<PAGE>
                                                                   Exhibit 10.21
    CONFIDENTIAL TREATMENT REQUESTED: CONFIDENTIAL PORTIONS OF THIS DOCUMENT
     HAVE BEEN REDACTED AND HAVE BEEN FILED SEPARATELY WITH THE COMMISSION.

                               RESELLERS AGREEMENT


         This Non-Exclusive Resellers Agreement (this "Agreement") is effective
as of the 18th day of October, 2000, by and between NOMOS(R) Corporation
(hereinafter "Supplier"), a manufacturer of IMRT solutions, having principal
office at 2591 Wexford Bayne Rd., Sewickley, PA, 15143, and Elekta Oncology
Systems Ltd. (hereinafter "Reseller"), a company involved in the manufacture,
marketing, sales, support, and distribution of Linear Accelerators, Simulators,
and Treatment Planning Systems, having its principal office located at Linac
House, Fleming Way, Crawley. England, UK and for North America at Elekta
Oncology Systems, Inc., 3155 Northwoods Parkway, Norcross, GA 30071:

                                    PREAMBLE

         WHEREAS, Supplier manufactures the CORVUS Planning System, known as
CORVUS, which Supplier is willing to provide to RESELLER on the terms and
conditions set forth herein; and

         WHEREAS, RESELLER intends to combine the CORVUS Planning System and
other equipment and/or software programs to create certain "RESELLER PRODUCT(S)"
as part of new accelerator sales and to market on a "turnkey" basis to
end-users,

         NOW, THEREFORE, in consideration of the premises hereof, and the mutual
obligations herein made and undertaken, the parties hereto agree as follows:

              1.  Definitions. For the purposes of this Agreement, the
definitions set forth in this Section shall apply to the respective capitalized
terms:

                  1.1      "CORVUS PLANNING SYSTEM." The hardware and software
                           products (including all model conversions, elements,
                           and accessories) that are listed in the attached
                           Exhibit A.

                  1.2      "DEMONSTRATION SYSTEMS." A prototype version of
                           CORVUS Planning System may be procured by RESELLER
                           from Supplier under this Agreement for use in the
                           creation and demonstration of RESELLER Products in a
                           non-clinical environment. The configuration of the
                           Demonstration System is described in more detail in
                           the attached Exhibit B.

                  1.3      "DOCUMENTATION." Those printed materials including
                           instruction manuals and marketing materials
                           pertaining to the CORVUS Planning System to be
                           furnished therewith, as described in the attached
                           Exhibit C





<PAGE>

                  1.4      "END-USER." A prospective linear accelerator customer
                           of RESELLER to whom RESELLER offers RESELLER Products
                           for use in the regular course of such customer's
                           business and not for resale.

                  1.5      "END-USER LICENSE AGREEMENT." The form of Supplier's
                           agreement under which Supplier directly grants an
                           End-User the right and license to use the CORVUS
                           Planning System as part of an RESELLER Product as
                           described in Attachment B, 2. 1.

                  1.6      "ENHANCEMENT(S)." Computer program modifications or
                           additions, other than Maintenance Modifications, that
                           may be integrated with the CORVUS Planning System or
                           offered separately by Supplier and that alter the
                           functionality of the CORVUS Planning System or add
                           new functions thereto.

                  1.7      "ERROR." A defect in the CORVUS Planning System that
                           prevents it from functioning in substantial
                           conformity with the published Specifications
                           pertaining thereto.

                  1.8      "MAINTENANCE MODIFICATION(S)." Computer software
                           changes to be integrated with the CORVUS Planning
                           System to correct any Errors therein, but that do not
                           alter the functionality of the CORVUS Planning System
                           or add new functions thereto.

                  1.9      "MARKETING TERRITORY." WorldWide, excluding Hong
                           Kong, Peoples Republic of China, Korea and Taiwan.

                  1.10     "RESELLER PRODUCTS." One or more combinations of
                           CORVUS Planning System with other equipment and
                           computer software independently developed or procured
                           by RESELLER, to be offered by RESELLER, together with
                           related services, to End-Users on a turnkey basis.

                  1.11     "PROGRAMS." The computer software, including all
                           Maintenance Modifications and Enhancements thereto
                           which constitute the basic operating system of the
                           CORVUS Planning System, is to be provided to
                           End-Users by RESELLER in unmodified form.

         2. RESELLER CERTIFICATION. RESELLER hereby certifies and agrees that,
in consideration of the benefits of this Agreement, including the discounts
granted to RESELLER with respect to CORVUS Planning System, RESELLER will add
significant value to, and enhance the functionality and/or capability of, the
CORVUS Planning System in conjunction with the CORVUS Planning System with other
computer equipment and/or computer software programs to produce RESELLER
Products, and shall offer such RESELLER on a turnkey basis. RESELLER further
certifies and agrees that it will market the CORVUS Planning System solely as
part of RESELLER Products and that RESELLER Products will be marketed by
RESELLER





                                      -2-
<PAGE>

for its own account in the normal course of its business solely to End-Users
having no affiliation or control relationship with RESELLER. In the event that
any of the foregoing representations and undertakings prove untrue at any time
during the term of this Agreement, Supplier shall have the right to terminate
this Agreement as to any or all further shipments to RESELLER or as to any or
all further copying and distribution of the CORVUS Planning System (including
any derivative works thereof) by RESELLER in the manner prescribed in Section 16
hereof.

         3.       Supplier's Responsibilities.

                  3.1      Subject to the terms and conditions of this
                           Agreement, Supplier shall:

                           1.       in respect of each potential order for
                                    CORVUS, provide RESELLER with information
                                    that is necessary in order to enable
                                    RESELLER to provide accurate advice and
                                    information to a potential Customer and,
                                    thereafter, shall provide such information
                                    as is reasonably requested by RESELLER.

                           2.       subsequent to Suppliers approval of an
                                    order, comply with the Regulations and the
                                    Product Specifications or Customer
                                    Specifications, as the case may be, with
                                    regard to manufacture of the Products.

