Exhibit
      10.2

     

    WARRANT
      AGREEMENT 

     

    WARRANT
      AGREEMENT dated as of [__], 2007 between North American Scientific, Inc., a
      Delaware corporation (the “Company”),
      and
      [Computershare Investor Services, a ___________ corporation] (the “Warrant
      Agent”).

     

    The
      Company proposes to issue stock purchase warrants (hereinafter called the
“Warrants”).
      Each
      Warrant entitles the holder thereof to purchase, within seven (7) years from
      the
      offering date, one share of common stock, par value $0.01 per share (the
“Common
      Stock”),
      at a
      purchase price equal to $0.246 per share. The Warrant Agent, at the request
      of
      the Company, has agreed to act as the agent of the Company in connection with
      the issuance, registration, transfer, exchange, and exercise of the
      Warrants.

     

    NOW,
      THEREFORE, in consideration of the premises and mutual agreements herein set
      forth:

     

    SECTION
      1. Appointment
      of Warrant Agent.
      The
      Company hereby appoints the Warrant Agent to act as agent for the Company in
      accordance with the instructions hereinafter set forth in this Agreement, and
      the Warrant Agent hereby accepts such appointment. The Company may from time
      to
      time appoint such Co-Warrant Agents as it may deem necessary or desirable.
      The
      Company shall promptly notify the Warrant Agent from time to time in writing
      of
      the number of Warrants to be issued and furnish written instructions in
      connection therewith.

     

    SECTION
      2. Form
      of Warrant Certificates.
      The
      Warrant Certificates (and the forms of election to purchase shares and of
      assignment to be printed on the reverse thereof) shall be substantially of
      the
      tenor and purport recited in Exhibit
      A
      hereto
      and may have such letters, numbers or other marks of identification or
      designation and such legends, summaries or endorsements printed, lithographed
      or
      engraved thereon as the Company may deem appropriate and as are not inconsistent
      with the provisions of this Warrant Agreement, or as may be required to comply
      with any law or with any rule or regulation made pursuant thereto or with any
      rule or regulation of any national security association and/or stock exchange
      on
      which the Warrants may from time to time be listed or quoted, or to conform
      to
      usage. The Warrant Certificates shall be dated as of the date of issuance
      thereof by the Warrant Agent, either upon initial issuance or upon transfer
      or
      exchange, and each Warrant represented by a Warrant Certificate initially shall
      entitle the holder thereof to purchase one share of Common Stock, but the number
      of such shares and the purchase price per share of Common Stock shall be subject
      to adjustments as provided herein.

     

    SECTION
      3. Countersignature
      and Registration.
      The
      Warrant Certificates shall be executed on behalf of the Company by the President
      and Chief Executive Officer and the Chief Financial Officer, by facsimile
      signature, and shall be attested by the Secretary of the Company by facsimile
      signature. The Warrant Certificates shall be manually countersigned by the
      Warrant Agent and shall not be valid for any purpose unless so countersigned.
      In
      case any officer of the Company who shall have signed any of the Warrant
      Certificates shall cease to be such officer of the Company before
      countersignature by the Warrant Agent and issuance and delivery by the Company,
      such Warrant Certificates, nevertheless, may be countersigned by the Warrant
      Agent, issued and delivered with the same force and effect as though the person
      who signed such Warrant Certificates had not ceased to be such officer of the
      Company; and any Warrant Certificates may be signed on behalf of the Company
      by
      any person who, at the actual date of the execution of such Warrant
      Certificates, shall be a proper officer of the Company to sign such Warrant
      Certificates, although at the date of the execution of this Warrant Agreement
      any such person was not such an officer.

     

    
      
         

      

      
         

        
          

        

      

      
         

      

    

    The
      Warrant Agent will keep or cause to be kept, at one of its offices in the [City
      of Glendale, State of California], books for registration and transfer of the
      Warrant Certificates issued hereunder. Such books shall show the names and
      addresses of the respective holders of the Warrant Certificates, the number
      of
      Warrants evidenced on its face by each of the Warrant Certificates, and the
      date
      of each of the Warrant Certificates.

