Exhibit 10.1

FOURTH AMENDMENT
TO
RIGHTS AGREEMENT
 
This FOURTH AMENDMENT (this “Amendment”) dated as of January 14, 2008 to the
Rights Agreement, dated as of October 14, 1998 (the “ Rights Agreement“), as
previously amended, by and between North American Scientific, Inc., a Delaware
corporation (the “Company“), and Computershare Trust Company, N.A., a federally
chartered trust company (successor Rights Agent to U.S. Stock Transfer
Corporation) (the “Rights Agent“), is entered into between such parties.
Capitalized terms used but not defined herein are used herein as defined in the
Rights Agreement.
 
WHEREAS, the Board of Directors of the Company has authorized and approved a
private placement involving the offering, sale and issuance by the Company of
shares (the “Shares”) of the Company’s common stock, par value $0.01 per share
(“Common Stock”), and warrants to purchase additional shares of Common Stock
(the “Warrants,” and collectively with the additional shares of Common Stock
purchasable thereby and the Shares, the “Securities”) to a limited group of
sophisticated investors (the “Investors”) pursuant to Securities Purchase
Agreements and related transaction agreements or instruments (the “2008 Private
Placement”). The Securities Purchase Agreement dated as of December 12, 2007 by
and among the Company and the Investors in connection with the foregoing and any
other related transaction agreements or instruments are referred to herein as
the “2008 Private Placement Documents”;

WHEREAS, the willingness of the investors to enter into the Securities Purchase
Agreements is conditioned upon, among other things, the supplement or amendment
of the Rights Agreement on the terms set forth herein;

WHEREAS, no “Distribution Date,” “Share Acquisition Date,” “Redemption Date” or
“Final Expiration Date” (as such terms are defined in the Rights Agreement) has
occurred;

WHEREAS, pursuant to Section 26 of the Rights Agreement, under circumstances set
forth therein, (i) the Company may supplement or amend any provision of the
Rights Agreement without the approval of any holders of certificates
representing shares of Common Stock of the Company, and (ii) upon the delivery
of a certificate from an appropriate officer of the Company which states that
the proposed supplement or amendment is in compliance with the terms of Section
26 of the Rights Agreement, the Rights Agent shall execute such supplement or
amendment;

WHEREAS, the Company desires to amend the Rights Agreement as set forth herein
and to direct the Rights Agent to execute this Amendment;

WHEREAS, this Amendment shall become effective immediately; and

 
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WHEREAS, the Board of Directors of the Company has adopted a resolution
determining that the amendment of the Rights Agreement on the terms set forth
herein is advisable and in the best interests of the Company and its
stockholders;

NOW, THEREFORE, in consideration of the premises and the mutual agreements
herein set forth, the parties agree as follows:

1. Effectiveness of this Amendment. This Amendment is executed pursuant to the
first sentence of Section 26 of the Rights Agreement. The Company, by its
execution of this Amendment, hereby directs the Rights Agent to execute this
Amendment. This Amendment shall take effect immediately upon the execution
hereof by the Company and the delivery of the certificate required pursuant to
Section 26 of the Rights Agreement; provided, however, that if the 2008 Private
Placement is not closed for any reason, this Amendment shall be deemed rescinded
and of no further force and effect.

2. Certification of Appropriate Officer. The undersigned officer of the Company,
being duly authorized on behalf of the Company, hereby certifies on behalf of
the Company to the Rights Agent that (a) he is an “appropriate officer” as such
term is used in Section 26 of the Rights Agreement, and (b) this Amendment is in
compliance with Section 26 of the Rights Agreement.

3. Defined Terms. All capitalized terms used but not defined in this Amendment
shall have the meanings assigned to them in the Rights Agreement.

4. No Other Provisions Affected. Except to the extent expressly amended by this
Amendment, all of the provisions of the Rights Agreement shall remain in full
force and effect.

5. Amendment to the Rights Agreement. The Rights Agreement is hereby amended as
follows:

(a) Acquiring Person. The definition of “Acquiring Person” in Section 1(a) of
the Rights Agreement is hereby amended by adding to the end of the first
paragraph thereof the following:

“; provided further, however, that the investors in the 2008 Private Placement
(the “2008 Investors”) shall not be deemed to be an “Acquiring Person” due to
(a) the execution and delivery of the 2008 Private Placement Documents, (b) the
announcement or commencement thereof, including, without limitation, the
acquisition by the 2008 Investors of any of the Securities issued or issuable
pursuant to the 2008 Private Placement, and/or (c) the exercise of stock options
to purchase shares of the Company’s common stock held by the 2008 Investors or
their affiliates or the acquisition by the 2008 Investors or their affiliates of
shares of the Company’s common stock as a result of grants made to the 2008
Investors or their affiliates or acquisitions of shares of the Company’s common
stock by the 2008 Investors or their affiliates in connection with such 2008
Investors’ or their affiliates’ role as a member of the board of directors of
the Company.”

