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                             MASTER LEASE AGREEMENT

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                Master Lease Agreement No. 11150 ("MASTER LEASE")

LESSOR: PRIME LEASING, INC.,             LESSEE: Phymed Diagnostic Imaging
                                         Center-White Rock, Inc.
an Illinois corporation ("LESSOR")       an Texas Limited Partnership ("LESSEE")
10275 W. Higgins Road                    9603 White Rock Trail
Rosemont, IL  60018                      Dallas, TX   75238
847/294-6000                             Phone:


WHEREAS,  LESSOR desires to lease certain equipment  ("Equipment") to LESSEE and
may lease additional equipment (referred to as "Additional Equipment") to Lessee
in the future (the  Equipment and the  Additional  Equipment  being  referred to
collectively  as the  "Equipment");  WHEREAS,  LESSEE  desires to lease  certain
Equipment  from  LESSOR and may lease  Additional  Equipment  from Lessor in the
future; and WHEREAS, to facilitate the lease of the Equipment, the parties agree
to enter into this MASTER LEASE and to  incorporate  by  reference  from time to
time in lease  schedules  (hereinafter  referred  to as "Lease  Schedules",  and
individually  as a "Lease  Schedule")  which will be attached  hereto and made a
part hereof, various units of Equipment; NOW, THEREFORE, in consideration of the
mutual promises contained herein and other good and valuable consideration,  the
parties hereto agree as follows:

         TERMS, CONDITIONS AND COVENANTS OF LEASE

1. LEASE:  This MASTER LEASE sets forth the terms and conditions by which LESSOR
agrees to lease to LESSEE and LESSEE  agrees to lease from LESSOR the  Equipment
as listed and described in each Lease Schedule  executed pursuant to this MASTER
LEASE.  Each Lease  Schedule shall be separate and distinct for all purposes and
shall incorporate  therein all the terms and conditions of this MASTER LEASE. If
there is a conflict  between the Lease Schedule and this MASTER LEASE, the terms
and conditions of this MASTER LEASE shall govern and control.

2.   TERM:

a. The term of this MASTER  LEASE shall begin on the date of execution by LESSOR
and shall continue in effect  thereafter  until all of LESSEE'S  obligations and
liabilities  under this MASTER  LEASE and every Lease  Schedule  have been fully
performed or otherwise discharged.

b. The lease term for each Lease  Schedule  shall commence on the earlier of the
Equipment  installation,  first  clinical use, or the cutover date  (hereinafter
referred to as "Commencement  Date").  If any Equipment under the Lease Schedule
is not newly installed,  then the Commencement Date shall be the date upon which
title to the Equipment  passes to LESSOR.  The lease term shall continue for the
number of months set forth in the Lease  Schedule  (hereinafter  referred  to as
"Initial Term") and continue for any extended or renewal term. The first payment
date of the  Initial  Term  shall  be the  first  day of the  month  immediately
following the Commencement  Date (or beginning on the Commencement  Date if that
date is on the first day of the month).

d. LESSEE shall  deliver to LESSOR a Certificate  of Acceptance  within five (5)
days of the  Commencement  Date. If Lessee fails to deliver the  Certificate  of
Acceptance,  LESSEE shall be deemed to have  accepted the Equipment as installed
and operational as of the  Commencement  Date unless LESSEE gives LESSOR written
notice of each defect within five (5) days of the Commencement Date.

3. RENT AND PAYMENTS:  LESSEE'S obligation to pay rent under each Lease Schedule
shall begin on the Commencement Date and continue for the term. The monthly rent
(hereinafter  referred  to as  "Monthly  Rent") set forth in the Lease  Schedule
shall be due and  payable  in advance  on the first day of each  calendar  month
during the Initial Term without notice or demand  notwithstanding  the fact that
LESSOR may, as a convenience only, invoice LESSEE. If the Commencement Date of a
Lease Schedule shall be other than the first day of the month, LESSEE shall make
a rental payment (hereinafter  referred to as "Interim Rent") equal to 1/30th of
the Monthly Rent set forth in the Lease Schedule for each day beginning with the
Commencement  Date to and  including  the  last  day of the  month  prior to the
beginning of the Initial Term.  Any amounts  payable by LESSEE under this MASTER