     

    The
      Warrant Agent shall countersign a Warrant Certificate only (a) upon initial
      issuance of the Warrants in accordance with the written order signed by an
      authorized officer of the Company or (b) upon exchange, transfer or substitution
      for one or more previously countersigned Warrant Certificates as hereinafter
      provided.

     

    SECTION
      4. Transfer
      and Exchange.
      Subject
      to Section 6 hereof, the Warrant Agent shall, from time to time, register the
      transfer, in whole or in part, of any outstanding Warrant Certificate upon
      the
      books to be maintained by the Warrant Agent for that purpose, upon surrender
      thereof for transfer properly endorsed or accompanied by appropriate instruments
      of transfer and written instructions for transfer. Upon any such registration
      of
      transfer, a new Warrant Certificate shall be issued to the transferee and the
      surrendered Warrant Certificate shall be canceled by the Warrant Agent. Any
      Warrant Certificate may be exchanged at the option of the holder thereof, upon
      surrender at the office of the Warrant Agent specified in Section 21 hereof,
      for
      another Warrant Certificate, or other Warrant Certificates of different
      denominations, representing in the aggregate the right to purchase a like number
      of shares of Common Stock. No fractional Warrant Certificates will be issued.
      The Company may require payment of a sum sufficient to cover any tax or
      governmental charge that may be imposed in connection with any transfer or
      exchange of Warrant Certificates.

     

    SECTION
      5. Warrant
      Common Stock.
      As
      hereinafter used in this Agreement, “Warrant
      Common Stock”
shall
      mean only Common Stock, and stock of any other class into which such presently
      authorized Common Stock may hereafter be changed, issuable upon exercise or
      exchange of the Warrant. In case, by reason of the operation of Section 7,
      the
      Warrants shall entitle the registered holders thereof to purchase any other
      shares of stock or other securities or property of the Company or of any other
      corporation, any reference in this Agreement to the exercise of Warrants shall
      be deemed to refer to and include the purchase of such other shares of stock
      or
      other securities or property upon such exercise.

     

    SECTION
      6. Warrant
      Price.
      The
      purchase price for each share of Common Stock pursuant to the exercise of a
      Warrant shall be equal to $0.246 per share (the “Warrant
      Price”),
      in
      each case as adjusted pursuant to Section 7 hereof, and shall be payable in
      lawful money of the United States of America in accordance with Section 9
      hereof.

     

    
      
         

      

      
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    SECTION
      7. Warrant
      Adjustments.
      The
      Warrant Price and the number of shares purchasable upon exercise of a Warrant
      shall be subject to adjustment as follows:

     

    (a) Stock
      Dividends, Subdivisions, Combinations and Reclassifications.
      In case
      the Company shall at any time after the date of this Agreement (i) declare
      a
      dividend on the Common Stock payable in shares of Common Stock, (ii) subdivide
      the outstanding Common Stock, (iii) combine the outstanding Common Stock into
      a
      smaller number of shares, or (iv) issue any shares of its capital stock in
      a
      reorganization or reclassification of the Common Stock (including any such
      reorganization or reclassification in connection with a consolidation or merger
      in which the Company is the continuing corporation), the Warrant Price in effect
      at the time of the record date for such dividend or of the effective date of
      such subdivision, combination, reorganization or reclassification, and/or the
      number and kind of shares of capital stock issuable upon exercise of the
      Warrants on such date shall be proportionately adjusted so that the holder
      of
      any Warrant exercised after such time shall be entitled to receive the aggregate
      number and kind of shares of capital stock which, if such Warrant had been
      exercised immediately prior to such date and at a time when the Common Stock
      transfer books of the Company were open, such holder would have owned upon
      such
      exercise and been entitled to receive by virtue of such dividend, subdivision,
      combination, reorganization or reclassification. Such adjustment shall be made
      successively whenever any event listed above shall occur.