                           3.       provide promotional materials, including
                                    product brochures, videos and CD-ROMs, and
                                    supply RESELLER with quantities upon request
                                    sufficient for presentation to prospective
                                    customers and End-Users as part of the
                                    marketing of RESELLER Products;

                           4.       supply to Elekta on request such
                                    documentation as Elekta may reasonably
                                    require to satisfy itself that all filing
                                    requirements imposed by the Regulations have
                                    been supplied to the appropriate regulatory
                                    authority or agency;

                           5.       grant RESELLER the rights and licenses to
                                    the CORVUS Planning System as set forth in
                                    Section 5 hereof;

                           6.       provide technical support for CORVUS
                                    Planning System as set forth in Section 8
                                    hereof;

                           7.       ship CORVUS Planning System to RESELLER as
                                    set forth in Section 1.2 hereof;

                           8.       warrant the CORVUS Planning System as set
                                    forth 'In Section 14 hereof;

                           9.       indemnify RESELLER as set forth in Section
                                    15 hereof;




                                      -3-
<PAGE>

                           10.      offer RESELLER Enhancements in the CORVUS
                                    Planning System on terms no less favorable
                                    than those offered to any similarly situated
                                    RESELLER.

                           11.      pass on to RESELLER promptly any complaints
                                    or unusual comments (whether favorable or
                                    unfavorable) with respect to CORVUS that it
                                    may receive;

                           12.      from time to time consult with RESELLER's
                                    representatives for the purpose of assessing
                                    the state of the market and communicating
                                    Product updates;

                           13.      ensure that all submission requirements
                                    imposed by Regulatory have been made to the
                                    appropriate regulatory authorities or
                                    agencies. SUPPLIER will supply to RESELLER
                                    upon request such documentation as RESELLER
                                    may reasonably require to satisfy itself the
                                    above has been met;

                           14.      supply to RESELLER all manuals and screen
                                    displays for CORVUS in English.

                  3.2      Customer Feedback Reporting

                           1.       If RESELLER receives a Customer complaint,
                                    oral or written, RESELLER will forward all
                                    material information to SUPPLIER, through
                                    the Customer Feedback Reporting Process, who
                                    will them become the owner;

                           2.       In the case where the incident complained of
                                    constitutes a reportable event according to
                                    the Regulations, RESELLER and SUPPLIER share
                                    responsibility to report to regulatory
                                    authorities as appropriate within the time
                                    frame defined;

                           3.       Defects and incidents shall be categorized
                                    and SUPPLIER will use best efforts to
                                    respond and deal with the complaint within
                                    the following timescales:

                                    a.       where the incident damage or defect
                                             complained of causes, threatens or
                                             may cause or threaten danger for a
                                             patient or personnel operating a
                                             Product, SUPPLIER shall rectify the
                                             same within 30 business days, All
                                             complaints relating to the same
                                             shall be replied to in full in
                                             writing within 7 Business Days;

                                    b.       where the incident, damage or
                                             defect complained of disables or
                                             impairs the use of CORVUS or causes
                                             an






                                      -4-
<PAGE>

                                             abnormal termination of the
                                             application/control of CORVUS,
                                             SUPPLIER shall rectify the same
                                             within 45 Business Days. All
                                             complaints relating to same shall
                                             be replied to in full in writing
                                             within 10 Business Days;

                                    c.       all other incidents, damage,
                                             defects, difficulties or requests
                                             shall be dealt with within 90
                                             Business Days. All complaints
                                             relating to the same shall be
                                             replied to in full in writing
                                             within 28 Business Days;

                                    d.       Time frames specified in this
                                             clause shall not override any time
                                             frames set down in a Regulation or
                                             imposed by the relevant regulatory
                                             body.

                           4.       In connection with remedial action
                                    generally, SUPPLIER shall use all reasonable
                                    efforts to rectify or solve the same and
                                    SUPPLIER agrees to provide RESELLER with
                                    specific corrective actions to reported
                                    field problems. Reasonable efforts shall be
                                    made by SUPPLIER to provide Customers with a
                                    written methodology, temporary modification,
                                    alternative or modification upgrade.

                           5.       SUPPLIER desires to undertake a recall of
                                    any CORVUS, SUPPLIER will immediately notify
                                    RESELLER and the parties will promptly
                                    discuss such recall, with such notification
                                    and discussion being made prior to any
                                    recall, to the extent permitted, in SUPPLIER
                                    judgment, by any applicable legal or safety
                                    constraints. Each party will maintain
                                    complete and accurate records for such
                                    periods as may be required by the
                                    Regulations in relation to CORVUS and will
                                    during, normal working hours provide the
                                    other with access to such records to the
                                    extent necessary to effect any recall. The
                                    parties will discuss and cooperate with each
                                    other in good faith as to the initiation and
                                    conduct of any recall, including
                                    communications with Customers in order to
                                    minimize the risk to any party for failure
                                    to follow any legal requirements for such
                                    recall.

                           6.       SUPPLIER shall provide RESELLER with a
                                    product performance report for CORVUS at
                                    periodic intervals if SUPPLIER deems
                                    appropriate.

         4.       RESELLER'S RESPONSIBILITIES.

         Subject to the terms and conditions of this Agreement, RESELLER shall:





                                      -5-
<PAGE>

                  1.       Combine the CORVUS Planning System with other
                           equipment and/or computer software programs
                           independently developed or procured by RESELLER so as
                           to create RESELLER Products;

                  2.       Market, sell, and deliver RESELLER Products to
                           End-Users in the Marketing Territory;

                  3.       Present the End-User License Agreement to all
                           prospective customers, obtain duly executed copies of
                           the End-User License Agreement from each End-User
                           prior to delivery of the CORVUS Planning System as
                           part of any RESELLER Products, and forward one copy
                           of each End-User License Agreement to Supplier
                           promptly after its signing;

                  4.       Order, pay for, take delivery of, and accept the
                           CORVUS Planning System as set forth in Section 12
                           hereof;

                  5.       Protect Supplier's proprietary rights in the CORVUS
                           Planning System as set forth in Section 6 hereof;

                  6.       Grant Supplier security interests and assist in their
                           perfection as set forth in Section 10 hereof; and

                  7.       Provide reseller exemption certificates to Supplier
                           as set forth in Section 11 hereof.

