospectus contained in the Exchange Offer Registration Statement, (iii) the
date on which such Security has been effectively registered under the Securities
Act and disposed of in accordance with the Shelf Registration or (iv) the date
on which such Security is distributed to the public pursuant to Rule 144 under
the Securities Act or may be distributed to the public pursuant to Rule 144(k)
under the Securities Act.

                  TRUSTEE: The trustee under the Indenture and, if any, the
trustee under any indenture governing the Exchange Securities or the Private
Exchange Securities.

                  UNDERWRITTEN REGISTRATION or UNDERWRITTEN OFFERING: A
registration in which securities of the Issuer are sold to an underwriter for
reoffering to the public.

                  WEEKLY LIQUIDATED DAMAGES AMOUNT: With respect to any Event,
an amount per week per $1,000 principal amount of Transfer Restricted Securities
equal to $0.05 for the first 90-day period immediately following the applicable
Event Date, increasing by an additional $0.05 per week per $1,000 principal
amount of Transfer Restricted Securities with respect to each subsequent 90-day
period, up to a maximum amount of $0.25 per week per $1,000 principal amount of
Transfer Restricted Securities.

2.       EXCHANGE OFFER.

         (a) The Issuer and the Guarantors shall:

                  (i) prepare and file with the SEC as soon as practicable after
the date hereof, but in no event later than the Filing Date, a registration
statement (the "EXCHANGE OFFER REGISTRATION STATEMENT") on an appropriate form
under the Securities Act with respect to a proposed offer (the "EXCHANGE OFFER")
to the Holders to issue and deliver to such Holders, in exchange for the Notes,
a like aggregate principal amount of Exchange Securities;

                  (ii) use their respective best efforts to cause the Exchange
Offer Registration Statement to become effective on or prior to the
Effectiveness Date;

                  (iii) use their respective best efforts to keep the Exchange
Offer Registration Statement effective until the consummation of the Exchange
Offer pursuant to its terms; and

                                       5
<PAGE>

                  (iv) unless the Exchange Offer would not be permitted by
applicable law or by a policy of the SEC, commence the Exchange Offer and use
their respective best efforts to, on or prior to the 30th Business Day after the
Exchange Offer Registration Statement is declared effective, consummate the
Exchange Offer and issue Exchange Securities in exchange for all Notes tendered
prior thereto in the Exchange Offer.

The Exchange Offer shall not be subject to any conditions, other than that the
Exchange Offer does not violate applicable law or any applicable interpretation
of the staff of the SEC.

         (b) The Exchange Securities shall be issued under, and entitled to the
benefits of, the Indenture or a trust indenture that is identical to the
Indenture (other than such changes as are necessary to comply with any
requirements of the SEC to effect or maintain the qualification thereof under
the TIA).

         (c) In connection with the Exchange Offer, the Issuer and the
Guarantors shall:

                  (i) mail to each Holder a copy of the Prospectus forming part
of the Exchange Offer Registration Statement, together with an appropriate
letter of transmittal that is an exhibit to the Exchange Offer Registration
Statement, and any related documents;

                  (ii) keep the Exchange Offer open for not less than 20
Business Days after the date notice thereof is mailed to the Holders (or longer
if required by applicable law);

                  (iii) utilize the services of a depositary for the Exchange
Offer with an address in the Borough of Manhattan, The City of New York;

                  (iv) permit Holders to withdraw tendered Notes at any time
prior to the close of business, New York time, on the last Business Day on which
the Exchange Offer shall remain open; and

                  (v) otherwise comply with all laws applicable to the Exchange
Offer.

         (d) As soon as practicable after the close of the Exchange Offer, the
Issuer and the Guarantors shall:

                  (i) accept for exchange all Notes validly tendered and not
properly withdrawn pursuant to the Exchange Offer;

                                       6
<PAGE>

                  (ii) deliver to the Trustee for cancellation all Notes so
accepted for exchange; and

                  (iii) cause the Trustee promptly to authenticate and deliver
to each Holder of Notes, Exchange Securities equal in aggregate principal amount
to the Notes of such Holder so accepted for exchange.

         (e) Interest on each Exchange Security and each Private Exchange
Security will accrue from the last interest payment date on which interest was
paid on the Notes surrendered in exchange therefor or, if no interest has been
paid on the Notes, from the date of original issue of the Notes. Each Exchange
Security and each Private Exchange Security shall bear interest at the rate set
forth thereon; provided, that interest with respect to the period prior to the
issuance thereof shall accrue at the rate or rates borne by the Notes
surrendered in exchange therefor from time to time during such period.

         (f) The Issuer and the Guarantors shall include within the Prospectus
contained in the Exchange Offer Registration Statement a section entitled "Plan
of Distribution," containing a summary statement of the positions taken or
policies made by the staff of the SEC with respect to the potential
"underwriter" status of any broker-dealer that is the beneficial owner (as
defined in Rule 13d-3 under the Exchange Act) of Exchange Securities received by
such broker-dealer in the Exchange Offer (a "PARTICIPATING BROKER-DEALER"). Such
"Plan of Distribution" section shall also allow the use of the Prospectus by all
Persons subject to the prospectus delivery requirements of the Securities Act,
including (without limitation) all Participating Brokers-Dealers, and include a
statement describing the means by which Participating Broker-Dealers may resell
the Exchange Securities. The Issuer and the Guarantors shall use their
respective best efforts to keep the Exchange Offer Registration Statement
continuously effective and to amend and supplement the Prospectus to be lawfully
delivered by all Persons subject to the prospectus delivery requirement of the
Securities Act for such period of time as any such Person must comply with such
prospectus delivery requirement in order to resell the Exchange Securities;
provided that such period shall not exceed 180 days after consummation of the
Exchange Offer (as such period may be extended pursuant to the last paragraph of
Section 5 hereof)(the "APPLICABLE PERIOD").

         (g) If, prior to consummation of the Exchange Offer, any Initial
Purchaser holds any Notes acquired by it and having the status as an unsold
allotment in the initial distribution of the Notes, the Issuer and the
Guarantors shall, upon the request of such Initial Purchaser, simultaneously
with the delivery of the

                                       7
<PAGE>

Exchange Securities in the Exchange Offer, issue (pursuant to the same indenture
as the Exchange Securities and subject to transfer restrictions thereon) and
deliver to such Initial Purchaser, in exchange for the Notes held by such
Initial Purchaser (the "PRIVATE EXCHANGE"), a like principal amount of debt
securities of the Issuer, including guarantees endorsed thereon, that are
identical to the Exchange Securities (the "PRIVATE EXCHANGE SECURITIES"). The
Private Exchange Securities shall bear the same CUSIP number as the Exchange
Securities.

         (h) The Issuer may require each Holder participating in the Exchange
Offer to represent to the Issuer and the Guarantors that, at the time of the
consummation of the Exchange Offer: (i) any Exchange Securities received by such
Holder in the Exchange Offer will be acquired in the ordinary course of its
business; (ii) such Holder will have no arrangement or understanding with any
Person to participate in the distribution of the Exchange Securities within the
meaning of the Securities Act or the resale of the Exchange Securities in
violation of the Securities Act; (iii) if such Holder is not a broker-dealer,
that it is not engaged in and does not intend to engage in, the distribution of
the Exchange Securities; (iv) if such Holder is a broker-dealer that will
receive Exchange Securities for its own account in exchange for Notes that were
acquired as a result of market-making or other trading activities, that it will
deliver a prospectus, as required by law, in connection with any resale of such
Exchange Securities; and (v) if such Holder is an affiliate of the Issuer, that
it will comply with the registration and prospectus delivery requirements of the
Securities Act applicable to it.

         (i) If: (i) the Issuer and the Guarantors are not required to file an
Exchange Offer Registration Statement or permitted to consummate the Exchange
Offer because the Exchange Offer is not permitted by applicable law or SEC
policy (after compliance with the procedures set forth in Section 5 below); (ii)
subsequent to the consummation of the Private Exchange, any Holder of Private
Exchange Securities so requests; (iv) the Exchange Offer is not consummated for
any reason within 30 Business Days of the Effectiveness Date; or (v) in the case
of (A) any Holder prohibited by applicable law or SEC policy from participating
in the Exchange Offer, (B) any Holder participating in the Exchange Offer that
receives Exchange Securities that may not be sold by such Holder to the public
without delivering a prospectus and the Prospectus contained in the Exchange
Offer Registration Statement is not available for such resales, or (C) any
broker-dealer that holds Notes acquired directly from the Issuer or any of its
affiliates and, in each such case contemplated by this clause (v), such Holder
notifies the Issuer within 20 Business Days of consummation of the Exchange
Offer, then the Issuer shall, within five Business Days thereof, deliver to the
Holders and the Trustee notice thereof (the "SHELF NOTICE") and shall as soon as
possible thereafter (and in any event on or prior to the Shelf Filing Date) file
an Initial Shelf Registration pursuant to Section 3.