 
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(b) Distribution Date. Section 1(g) of the Rights Agreement is hereby amended by
inserting the following sentence at the end of such Section 1(g):

“In addition, notwithstanding anything to the contrary contained herein, no
Distribution Date shall occur solely as a result of the execution and delivery
of the 2008 Private Placement Documents (or any amendments thereto in accordance
with the terms thereof), or any actions taken by the 2008 Investors pursuant to
the terms of any of the 2008 Private Placement Documents or the consummation of
the transactions contemplated by the 2008 Private Placement Documents or the
announcement or commencement thereof, including, without limitation, the
acquisition by the 2008 Investors of any of the Securities issued or issuable
pursuant to the 2008 Private Placement Documents.”

(c) Share Acquisition Date. Section 1(v) of the Rights Agreement is hereby
amended by inserting the following sentence at the end of such Section 1(v):

“In addition, notwithstanding anything to the contrary contained herein, no
Share Acquisition Date shall occur solely as a result of the execution and
delivery of the 2008 Private Placement Documents (or any amendments thereto in
accordance with the terms thereof), or any actions taken by the 2008 Investors
pursuant to the terms of any of the 2008 Private Placement Documents or the
consummation of the transactions contemplated by the 2008 Private Placement
Documents or the announcement or commencement thereof, including, without
limitation, the acquisition by the 2008 Investors of any of the Securities
issued or issuable pursuant to the 2008 Private Placement Documents.”
 
(d) Adjustment of Purchase Price, Number and Kind of Securities or Number of
Rights. Section 11(a)(ii)(C) of the Rights Agreement is hereby amended by adding
to the end of the first paragraph thereof the following:
 
“; provided further, however, that a Person shall not be deemed to have become
the Beneficial Owner of 20% or more of the Common Shares then outstanding for
the purposes of this Section 11(a)(ii)(C) as a result of the exercise of stock
options to purchase shares of the Company’s common stock held by the 2008
Investors or their affiliates or the acquisition by the 2008 Investors or their
affiliates of shares of the Company’s common stock as a result of grants made to
the 2008 Investors or their affiliates or acquisitions of shares of the
Company’s common stock by the 2008 Investors or their affiliates in connection
with such 2008 Investors’ or their affiliates’ role as a member of the board of
directors of the Company.”
 
(e) Adjustment of Purchase Price, Number and Kind of Securities or Number of
Rights. Section 11 of the Rights Agreement is hereby amended by adding to the
end thereof the following:
 
“(o) Notwithstanding anything to the contrary contained herein, the provisions
of this Section 11 shall not apply to or be triggered by the execution and
delivery of the of the 2008 Private Placement Documents (or any amendments
thereto in accordance with the terms thereof), or any actions taken by the 2008
Investors pursuant to the terms of any of the 2008 Private Placement Documents,
or the consummation of the transactions contemplated by the 2008 Private
Placement Documents, or the announcement or commencement thereof, including,
without limitation, the acquisition by the 2008 Investors of any of the
Securities issued or issuable pursuant to the 2008 Private Placement Documents.”

 
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(f) Consolidation, Merger or Sale or Transfer of Assets or Earning Power.
Section 13 of the Rights Agreement is hereby amended by adding to the end
thereof the following:

“(f) Notwithstanding anything to the contrary contained herein, the provisions
of this Section 13 shall not apply to or be triggered by the execution or
delivery of the of the 2008 Private Placement Documents (or any amendments
thereto in accordance with the terms thereof), or any actions taken by the 2008
Investors pursuant to the terms of any of the 2008 Private Placement Documents,
or the consummation of the transactions contemplated by the 2008 Private
Placement Documents, or the announcement or commencement thereof, including,
without limitation, the acquisition by the 2008 Investors of any of the
Securities issued or issuable pursuant to the 2008 Private Placement Documents.”

(g) References to Rights Agent. All references in the Rights Agreement to “U.S.
Stock Transfer Corporation” shall for all purposes be deemed to refer to
“Computershare Trust Company, N.A.”

(h) Amendment to Section 1(c) of the Rights Agreement. Section 1(c) of the
Rights Agreement is hereby amended by deleting the phrase “State of California”
and replacing it with the phrase “Commonwealth of Massachusetts”.

(i) Amendment to Section 1(d) of the Agreement. Section 1(d) of the Rights
Agreement is hereby amended by deleting the term “Pacific” in both instances and
replacing each with the term “Eastern”.

(j) Amendment to Section 2 of the Agreement. Section 2 of the Agreement is
hereby amended by (i) adding the following language to the end of the second
sentence: “; upon ten (10) days’ prior written notice to the Rights Agent.”; and
(ii) adding the following language after the last sentence: “The Rights Agent
shall have no duty to supervise, and shall in no event be liable for, the acts
or omissions of any such Co-Rights Agent.”