          5.       LICENSES GRANTED.

                  Supplier hereby grants to RESELLER a nonexclusive,
nontransferable right and license to copy the CORVUS Planning System Programs
for use as part of RESELLER Programs, to End-Users who have duly executed an
End-User License Agreement in the Marketing Territory during the term of this
Agreement. No modification or preparation of derivative works of the CORVUS
Planning System Program whatsoever is permitted.

          6.      Confidentiality of Information; Protection-and Security.

                  6.1      RESELLER shall use all reasonable efforts to protect
                           and defend the proprietary nature of the CORVUS
                           Planning System, including Enhancements and any
                           derivative works of the CORVUS Planning System.
                           Except as expressly provided otherwise in this
                           Agreement, RESELLER shall not copy, modify,
                           transcribe, store, translate, sell,lease, or
                           otherwise transfer or distribute any of the CORVUS
                           Planning System, including Enhancements, in whole or
                           in part, without prior authorization in writing from
                           Supplier.




                                      -6-
<PAGE>

                  6.2      All CORVUS Planning Systems incorporated into
                           RESELLER Products shall be marked with such
                           copyright, patent, or other notices; proprietary
                           legends; or restrictions as Supplier may require.

                  6.3      Unless specifically covered by a separate, signed
                           agreement, all information provided to Supplier by
                           RESELLER shall not be regarded as confidential or
                           proprietary.

         7. Expenses. It is expressly understood and agreed that Supplier is
under no obligation or requirement to reimburse RESELLER for any expenses or
costs incurred by RESELLER in the performance of its responsibilities under this
Agreement except as explicitly stated herein. Any costs or expenses incurred by
RESELLER shall be at RESELLER's sole risk and upon its independent business
judgment that such costs and expenses are appropriate.

         8.       Technical Support 37 Supplier:

                  Supplier shall provide End-Users with all other necessary
maintenance, training, and support. Under warranty or at standard CORVUS Service
Agreement rates. Such services shall include, without limitation, the following:

                  1.       Technical training regarding operation of the CORVUS
                           Planning System as set out in Exhibit A

                  2.       Consulting support is available to End-User(s)
                           regarding proper utilization, and optimization of
                           use, for the CORVUS Planning System

                  3.       Telephone hotline support during normal business
                           hours. Normal business hours are between 8:30AM and
                           5:30PM, relating to Eastern Standard Time zone.

                  4.       Maintenance and repair of CORVUS Planning System

                  5.       Distribution and application of Maintenance
                           Modifications and Enhancements.

         9.       TITLE.

                  9.1      Title to the CORVUS Planning Systems purchased under
                           this Agreement shall pass to RESELLER upon shipment
                           of such CORVUS Planning Systems to RESELLER from
                           Supplier's plant or warehouse.

                  9.2      Risk of loss or damage to the CORVUS Planning Systems
                           purchased under this Agreement shall pass to RESELLER
                           upon delivery to RESELLER or customer end point of
                           such CORVUS Planning Systems from Supplier's plant or
                           warehouse.




                                      -7-
<PAGE>

                  9.3      Title to the CORVUS Planning Systems Programs,
                           including any Enhancements, shall at all times remain
                           and vest solely with Supplier. RESELLER agrees that
                           it will not claim or assert title to any such
                           materials or attempt to transfer any title to
                           End-Users or any third parties.

         10. Security Interest. RESELLER hereby grants Supplier, and Supplier
hereby reserves, a purchase money security interest in and to all CORVUS
Planning Systems and all license rights in the CORVUS Planning Systems Programs,
including any Enhancements, delivered to RESELLER under this Agreement from time
to time, as security for the payment and performance by RESELLER of all its
obligations and liabilities to Supplier under this Agreement. RESELLER agrees to
assist and cooperate fully with Supplier in the perfection and enforcement of
such security interest. This security will not subsist in any products delivered
to Elekta customers but will remain in effect as to any proceeds received by
RESELLER from its Customers.

         11. Reseller Exemption Certification. RESELLER hereby certifies that it
either holds or will acquire prior to offering for resale a valid Reseller
Exemption Certificate issued by each taxing jurisdiction or entity in the
Marketing Territory where such certificate is required as a condition for the
avoidance of applicable sales or use taxes, covering any Computer Equipment to
be resold and any Programs to be licensed or sublicensed under this Agreement.
Prior to any shipment of RESELLER Products under this Agreement, RESELLER will
provide Supplier with a copy of each such certificate, thereby entitling
RESELLER to be treated by Supplier as exempt from collection of tax on such
RESELLER Products in each jurisdiction or entity from which a certificate is
obtained. RESELLER shall promptly notify Supplier of any additions, deletions,
or changes to such certificates. RESELLER shall indemnify and hold harmless
Supplier from and against any taxes, duties, tariffs, or other assessments
levied by or on behalf of any taxing jurisdiction or entity that fails to issue,
or disputes the validity or coverage of, any such exemption certificates.

         12.      Order, Delivery, and Administration

                  12.1 RESELLER shall place periodic. orders for CORVUS Planning
Systems during the term of this Agreement. The price for particular categories
of CORVUS Planning Systems and the discounts are separately set forth in
Attachment A. The terms and conditions of this Agreement, and Supplier's
standard Statement of Limited Warranty applicable to the CORVUS Planning
Systems, as in effect from time to time, shall control any and all procurement
of CORVUS Planning Systems by or on behalf of RESELLER hereunder and shall
supersede the terms of any purchase orders for CORVUS Planning Systems issued by
RESELLER at any time.

                  12.2 RESELLER shall use all reasonable efforts to attain a
global goal of $[* * *] in a rolling 12 month period of aggregate purchases of
CORVUS Planning Systems from Supplier for integration in RESELLER Products.
Supplier shall be entitled, in its discretion,


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

* * * Confidential material redacted and filed separately with the Commission.


                                      -8-
<PAGE>
to terminate this Agreement pursuant to Section 16 hereof if RESELLER fails to
attain such goal for any 12 consecutive months.