                                       8
<PAGE>

3.       SHELF REGISTRATION.

                  If at any time a Shelf Notice is required to be delivered
pursuant to Section 2(i), then:

         (a) Initial Shelf Registration. The Issuer and the Guarantors shall
prepare and file with the SEC a Registration Statement for an offering to be
made on a continuous basis pursuant to Rule 415 covering all of the Transfer
Restricted Securities (the "INITIAL SHELF REGISTRATION") subject to the Issuer's
right pursuant to Section 3(c) to exclude the Transfer Restricted Securities of
Holders that have not provided the information required to be furnished by such
Holders pursuant to Section 3(c) hereof. The Issuer and the Guarantors shall
file with the SEC the Initial Shelf Registration as soon as possible following
the occurrence of the event described in Section 2(i) that triggered such filing
obligation, but in no event later than the Shelf Filing Date. The Initial Shelf
Registration shall be on Form S-1 or another appropriate form permitting
registration of such Transfer Restricted Securities for resale by such Holders
in the manner or manners designated by them (including, without limitation, one
or more underwritten offerings). The Issuer and the Guarantors (i) shall not
permit any securities other than the Transfer Restricted Securities to be
included in any Shelf Registration, and (ii) shall use their respective best
efforts to cause the Initial Shelf Registration to be declared effective under
the Securities Act on or prior to the Shelf Effectiveness Date) and to keep the
Initial Shelf Registration continuously effective under the Securities Act until
the date that is 24 months after the Closing Date (subject to extension pursuant
to the last paragraph of Section 5 hereof) (the "EFFECTIVENESS PERIOD"), or such
shorter period ending when (i) all Transfer Restricted Securities covered by the
Initial Shelf Registration have been sold in the manner set forth and as
contemplated in the Initial Shelf Registration, (ii) a Subsequent Shelf
Registration covering all of the Transfer Restricted Securities covered by and
not sold under the Initial Shelf Registration or an earlier Subsequent Shelf
Registration has been declared effective under the Securities Act; provided,
however, that the Effectiveness Period in respect of the Initial Shelf
Registration shall be extended to the extent required to permit dealers to
comply with the applicable prospectus delivery requirements of Rule 174 under
the Securities Act and as otherwise provided herein and shall be subject to
reduction to the extent that the applicable provisions of Rule 144 are amended
or revised, (iii) such Transfer Restricted Securities are eligible for resale
pursuant to Rule 144(k) under the Securities Act or (iv) there cease to be any
outstanding Transfer Restricted Securities.

                                       9
<PAGE>

         (b) Subsequent Shelf Registrations. If any Shelf Registration ceases to
be effective for any reason at any time during the Effectiveness Period (other
than because of the sale of all of the Transfer Restricted Securities registered
thereunder), the Issuer and the Guarantors shall use their respective best
efforts to obtain the prompt withdrawal of any order suspending the
effectiveness thereof, and in any event shall within 30 days of such cessation
of effectiveness file an amendment to the Shelf Registration in a manner
reasonably expected to obtain the withdrawal of the order suspending the
effectiveness thereof, or file an additional "shelf" Registration Statement
pursuant to Rule 415 covering all of the Transfer Restricted Securities (a
"SUBSEQUENT SHELF REGISTRATION"). If a Subsequent Shelf Registration is filed,
the Issuer and the Guarantors shall use their respective best efforts to cause
the Subsequent Shelf Registration to be declared effective as soon as
practicable after such filing and to keep such Subsequent Shelf Registration
continuously effective for a period equal to the number of days in the
Effectiveness Period less the aggregate number of days during which the Initial
Shelf Registration, and any previously filed Subsequent Shelf Registration, were
previously effective.

         (c) Provision of Information. The Issuer and the Guarantors may exclude
from any Shelf Registration the Transfer Restricted Securities of any Holder
who, without reasonable basis, fails to furnish to the Issuer in writing, within
20 days after receipt of a written request therefor, the information specified
in Item 507 or 508, as applicable, of Regulation S-K under the Securities Act
for use in connection with any Shelf Registration or Prospectus or preliminary
Prospectus included therein. No such Holder shall be entitled to liquidated
damages pursuant to Section 4 unless and until such Holder shall have provided
all such information. Each Holder whose Transfer Restricted Securities are to be
included in a Shelf Registration Statement agrees to furnish to the Issuer all
additional information required to be disclosed in order to make the information
previously furnished to the Issuer by such Holder not materially misleading.

4.       LIQUIDATED DAMAGES.

         (a) The Issuer and the Guarantors acknowledge and agree that the
Holders will suffer damages, and that it would not be feasible to ascertain the
extent of such damages with precision, if the Issuer and the Guarantors fail to
fulfill their respective obligations hereunder. Accordingly, in the event of
such failure, the Issuer and the Guarantors jointly and severally agree to pay
liquidated damages to each Holder under the circumstances and to the extent set
forth below:

                  (i) if the Exchange Offer Registration Statement has not been
filed with the SEC on or prior to the Filing Date;

                  (ii) if the Exchange Offer Registration Statement is not
declared effective by the SEC on or prior to the Effectiveness Date; or

                                       10
<PAGE>

                  (iii) if the Exchange Offer is not consummated on or before
the 30th Business Day after the date on which the Exchange Offer Registration
Statement is declared effective by the SEC;

                  (iv) if an Exchange Offer Registration Statement is filed and
declared effective by the SEC but thereafter ceases to be effective during the
Applicable Period;

                  (v) if obligated to file a Shelf Registration and the Issuer
and the Guarantors fail to file such Shelf Registration with the SEC on or prior
to the Shelf Filing Date;

                  (vi) if a Shelf Registration is filed and such Shelf
Registration is not declared effective on or prior to the Shelf Effectiveness
Date; or

                  (vii) if a Shelf Registration is filed and declared effective
by the SEC but thereafter ceases to be effective during the Effectiveness
Period;

(each of the foregoing an "EVENT," and the date on which the Event occurs being
referred to herein as an "EVENT DATE").

                  Upon the occurrence of any Event, the Issuer shall pay, or
cause to be paid (and the Guarantors hereby guarantee the payment of), in
addition to amounts otherwise due under the Indenture and the Transfer
Restricted Securities, as liquidated damages, and not as a penalty, to each
Holder for each weekly period beginning on the Event Date an amount equal to the
Weekly Liquidated Damages Amount per $1,000 principal amount of Transfer
Restricted Securities held by such Holder; provided, that such liquidated
damages will, in each case, cease to accrue (subject to the occurrence of
another Event) on the date on which all Events have been cured. The Issuer and
the Guarantors shall not be required to pay liquidated damages for more than one
Event at any given time. An Event under clause (i) above shall be cured on the
date that the Exchange Offer Registration Statement (or, if an Initial Shelf
Registration is required to be filed pursuant to clause (i) or (ii) of Section
2(i), the date that such Initial Shelf Registration) is filed with the SEC; an
Event under clause (ii) above shall be cured on the date that the Exchange Offer
Registration Statement (or, if an Initial Shelf Registration is required to be
filed pursuant to clause (i) or (ii) of Section 2(i), the date that such Initial
Shelf Registration) is declared effective by the SEC; an Event under clause
(iii) above shall be cured on the earlier of the date (A) the Exchange Offer is
consummated with respect to all Notes validly tendered or (B) the Issuer
delivers a Shelf Notice to the

                                       11
<PAGE>

Holders and the Trustee pursuant to clause (i) or (ii) of Section 2(i); an Event
under clause (iv) above shall be cured on the date on which the Exchange Offer
Registration Statement is no longer subject to an order suspending the
effectiveness thereof or proceedings relating thereto; an Event under clause (v)
above shall be cured on the date that such Shelf Registration is filed with the
SEC; an Event under clause (vi) above shall be cured on the date that such Shelf
Registration is declared effective by the SEC; and an Event under clause (vii)
above shall be cured on the earlier of (A) the date on which the applicable
Shelf Registration is no longer subject to an order suspending the effectiveness
thereof or proceedings relating thereto or (B) a new Subsequent Shelf
Registration is declared effective.