<PAGE>

LEASE  other  than the  Monthly  Rent and  Interim  Rent  shall be  deemed to be
additional rent (hereinafter referred to as "Additional Rent") and shall be paid
within twenty (20) days of invoicing by LESSOR.  Rent shall be paid to LESSOR at
the address  designated  herein or at such other place as LESSOR  designates  in
writing,  or if to an assignee of LESSOR,  at such place as such assignee  shall
designate  in  writing,  by  check  or wire  transfer  so  that  all  funds  are
immediately  available.  As used herein,  the term "rent" shall mean all Monthly
Rent, Interim Rent and Additional Rent. THIS IS A NON-CANCELABLE  LEASE.  LESSEE
shall pay the total  rents for the entire term to LESSOR,  or LESSOR'S  assignee
(as  defined  herein),   and  such  payment  of  rents  shall  be  absolute  and
unconditional  without  right to  setoff,  reduction,  abatement,  counterclaim,
recoupment, or defense of any kind whatsoever.

a.  SERVICE  CHARGE:  In the event  that any rent is not  received  by LESSOR or
LESSOR'S assignee within five (5) days of the due date thereof, LESSEE shall pay
a service  charge of five  percent  (5%) of the past due  payment  and shall pay
interest at the rate of 1.5 percent  (1.5%) per month or the maximum legal rate,
whichever is less, until all past due rents are received.

b. LEASE BASIS COST:  The term "Lease  Basis Cost" as used herein means the cost
of acquiring,  delivering and installing the Equipment including but not limited
to all parts, materials, labor, services,  transportation,  taxes, and all other
charges of every kind and nature associated therewith.

c. NON-PERFORMANCE: If LESSEE fails to perform any of its covenants, warranties,
terms or  conditions  herein,  LESSOR may,  at its  option,  perform on LESSEE'S
behalf  and all  monies  advanced  by  LESSOR  shall be  repayable  by LESSEE as
Additional Rent.  However,  in no event shall LESSOR'S  performance on behalf of
LESSEE be deemed to relieve LESSEE of its obligations hereunder.

4. LEGAL TITLE, LIENS, TAXES AND QUIET ENJOYMENT: During the term of this MASTER
LEASE, legal title to all Equipment shall at all times vest in LESSOR.  LESSEE'S
interest in the Equipment  shall be limited to its possession and use and LESSEE
shall  not have or  assert  any  right,  title or  interest  therein,  except as
expressly  set forth herein,  and shall  protect,  indemnify and defend,  at its
expense,  LESSOR'S legal title. LESSEE shall, at its expense, keep the Equipment
free and clear of any lien or encumbrance of any kind whatsoever  except that of
LESSOR arising  hereunder.  LESSEE warrants that the Equipment will at all times
remain  personal  property,  regardless  of how it may be  affixed  to any  real
property.  Prior to LESSOR'S  acceptance  of this  MASTER  LEASE,  LESSEE  shall
provide LESSOR with a waiver, in form satisfactory to LESSOR, by the landlord or
mortgagee of the premises in which the Equipment is located,  of such landlord's
or  mortgagee's  rights in and to the  Equipment  and/or the rent due under this
MASTER  LEASE.  In lieu of such  waiver,  LESSEE  hereby  agrees to hold  LESSOR
harmless  and  indemnify  LESSOR  with  regard to any and all  claims,  actions,
damages,  costs and attorneys fees asserted by any landlord or mortgagee against
LESSOR or the Equipment herein. LESSEE shall pay all taxes,  assessments or fees
assessed  against the  Equipment  or payable by LESSOR or LESSEE with respect to
the  Equipment,  including  any interest or penalties  therein,  excepting  only
federal or state taxes  based on the net income of LESSOR and without  regard to
LESSOR'S  agreement to invoice LESSEE for such amounts.  LESSEE  agrees,  to the
extent  permissible  by law,  to prepare and file all  required  tax returns and
other  reports  (other  than  reports  regarding  LESSOR'S  income tax) with any
federal,  state or other  regulatory  authority.  LESSEE further agrees,  to the
extent  permitted by law, to take such actions and to file such documents as may
be required to ensure that the valuation of the  Equipment,  as reflected on the
records and tax rolls of applicable taxing authorities, does not exceed the fair
market value of the  Equipment.  To the extent  LESSEE is not  permitted to file
such returns, reports, or documents,  LESSEE shall prepare them and provide them
to LESSOR  for  filing  prior to the date such  return or report is due.  LESSOR
shall have the right to affix a stencil,  plate,  label or other  indicia of its
ownership  to the  Equipment  and  LESSEE  shall  not  remove  or  conceal  such
identification.  LESSEE shall have the right to quiet enjoyment of the Equipment
during the term of the Lease Schedule, so long as no event of default (as herein
defined) occurs.