                  12.3 Supplier's shipment of the CORVUS Planning Systems
ordered by RESELLER shall be made consistent with Supplier's available
production volume and established shipping priorities. Supplier shall issue a
confirmation for each order submitted indicating the delivery date for each
CORVUS Planning System ordered. When such confirmation has been issued, it shall
be binding between the parties. Delivery shall not be more than 60 Business Days
after the date of issue of the Order beginning in 15t Quarter 2001 unless
otherwise agreed in writing by the Supplier. The Supplier shall notify Elekta
promptly if it anticipates any potential delay in fulfilling any Order by the
specified date.

                  12.4 RESELLER warrants that they shall maintain liability
insurance, including product liability insurance in accordance with RESELLER
corporate insurance indemnity.

          13.     Payment

                  13.1 RESELLER shall make payment to Supplier for all CORVUS
Planning Systems in accordance with the schedule set forth in Attachment A.
Supplier reserves the right to halt shipment of CORVUS Planning Systems, in
whole or in part, in the event of any delinquency in payment for any prior order
or shipment.

                  13.2 Terms and conditions of payment. All prices and all
payments made by Elekta to the Supplier hereunder shall be in the Currency $USD;

All prices are inclusive of:

Price agreed EX Works (Incoterms 1990). Freight and insurance will be charged
additionally to the address shown in the order; and

Warranty and the provision of any service thereunder during the applicable
warranty period and,

The RESELLER shall pay for the product according to the following payment
schedule:

         [* * *]% at time of Order, paid with purchase order;
         [* * *]% upon notification of shipment, and
         [* * *]% at time of acceptance. Acceptance is defined as demonstration
         of the Product to meet its specifications as defined in customer
         acceptance test procedure.

(See Attachment D).

The RESELLER and the SUPPLIER may discuss and mutually agree on a case by case
basis special payment terms based on payment terms received from the end user.


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

* * * Confidential material redacted and filed separately with the Commission.



                                      -9-
<PAGE>



 All payments are due upon receipt of invoice.

All prices are exclusive of VAT and similar taxes, which will be paid by
RESELLER. Demonstration System procured by RESELLER from Supplier under this
Agreement shall be supplied at cost price.

RESELLER shall collect from End-Users and pay over to Supplier, or shall cause
EndUsers to pay, the license fees for the CORVUS Planning Systems payable under
the EndUser License Agreement.

          14.      LIMITED WARRANTIES

                  14.1 Supplier warrants that all CORVUS Planning Systems will,
at the time of delivery, conform in all material respects to Supplier's most
current published Specifications pertaining to the CORVUS Planning Systems.
Supplier further warrants that the CORVUS Planning Systems will, under normal
and anticipated use, and when used in the specified operating environment, be
free from material operating defects. RESELLER may pass this warranty on to each
End-User by providing such End-User with a copy of Supplier's Standard Statement
of Limited Warranty.

                  14.2 Supplier's sole warranty regarding the CORVUS Planning
System is set forth in the End-User License Agreement.

                  14.3 The exclusive remedy of RESELLER and of any End-User
against Supplier for breach of any of the foregoing warranties shall be to seek
repair or replacement of the affected CORVUS Planning Systems, and, if such
repair or replacement is not effected after reasonable notice and opportunity
for remedial action by Supplier, to obtain repayment of any sales price or
royalty fee paid to Supplier for the affected CORVUS Planning Systems.

                  14.4 EXCEPT AS SET FORTH IN THIS SECTION 14, SUPPLIER
DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, WITHOUT
LIMITATION, ANY WARRANTIES AS TO THE SUITABILITY OR MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE OF ANY PRODUCTS OR PROGRAMS FURNISHED HEREUNDER OR
FOR ANY RESELLER PRODUCTS PREPARED BY RESELLER. IN NO EVENT SHALL SUPPLIER BE
LIABLE FOR ANY LOST OR ANTICIPATED PROFITS, OR ANY INCIDENTAL, EXEMPLARY,
SPECIAL, OR CONSEQUENTIAL DAMAGES, REGARDLESS OF WHETHER SUPPLIER WAS ADVISED OF
THE POSSIBILITY OF SUCH DAMAGES.

                  14.5 No action arising or resulting from this Agreement,
regardless of its form, may be brought by either party more than 2 years after
delivery of the affected products or programs by Supplier to RESELLER.

          15.     INDEMNIFICATION





                                      -10-
<PAGE>

                  15.1     By Supplier:

                           15.1.a Supplier hereby indemnifies and holds
harmless RESELLER from and against any claims, actions, or demands alleging that
the CORVUS Planning System infringe any patent, trademark, copyright, or other
intellectual property right of any third party. RESELLER shall permit Supplier
to replace or modify any affected CORVUS Planning System so to avoid
infringement, or to procure the right for RESELLER to continue use and
remarketing of such items. If neither of such alternatives is reasonably
possible, the infringing items shall be returned to Supplier and Supplier's sole
liability shall be refund amounts paid therefor by RESELLER. Supplier shall have
no obligation hereunder for or with respect to claims, actions, or demands
alleging infringement that arise by reason of combination of noninfringing items
with any items not supplied by Supplier.

                           15.1.b Supplier further indemnifies and holds
harmless RESELLER from and against any claims, actions, or demands arising out
of a breach by Supplier of Supplier's Standard Statement of Limited Warranty
with respect to any category of CORVUS Planning System, or a breach of the
End-User License Agreement with respect to the CORVUS Planning System. The
foregoing indemnity shall not apply to claims, demands, or actions arising from
the use of the CORVUS Planning System other than CORVUS Planning System
Equipment made by or on behalf of RESELLER or any EndUser.

                  15.2 RESELLER hereby indemnifies and holds harmless Supplier
from and against any and all claims, actions, or demands arising with respect to
any RESELLER Products, with the sole exception of those matters for which
Supplier bears responsibility under Section 15.1 hereof.

                  15.3 The foregoing indemnities are conditioned on prompt
written notice of any claim, action, or demand for which indemnity is claimed;
complete control of the defense and settlement thereof by the indemnifying
party; and cooperation of the other party in such defense.

          16.      TERMINATION

                  16.1 Supplier may terminate this Agreement if RESELLER at any
time fails to comply with the certification required under Section 21 hereof.

                  16.2 Supplier may terminate this Agreement for failure of
RESELLER to attain the annual goals set forth in Section 12 hereof for any 12
consecutive month period.