     

    (b) Rights
      Upon Distribution of Assets or Other Property.
      In case
      the Company shall at any time after the date of this Agreement declare or make
      any dividend or other distribution of its assets (or rights to acquire its
      assets) to holders of shares of Common Stock, by way of return of capital or
      otherwise (including, without limitation, any distribution of cash, stock or
      other securities not addressed by Section 7(a), property or options not
      addressed by Section 7(a) by way of a dividend, spin off, reclassification,
      corporate rearrangement, scheme of arrangement or other similar transaction)
      (a
“Distribution”),
      then,
      in each such case:

     

    (i) any
      Warrant Price in effect immediately prior to the close of business on the record
      date fixed for the determination of holders of shares of Common Stock entitled
      to receive the Distribution shall be reduced, effective as of the close of
      business on such record date, to a price determined by multiplying such Warrant
      Price by a fraction of which (i) the numerator shall be the Closing Bid Price
      (as defined below) of a share of Common Stock on the trading day immediately
      preceding such record date minus the value of the Distribution (as determined
      in
      good faith by the Company’s Board of Directors) applicable to one share of
      Common Stock, and (ii) the denominator shall be the Closing Bid Price of the
      shares of Common Stock on the trading day immediately preceding such record
      date; and

     

    (ii) the
      number of Warrant Shares shall be increased to a number of shares equal to
      the
      number of shares of Common Stock obtainable immediately prior to the close
      of
      business on the record date fixed for the determination of holders of shares
      of
      Common Stock entitled to receive the Distribution multiplied by the reciprocal
      of the fraction set forth in the immediately preceding paragraph (ii); provided
      that in the event that the Distribution is of shares of common stock
      (“Other
      Shares of Common Stock”)
      of a
      company whose common shares are traded on a national securities exchange or
      a
      national automated quotation system, then any holder of each Warrant may elect
      to receive a warrant to purchase Other Shares of Common Stock in lieu of an
      increase in the number of Warrant Shares, the terms of which shall be identical
      to those of this Agreement and the Warrants, except that such warrant shall
      be
      exercisable into the number of shares of Other Shares of Common Stock that
      would
      have been payable to the holder of each Warrant pursuant to the Distribution
      had
      such holder exercised its Warrant immediately prior to such record date and
      with
      an aggregate exercise price equal to the product of the amount by which the
      exercise price of such Warrant was decreased with respect to the Distribution
      pursuant to the terms of the immediately preceding paragraph (i) and the number
      of Warrant Shares calculated in accordance with the first part of this paragraph
      (ii).

     

    
      
         

      

      
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    (iii) As
      used
      above, “Closing
      Bid Price”
means
      the last closing bid price for the Common Stock on the Nasdaq Global Market,
      as
      reported by Bloomberg Financial Markets or its successor (“Bloomberg”),
      or,
      if the Nasdaq Global Market operates on an extended hours basis and does not
      designate the closing bid price or the closing trade price, as the case may
      be,
      then the last bid price of such security prior to 4:00:00 p.m., New York Time,
      as reported by Bloomberg, or, if the Nasdaq Global Market is not the principal
      securities exchange or trading market for such security, the last closing bid
      price of such security on the principal securities exchange or trading market
      where such security is listed or traded as reported by Bloomberg, or if the
      foregoing do not apply, the last closing bid price of such security in the
      over-the-counter market on the electronic bulletin board for such security
      as
      reported by Bloomberg, or, if no closing bid price is reported for such security
      by Bloomberg, the average of the bid prices, or the ask prices, respectively,
      of
      any market makers for such security as reported in the “pink sheets” by Pink
      Sheets LLC (formerly the National Quotation Bureau, Inc.). If the Closing Bid
      Price cannot be calculated on a particular date on any of the foregoing bases,
      the Closing Bid Price of such security on such date shall be the fair market
      value as mutually determined by the Company and the holder of the
      Warrant.