         (b) The Issuer shall notify the Trustee of the occurrence of an Event
within five Business Days after each Event Date. The Issuer shall pay the
liquidated damages due on the Transfer Restricted Securities by depositing with
the Trustee, in trust, for the benefit of the Holders thereof, by 12:00 noon,
New York City time, on or before the applicable semi-annual interest payment
date for the Transfer Restricted Securities, immediately available funds in sums
sufficient to pay the liquidated damages then due. The liquidated damages amount
due shall be payable in the same manner as interest payments on the Notes on
each interest payment date to the record Holder entitled to receive the interest
payment to be made on such date as set forth in the Indenture.

5.       REGISTRATION PROCEDURES.

                  In connection with the registration of any Securities pursuant
to Sections 2 or 3 hereof, the Issuer and the Guarantors shall effect such
registrations to permit the sale of such Securities in accordance with the
intended method or methods of disposition thereof, and pursuant thereto the
Issuer and the Guarantors shall:

         (a) Prepare and file with the SEC, as soon as practicable after the
date hereof but in any event on or prior to the Filing Date, with respect to an
Exchange Offer Registration Statement, and on or prior to the Shelf Filing Date,
with respect to a Shelf Registration, as prescribed by Sections 2 and 3,
respectively, and use their respective best efforts to cause each such
Registration Statement to become effective and remain continuously effective for
the Applicable Period or Effectiveness Period, as applicable, as provided in
this Agreement; provided, that if (i) such filing is pursuant to Section 3 or
(ii) a Prospectus contained in an Exchange Offer Registration Statement filed
pursuant to Section 2 is required to be delivered under the Securities Act by
any Participating Broker-Dealer who seeks to sell Exchange Securities during the
Applicable Period, before filing any Registration Statement or Prospectus or any
amendments or supplements thereto, (A) the Issuer shall notify the Holders of
the Transfer Restricted Securities covered by such Registration

                                       12
<PAGE>

Statement, their Special Counsel, each Participating Broker-Dealer, the managing
underwriters, if any, and their counsel of such filing at least five Business
Days prior to making such filing, (B) if requested, the Issuer and the
Guarantors shall furnish to and afford the Holders of the Transfer Restricted
Securities covered by such Registration Statement, their Special Counsel, each
Participating Broker-Dealer, the managing underwriters, if any, and their
counsel a reasonable opportunity to review, and shall make available for
inspection by such Persons, copies of all such documents (including copies of
any documents to be incorporated by reference therein and all exhibits thereto)
proposed to be filed and such financial and other information and books and
records of the Issuer and the Guarantors, as shall be necessary, in the opinion
of Special Counsel and the respective counsels to such Participating
Broker-Dealers and underwriters, to conduct a reasonable due diligence
investigation within the meaning of the Securities Act, and (C) the Issuer and
the Guarantors shall cause the members, managers, officers, directors and
employees of the Issuer and the Guarantors, and counsel and independent
certified public accountants of the Issuer and the Guarantors, to respond to
such inquiries, as shall be necessary, in the opinion of Special Counsel and the
respective counsels to such Participating Broker-Dealers and underwriters, to
conduct a reasonable due diligence investigation within the meaning of the
Securities Act. The Issuer and the Guarantors may require each Holder to enter
into a customary confidentiality agreement prepared by the Issuer and the
Guarantors and reasonably acceptable in form and substance to such Holders, that
requires such Holders to keep confidential any non-public information relating
to the Issuer and the Guarantors received by such Holder, to refrain from using
such information as the basis for any market transactions in the securities of
the Issuer and not to disclose such information (other than to an affiliate or
prospective purchaser who agrees in writing to respect the confidentiality
provisions of this Section 5(a)) until such information has been made generally
available to the public unless the release of such information is required by
law or necessary to respond to inquiries of regulatory authorities. The Issuer
and the Guarantors shall not file any Registration Statement or Prospectus or
any amendments or supplements thereto that the Holders must be afforded an
opportunity to review prior to the filing of such document, if the Holders of a
majority in aggregate principal amount of the Transfer Restricted Securities
covered by such Registration Statement, their Special Counsel, any Participating
Broker-Dealer or the managing underwriters, if any, or their counsel shall
reasonably object to such filing within five Business Days after receipt of the
Issuer's notice of filing described above in this Section 5(a). A Holder shall
be deemed to have reasonably objected to such filing if such Registration
Statement, amendment, Prospectus or supplement, as applicable, as proposed to be
filed, contains an untrue statement of a material fact or omits to state any
material fact necessary to make the statements therein not misleading or fails
to comply with the applicable requirements of the Securities Act.

                                       13
<PAGE>

         (b) Provide an indenture trustee for the Transfer Restricted Securities
or the Exchange Securities, as the case may be, and cause the Indenture (or
other indenture relating to the Transfer Restricted Securities) to be qualified
under the TIA not later than the effective date of the first Registration
Statement; in connection therewith, effect such changes to such indenture as may
be required for such indenture to be so qualified in accordance with the terms
of the TIA; and execute, and use their respective best efforts to cause such
trustee to execute, all documents as may be required to effect such changes, and
all other forms and documents required to be filed with the SEC to enable such
indenture to be so qualified in a timely manner.

         (c) Prepare and file with the SEC such pre-effective amendments and
post-effective amendments to the Registration Statement as may be necessary in
order to cause the Registration Statement to become effective and to keep such
Registration Statement continuously effective for the time periods required
hereby; cause the related Prospectus to be supplemented by any Prospectus
supplement required by applicable law, and as so supplemented to be filed
pursuant to Rule 424 (or any similar provisions then in force) under the
Securities Act, and comply in all material respects with Rules 424, 430A and
462, as applicable, under the Securities Act; and comply in all material
respects with the provisions of the Securities Act and the Exchange Act
applicable thereto with respect to the disposition of all securities covered by
such Registration Statement, as so amended, or in such Prospectus, as so
supplemented, in accordance with the intended methods of distribution set forth
in such Registration Statement, as so amended, and such Prospectus, as so
supplemented.

         (d) Furnish to such selling Holders and Participating Broker-Dealers
who so request (i) upon the Issuer's and the Guarantors' receipt, a copy of the
order of the SEC declaring such Registration Statement and any post-effective
amendment thereto effective, (ii) such reasonable number of copies of such
Registration Statement and of each amendment and supplement thereto (in each
case including any documents incorporated therein by reference and all exhibits
(including exhibits incorporated by reference) to such Registration Statement
and each such amendment and supplement), (iii) such reasonable number of copies
of the Prospectus included in such Registration Statement (including each
preliminary prospectus and each supplement thereto), and such reasonable number
of copies of the final Prospectus as filed by the Issuer and the Guarantors
pursuant to Rule 424(b) under the Securities Act, in conformity in all material
respects with the applicable requirements of the Securities Act, and (iv) such
other documents (including any amendments and supplements required to be filed
pursuant to Section 5(c) and any documents incorporated therein by reference and
all exhibits thereto, including exhibits

                                       14
<PAGE>

incorporated by reference), as any such Person may reasonably request. The
Issuer and the Guarantors hereby consent to the use (in accordance with
applicable law) of the Prospectus by each of the selling Holders of Transfer
Restricted Securities and by each such Participating Broker-Dealer, as the case
may be, and the underwriters or agents, if any, and dealers (if any), in
connection with the offering and sale of the Transfer Restricted Securities
covered by, or the sale by Participating Broker-Dealers of the Exchange
Securities pursuant to, such Prospectus and any amendment or supplement thereto.