                  16.3 Should either party commit a material breach of its
obligations hereunder, or should any of the representations of either party in
this Agreement prove to be untrue in any material respect, the other party may,
at its option, terminate this Agreement, by 60 days' written notice of
termination, which notice shall identify and describe the basis for such
termination. If, prior to expiration of such period, the defaulting party cures
such default, termination shall not take place.




                                      -11-
<PAGE>

                  16.4 Either party hereto may, at its option and without
notice, terminate this Agreement, effective immediately, should the other party
hereto (1) admit in writing its inability to pay its debts generally as they
become due; (2) make a general assignment for the benefit of creditors; (3)
institute proceedings to be adjudicated a voluntary bankrupt, or consent to the
filing of a petition of bankruptcy against it, (4) be adjudicated by a court of
competent jurisdiction as being bankrupt or insolvent; (5) seek reorganization
under any bankruptcy act, or consent to the filing of a petition seeking such
reorganization; or (6) have a decree entered against it by a court of competent
jurisdiction appointing a receiver, liquidator, trustee, or assignee in
bankruptcy or in insolvency covering all or substantially all of such party's
property or providing for the liquidation of such party's property or business
affairs; or (7) with or without cause, if without cause then a 60 day minimum
notice shall be given by either party.

                  16.5 Termination of this Agreement shall not relieve either
party of the obligations incurred hereunder pursuant to Sections 6, 10, 11,
14-16, and 18 hereof, which Sections shall survive such termination.

                   16.6    On termination of this Agreement

                           16.6.1   The Supplier shall have the right to cancel
                                    all unfulfilled orders previously placed by
                                    RESELLER and accepted by the Supplier with
                                    the exception of orders required by RESELLER
                                    to fulfill contracts with Customers entered
                                    into prior to termination, which the
                                    Supplier shall continue to be bound to
                                    perform only if all outstanding payments
                                    have been and continue to be made by
                                    RESELLER.

                           16.6.2  RESELLER shall promptly return to the
                                   Supplier (or as the Supplier directs) all
                                   samples, technical pamphlets, photographs and
                                   advertising materials and any other
                                   materials, documents, papers or property of
                                   the Supplier whether supplied to RESELLER by
                                   the Supplier or its Associates or which
                                   RESELLER may otherwise have under its control
                                   at the time of termination, in each case
                                   related to the Products, and shall neither
                                   make nor retain copies of any of these, save
                                   that the Supplier shall permit RESELLER
                                   complete access to and to make copies of all
                                   relevant product drawings, Product
                                   Specifications, Customer Specifications, or
                                   similar records to permit RESELLER to fulfill
                                   commitments existing at the date thereof or
                                   continuing on an ongoing basis thereafter.

         17.      LIMITATION OF REPRESENTATIONS AND USE OF NAME BY RESELLER

                  17.1 RESELLER shall make no representations concerning
Supplier, the CORVUS Planning System, including any Maintenance Modifications or
Enhancements, except as set forth in the printed documentation furnished to
RESELLER by Supplier. RESELLER shall not reproduce, reference, distribute, or
utilize any trade name or trademark of Supplier, except



                                      -12-
<PAGE>

solely for purposes of identifying Supplier's products and programs, without the
prior written approval of Supplier.

                  17.2 RESELLER shall submit to Supplier for approval, prior to
use, distribution, or disclosure, any advertising, promotion, or publicity in
which the trade name or trademarks of the Supplier are used, or which is
otherwise undertaken pursuant to this Agreement. Supplier shall have the right
to require, at its discretion, the correction or deletion of any misleading,
false, or objectionable material from any such advertising, promotion, or
publicity.

                  17.3 RESELLER shall disclose the relationship between itself
and Supplier to End-Users, including the fact that RESELLER is receiving a
discount on products procured under this Agreement.

         18. Independent Contractor Status. RESELLER is an independent
contractor under this Agreement, and nothing herein shall be construed to create
a partnership, joint venture, or agency relationship between the parties hereto
with the sole exception that RESELLER acts as a licensing agent of Supplier with
respect to the CORVUS Planning System as provided herein. RESELLER shall have no
authority to enter into agreements of any kind on behalf of Supplier, other than
the presentation to customers of the End-User License Agreement with respect to
the CORVUS Planning System in strict accordance with the terms of this
Agreement, and shall have no further power or authority to bind or obligate
Supplier in any manner to any third party.

         19. COMPLIANCE WITH LAW. RESELLER shall comply with all applicable laws
and regulations of governmental bodies or agencies in its performance under this
Agreement.

         20. NO ASSIGNMENT. RESELLER represents that it is acting on its Own
behalf and is not acting as an agent for or on behalf of any third party, and
further agrees that it may not assign its rights or obligations under this
Agreement without the prior written consent of Supplier.

         21. NOTICES. All notices and other communications required or permitted
to be given under this Agreement shall be in writing and shall be considered
effective when deposited in the UK or U.S. mail as registered mail, return
receipt requested, postage prepaid, and addressed to the party at the address
noted above, unless by such notice a different address shall have been
designated in writing.

         22. GOVERNING LAW. All questions concerning the validity, operation,
interpretation, and construction of this Agreement will be governed by and
determined in accordance with the laws of the State of Pennsylvania.

         23. NO WAIVER. Neither party shall by mere lapse of time without giving
notice or taking other action hereunder be deemed to have waived any breach by
the other party of any of the provisions of this Agreement. Further, the waiver
by either party of a particular breach of this Agreement by the other party
shall not be construed as, or constitute, a continuing waiver of such breach, or
of other breaches of the same or other provisions of this Agreement.




                                      -13-
<PAGE>

         24. FORCE MAJEURE. Neither party shall be in default if failure to
perform any obligation hereunder is caused solely by supervening conditions
beyond that party's control, including acts of God, civil commotions, strikes,
labor disputes, and governmental demands or requirements.

         25. SEVERABILITY. If any provision of this Agreement shall be held
illegal, unenforceable, or in conflict with any law of a federal, state, or
local government having jurisdiction over this Agreement, the validity of the
remaining portions or provisions hereof shall not be affected thereby.