     

    (c) Consolidation,
      Merger or Sale of Assets.
      If,
      while any Warrants remain unexercised, the Company shall at any time consolidate
      with or merge into another corporation, the holder of any Warrants will
      thereafter receive, upon the exercise thereof in accordance with the terms
      of
      this Agreement, the securities or property to which the holder of the number
      of
      shares of Common Stock then deliverable upon the exercise or conversion of
      such
      Warrants would have been entitled upon such consolidation or merger, and the
      Company shall take such steps in connection with such consolidation or merger
      as
      may be necessary to assure that the provisions hereof shall thereafter be
      applicable, as nearly as reasonably may be, in relation to any securities or
      property thereafter deliverable upon the exercise of the Warrants. The Company
      or the successor corporation, as the case may be, shall execute and deliver
      to
      the Warrant Agent a supplemental agreement so providing, and the terms of any
      agreement pursuant to which any such consolidation or merger is effected shall
      include terms requiring the Company or the successor corporation to comply
      with
      the provisions of this subsection (c). A sale of all or substantially all the
      assets of the Company for a consideration (apart from the assumption of
      obligations) consisting primarily of securities shall be deemed a consolidation
      or merger for the foregoing purposes. The provisions of this subsection (c)
      shall similarly apply to successive mergers or consolidations or sales or other
      transfers.

     

    (d) Calculations
      to the Nearest Cent and One-Hundredth of a Share.
      No
      adjustment in the Warrant Price shall be required unless such adjustment would
      require an increase or decrease of at least 1% in such price; provided, however,
      that any adjustments which by reason of this Section 7(d) are not required
      to be
      made shall be carried forward and taken into account in any subsequent
      adjustment. All calculations under this Section 7 shall be made to the nearest
      cent and to the nearest one-hundredth of a share as the case may be.
      Notwithstanding the first sentence of this subsection (d), any adjustment
      required by this Section 7 shall be made no later than the earlier of six months
      from the date of the transaction which mandates such adjustment or the
      expiration of the right to exercise any Warrant.

     

    
      
         

      

      
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    (e) Notice
      of Warrant Adjustment.
      Whenever the Warrant Price or the number of shares purchasable upon exercise
      of
      a Warrant shall be adjusted as provided in this Section 7, the Company shall
      forthwith file with the Warrant Agent a certificate, signed by a firm of
      independent public accountants, showing in detail the facts requiring such
      adjustment and the Warrant Price and number of shares so purchasable that will
      be effective after such adjustment. The Company shall also cause a notice
      setting forth any adjustments to be sent by mailing first class, postage
      prepaid, to each registered holder of a Warrant or Warrants at its address
      appearing on the Warrant register and, at its option, may cause a copy of such
      notice to be published once in an English language newspaper of general
      circulation in the City of New York, New York. The Warrant Agent shall have
      no
      duty with respect to any certificate filed with it except to keep the same
      on
      file and available for inspection by registered holders of Warrants during
      reasonable business hours. The Warrant Agent shall not at any time be under
      any
      duty or responsibility to any holder of a Warrant to determine whether any
      facts
      exist which may require any adjustment of the Warrant Price, or with respect
      to
      the nature of any adjustment of the Warrant Price when made, or with respect
      to
      the method employed in making such adjustment.

     

    (f) Other
      Notices.
      In case
      the Company after the date hereof shall propose to take any action of the type
      described in subsections (a), (b) or (c) of this Section 7, the Company shall
      file with the Warrant Agent a certificate, signed by the President and Chief
      Executive Officer or the Chief Financial Officer of the Company and by its
      Secretary or Assistant Secretary specifying, in the case of any action of the
      type specified in subsections (a), (b) or (c), the date on which such action
      shall take place and shall also set forth such facts with respect thereto as
      shall be reasonably necessary to indicate the effect of such action (to the
      extent such facts may be known on the date of such notice) on the Warrant Price
      and the number, or kind, or class of shares or other securities or property
      which shall be purchasable upon exercise of Warrants. The Company shall also
      cause a notice setting forth any adjustments to be sent by mailing first class,
      postage prepaid, to each registered holder of a Warrant Certificate or Warrant
      Certificates at its address appearing on the Warrant register and, at its
      option, may cause a copy of such notice to be published once in an English
      language newspaper of general circulation in the City of New York, New York.
      Failure to give such notice or any defect therein shall not affect the legality
      or validity of such action.