         (e) If (A) a Shelf Registration is filed pursuant to Section 3 or (B) a
Prospectus contained in an Exchange Offer Registration Statement filed pursuant
to Section 2 is required to be delivered under the Securities Act by any
Participating Broker-Dealer who seeks to sell Exchange Securities during the
Applicable Period, notify the selling Holders of Transfer Restricted Securities,
their Special Counsel, each Participating Broker-Dealer and the managing
underwriters, if any, as soon as practicable (but in any event within five
Business Days), and, if requested by such Person, confirm such notice in
writing, (i) when a Prospectus or any Prospectus supplement or Registration
Statement or post-effective amendment has been filed, and, with respect to a
Registration Statement or any post-effective amendment, when the same has become
effective under the Securities Act, (ii) of the issuance by the SEC of any stop
order suspending the effectiveness of a Registration Statement or of any order
preventing or suspending the use of any Prospectus or the initiation of any
proceedings for that purpose, (iii) if, at any time when a Prospectus is
required by the Securities Act to be delivered in connection with sales of the
Transfer Restricted Securities, the representations and warranties of the Issuer
and the Guarantors contained in any agreement (including any underwriting
agreement) contemplated by Section 5(n) below cease to be true and correct in
any material respect, (iv) of the receipt by the Issuer or any of the Guarantors
of any notification with respect to the suspension of the qualification or
exemption from qualification of a Registration Statement or any of the Transfer
Restricted Securities or the Exchange Securities to be sold by any Participating
Broker-Dealer for offer or sale in any jurisdiction, or the contemplation,
initiation or threatening of any proceeding for such purpose, (v) of the
happening of any event that makes any statement made in such Registration
Statement or related Prospectus or any document incorporated or deemed to be
incorporated therein by reference to be untrue in any material respect or that
requires the making of any additions to or changes in such Registration
Statement, Prospectus or documents so that it will not 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, in light of the
circumstances under which such statements were made, not misleading, (vi) of the
Issuer's and the Guarantors' reasonable determination that a post-effective
amendment to a Registration Statement would be

                                       15
<PAGE>

appropriate, and (vii) of any request by the SEC for amendments to the
Registration Statement or supplements to the Prospectus or for additional
information relating thereto.

         (f) Use their respective best efforts to register or qualify, and, if
applicable, to cooperate with the selling Holders of Transfer Restricted
Securities, the underwriters, if any, and their respective counsel in connection
with the registration or qualification (or exemption from such registration or
qualification) of, Transfer Restricted Securities to be included in a
Registration Statement for offer and sale under the securities or Blue Sky laws
of such jurisdictions within the United States as any selling Holder,
Participating Broker-Dealer or the managing underwriters, if any, reasonably
request in writing; and, if Securities are offered other than through an
Underwritten Offering, the Issuer and the Guarantors shall cause their
respective counsel to perform Blue Sky investigations and file registrations and
qualifications required to be filed pursuant to this Section 5(f) at the expense
of the Issuer and the Guarantors; keep each such registration or qualification
(or exemption therefrom) effective during the period such Registration Statement
is required to be kept effective and do any and all other acts or things
necessary or advisable to enable the disposition in such jurisdictions of the
Securities covered by the applicable Registration Statement; provided, however,
that neither the Issuer nor any Guarantor shall be required to (i) register or
qualify generally to do business in any jurisdiction where it is not then so
qualified, (ii) take any action that would subject it to general service of
process in any jurisdiction where it is not then so subject or (iii) take any
action that would subject it to general taxation in respect of doing business in
any such jurisdiction where it is not then so subject.

         (g) Use their respective commercially reasonable efforts to prevent the
issuance of any order suspending the effectiveness of a Registration Statement
or preventing or suspending the use of a Prospectus or suspending the
qualification (or exemption from qualification) of any of the Securities for
sale in any jurisdiction, and, if any such order is issued, use their respective
best efforts to obtain the withdrawal or lifting of any such order at the
earliest possible time.

         (h) If (i) a Shelf Registration is filed pursuant to Section 3 or (ii)
a Prospectus contained in an Exchange Offer Registration Statement filed
pursuant to Section 2 is required to be delivered under the Securities Act by
any Participating Broker-Dealer who seeks to sell Exchange Securities during the
Applicable Period, and if requested by the managing underwriters, if any, such
Participating Broker-Dealer or the Holders of a majority in aggregate principal
amount of the Transfer Restricted Securities, (A) promptly incorporate in a
Prospectus supplement or post-effective amendment such information as the
managing underwriters, if any, or such

                                       16
<PAGE>

Holders reasonably request to be included therein as required to comply with any
applicable law and (B) make all required filings of such Prospectus supplement
or such post-effective amendment as soon as practicable after the Issuer and the
Guarantors have received notification of such matters required by applicable law
to be incorporated in such Prospectus supplement or post-effective amendment.

         (i) If (i) a Shelf Registration is filed pursuant to Section 3 or (ii)
a Prospectus contained in an Exchange Offer Registration Statement filed
pursuant to Section 2 is required to be delivered under the Securities Act by
any Participating Broker-Dealer who seeks to sell Exchange Securities during the
Applicable Period, cooperate with the selling Holders, such Participating
Broker-Dealer and the managing underwriters, if any, to facilitate the
preparation and delivery of certificates representing Transfer Restricted
Securities to be sold, which certificates shall not bear any restrictive legends
and shall be in a form eligible for deposit with The Depository Trust Company
("DTC"); and enable such Transfer Restricted Securities to be in such
denominations and registered in such names as the managing underwriters, if any,
such Participating Broker-Dealer or the Holders may request.

         (j) If (i) a Shelf Registration is filed pursuant to Section 3 or (ii)
a Prospectus contained in an Exchange Offer Registration Statement filed
pursuant to Section 2 is required to be delivered under the Securities Act by
any Participating Broker-Dealer who seeks to sell Exchange Securities during the
Applicable Period, upon the occurrence of any event contemplated by Section
5(e)(v), 5(e)(vi) or 5(e)(vii), soon as practicable prepare a post-effective
amendment to the Registration Statement, a supplement to the related Prospectus
or a supplement or amendment to any such document incorporated or deemed to be
incorporated therein by reference, or file any other required document so that,
as thereafter delivered to the purchasers of the Transfer Restricted Securities
being sold thereunder or to the purchasers of the Exchange Securities to whom
such Prospectus will be delivered by a Participating Broker-Dealer, such
Prospectus will not contain an 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, in light of the circumstances under which they were made,
not misleading, and, if SEC review is required, use their respective best
efforts to cause such post-effective amendment to be declared effective as soon
as practicable.

         (k) Use their respective best efforts to cause the Securities covered
by a Registration Statement to be rated with the appropriate rating agencies, if
appropriate, and if so requested by the holders of a majority in aggregate
principal amount of Securities covered by such Registration Statement or the
managing underwriters, if any.

                                       17
<PAGE>

         (l) Prior to the effective date of the first Registration Statement
relating to the Securities, (i) provide the applicable trustee with printed
certificates for the Securities in a form eligible for deposit with DTC and (ii)
provide a CUSIP number for each of the Securities.

         (m) Use their respective best efforts to cause all Securities covered
by such Registration Statement to be listed on each securities exchange, if any,
on which similar debt securities issued by the Issuer are then listed.

         (n) If a Shelf Registration is filed pursuant to Section 3, enter into
such customary agreements (including, if requested, an underwriting agreement in
form, scope and substance as is customary in Underwritten Offerings) and take
all such other actions in connection therewith (including those reasonably
requested by the managing underwriters, if any, or the Holders of a majority in
aggregate principal amount of Transfer Restricted Securities being sold) in
order to expedite or facilitate the registration or the disposition of such
Transfer Restricted Securities, and in such connection, whether or not an
underwriting agreement is entered into and whether or not the registration is an
Underwritten Registration, (i) make such representations and warranties to the
Holders and the underwriters, if any, with respect to the business of the Issuer
and its respective subsidiaries, and the Registration Statement, Prospectus and
documents, if any, incorporated or deemed to be incorporated by reference
therein, in each case, in form, substance and scope as are customarily made by
issuers to underwriters in Underwritten Offerings, and confirm the same if and
when reasonably requested; (ii) obtain opinions of counsel to the Issuer and the
Guarantors and updates thereof (which counsel and opinions (in form, scope and
substance) shall be reasonably satisfactory to the managing underwriters, if
any, and the Holders of a majority in aggregate principal amount of the Transfer
Restricted Securities being sold), addressed to each selling Holder and each of
the underwriters, if any, covering the matters customarily covered in opinions
requested in Underwritten Offerings; (iii) obtain "cold comfort" letters and
updates thereof (which letters and updates (in form, scope and substance) shall
be reasonably satisfactory to the managing underwriters, if any, and the Holders
of a majority in aggregate principal amount of the Transfer Restricted
Securities being sold) from the independent certified public accountants of the
Issuer and the Guarantors (and, if necessary, any other independent certified
public accountants of any subsidiary of the Issuer or of any business acquired
by the Issuer for which financial statements and financial data are, or are
required to be, included in the Registration Statement), addressed to each of
the underwriters, if any, and each selling Holder, such letters to be in
customary form and covering matters of the type customarily covered in "cold
comfort" letters in connection with Underwritten Offerings and such other
matters as reasonably requested by underwriters, if any, or the Holders of a
majority in aggregate principal amount of the Transfer Restricted Securities
being sold; and (iv)

                                       18
<PAGE>

deliver such documents and certificates as may be reasonably requested by the
Holders of a majority in principal amount of the Transfer Restricted Securities
being sold and the managing underwriters, if any, to evidence the continued
validity of the representations and warranties of the Issuer and the Guarantors
and their respective subsidiaries made pursuant to clause (i) above and to
evidence compliance with any conditions contained in the underwriting agreement
or other similar agreement entered into by the Issuer and the Guarantors.