         26. NO CONFLICT OF INTEREST. RESELLER represents and warrants that it
has full power and authority to undertake the obligations set forth in this
Agreement. RESELLER currently have in place Non-Exclusive agreements which do
not render it incapable of satisfactorily performing its obligations hereunder,
or place it in a position of conflict of interest, or be inconsistent or in
conflict with its obligations hereunder.

         27. SCOPE OF AGREEMENT. Each of the parties hereto acknowledges that it
has read this Agreement, understands it, and agrees to be bound by its terms.
The parties further agree that this Agreement is the complete and exclusive
state of agreement and supersedes all proposals (oral or written),
understandings, representations, conditions, warranties, covenants, and all
other communications between the parties relating thereto. This Agreement may be
amended only by a writing that refers to this Agreement and is signed by both
parties.

         28. NOTICES. Any notice or other document to be given under this
agreement shall be in writing and shall be delivered personally or sent by
pre-paid first class mail ( or pre-paid airmail if posted to an address outside
the United Kingdom), overnight 'courier or facsimile transmission to the
respective address or facsimile number set out below or as may have been last
notified in writing by one party or the other party hereto:

                           To:     Elekta Oncology Systems, Ltd.
                                   Linac House, Fleming Way
                                   Crawley
                                   West Sussex RH10 2RR
                                   United Kingdom
                                   ATTN:  President





                                      -14-
<PAGE>



IN WITNESS WHEREOF this agreement is hereby executed on behalf of each of the
parties hereto by its duly authorized officer on and as of the date set at the
beginning of this document and shall continue for a period of 24 months.

Signed for and on behalf of
NOMOS CORPORATION:

/s/ William W. Wells          10/18/00
-------------------------------------------
William W. Wells
Vice President, Sales and Marketing

In the presence of:

/s/ [Illegible]
-------------------------------------------


Signed for and on behalf of
ELEKTA ONCOLOGY SYSTEMS, LTD:

/s/ Volker W. Stieber
-------------------------------------------
Volker W. Stieber
President and CEO

In the presence of:

/s/ Peter I. Gaccione
-------------------------------------------
Peter I. Gaccione
Vice President








                                      -15-
<PAGE>










                                    EXHIBIT A

                              CORVUS SPECIFICATIONS

                            [AVAILABLE UPON REQUEST]





<PAGE>





                                    EXHIBIT B

                       DEMONSTRATION SYSTEM SPECIFICATIONS

                            [AVAILABLE UPON REQUEST]



<PAGE>





                            EXHIBIT C, DOCUMENTATION

                             CORVUS(R) USER'S MANUAL

                              BEAM UTILITIES MANUAL

                                 CORVUS BROCHURE





<PAGE>




                                  ATTACHMENT A

                     ELEKTA PRICING, CORVUS PLANNING SYSTEM
                       PRICING IN EFFECT THROUGH 12/31/00



                                      List Price         Elekta Transfer Price
                                      ----------         ---------------------

1.     Domestic Basic CORVUS:         $175,000                 $[* * *]

2.     Domestic CORVUS Plus*          $200,545                 $[* * *]

3.     Int'l Basic CORVUS             $200,000                 $[* * *]

4.     Int'l CORVUS Plus*             $225,545                 $[* * *]



*      CORVUS PLUS Includes Options listed below and reflects a [* * *]%
       discount from list price on those options.


Image Fusion
Phantom Plan
Verification Phantom

 See Corresponding Proposals in Attachment B














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

* * * Confidential material redacted and filed separately with the Commission.

<PAGE>





                                  ATTACHMENT B

                               PROPOSAL TEMPLATES

                            [AVAILABLE UPON REQUEST]






<PAGE>







                                  ATTACHMENT C

                         ADDITIONAL TERMS AND CONDITIONS



Equipment

1.1   Risk of loss and title to the Equipment described in the Proposal shall
vest in Customer upon date of Delivery. Delivery means the date NOMOS delivers
the Equipment to a carrier of its choice. NOMOS will retain a security interest
in the Equipment until the Total Price for CORVUS is paid in full. Customer
will execute financing statements requested by NOMOS to perfect its security
interest in the Equipment. Customer shall keep the Equipment in good order and
repair until the Total Price for CORVUS has been paid in full.

Software

2.1   NOMOS grants Customer a nonexclusive, non-transferable, perpetual license
to use the Software described in the Proposal only for Customer's own internal
use and only on the Equipment which is part of CORVUS. Customer will not
modify, reverse assemble, or reverse compile the Software. NOMOS may
immediately terminate Customer's license to use the Software upon written
notice to Customer in the event Customer breaches any provision of Section 2.1
or Section 6.1 of this Attachment.

Warranty

3.1   NOMOS warrants that for one (1) year following completion of Acceptance
Testing (defined as demonstration of Product to meet its specifications), the
Equipment and the Software will substantially conform to the applicable
Documentation. NOMOS does not warrant that the Equipment and/or the Software
will meet Customer's requirements, that the operation of the Equipment or
Software will be uninterrupted, or that the Software will be free of errors.

3.2   NOMOS will make reasonable efforts to correct any breach of warranty
specified in Section 3.1 during the Warranty Period. If NOMOS cannot correct
the breach of warranty, NOMOS shall, at NOMOSA option, (i) replace the
Equipment or Software, or (ii) return the Total Price for CORVUS to Customer,
less a reasonable fee for Customers use of CORVUS. If NOMOS determines that any
alleged breach of warranty is caused by one of the factors listed in Section
3.3, Customer agrees to pay NOMOS its then current time and materials rates for
investigating and/or correcting the problem.

3.3   The following acts shall void the warranty obligations of NOMOS: (i)
modification or attempted modification of the Equipment and/or the Software;
(ii) failure to implement






<PAGE>

corrections, improvements, or revisions to the Equipment and/or the Software
provided by NOMOS; (iii) use of any unauthorized hardware with the Software or
any unauthorized software with the Equipment; or (iv) failure to fulfill
Customers obligations regarding CORVUS.