     

    (g) No
      Change in Warrant Terms on Adjustment.
      Irrespective of any of the adjustments in the Warrant Price or the number of
      shares of Warrant Common Stock, Warrant Certificates theretofore or thereafter
      issued may continue to express the same prices and number of shares as are
      stated in a similar Warrant Certificate issuable initially, or at some
      subsequent time, pursuant to this Agreement and such number of shares specified
      therein shall be deemed to have been so adjusted.

     

    (h) Treasury
      Shares.
      Shares
      of Common Stock at any time owned by the Company shall not be deemed to be
      outstanding for purposes of any computation under this Section 7.

     

    
      
         

      

      
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    (i) Optional
      Reduction in Warrant Price.
      Anything in this Section 7 to the contrary notwithstanding, the Company shall
      be
      entitled to make such reductions in the Warrant Price, in addition to those
      adjustments required by this Section 7, as it in its sole discretion shall
      determine to be necessary in order that any (1) consolidation
      or subdivision of the Common Stock, (2) issuance wholly for cash of any Common
      Stock at less than the Current Market Price, (3) issuance wholly for cash of
      Common Stock or securities which by their terms are convertible into or
      exchangeable for Common Stock, (4) stock
      dividend, or (5) issuance
      of rights, options or warrants referred to hereinabove in this Section 7,
      hereinafter made by the Company to its common stockholders, shall not be taxable
      to them.

     

    The
      Company may, at its option, at any time during the term of the Warrants, reduce
      the then current Warrant Price to any amount deemed appropriate by the Board
      of
      Directors of the Company, for any length of time.

     

    SECTION
      8. Current
      Market Price.
      For all
      purposes of this Agreement, the Current Market Price per share of Common Stock
      on any date shall be deemed to be the average of the daily closing prices for
      the five consecutive business days commencing before such date. The closing
      price for each day shall be the average of the closing bid and asked prices,
      as
      reported by the Nasdaq Global Market or a similar source selected from time
      to
      time by the Company for the purpose. If on any such date the shares of Common
      Stock are not quoted by any such source, the fair value of such shares on such
      date, as determined by the Board of Directors of the Company, shall be
      used.

     

    SECTION
      9. Exercise
      of Warrants.
      (a)
      Subject to the provisions of this Agreement, at any time 180 days after the
      date
      hereof and at or prior to 12:30 p.m. Pacific Time on [__], 2014, each registered
      holder of Warrants shall have the right, which may be exercised as in such
      Warrant Certificates expressed, to purchase from the Company (and the Company
      shall issue and sell to such registered holders of Warrants) all or part of
      the
      number of fully paid and nonassessable shares of Warrant Common Stock specified
      in such Warrant Certificates (subject to the adjustments as herein provided),
      upon surrender to the Company at the office of the Warrant Agent specified
      in
      Section 21 hereof, of such Warrant Certificates with the exercise form on the
      reverse thereof duly filled in and signed, and upon payment to the Warrant
      Agent
      to the account of the Company of the Warrant Price for the number of shares
      of
      Warrant Common Stock in respect of which such Warrants are then exercised.
      The
      date of exercise of any Warrant shall be deemed to be the date of its receipt
      by
      the Warrant Agent duly filled in and signed and accompanied by proper funds
      as
      hereinafter provided. Payment of such Warrant Price may be made in wire transfer
      in immediately available funds, cash, or by certified or official bank check.
      No
      adjustment shall be made for any cash dividends on shares of Warrant Common
      Stock issuable upon exercise of a Warrant. Upon such surrender of Warrants,
      and
      payment of the Warrant Price as aforesaid, the Company shall issue and cause
      to
      be delivered with all reasonable dispatch to or upon the written order of the
      registered holder of such Warrants and in such name or names as such registered
      holder may designate, a certificate or certificates for the number of full
      shares of Warrant Common Stock so purchased upon the exercise of such Warrants
      together with cash as provided in Section 11 of this Agreement, in respect
      of
      any fraction of a share of such stock issuable upon such surrender.