<PAGE>


5.  LOCATION,  USE,  MODIFICATIONS  AND  ALTERATIONS:  LESSEE shall not move, or
permit the movement of, the Equipment from the location (hereinafter referred to
as "Equipment  Location") specified in the Lease Schedule without LESSOR'S prior
written  consent.  LESSEE  shall not use,  or permit the use of,  the  Equipment
unless such use is consistent  with LESSEE'S  business,  by qualified  operators
under  LESSEE'S   control  and  in  compliance  with  (A)  applicable  laws  and
regulations;   (B)  the   specifications   of,  and  use  contemplated  by,  the
manufacturer of the Equipment  (hereinafter referred to as "Manufacturer");  (C)
the terms of LESSEE'S insurance  coverage;  and (D) the requirements of LESSEE'S
maintenance  agreement  regarding  the  Equipment.  LESSEE  shall  not  make any
modifications,  alterations or additions to the Equipment without LESSOR'S prior
written consent (other than Manufacturer's  Changes, as such term is hereinafter
defined)  unless said additions (A) are readily  removable  without  causing any
damage to the Equipment and (B) do not impair the quality,  safety,  function or
marketability  of  the  Equipment  (hereinafter  referred  to  as  a  "Permitted
Modification").  Any  Permitted  Modification  shall not become the  property of
LESSOR  and  shall not be  subject  to the Lease  Schedule,  provided  that upon
termination  or  expiration  of the term,  LESSEE  shall  remove  all  Permitted
Modifications and restore the Equipment to its original condition (ordinary wear
and tear  excepted),  all at no  expense  to  LESSOR.  LESSEE  shall  permit the
Manufacturer,  its agents or its  contractors,  access to the  Equipment for the
purpose of performing such upgrades, recall orders or engineering changes as the
Manufacturer  shall require to enhance or maintain the  Equipment's  standard of
performance  (herein defined as  "Manufacturer's  Changes"),  all of which shall
immediately become the property of LESSOR and be subject to the Lease Schedule.

6.  MAINTENANCE  AND INSPECTION:  THIS IS A NET LEASE.  LESSEE shall, at its own
expense,  maintain the  Equipment in good  condition  and repair and furnish all
necessary repairs,  parts,  materials and supplies.  At all times herein, LESSEE
shall  keep  in  full  force  and  effect  a  maintenance   agreement  with  the
Manufacturer or, with LESSOR'S consent,  with an equivalent service organization
that routinely maintains such Equipment  (hereinafter referred to as "Equivalent
Service Organization"). During reasonable business hours and subject to LESSEE'S
reasonable security precautions, LESSEE shall permit LESSOR access to all of the
Equipment  for the purpose of  inspecting  the  Equipment to determine  LESSEE'S
compliance  with this MASTER  LEASE.  If LESSEE is not in  compliance  with this
MASTER LEASE, LESSOR shall notify LESSEE in writing of the acts of noncompliance
and LESSEE shall  immediately cease using the Equipment until full compliance is
achieved.