         (o) Comply with all applicable rules and regulations of the SEC and
make generally available to their respective security holders earnings
statements satisfying the provisions of Section 11(a) of the Securities Act and
Rule 158 thereunder (or any similar rule promulgated under the Securities Act)
no later than 45 days after the end of any 12-month period (or 90 days after the
end of any 12-month period if such period is a fiscal year) (i) commencing on
the first day of the fiscal quarter following each fiscal quarter in which
Transfer Restricted Securities are sold to underwriters in a firm commitment or
best efforts Underwritten Offering and (ii) if not sold to underwriters in such
an offering, commencing on the first day of the first fiscal quarter of the
Issuer after the effective date of a Registration Statement, which statements
shall cover said 12-month periods.

         (p) Upon consummation of an Exchange Offer or Private Exchange, obtain
an opinion of counsel to the Issuer and the Guarantors (in form, scope and
substance reasonably satisfactory to the Initial Purchasers), addressed to all
Holders participating in the Exchange Offer or Private Exchange, as the case may
be, to the effect that (i) the Issuer and the Guarantors have duly authorized,
executed and delivered the Exchange Securities or the Private Exchange
Securities, as the case may be, and the Indenture and (ii) the Exchange
Securities or the Private Exchange Securities, as the case may be, and the
Indenture constitute legal, valid and binding obligations of the Issuer and the
Guarantors, enforceable against the Issuer and the Guarantors in accordance with
their respective terms, except as such enforcement may be limited by (A)
applicable bankruptcy, insolvency, reorganization, moratorium and similar laws
now or hereafter in effect relating to or affecting creditors' rights generally
and (B) general principles of equity (regardless of whether enforceability is
considered in a proceeding in equity or at law).

         (q) If an Exchange Offer or Private Exchange is to be consummated, upon
delivery of the Transfer Restricted Securities by such Holders to the Issuer and
the Guarantors (or to such other Person as directed by the Issuer and the
Guarantors) in exchange for the Exchange Securities or the Private Exchange
Securities, as the case may be, the Issuer and the Guarantors shall mark, or
caused to be marked, on such Transfer Restricted Securities that such Transfer
Restricted Securities are being

                                       19
<PAGE>

cancelled in exchange for the Exchange Securities or the Private Exchange
Securities, as the case may be, and in no event shall such Transfer Restricted
Securities be marked as paid or otherwise satisfied.

         (r) Cooperate with each seller of Transfer Restricted Securities
covered by any Registration Statement and each underwriter, if any,
participating in the disposition of such Transfer Restricted Securities and
their respective counsel in connection with any filings required to be made with
the NASD.

         (s) Use their respective commercially reasonable efforts to take all
other steps necessary to effect the registration of the Transfer Restricted
Securities covered by a Registration Statement contemplated hereby.

                  Each Holder and each Participating Broker-Dealer agrees by
acquisition of such Transfer Restricted Securities or Exchange Securities that,
upon receipt of written notice from the Issuer and the Guarantors of the
happening of any event of the kind described in Section 5(e)(ii), 5(e)(iv),
5(e)(v), 5(e)(vi) or 5(e)(vii), such Holder will forthwith discontinue
disposition (in the jurisdictions specified in a notice of a 5(e)(iv) event, and
elsewhere in a notice of a 5(e)(ii), 5(e)(v), 5(e)(vi) or 5(e)(vii) event) of
such Securities covered by such Registration Statement or Prospectus until the
earlier of (i) such Holder's receipt of the copies of the supplemented
Prospectus contemplated by Section 5(j); or (ii) the time such Holder is advised
in writing (the "ADVICE") by the Issuer and the Guarantors that offers or sales
in a particular jurisdiction may be resumed, or that the use of the applicable
Prospectus may be resumed, as the case may be, and has received copies of any
amendments or supplements thereto. If so directed by the Issuer in such notice,
each Holder and each Participating Broker-Dealer will deliver to the Issuer (at
the Issuer's expense) all copies of the Prospectus covering such Securities that
was current at the time of such Holder's or Participating Broker-Dealer's
receipt of such notice. If the Issuer and the Guarantors shall give such notice,
each of the Effectiveness Period and the Applicable Period shall be extended by
the number of days during such periods from and including the date of the giving
of such notice to and including the date when each seller of such Securities
covered by such Registration Statement shall have received (x) the copies of the
amended or supplemented Prospectus contemplated by Section 5(j) or (y) the
Advice.

6.       REGISTRATION EXPENSES.

         (a) All fees and expenses incident to the performance of or compliance
with this Agreement by the Issuer and the Guarantors shall be borne by the
Issuer and the Guarantors whether or not the Exchange Offer is consummated or
the Exchange Offer Registration Statement or a Shelf Registration is filed or
becomes effective, including, without limitation:

                                       20
<PAGE>

                  (i) all registration and filing fees (including, without
limitation, (A) fees with respect to filings required to be made with the NASD
and (B) fees and expenses of compliance with state securities or Blue Sky laws
(including, without limitation, reasonable fees and disbursements of counsel in
connection with Blue Sky qualifications of the Transfer Restricted Securities or
Exchange Securities and determination of the eligibility of the Transfer
Restricted Securities or Exchange Securities for investment under the laws of
such jurisdictions (x) where the Holders are located, in the case of the
Exchange Securities, or (y) as provided in Section 5(f), in the case of Transfer
Restricted Securities or Exchange Securities to be sold by a Participating
Broker-Dealer during the Applicable Period));

                  (ii) printing expenses (including, without limitation,
expenses of printing certificates for Transfer Restricted Securities or Exchange
Securities in a form eligible for deposit with DTC and of printing prospectuses
if the printing of prospectuses is requested by the managing underwriters, if
any, or, in respect of Transfer Restricted Securities or Exchange Securities to
be sold by a Participating Broker-Dealer during the Applicable Period, by the
Holders of a majority in aggregate principal amount of the Transfer Restricted
Securities included in any Registration Statement or of such Exchange
Securities, as the case may be);

                  (iii) messenger, telephone, duplication, word processing and
delivery expenses incurred by the Issuer and the Guarantors in the performance
of their obligations hereunder;

                  (iv) fees and disbursements of counsel for the Issuer, the
Guarantors and, subject to Section 6(b), the Holders;

                  (v) fees and disbursements of all independent certified public
accountants referred to in Section 5(n)(iii) (including, without limitation, the
expenses of any special audit and "cold comfort" letters required by or incident
to such performance);

                  (vi) fees and expenses of any "qualified independent
underwriter" or other independent appraiser participating in an offering
pursuant to Section 2720 of the Conduct Rules of the NASD, but only where the
need for such a "qualified independent underwriter" arises due to a relationship
with the Issuer and the Guarantors;

                  (vii) Securities Act liability insurance, if the Issuer and
the Guarantors so desire such insurance;

                                       21
<PAGE>

                  (viii) fees and expenses of all other Persons, including
special experts, retained by the Issuer or the Guarantors, internal expenses of
the Issuer and the Guarantors (including, without limitation, all salaries and
expenses of their respective officers and employees performing legal or
accounting duties), and the expenses of any annual audit; and

                  (ix) rating agency fees and the fees and expenses incurred in
connection with the listing of the Securities to be registered on any securities
exchange.

         (b) The Issuer and the Guarantors shall reimburse the Holders for the
reasonable fees and disbursements of not more than one counsel (in addition to
appropriate local counsel) chosen by the Holders of a majority in aggregate
principal amount of the Transfer Restricted Securities to be included in any
Registration Statement and other reasonable and necessary out-of-pocket expenses
of the Holders incurred in connection with the registration of the Transfer
Restricted Securities; provided, however, that neither the Issuer nor any
Guarantor shall be required pursuant hereto to pay any underwriting discounts or
commissions.