     

    
      
         

      

      
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    Each
      person in whose name any certificate for shares of Common Stock is issued upon
      the exercise of Warrants shall for all purposes be deemed to have become the
      holder of record of the Common Stock represented thereby on, and such
      certificate shall be dated, the date upon which the Warrant Certificate
      evidencing such Warrants was duly surrendered and payment of the Warrant Price
      (and any applicable transfer taxes) was made; provided, however, that if the
      date of such surrender and payment is a date upon which the Common Stock
      transfer books of the Company are closed, such person shall be deemed to have
      become the record holder of such shares on, and such certificate shall be dated,
      the next succeeding business day on which the Common Stock transfer books of
      the
      Company are open.

     

    (b)
      In
      addition to the method of payment set forth in paragraph 9(a) and in lieu of
      any
      cash payment required thereunder, each registered holder of the Warrants shall
      have the right to exercise the Warrant in full or in part by surrendering to
      the
      Company at the office of the Warrant Agent specified in Section 21 hereof,
      such
      Warrant Certificates with the exercise form on the reverse thereof duly filled
      in and signed. The number of shares of Warrant Common Stock to be issued
      pursuant to this paragraph (b) shall be equal to the difference
      between:

     

    (i) the
      number of shares of Warrant Common Stock in respect of which the Warrant
      Certificate is exercised; and

     

    (ii) a
      fraction, the numerator of which shall be the number of shares of Common Stock
      in respect of which the Warrant Certificate is exercised multiplied by the
      Warrant Price and the denominator of which shall be the Current Market Price
      (as
      defined in Section 8 hereof) of the Common Stock.

     

    (c)
      [Limitations
      on Exercise of Warrants.
      Notwithstanding anything to the contrary contained herein, the number of Warrant
      Shares that may be acquired by a registered holder of Warrants upon any exercise
      of Warrants (or otherwise in respect hereof) shall be limited to the extent
      necessary to insure that, following such exercise (or other issuance), the
      total
      number of shares of Common Stock then beneficially owned by such holder and
      its
      affiliates for purposes of Section 13(d) of the Securities Exchange Act of
      1934,
      as amended (the “Exchange
      Act”),
      does
      not exceed 14.9% of the total number of issued and outstanding shares of Common
      Stock (including for such purpose the shares of Common Stock issuable upon
      such
      exercise of Warrants). For such purposes, beneficial ownership shall be
      determined in accordance with Section 13(d) of the Exchange Act and the rules
      and regulations promulgated thereunder.]
      [Note:
      this provision would be for the investors that do not want to trip this 14.9%
      threshold. For the warrants issued to Three Arch Partners and any other investor
      who so chooses, there would be no limitation on
      exercise.]

     

    SECTION
      10. Unexercised
      Warrants.
      To the
      extent that any Warrant Certificates remain outstanding at the expiration of
      the
      period during which the Warrants are exercisable, the unexercised Warrants
      represented thereby shall be deemed null and void.

     

    SECTION
      11. Elimination
      of Fractions.
      The
      Company shall not be required to issue fractional shares of stock upon any
      exercise of Warrants. As to any final fraction of a share which the same
      registered holder of one or more Warrants, the rights under which are exercised
      in the same transaction or series of related transactions, would otherwise
      be
      entitled to purchase upon such exercise, the Company shall pay a cash adjustment
      in respect of such final fraction in an amount equal to the same fraction of
      the
      Current Market Price (as determined in the manner prescribed in Section 8
      hereof) on the business day which next precedes the day of
      exercise.

     

    
      
         

      

      
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    SECTION
      12. Issue
      Taxes.
      The
      Company will pay documentary stamp taxes, if any, attributable to the initial
      issuance of shares of Warrant Common Stock upon the exercise of any Warrant;
      provided, however, that neither the Company nor the Warrant Agent shall be
      required to pay any tax or taxes which may be payable in respect of any transfer
      involved in the issue or delivery of any certificates for shares of Warrant
      Common Stock in a name other than that of the registered holder of Warrants,
      in
      respect of which such shares are initially issued.

     

    SECTION
      13. Reservation
      of Shares.
      The
      Company shall at all times during the period in which the Warrants are
      exercisable reserve and keep available out of its authorized but unissued stock,
      for the purpose of effecting the issuance of stock upon exercise of Warrants,
      such number of shares of its duly authorized Warrant Common Stock as shall
      from
      time to time be sufficient to effect the issuance of shares of Warrant Common
      Stock upon exercise of all Warrants at the time outstanding.