7.  DISCLAIMER  OF  WARRANTIES:   LESSEE  has  selected  at  its  own  risk  the
Manufacturer,  size and design of the Equipment. LESSEE acknowledges that LESSOR
is not the Manufacturer,  or its agent or distributor,  and that LESSOR MAKES NO
REPRESENTATIONS  OR  WARRANTY  OF  ANY  KIND  WHATSOEVER,  EXPRESS  OR  IMPLIED,
INCLUDING BUT NOT LIMITED TO  REPRESENTATIONS  OR WARRANTIES WITH RESPECT TO THE
MERCHANTABILITY,   VALUE,  CONDITION,   QUALITY,  DESIGN,  CAPACITY,   MATERIAL,
WORKMANSHIP  OR  FITNESS OR  SUITABILITY  FOR ANY  PURPOSE OR USE BY LESSEE,  OR
PATENT,  COPYRIGHT  OR  TRADEMARK  INFRINGEMENT.  LESSOR SHALL NOT BE LIABLE FOR
LOSSES OR DAMAGES THEREFROM,  INCLUDING BUT NOT LIMITED TO LOSS OF BUSINESS,  OR
ACTUAL OR  ANTICIPATED  PROFITS,  OR OTHER DIRECT,  INCIDENTAL OR  CONSEQUENTIAL
DAMAGES OF ANY KIND WHATSOEVER  ARISING FROM THIS MASTER LEASE OR THE EQUIPMENT.
So long as no Event of Default (as herein  defined) has  occurred and  continues
uncured,   LESSOR   assigns   LESSEE  all  of   Manufacturer's   warranties  and
indemnifications,  to  the  extent  said  warranties  and  indemnifications  are
assignable.

8. RISK OF LOSS: LESSEE hereby assumes and shall bear the entire risk of changes
to, loss,  theft,  damage,  destruction or seizure  (hereinafter  referred to as
"Event of Loss") of the Equipment from every cause whatsoever.  No Event of Loss
shall  relieve  LESSEE of its  obligations  to pay rent or to perform  any other
obligation  under this  MASTER  LEASE.  If any of the  Equipment  is damaged and
repairable,  LESSEE shall promptly  notify LESSOR of the occurrence of the Event
of Loss and shall, at LESSEE'S  expense within thirty (30) days of such Event of
Loss,  cause  repairs to be made to the Equipment to restore it to the condition
required  pursuant  to Section 6 herein.  If the  Equipment  is  damaged  beyond
repair,  LESSEE shall  promptly  notify LESSOR of the occurrence of the Event of
Loss and shall,  at  LESSEE'S  expense  within  thirty (30) days of the Event of
Loss:  (A) replace the Equipment  with like equipment in good repair and working
order or (B) pay to LESSOR in cash the  following:  (1) the  greater  of (a) ten
percent (10%) of the Lease Basis Cost or (b) the actual fair market value of the
Equipment  calculated  as of the date of the Event of Loss;  and (2) all amounts
which have  accrued and have not been paid by LESSEE to LESSOR under this MASTER
LEASE  through the date of the Event of Loss;  and (3) the present  value of the
unpaid rent  discounted  at a rate of five percent (5%) for the remainder of the
Initial Term for each Lease  Schedule  covering the Equipment  (the total amount
described in (1), (2), and (3) above is hereinafter  collectively referred to as
"Casualty Value").