7.       INDEMNIFICATION.

         (a) Indemnification by the Issuer and the Guarantors. The Issuer and
the Guarantors, jointly and severally, shall, without limitation as to time,
indemnify and hold harmless each Holder, each Person who controls (within the
meaning of Section 15 of the Securities Act or Section 20(a) of the Exchange Act
(any of such persons being hereinafter referred to as a "CONTROLLING PERSON"))
each such Holder and the members, managers, officers, directors, partners,
employees, representatives and agents of each such Holder and controlling person
(collectively, the "HOLDER INDEMNIFIED PARTIES"), to the fullest extent lawful,
from and against any and all losses, claims, damages, liabilities, costs
(including, without limitation, costs of preparation and reasonable attorneys'
fees) and expenses (including, without limitation, costs and expenses incurred
in connection with investigating, preparing, pursuing or defending against any
of the foregoing) (collectively, "LOSSES"), as incurred, directly or indirectly
caused by, related to, based upon, arising out of or in connection with any
untrue or alleged untrue statement of a material fact contained in any
Registration Statement, preliminary prospectus, Prospectus or form of
prospectus, or in any amendment or supplement thereto, or any omission or
alleged omission to state therein a material fact required to be stated therein
or necessary to make the statements therein, in the light of the circumstances
under which they were made, not misleading, except insofar as such Losses are
based upon information relating to a Holder and furnished in writing to the
Issuer and the Guarantors by such Holder expressly for use therein; provided,
that the Issuer and the Guarantors shall

                                       22
<PAGE>

not be liable under the indemnity provided in this Section 7(a) to any Holder
Indemnified Party to the extent that such Loss results solely from an untrue
statement of a material fact contained in, or the omission of a material fact
from, any preliminary prospectus, which untrue statement or omission was
corrected in the Prospectus (as then amended or supplemented) if it shall have
been determined by a court of competent jurisdiction by final and nonappealable
judgment that (i) such Holder sold the Securities concerned to the person
alleging such Loss and failed to send or give, at or prior to the written
confirmation of such sale, a copy of the Prospectus (as then amended or
supplemented), if required by law to have so delivered it, and (ii) the Issuer
had previously furnished copies thereof to such Holder within a reasonable
amount of time prior to such sale or such confirmation, and (iii) the corrected
Prospectus, if delivered, would have been a complete defense against the person
asserting such Loss. The Issuer and each of the Guarantors shall also indemnify
underwriters, selling brokers, dealer managers and similar securities industry
professionals participating in the distribution, their members, managers,
officers, directors, agents and employees and each of their respective
controlling persons to the same extent as provided above with respect to the
indemnification of the Holder Indemnified Parties.

         (b) Indemnification by Holders of Transfer Restricted Securities. In
connection with any Registration Statement, preliminary prospectus, Prospectus
or form of prospectus, or any amendment or supplement thereto, in which a Holder
is participating, such Holder shall furnish to the Issuer and the Guarantors in
writing such information as the Issuer and the Guarantors reasonably request for
use in connection with any such Registration Statement, preliminary prospectus,
Prospectus or form of prospectus, any amendment or supplement thereto, and
shall, severally and not jointly, without limitation as to time, indemnify and
hold harmless the Issuer, the Guarantors and each other Holder and each of their
respective members, partners, managers, directors, officers, agents and
employees, each controlling person of the Issuer or any of the Guarantors and
the members, partners, managers, directors, officers, agents or employees of
such controlling persons, to the fullest extent lawful, from and against any and
all Losses, as incurred, arising out of or based upon any untrue or alleged
untrue statement of a material fact contained in any such Registration
Statement, preliminary prospectus, Prospectus or form of prospectus, or any
amendment or supplement thereto, or any omission or alleged omission to state
therein a material fact required to be stated therein or necessary to make the
statements therein, in the light of the circumstances under which they were
made, not misleading to the extent, but only to the extent, that such untrue
statement or alleged untrue statement of a material fact or omission or alleged
omission of a material fact is contained in or omitted from any information so
furnished in writing by such Holder to the Issuer and the Guarantors expressly
for use in any Registration

                                       23
<PAGE>

Statement, preliminary prospectus, Prospectus or form of prospectus, or any
amendment or supplement thereto. In no event shall the liability of any selling
Holder be greater in amount than the dollar amount of the proceeds (net of
payment of any and all Losses such Holder has been required to pay) received by
such Holder upon the sale of the Transfer Restricted Securities giving rise to
such indemnification obligation.

         (c) Conduct of Indemnification Proceedings. If any Proceeding shall be
brought or asserted against any Person entitled to indemnification hereunder (an
"INDEMNIFIED PARTY"), such indemnified party shall promptly notify the party or
parties from which such indemnification is sought (the "INDEMNIFYING PARTIES")
in writing; provided, that the failure to so notify the indemnifying parties
shall not relieve the indemnifying parties from any obligation or liability
except to the extent (but only to the extent) that it shall be finally
determined by a court of competent jurisdiction (which determination is not
subject to appeal) that the indemnifying parties have been prejudiced materially
by such failure.

                  The indemnifying parties shall have the right, exercisable by
giving written notice to an indemnified party, within 20 Business Days after
receipt of written notice from such indemnified party of such Proceeding, to
assume, at their expense, the defense of any such Proceeding; provided, that an
indemnified party shall have the right to employ separate counsel in any such
Proceeding and to participate in the defense thereof, but the fees and expenses
of such counsel shall be at the expense of such indemnified party or parties
unless: (i) the indemnifying parties have agreed to pay such fees and expenses;
(ii) the indemnifying parties shall have failed promptly to assume the defense
of such Proceeding or shall have failed to employ counsel reasonably
satisfactory to such indemnified party; or (iii) the named parties to any such
Proceeding (including any impleaded parties) include both such indemnified party
and one or more indemnifying parties (or any affiliates or controlling persons
of any of the indemnifying parties), and such indemnified party shall have been
advised by counsel that there may be one or more defenses available to such
indemnified party that are in addition to, or in conflict with, those defenses
available to the indemnifying party or such affiliate or controlling person (in
which case, if such indemnified party notifies the indemnifying parties in
writing that it elects to employ separate counsel at the expense of the
indemnifying parties, the indemnifying parties shall not have the right to
assume the defense thereof and the reasonable fees and expenses of such counsel
shall be at the expense of the indemnifying parties; it being understood,
however, that the indemnifying parties shall not, in connection with any one
such Proceeding or separate but substantially similar or related Proceedings in
the same jurisdiction arising out of the same general allegations or
circumstances, be liable for the fees and expenses of more than one separate

                                       24
<PAGE>

firm of attorneys (together with appropriate local counsel) at any time for such
indemnified party).

                  No indemnifying party shall be liable for any settlement of
any such Proceeding effected without its written consent, but if settled with
its written consent, or if there be a final judgment for the plaintiff in any
such Proceeding, each indemnifying party jointly and severally agrees, subject
to the exceptions and limitations set forth above, to indemnify and hold
harmless each indemnified party from and against any and all Losses by reason of
such settlement or judgment. The indemnifying party shall not consent to the
entry of any judgment or enter into any settlement that does not include as an
unconditional term thereof the giving by the claimant or plaintiff to each
indemnified party of a release, in form and substance reasonably satisfactory to
the indemnified party, from all liability in respect of such Proceeding for
which such indemnified party would be entitled to indemnification hereunder
(whether or not any indemnified party is a party thereto).

         (d) Contribution. If the indemnification provided for in this Section 7
is unavailable to an indemnified party or is insufficient to hold such
indemnified party harmless for any Losses in respect of which this Section 7
would otherwise apply by its terms (other than by reason of exceptions provided
in this Section 7), then each applicable indemnifying party, in lieu of
indemnifying such indemnified party, shall have a joint and several obligation
to contribute to the amount paid or payable by such indemnified party as a
result of such Losses, (i) in such proportion as is appropriate to reflect the
relative benefits received by the indemnifying party, on the one hand, and such
indemnified party, on the other hand, from their sale of Transfer Restricted
Securities, or (ii) if the allocation provided by clause (i) above is not
permitted by applicable law, in such proportion as is appropriate to reflect not
only the relative benefits referred to in clause (i) above but also the relative
fault of the indemnifying party, on the one hand, and such indemnified party, on
the other hand, in connection with the actions, statements or omissions that
resulted in such Losses as well as any other relevant equitable considerations.
The relative fault of such indemnifying party, on the one hand, and indemnified
party, on the other hand, shall be determined by reference to, among other
things, whether any untrue or alleged untrue statement of a material fact or
omission or alleged omission to state a material fact 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 any such statement or omission. The amount paid or payable by an
indemnified party as a result of any Losses shall be deemed to include any legal
or other fees or expenses incurred by such party in connection with any
Proceeding, to the extent such party would have been indemnified for such fees
or expenses if the indemnification provided for in Section 7(a) or 7(b) were
available to such party.