3.4   THE WARRANTY CONTAINED IN THIS SECTION IS IN LIEU OF ALL OTHER WARRANTIES,
EXPRESS, IMPLIED OR STATUTORY, INCLUDING WITHOUT LIMITATION THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE AND
WARRANTIES ARISING FROM COURSE OF DEALING OR USAGE OF TRADE.

Limitation of Liability

4.1   IN NO EVENT SHALL NOMOSA LIABILITY TO CUSTOMER EXCEED THE TOTAL PURCHASE
PRICE FOR CORVUS. NO ACTION REGARDLESS OF FORM MAY BE BROUGHT BY CUSTOMER
AGAINST NOMOS MORE THAN ONE (1) YEAR AFTER THE CAUSE OF ACTION HAS ARISEN.

4.2   NOMOS SHALL NOT BE LIABLE TO CUSTOMER OR TO ANY OTHER PARTY FOR ANY
SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES WHATSOEVER EVEN IF NOMOS
HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

Indemnification

5.1   If promptly notified in writing by Customer of an action, NOMOS agrees to
defend or settle at its option, and hold Customer harmless from, any action at
law or in equity arising from a claim that Customer's use of CORVUS infringes
any United States patent or copyright; provided that Customer gives NOMOS the
right to control and direct the investigation, preparation, defense, and
settlement of each claim and Customer fully cooperates with NOMOS or its
designee in connection with any and all claims. NOMOS shall have no liability
for claims based on Customer's use CORVUS with other programs or data, or
unauthorized hardware, or any modifications to CORVUS.

5.2   Customer shall indemnify, save harmless and defend NOMOS at Customer's
expense from and against any losses, damages, claims, or liabilities of any
nature, including but not limited to costs, expenses and reasonable attorney's
fees, which are threatened, brought against or incurred by NOMOS caused by
Customer's failure to comply with its obligations.

Confidentiality

6.1   Customer acknowledges CORVUS contains confidential, proprietary and trade
secret information of NOMOS and other third parties ("Confidential
Information"). Customer will not disclose, allow to be disclosed or otherwise
make available any Confidential Information to any third party without the
express written consent of NOMOS. Customer agrees to take the same precautions
to protect the confidentiality of the Confidential Information as it takes to
protect Customer's own confidential information.




<PAGE>

Equal Employment Opportunity/Affirmative Action Compliance

7.1   Incorporated into this Agreement are the provisions of Section 202 of
Executive Order 11246 as well as its implementing regulations; Section 503 of
the Rehabilitation Act of 1973, as amended; and the Vietnam Era Veterans
Readjustment Act. NOMOS certifies that it does not maintain any racially
segregated facilities; that unless otherwise exempt, it has developed and
maintains an Affirmative Action Program pursuant to 31 CFR 60-2: and that unless
otherwise exempt, it has filed an Annual Report EEO-l with the Joint Reporting
Committee. The parties to this Agreement represent and warrant that they each
believe in good faith that they are in compliance with all of the Federal,
State, and local laws which govern employment relationships and that neither
party will, during the performance of this Agreement, engage in any
discrimination based upon race, color, sex, religion, national origin,
disability or veteran's status.

Force Majeure

8.1   In the event that either party shall be delayed or hindered in, or
prevented from, the performance of any work, service or other acts required
under this Agreement to be performed by the party and such delay or hindrance
is due to strikes, lockouts, acts of God, governmental restrictions, enemy act,
civil commotion, unavoidable fire or other casualty, or other causes of a like
nature, service or other act shall be excused for a period of such delay and
the period for the performance of such work, service or other act shall be
extended for a period equivalent to the period of such delay. In no event shall
such delay constitute a termination of this Agreement. The provisions of this
paragraph shall not operate to excuse Customer from promptly remitting any
payments due hereunder. Written notice of any such delays, other than temporary
or emergency interruptions, shall be given to the other party as well as
written notice of the cessation of the same.

Default and Termination

9.1   Events of Default. Any one or more of the following shall constitute an
"Event of Default" under this Agreement:

      Payment Default. Failure by Customer to remit any payment provided for
under this Agreement for a period of seven (7) days after written notice from
NOMOS to Customer that such payment is due and unpaid.

      Non-Performance Default. Failure by Customer to perform or observe any
other covenant or condition contained in this Agreement which failure shall
continue for a period of thirty (30) days after written notice thereof by NOMOS
to Customer.

      Assignment for Benefit of Creditors. An assignment by Customer for the
benefit of creditors or the appointment of a receiver for Customer by legal
proceedings or otherwise.




<PAGE>

      Bankruptcy. Institution of bankruptcy proceedings by Customer, or
institution of bankruptcy proceedings against Customer which are not withdrawn
or dismissed within sixty (60) days after the institution of said proceedings.

9.2   Termination. In the event that Customer commits or allows an Event of
Default to occur or NOMOS terminates Customer's license to use the Software
pursuant to Section 2.1 herein, all amounts payable hereunder shall, at NOMOS'
option, immediately become due and payable as if by the terms of this Agreement
it were all payable in advance. At such time NOMOS may also serve Customer with
written notice as to the effective date of termination of the Agreement. In such
event, Customer shall have no right to avoid such termination by payment of any
sum due or by the performance of any condition, term or covenant broken.
Notwithstanding any statute, rule or law or decision of any court to the
contrary, Customer shall remain liable even after termination of this Agreement,
for the Total Price or any portion thereof due or to become due hereunder.

Miscellaneous

10.1  This Agreement is not transferable or assignable by Customer and any
attempted transfer or assignment will be void and of no force and effect. This
Agreement constitutes the complete and exclusive statement of the agreement
between the parties and supersedes all other contemporaneous or prior written or
oral agreements, representations or communications relating to the subject
matter of this Agreement. All notices under this Agreement shall be effective
when sent by overnight courier or certified mail, postage prepaid, to the other
party at the other party's last known address. Any failure of either party to
enforce any of the provisions of this Agreement will not be construed as a
waiver of such provisions or the right thereafter to enforce each and every such
provision. This Agreement may only be amended by a written amendment signed by
both parties.



<PAGE>





                                  ATTACHMENT D

                             CORVUS ACCEPTANCE TEST



3.9      Planning System

This test attempts to check the functionality of the basic CORVUS software. If
available, the user will read in a set of images from their CT or MR system and
import them into CORVUS. A plan in prescription mode will be calculated,
printouts made, and the approved plan transferred to the appropriate delivery
device.