 
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(k) Amendment to Section 21 of the Agreement. Section 21 of the Agreement is
hereby amended and replaced in its entirety as follows:

“Change of Rights Agent. The Rights Agent or any successor Rights Agent may
resign and be discharged from its duties under this Agreement upon 30 calendar
days’ notice in writing mailed to the Company and to each transfer agent of the
Common Shares by registered or certified mail, and to the holders of the Right
Certificates by first-class mail. In the event the transfer agency relationship
in effect between the Company and the Rights Agent terminates, the Rights Agent
will be deemed to have resigned automatically and be discharged from its duties
under this Agreement as of the effective date of such termination, and the
Company shall be responsible for sending any required notice. The Company may
remove the Rights Agent or any successor Rights Agent upon 30 calendar days’
notice in writing, mailed to the Rights Agent or successor Rights Agent, as the
case may be, and to each transfer agent of the Common Shares by registered or
certified mail, and to the holders of the Right Certificates by first-class
mail. If the Rights Agent shall resign or be removed or shall otherwise become
incapable of acting, the Company shall appoint a successor to the Rights Agent.
If the Company shall fail to make such appointment within a period of 30
calendar days after giving notice of such removal or after it has been notified
in writing of such resignation or incapacity by the resigning or incapacitated
Rights Agent or by the holder of a Right Certificate (who shall, with such
notice, submit his Right Certificate for inspection by the Company), then the
registered holder of any Right Certificate may apply to any court of competent
jurisdiction for the appointment of a new Rights Agent. Any successor Rights
Agent, whether appointed by the Company or by such a court, shall be a
corporation organized and doing business under the laws of the United States or
of any state of the United States, in good standing, which is authorized under
such laws to exercise corporate trust or stockholder services powers and is
subject to supervision or examination by federal or state authority and which
has at the time of its appointment as Rights Agent, along with its Affiliates, a
combined capital and surplus of at least $50 million. After appointment, the
successor Rights Agent shall be vested with the same powers, rights, duties and
responsibilities as if it had been originally named as Rights Agent without
further act or deed; but the predecessor Rights Agent shall deliver and transfer
to the successor Rights Agent any property at the time held by it hereunder, and
execute and deliver any further assurance, conveyance, act or deed necessary for
the purpose. Not later than the effective date of any such appointment, the
Company shall file notice thereof in writing with the predecessor Rights Agent
and each transfer agent of the Common Shares, and mail a notice thereof in
writing to the registered holders of the Right Certificates. Failure to give any
notice provided for in this Section 21, however, or any defect therein, shall
not affect the legality or validity of the resignation or removal of the Rights
Agent or the appointment of the successor Rights Agent, as the case may be.”

(l) Amendment to Section 26 of the Agreement. Section 26 of the Agreement is
hereby amended to add the following phrase at the end of the next to last
sentence thereof: “so long as such supplement or amendment shall not adversely
affect the rights, duties or obligations of the Rights Agent under this
Agreement.”
 
 
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(m) Amendment to the Agreement. The Rights Agreement is hereby amended to add
the following new section:

“Section 35. Force Majeure. Notwithstanding anything to the contrary contained
herein, the Rights Agent shall not be liable for any delays or failures in
performance resulting from acts beyond its reasonable control including, without
limitation, acts of God, terrorist acts, shortage of supply, breakdowns or
malfunctions, interruptions or malfunction of computer facilities, or loss of
data due to power failures or mechanical difficulties with information storage
or retrieval systems, labor difficulties, war, or civil unrest.”

6. References to the Rights Agreement. All references in the Rights Agreement,
and the exhibits thereto, to the Rights Agreement or any specific provision
thereof (including references that use the terms “hereto” and “hereof”), as well
as in the legends affixed to certificates issued for Common Stock pursuant to
Section 3(c) of the Rights Agreement, shall, without any specific references
expressly and individually to any of the foregoing amendments, automatically be
deemed references to the Rights Agreement or the applicable specific provisions
thereof (as the case may be) as amended by this Amendment, with the same force
and effect as if expressly and individually amended in that respect by this
Amendment.

7. Governing Law. This Amendment shall be governed by and construed in
accordance with the laws of the State of Delaware without reference to the
conflicts or choice of law principles thereof.

8. Counterparts. This Amendment may be executed in any number of counterparts,
each of which shall be deemed an original, and all of which together shall
constitute one and the same instrument.

9. Fax Transmission. A facsimile, telecopy or other reproduction of this
Amendment may be executed by one or more parties hereto, and an executed copy of
this Amendment may be delivered by one or more parties hereto by facsimile or
similar instantaneous electronic transmission device pursuant to which the
signature of or on behalf of such party can be seen, and such execution and
delivery shall be considered valid, binding and effective for all purposes. At
the request of any party hereto, all parties hereto agree to execute an original
of the Amendment as well as any facsimile, telecopy or other reproduction
thereof.

 
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IN WITNESS WHEREOF, the Parties have caused this Amendment to be duly executed
and attested as of the date and year first above written.
 
 
 
 
 
NORTH AMERICAN SCIENTIFIC, INC.
 
 
 
 
 
 
 
By:  
/s/ James W. Klingler
 
Name: James W. Klingler
 
Its: Sr.V.P. & Chief Financial Officer

 
 
 
 
 
COMPUTERSHARE TRUST COMPANY, N.A.
 
 
 
 
 
 
 
By:  
/s/ Kellie Gwinn
 
Name: Kellie Gwinn
 
Its:Vice President

 
 
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