<PAGE>


9. INSURANCE:  LESSEE shall provide and maintain,  at its sole cost and expense:
(1) all risk property  insurance on the Equipment for its full replacement value
in an amount no less  than the  Casualty  Value,  and (2)  comprehensive  public
liability  and property  damage  insurance on the  Equipment in amounts not less
than  $1,000,000.00 per occurrence and  $3,000,000.00 in the aggregate,  with an
insurer  reasonably  acceptable to LESSOR  considering  the risks to be insured.
LESSEE shall provide LESSOR or its assigns (in a form acceptable to LESSOR) with
certificates of insurance and a loss payable  endorsement in favor of LESSOR and
its  assigns,  as loss payee for  property  damage  coverage  and as  additional
insured for public liability coverage.  If specifically  requested in writing by
LESSOR,  LESSEE  shall  provide a copy of the  insurance  policy under which the
certificates  are issued.  The  insurance  endorsement  shall  provide  that the
coverage  shall not be materially  altered or cancelled  unless thirty (30) days
prior  written  notice has been given to LESSOR  and its  assigns,  and that the
coverage afforded to LESSOR and its assigns, shall not be rescinded, impaired or
invalidated  by any act or omission of LESSEE.  LESSOR may apply proceeds of any
such insurance to any of LESSEE'S  obligations  hereunder,  but shall pay excess
proceeds,  if any, to LESSEE upon LESSEE'S full  satisfaction of its obligations
hereunder.

10.  GENERAL  INDEMNIFICATION:  Except  for  liability  arising  from the  gross
negligence  or willful  misconduct of LESSOR,  its  employees or agents,  LESSEE
hereby  agrees to  indemnify,  defend,  protect  and hold  LESSOR,  its  agents,
employees,  directors and assigns  harmless from and against any and all claims,
losses, damages. injuries, suits, demands or expenses, including but not limited
to attorney's fees and costs of whatever kind and nature,  arising in connection
with the  Equipment,  including  without  limitation  its  selection,  purchase,
installation,  use, deinstallation,  delivery,  return or manufacture (including
without  limitation  patent,  trademark  or other  infringement).  LESSEE  shall
promptly notify LESSOR or its assigns of any matter hereby indemnified against.

11.  RETURN  OF  EQUIPMENT:  Upon  the  expiration  of  any  Lease  Schedule  or
termination  for any other  cause,  LESSEE at is sole  cost and  expense,  shall
assemble, crate, insure and deliver all of the Equipment, and all of the service
records relating thereto,  subject to the Lease Schedule,  to LESSOR in the same
good condition and repair as when received,  ordinary wear and teat excepted, to
such reasonable destination within the continental United States as LESSOR shall
designate.  LESSEE  shall  immediately  prior  to the  return  of  each  unit of
Equipment,  provide LESSOR a letter from the  Manufacturer  certifying that each
unit of Equipment is in good working order, ordinary wear and tear excepted, and
is eligible  for a  maintenance  agreement  by the  Manufacturer  or  Equivalent
Service  Organization.  LESSEE  shall  provide  LESSOR with at least one hundred
twenty (120) days written notice of the return of the Equipment. Notwithstanding
any other rights and remedies of LESSOR, if LESSEE fails to return the Equipment
to LESSOR or its designee within ten (10) days of the time required,  then until
such time as the Equipment is returned, LESSEE shall pay on demand as liquidated
damages,  not as a penalty,  and at LESSOR'S  election,  an amount  equal to (A)
twelve (12) months rent; or (B) one hundred twenty percent (120%) of the Monthly
Rent for each month or portion thereof until the Equipment is returned to LESSOR
as detailed herein.

12. LESSEE'S  REPRESENTATIONS AND WARRANTIES:  LESSEE represents and warrants to
LESSOR with regard to this MASTER  LEASE and each Lease  Schedule to be appended
hereto that:

a. The  execution,  delivery and  performance of this MASTER LEASE and any Lease
Schedule  have  been  duly  authorized  by all  necessary  action on the part of
LESSEE,  and this MASTER LEASE  constitutes  a valid and binding  obligation  of
LESSEE enforceable against LESSEE in accordance with its terms;

b. The  individual  executing  this  MASTER  LEASE on  behalf  of LESSEE is duly
authorized;

c.  Neither the  execution or delivery by LESSEE of this MASTER  LEASE,  nor the
performance  thereof  by  LESSEE,  conflicts  with,  results  in a breach  of or
constitutes  a default or violation of LESSEE'S  Certificate  of  Incorporation,
By-Laws,  applicable  law,  court order or any agreement or other  instrument to
which LESSEE is a party or by which it is bound;