                                       25
<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 that does not take account
of the equitable considerations referred to in the immediately preceding
paragraph. Notwithstanding the provisions of this Section 7(d), an indemnifying
party that is a selling Holder shall not be required to contribute, in the
aggregate, any amount in excess of such Holder's Maximum Contribution Amount. A
selling Holder's "MAXIMUM CONTRIBUTION AMOUNT" shall equal the excess, if any,
of (i) the aggregate proceeds received by such Holder pursuant to the sale of
such Transfer Restricted Securities over (ii) the aggregate amount of damages
that such Holder has otherwise been required to pay by reason of such untrue or
alleged untrue statement or omission or alleged omission. 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. The Holders' obligations to
contribute pursuant to this Section 7(d) are several in proportion to the
respective principal amount of the Transfer Restricted Securities held by each
Holder hereunder and not joint. The Issuer's and the Guarantors' obligations to
contribute pursuant to this Section 7(d) are joint and several.

                  The indemnity and contribution agreements contained in this
Section 7 are in addition to any liability that the indemnifying parties
otherwise may have to the indemnified parties.

8.       RULE 144 AND RULE 144A.

                  The Issuer and each of the Guarantors covenants that it shall
(a) file the reports required to be filed by it (if so required) under the
Securities Act and the Exchange Act in a timely manner and, if at any time any
such Person is not required to file such reports, it will, upon the request of
any Holder, make available to each Holder or beneficial owner of Transfer
Restricted Securities and to any prospective purchaser of Transfer Restricted
Securities designated by such Holder or beneficial owner the information
required by Rule 144A(d)(4) under the Securities Act to permit sales pursuant to
Rule 144A and (b) take such further action as any Holder may reasonably request,
all to the extent required from time to time to enable such Holder to sell
Transfer Restricted Securities without registration under the Securities Act
pursuant to the exemptions provided by Rule 144 and Rule 144A. Upon the request
of any Holder, the Issuer and each of the Guarantors shall deliver to such
Holder a written statement as to whether the Issuer or such Guarantor has
complied with such information requirements. Nothing in this Section 8 shall be
deemed to require the Issuer or any of the Guarantors to register any Securities
pursuant to the Exchange Act.

                                       26
<PAGE>

9.       UNDERWRITTEN REGISTRATIONS.

                  If any of the Transfer Restricted Securities covered by any
Shelf Registration are to be sold in an Underwritten Offering, the investment
banker or investment bankers and manager or managers that will manage the
offering will be selected by the Holders of a majority in aggregate principal
amount of such Transfer Restricted Securities included in such offering.

                  No Holder may participate in any Underwritten Registration
hereunder unless such Holder (a) agrees to sell such Holder's Transfer
Restricted Securities on the basis provided in any underwriting arrangements
approved by the Persons entitled hereunder to approve such arrangements and (b)
completes and executes all questionnaires, powers of attorney, underwriting
agreements and other documents reasonably required under the terms of such
underwriting arrangements.

10.      MISCELLANEOUS.

         (a) Remedies. In the event of a breach by the Issuer or any of the
Guarantors of any of their respective obligations under this Agreement, each
Holder, in addition to being entitled to exercise all rights provided herein, in
the Indenture or, in the case of the Initial Purchasers, in the Purchase
Agreement, or granted by law, including recovery of damages, will be entitled to
specific performance of its rights under this Agreement. The Issuer and the
Guarantors agree that monetary damages would not be adequate compensation for
any loss incurred by reason of a breach by the Issuer or any of the Guarantors
of any of the provisions of this Agreement and hereby further agree that, in the
event of any action for specific performance in respect of such breach, the
Issuer and the Guarantors shall waive the defense that a remedy at law would be
adequate.

         (b) No Inconsistent Agreements. The Issuer and the Guarantors have not
entered into, as of the date hereof, and shall not enter into, after the date of
this Agreement, any agreement with respect to any of their respective securities
that is inconsistent with the rights granted to the Holders in this Agreement or
otherwise conflicts with the provisions hereof.

         (c) Amendments and Waivers. The provisions of this Agreement, including
the provisions of this sentence, may not be amended, modified or supplemented,
and waivers or consents to departures from the provisions hereof may not be
given, unless the Issuer and the Guarantors have obtained the written consent of
Holders of at least a majority of the then outstanding aggregate principal
amount of Transfer Restricted Securities; provided, that Sections 4(a) and 7
shall not be amended, modified or supplemented, and waivers or consents to
departures from this

                                       27
<PAGE>

proviso may not be given, unless the Issuer has obtained the written consent of
each Holder. Notwithstanding the foregoing, a waiver or consent to depart from
the provisions hereof with respect to a matter that relates exclusively to the
rights of Holders whose securities are being sold pursuant to a Registration
Statement and that does not directly or indirectly affect the rights of other
Holders may be given by Holders of at least a majority in aggregate principal
amount of the Transfer Restricted Securities being sold by such Holders pursuant
to such Registration Statement; provided that the provisions of this sentence
may not be amended, modified or supplemented except in accordance with the
provisions of the immediately preceding sentence.

         (d) Notices. All notices and other communications (including, without
limitation, any notices or other communications to the Trustee) provided for or
permitted hereunder shall be made in writing by hand-delivery, certified
first-class mail with return receipt requested, next-day air courier or
facsimile:

                  (i) if to a Holder, at the most current address given by such
Holder to the Issuer in accordance with the provisions of this Section 10(d),
which address initially is, with respect to each Holder, the address of such
Holder maintained by the Registrar (as defined in the Indenture), with a copy to
Skadden, Arps, Slate, Meagher & Flom LLP, 300 South Grand Avenue, Suite 3400,
Los Angeles, California 90071, facsimile number (213) 687-5600, Attention:
Rodrigo A. Guerra, Esq.; and

                  (ii) if to the Issuer or any of the Guarantors, initially at
3600 Chase Tower, 2200 Ross Avenue, Dallas, Texas 75201, Attention: Chief
Financial Officer, and Attention: General Counsel, with a copy to Haynes and
Boone, LLP, 901 Main Street, Suite 3100, Dallas, Texas 75202, facsimile number
(214) 651-5000, Attention: William R. Hays, III, Esq., and thereafter at such
other address, notice of which is given in accordance with the provisions of
this Section 10(d).

                  All such notices and communications shall be deemed to have
been duly given: when delivered by hand, if personally delivered; five Business
Days after being deposited in the mail, postage prepaid, if mailed; one Business
Day after being timely delivered to a next-day air courier, if sent by next-day
air courier; and when receipt is acknowledged by the addressee, if sent by
facsimile.

                  Copies of all such notices, demands or other communications
shall be concurrently delivered by the Person giving the same to the Trustee
under the Indenture at the address specified in the Indenture.

                                       28
<PAGE>

         (e) Successors and Assigns. This Agreement shall inure to the benefit
of and be binding upon the successors and assigns of each of the parties,
including, without limitation and without the need for an express assignment,
subsequent Holders.

         (f) Counterparts. This Agreement may be executed in any number of
counterparts and by the parties hereto in separate counterparts, each of which
when so executed shall be deemed to be an original and all of which taken
together shall constitute one and the same agreement.

         (g) Headings. The headings in this Agreement are for convenience of
reference only and shall not limit or otherwise affect the meaning hereof. When
a reference is made in this Agreement to a Section, paragraph, subparagraph,
Schedule or Exhibit, such reference shall mean a Section, paragraph,
subparagraph, Schedule or Exhibit to this Agreement unless otherwise indicated.
The words "INCLUDE," "INCLUDES," and "INCLUDING" when used in this Agreement
shall be deemed in each case to be followed by the words "WITHOUT LIMITATION."
The phrases "THE DATE OF THIS AGREEMENT," "THE DATE HEREOF," and terms of
similar import, unless the context otherwise requires, shall be deemed to refer
to December 12, 2001. The words "HEREOF," "HEREIN," "HEREWITH," "HEREBY" and
"HEREUNDER" and words of similar import shall, unless otherwise stated, be
construed to refer to this Agreement as a whole and not to any particular
provision of this Agreement.