         NOTE: IN CERTAIN CASES, CUSTOMER EQUIPMENT REQUIRED FOR THE FOLLOWING
         TESTS MAY NOT HAVE BEEN INSTALLED OR CONFIGURED FOR INTERACTION WITH
         CORVUS, AS A RESULT OF THIS, IT IS IMPOSSIBLE TO VERIFY COMPLETE
         FUNCTIONALITY OF THE CORVUS SYSTEM, NOMOS PERSONNEL WILL SHOW THE
         CUSTOMER AS MUCH AS POSSIBLE THAT THE SOFTWARE WORKS AS DESCRIBED. THIS
         SHALL BE DEEMED SUFFICIENT ACCEPTANCE OF THESE TESTS.

SPECIFICATIONS

            -     CT and/or MR images can be read-in and imported into the
                  CORVUS System using the appropriate devices or network.

            -     A plan prescription can be approved and calculated for IMRT
                  delivery.

            -     The plan results can be reviewed, printouts made, and the
                  plan approved and transferred to the appropriate
                  media/network for delivery.

            -     The treatment plan can be delivered using the customer's
                  equipment.

            -     A CORVUS patient plan can be backed up and restored using the
                  DAT backup device.

            -     All CORVUS planning system hardware and software functions
                  correctly (floppy disk, DAT Tape, CD-ROM, Mouse, Screen,...)

TEST SETUP

STEP 1: Set up the site treatment planning system computer, with the Corvus
Treatment Planning System loaded.

STEP 2: Check for the interface with the CT tape reader and printers.





<PAGE>

STEP 3:   Have the linear accelerator and MLC available for the plan delivery
          or
          Have the linear accelerator and the NffMiC available with all
          peripheral devices needed to use the MIMiC for the plan delivery
          (compressor, power supply unit, umbilicals, and connections).

TEST METHOD

              Reading CT / MR Images
              ----------------------
              [REPEAT FOR EACH CT/MR FILTER PURCHASED]

STEP 1: Ready the images for use by CORVUS. (For media transfer, place media in
appropriate drive and place drive on-line. For network/DICOM transfer, send
images from the appropriate CT/MR device to the CORVUS workstation.)

STEP 2: Step 2: From the CORVUS Open Panel, select Read Raw Data using the
appropriate transfer device.

STEP 3: After checking all available images, CORVUS will display a panel
allowing selection of an individual image dataset. Select one dataset for
creation of a new patient document. CORVUS will then read the dataset and create
the new document.

STEP 4: Once patient document creation is complete, CORVUS will return to the
Open Panel, and the new patient document will be displayed. Select this document
and approve Patient Information.

STEP 5: CORVUS will then move to Image Registration mode. Review the images as
received to check for appropriate orientation and labeling of patient position
(Head First/Feet First, Prone/Supine, Axial/SagittaU...). Check that the screen
labels agree with the orientation.

         Prescription and Plan Calculation
         ---------------------------------

STEP 1: From the CORVUS Open Panel, select a sample patient that uses a
treatment machine and delivery device resembling the customer's equipment (e.g.
Varian w/MlMiC, Siemens w/MLC, ...).

STEP 2: Make a copy of the specific patient plan for calculation and testing.

STEP 3: Open the copy of the patient plan in Prescription mode. Approve the
prescription to restart the planning process.

STEP 4: Observe that the patient plan moves through the planning pipeline as
described in the CORVUS Users Manual.

              Results Review and Print-Outs
              -----------------------------




<PAGE>

STEP 1: Once the plan selected above has completed planning, open the patient in
Display mode.

STEP 2: Select on the Print Screen button in the lower left comer to print the
current screen. Check that the printout completes.

STEP 3: Select the Target Center Report from the Report Generator menu. Click
Print Report to print this report. Check that the printout completes.

STEP 4: Use the NeXTStep print utility [alt-P] to print the screen image. Check
that the printout completes.

              Plan Approval and Delivery
              --------------------------

STEP 1: Using the plan selected above, click on the Approve Plan button. At this
point, the system will check that all appropriate checks have been made on the
patient document, then transfer the patient information through the selected
transfer mode for delivery. This transfer mode could be floppy disk jMIMiC,
Varian DMLC), Network jVARiS, LANTiS) or other mechanisms as supported by NOMOS
and configured. Check that Plan Approval succeeds.

STEP 2: Following the instructions for the particular delivery device, set up
the linear accelerator for delivery of the treatment. This may require that the
Delivery Report information be printed by CORVUS for complete set-up of the
linear accelerator.

STEP 3: Import the delivery information into the accelerator or Verify & Record
system if needed. Check that the delivery parameters are accepted by the
delivery device.

STEP 4: Deliver the test treatment. Observe that the delivery instructions
written by CORVUS are processed and executed by the linear accelerator and
delivery equipment. Check that the treatment completes successfully.

              Patient Study Backup and Restore
              --------------------------------

STEP 1: Place a fresh DAT tape in the tape drive on the CORVUS Planning
workstation. Check that the tape loads into the drive, the mount lights flash
for a period of time, then turn a steady green, indicating proper loading of the
tape.

STEP 2: From the CORVUS Open panel, select a single patient study for backup.
Start the backup task and watch that it completes successfully and the screen
returns to the OPEN panel.

STEP 3: Remove the tape from the DAT drive, then re-load it.

STEP 4: From the CORVUS OPEN panel, select Restore from backup. CORVUS should
read the tape and provide the user with a list of studies contained on the tape.
Select the single study and start the restore process.




<PAGE>

STEP 5: Verify that the restore process completes successfully and that a copy
of the original study selected now is visible on the OPEN panel along with the
original study.

              CORVUS Planning System Hardware
              -------------------------------

Test any additional peripherals not operated during the above tests to verify
their proper operation. This might include floppy disk, CD-ROM drive, or other
CORVUS devices.

If all steps have been completed successfully, initial and date the Acceptance
Tests Signature form on the appropriate line. If a test fails, indicate the
device and type of failure in the space provided.