<PAGE>

d. LESSEE is duly organized and in good standing in its state of  incorporation,
is duly  qualified to do business in each  jurisdiction  where the  Equipment is
located and where such qualification is required;

e. Upon request by LESSOR,  LESSEE shall furnish its most recent  audited annual
financial  statements  prepared in accordance with generally accepted accounting
principles;  and LESSEE shall furnish its quarterly financial  statements within
___ days after the end of each quarter,  prepared in accordance  with  generally
accepted  accounting  principles,  and being certified as true and correct by an
authorized officer of LESSEE;

f. LESSEE shall provide to LESSOR any other  documents  reasonably  requested to
consummate  this  transaction  or any Lease  Schedule or as reasonably  required
under this MASTER LEASE;

g. No  approval,  consent or  authorization  is required  from any  governmental
authority with respect to the execution,  delivery or performance of this MASTER
LEASE, or if any such approval,  consent or  authorization  is required,  it has
been obtained.

13.  EVENT OF DEFAULT:  The  occurrence  of any of the  following  events  shall
constitute an event of default by LESSEE or its guarantor  (hereinafter referred
to as an "Event of Default"):

a. Failure to pay when due any  installment  of rent or other sum due hereunder,
and such failure shall continue for more than five (5) days; or

b. Failure to perform any other term or condition,  covenant,  representation or
warranty of this MASTER LEASE or any Lease Schedule,  and such failure continues
for a period of twenty (20) days after notice thereof; or

c. If LESSEE or its guarantor ceases doing business as a going concern,  becomes
insolvent,  admits in writing its inability to pay its debts as they become due,
makes an assignment for the benefit of its creditors, files a voluntary petition
or answer seeking any reorganization,  arrangement,  composition,  readjustment,
liquidation,  dissolution  or similar relief under any present or future federal
or state statute,  law or regulation,  admits,  consents to or acquiesces in the
appointment  of a receiver or trustee of any of its property,  the commission of
any act of  dissolution,  liquidation or the bankruptcy or death of the LESSEE'S
guarantor in the event that the Guarantor is a natural person; or

d.  Failure  within  sixty (60) days after the  commencement  of any  proceeding
against  LESSEE  or  its  guarantor  seeking  any  reorganization,  arrangement,
composition,  readjustment,  liquidation,  dissolution,  bankruptcy  or  similar
relief under any current or future federal or state  statute,  law or regulation
to obtain the dismissal of such proceeding; or

e. If any  warranty,  covenant  or  representation  made by  LESSEE to LESSOR is
false,  incorrect or untrue in any material respect; or if any Equipment subject
to a Lease Schedule is attached, levied upon, encumbered,  pledged or seized; or
LESSEE  defaults under any other  agreement  with LESSOR;  or defaults under any
other material lease, loan or agreement for the borrowing of money; or

f. There is a material  adverse  change in the financial  condition of LESSEE or
its guarantor.

14. REMEDIES: At any time after an Event of Default, LESSOR shall have the right
to exercise any one or more of the following cumulative remedies:

a. Accelerate without notice to LESSEE all of LESSEE'S obligations hereunder and
to sue for and recover all rents and other  amounts  which have accrued or shall
accrue under this MASTER LEASE,  all of which shall become  immediately  due and
payable upon demand by LESSOR;

b.  Require  that  LESSEE  assemble  the  Equipment  and deliver it to LESSOR as
provided  under Section 11 or enter the premises  where any Equipment is located
without  notice or process of law and take  possession of the Equipment  without
incurring  any  liability  to LESSEE or any other party for any damages  arising
from such taking of possession;

c.   Sell any or all of the Equipment at public or private sale or relet same;

d.  Terminate  this MASTER  LEASE or any Lease  Schedule as to any or all of the
Equipment; and

<PAGE>


e. At law or in  equity,  enforce  any of  LESSOR'S  rights or pursue  any other
remedy now or hereafter arising.