         (h) GOVERNING LAW. THIS AGREEMENT SHALL BE CONSTRUED AND INTERPRETED,
AND THE RIGHTS OF THE PARTIES SHALL BE DETERMINED IN ACCORDANCE WITH THE LAWS OF
THE STATE OF NEW YORK, INCLUDING WITHOUT LIMITATION, SECTIONS 5-1401 AND 5-1402
OF THE NEW YORK GENERAL OBLIGATIONS LAW AND RULE 327(b) OF NEW YORK CIVIL
PRACTICE LAWS AND RULES. THE ISSUER AND EACH GUARANTOR HEREBY IRREVOCABLY
SUBMITS TO THE JURISDICTION OF ANY NEW YORK STATE COURT SITTING IN THE BOROUGH
OF MANHATTAN IN THE CITY OF NEW YORK OR ANY FEDERAL COURT SITTING IN THE BOROUGH
OF MANHATTAN IN THE CITY OF NEW YORK IN RESPECT OF ANY SUIT, ACTION OR
PROCEEDING ARISING OUT OF OR RELATING TO THIS AGREEMENT, AND IRREVOCABLY ACCEPTS
FOR ITSELF AND IN RESPECT OF ITS PROPERTY, GENERALLY AND UNCONDITIONALLY,
JURISDICTION OF THE AFORESAID COURTS. THE ISSUER AND EACH GUARANTOR IRREVOCABLY
WAIVES, TO THE FULLEST EXTENT IT MAY EFFECTIVELY DO SO UNDER APPLICABLE LAW,
TRIAL BY JURY AND ANY OBJECTION THAT IT MAY NOW OR HEREAFTER HAVE TO THE LAYING
OF THE VENUE OF ANY SUCH SUIT, ACTION OR PROCEEDING BROUGHT IN ANY SUCH COURT

                                       29
<PAGE>

AND ANY CLAIM THAT ANY SUCH SUIT, ACTION OR PROCEEDING BROUGHT IN SUCH COURT HAS
BEEN BROUGHT IN AN INCONVENIENT FORUM. THE ISSUER AND EACH GUARANTOR IRREVOCABLY
CONSENTS, TO THE FULLEST EXTENT IT MAY EFFECTIVELY DO SO UNDER APPLICABLE LAW,
TO THE SERVICE OF PROCESS OF ANY OF THE AFOREMENTIONED COURTS IN ANY SUCH ACTION
OR PROCEEDING BY THE MAILING OF COPIES THEREOF BY REGISTERED OR CERTIFIED MAIL,
POSTAGE PREPAID, TO THE ISSUER OR SUCH GUARANTOR, AS THE CASE MAY BE, AT ITS
ADDRESS SET FORTH HEREIN, SUCH SERVICE TO BECOME EFFECTIVE 30 DAYS AFTER SUCH
MAILING. NOTHING HEREIN SHALL AFFECT THE RIGHT OF THE INITIAL PURCHASERS TO
SERVE PROCESS IN ANY OTHER MANNER PERMITTED BY LAW OR TO COMMENCE LEGAL
PROCEEDINGS OR OTHERWISE PROCEED AGAINST THE ISSUER OR ANY OF THE GUARANTORS IN
ANY OTHER JURISDICTION.

         (i) Severability. If any term, provision, covenant or restriction of
this Agreement is held by a court of competent jurisdiction to be invalid,
illegal, void or unenforceable, the remainder of the terms, provisions,
covenants and restrictions set forth herein shall remain in full force and
effect and shall in no way be affected, impaired or invalidated, and the parties
hereto shall use their respective best efforts to find and employ an alternative
means to achieve the same or substantially the same result as that contemplated
by such term, provision, covenant or restriction. It is hereby stipulated and
declared to be the intention of the parties that they would have executed the
remaining terms, provisions, covenants and restrictions without including any of
such that may be hereafter declared invalid, illegal, void or unenforceable.

         (j) Entire Agreement. This Agreement is intended by the parties as a
final expression of their agreement, and is intended to be a complete and
exclusive statement of the agreement and understanding of the parties hereto in
respect of the subject matter contained herein. There are no restrictions,
promises, warranties or undertakings, other than those set forth or referred to
herein, with respect to the registration rights granted by the Issuer and the
Guarantors in respect of securities sold pursuant to the Purchase Agreement.
This Agreement supersedes all prior agreements and understandings between the
parties with respect to such subject matter.

         (k) Attorneys' Fees. In any Proceeding brought to enforce any provision
of this Agreement, or where any provision hereof is validly asserted as a
defense, the prevailing party, as determined by the courts, shall be entitled to
recover reasonable

                                       30
<PAGE>

attorneys' fees in addition to its costs and expenses and any other available
remedy.

         (l) Securities Held by the Issuer or its Affiliates. Whenever the
consent or approval of Holders of a specified percentage of the principal amount
of Transfer Restricted Securities is required hereunder, Transfer Restricted
Securities held by the Issuer or its affiliates (as such term is defined in Rule
405 under the Securities Act) (other than any Holder deemed to be such an
affiliate solely by reason of its holdings of such Transfer Restricted
Securities or any Initial Purchaser deemed to be such an affiliate) shall not be
counted in determining whether such consent or approval was given by the Holders
of such required percentage.

                       [signature pages follow this page]

                                       31
<PAGE>

                  IN WITNESS WHEREOF, the parties have executed this Agreement
as of the date first written above.

                                               Very truly yours,

                                            RADIOLOGIX, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            GUARANTORS:

                                            IDE IMAGING PARTNERS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            PACIFIC IMAGING PARTNERS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR IMAGING, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

<PAGE>

                                            WB&A IMAGING PARTNERS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            TREASURE COAST IMAGING PARTNERS,
                                            INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            RADIOLOGIX SERVICES, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            ADVANCED IMAGING PARTNERS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            MID ROCKLAND IMAGING PARTNERS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

<PAGE>

                                            RADIOLOGY AND NUCLEAR MEDICINE
                                            IMAGING PARTNERS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            COMMUNITY IMAGING PARTNERS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            VALLEY IMAGING PARTNERS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            SAN JOSE IMAGING PARTNERS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            ADVANCED RADIOLOGY, LLC

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

<PAGE>

                                            ADVANCED MEDICAL IMAGING, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            M&S IMAGING PARTNERS I, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            M&S IMAGING PARTNERS, L.P.

                                            By: M&S Imaging Partners I, Inc.,
                                            its general partner

                                                By:
                                                    ----------------------------
                                                    Name:
                                                    Title:

                                            QUESTAR CLEVELAND, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR TAMPA, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

<PAGE>

                                            QUESTAR ORLANDO, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            ROCKY MOUNTAIN OPENSCAN MRI, LLC

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            PREMIER ADVANCED IMAGING NETWORK,
                                            LTD.

                                            By: Questar Orlando, Inc., its
                                            general partner

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR IMAGING MB, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR KANSAS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

<PAGE>

                                            QUESTAR PVH, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR SAN FRANCISCO, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR HENDERSON, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR TRISTATES, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR PHILADELPHIA, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

<PAGE>

                                            QUESTAR WESTWOOD, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR DULUTH, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR LINCOLN, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR H F M C, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR PALM SPRINGS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

<PAGE>

                                            QUESTAR ATLANTA, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR MT. LAUREL, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR LOWER BUCKS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR TOLEDO, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR SOUTH CHICAGO, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

<PAGE>

                                            QUESTAR NORTH GEORGIA, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR LOS ALAMITOS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR DES PLAINES, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR VICTORVILLE, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR COLUMBUS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

<PAGE>

                                            QUESTAR NAPERVILLE, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR QUAKERTOWN, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

                                            QUESTAR TUCSON, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

<PAGE>

                                            M&S IMAGING INVESTMENTS, INC.

                                            By:
                                                --------------------------------
                                                Name:
                                                Title:

<PAGE>
ACCEPTED AND AGREED TO:

JEFFERIES & COMPANY, INC.

By:
    ---------------------------
    Name:
    Title:

DEUTSCHE BANC ALEX. BROWN INC.

By:
    ---------------------------
    Name:
    Title:

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