LESSOR'S  remedies  hereunder are cumulative in nature,  not exclusive,  and the
exercise of any  particular  remedy  shall not be construed to be an election of
remedies  by LESSOR nor shall any waiver or delay by LESSOR of any of its rights
or remedies under this MASTER LEASE be construed as a waiver of LESSOR'S  rights
to enforce  that, or any other,  right or remedy in the future.  Notwithstanding
LESSOR'S election of remedies,  LESSEE shall remain liable for the present value
of all rents  discounted  at a rate of five percent (5%) and other amounts which
have accrued or would have accrued  during the Initial  Term, in addition to (A)
all of LESSOR'S costs and expenses  incurred in enforcing its rights  hereunder,
or in taking  of  possession,  storing,  repairing,  selling  or  reletting  the
Equipment,  (B) court costs and  reasonable  attorney's  fees, and (C) an amount
equal to the greater of (1) ten percent (10%) of the Lease Basis Cost or (2) the
fair market value  calculated as of the date of such Event of Default,  less (D)
the net  proceeds  of a public or  private  sale or  reletting,  if any,  of the
Equipment,  at the present  value,  if  necessary,  discounted at a rate of five
percent (5%) and (E) any insurance  proceeds  recovered by LESSOR from insurance
coverage  provided by LESSEE.  However,  in no event shall LESSOR'S  exercise of
more than one of its remedies entitle LESSOR to recover from LESSEE an amount in
excess of that referred to in this section.

15.  ASSIGNMENT AND SUBLEASE:

a. LESSOR'S  ASSIGNMENT:  LESSEE  understands and  acknowledges  that LESSOR has
entered  into this  MASTER  LEASE and shall  enter into each Lease  Schedule  in
anticipation of assigning,  mortgaging, or otherwise transferring its rights and
interests thereunder and/or in the Equipment (but not its obligations) to others
(hereinafter  referred to as  "Assignees")  without  notice to or the consent of
LESSEE. Accordingly, LESSOR and LESSEE agree that:

(1)  LESSEE  will,  after due  notice,  acknowledge  in writing  such  notice of
assignment as reasonably  requested by LESSOR or its Assignee,  and pay directly
to the  designated  Assignee the amounts  which  become due under each  assigned
Lease  Schedule and such payment  shall be absolute and  unconditional,  without
reduction,  abatement,  offset or counterclaim of any kind.  Notwithstanding the
foregoing,  LESSEE reserves its rights to have recourse  directly against LESSOR
on account of any claim it may have against LESSOR.

(2) Any Assignee may reassign its rights and interests  hereunder  with the same
effect as the original assignment.

(3) LESSEE agrees to execute all filings pursuant to the Uniform Commercial Code
as well as any other documents  reasonably  requested by LESSOR or its Assignee.
Any  Assignee  shall  not be  liable to  LESSEE  for any  obligations  of LESSOR
hereunder.

b. LESSEE'S  ASSIGNMENT AND SUBLEASE:  Without  LESSOR'S prior written  consent,
LESSEE shall not: (A) assign any of its  obligations  hereunder,  (B) attempt to
sublease the Equipment or (C) attempt to sell,  transfer,  hypothecate,  dispose
of, lend or abandon the Equipment or any of LESSEE'S rights in it.

16.  CHOICE OF LAW AND FORUM:  This MASTER  LEASE and the  provisions  contained
herein  shall be deemed to have been  executed  at LESSOR'S  principal  place of
business in Rosemont, Illinois and shall be governed in all respects by the laws
of the State of Illinois.  LESSOR and LESSEE on behalf of  themselves  and their
assignees  further agree that courts located in the State of Illinois shall have
jurisdiction over any matters arising out of this MASTER LEASE and hereby submit
themselves to the personal jurisdiction of the Illinois courts.

17. NOTICES:  All notices or demands provided for herein shall be in writing and
shall be deemed given when  delivered  or  deposited in the United  States mail,
first  class,  postage  prepaid,  addressed  to the parties at their  respective
addresses set forth above, or at such other address as may be provided from time
to time.

18.  SURVIVAL OF  OBLIGATIONS:  All the terms and  conditions,  representations,
covenants,  warranties and agreements  contained in this MASTER LEASE and in any
Lease  Schedule or in any document in  connection  herewith  shall  specifically
survive the expiration or termination of this MASTER LEASE.

19. SEVERABILITY:  To the extent any provision of this MASTER LEASE or any Lease
Schedule is deemed partially or wholly invalid or unenforceable under applicable
law, such provision shall be effective to the extent valid and enforceable,  and
all other provisions shall remain in full force and effect.

20.  LESSOR'S  CONSENT:  When LESSOR'S  consent is required by the terms of this
MASTER LEASE, such consent shall not be unreasonably withheld.

<PAGE>


21. LEASE  SCHEDULE  REAFFIRMATION:  The  execution by LESSOR and LESSEE of each
Lease  Schedule  shall  constitute a  reaffirmation  by LESSEE of its covenants,
representations  and warranties  herein and that the same are true,  correct and
complete with respect to the Lease  Schedule as of the date of execution of each
Lease Schedule.

22.  HEADINGS:  All section  headings of this MASTER  LEASE are for  convenience
only,  and shall not in any way limit or  affect  the  meaning  or scope of this
MASTER LEASE or its provisions.

23. NO  WAIVER:  No delay,  omission  or failure to act by LESSOR at any time to
exercise or enforce any right or remedy herein provided shall be a waiver of any
such right or remedy to which LESSOR is entitled, nor shall it in any way affect
the right of LESSOR to enforce such provisions thereafter.

24. ENTIRE AGREEMENT:  This MASTER LEASE constitutes the entire agreement of the
parties hereto and no other written or oral  representations or warranties shall
be binding upon the parties hereto.  NO AGENT OR EMPLOYEE OF THE MANUFACTURER OR
SELLER OF THE EQUIPMENT IS AUTHORIZED TO BIND LESSOR TO THIS MASTER LEASE OR ANY
OTHER  AGREEMENT  OR TO  WAIVE  OR  MODIFY  ANY OF THE  PROVISIONS  HEREOF.  Any
modification  or waiver of any of the provisions  herein shall be effective only
if in writing and executed by all of the parties hereto,  provided  however that
LESSOR may add applicable  Equipment serial or  identification  numbers to Lease
Schedules and financing statements.

25.  SUCCESSOR:  This MASTER LEASE and each Lease Schedule shall be binding upon
and  shall  inure  to  the  benefit  of  LESSOR,  LESSEE  and  their  respective
successors, legal representatives and assigns.

26.  ADDITIONAL  FILINGS:  In the event that LESSEE  fails or refuses to execute
and/or file Uniform Commercial Code financing statements or other instruments or
recordings  which LESSOR or its Assignee  reasonably deems necessary to perfect,
or maintain  perfection  of,  LESSOR'S or its  Assignee's  interests  hereunder,
LESSEE   hereby   appoints   LESSOR  or  its   Assignee  as   LESSEE'S   limited
attorney-in-fact  to execute and record all  documents  reasonably  necessary to
perfect or maintain the perfection of LESSOR'S interest hereunder.  LESSEE shall
pay  LESSOR  or its  Assignee  for any costs and fees  relating  to the  filings
including,  but not limited to, costs,  fees,  searches,  document  preparation,
documentary stamps, privilege taxes and reasonable attorneys' fees.

27. MULTIPLE LESSEES: If more than one LESSEE is named within this MASTER LEASE,
the liability of each shall be joint and several.

28. LEASE  ACCEPTANCE:  At no time shall this MASTER LEASE or the Lease Schedule
be deemed to  constitute  an offer  binding  upon LESSOR until it is accepted by
execution of LESSOR at its corporate office in Rosemont, Illinois.


PRIME LEASING, INC.,                            PHYMED DIAGNOSTIC IMAGING
                                                CENTER-WHITE ROCK, INC.

              LESSOR                                             LESSEE


By:                                             By:
   ----------------------------------
Name (Printed):                                 Name           (Printed):
               ----------------------

Title:                                          Title:
      -------------------------------


Date:      , 2000 Date: February 11, 2000
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