     

    SECTION
      14. Merger
      or Consolidation or Change of Name of Warrant Agent.
      Any
      corporation into which the Warrant Agent may be merged or with which it may
      be
      consolidated, or any corporation resulting from any merger or consolidation
      to
      which the Warrant Agent shall be a party, or any corporation succeeding to
      the
      corporate trust business of the Warrant Agent, shall be the successor to the
      Warrant Agent hereunder without the execution or filing of any paper or any
      further act on the part of any of the parties hereto, anything herein to the
      contrary notwithstanding. In the case of Warrants which have been countersigned
      by the Warrant Agent, but not delivered at the time any such successor to the
      Warrant Agent succeeds to the agency created by this Agreement, any such
      successor may adopt the countersignature of the original Warrant Agent and
      deliver such Warrants so countersigned; and in case at that time any of the
      Warrants shall not have been countersigned, any successor to the Warrant Agent
      may countersign such Warrants either in the name of the predecessor Warrant
      Agent or in the name of the successor Warrant Agent; and in all such cases
      such
      Warrants shall have the full force and effect provided in the Warrants and
      in
      this Agreement.

     

    In
      case
      at any time the name of the Warrant Agent shall be changed and at such time
      any
      of the Warrants shall have been countersigned but not delivered, the Warrant
      Agent may adopt the countersignature under its prior name and deliver Warrant
      Certificates so countersigned, and in case at that time any of the Warrant
      Certificates shall not have been countersigned, the Warrant Agent may
      countersign such Warrant Certificates either in its prior name or in its changed
      name; and in all such cases such Warrant Certificates shall have the full force
      and effect provided in the Warrant Certificates and in this
      Agreement.

     

    SECTION
      15. Disposition
      of Proceeds on Exercise of Warrants, etc.
      The
      Warrant Agent shall account promptly to the Company with respect to Warrants
      exercised and concurrently pay to the Company all moneys received by the Warrant
      Agent for the purchase of shares of Common Stock through the exercise of such
      Warrants.

     

    The
      Warrant Agent shall keep copies of this Agreement available for inspection
      by
      holders of Warrants during normal business hours at its office specified in
      Section 21 hereof.

     

    
      
         

      

      
        8

        
          

        

      

      
         

      

    

    SECTION
      16. Supplements
      and Amendments.
      The
      parties hereto may from time to time supplement or amend this Agreement without
      the approval of any holders of Warrants to cure any ambiguity or to correct
      or
      supplement any provision contained in this Agreement which may be defective
      or
      inconsistent with any other provision contained herein, or to make such other
      provisions with respect to any change or any supplemental agreement as the
      parties may deem necessary or desirable and which shall not materially adversely
      affect the interests of the registered holders of the Warrants. 

     

    SECTION
      17. Mutilated
      or Missing Warrant Certificates.
      If any
      Warrant shall be mutilated, lost, stolen or destroyed the Warrant Agent shall
      deliver a new Warrant Certificate of like tenor and denomination in exchange
      and
      substitution therefor upon surrender and cancellation of the mutilated Warrant
      Certificate or, in the case of a lost, stolen or destroyed Warrant Certificate,
      upon receipt of evidence satisfactory to the Company and the Warrant Agent
      of
      the loss, theft or destruction of such Warrant Certificate and, in either case,
      upon receipt of such indemnity as the Company and the Warrant Agent may
      reasonably require. Applicants for substitute Warrant Certificates shall also
      comply with such other reasonable regulations and pay such other reasonable
      charges as the Warrant Agent or the Company may prescribe. Any such new Warrant
      Certificate shall constitute an original contractual obligation of the Company,
      whether or not the allegedly lost, stolen, mutilated or destroyed Warrant
      Certificate shall be at any time enforceable by anyone.

     

    SECTION
      18. Duties
      of the Warrant Agent.
      The
      Warrant Agent undertakes the duties and obligations imposed by this Warrant
      Agreement upon the following terms and conditions, by all of which the Company
      and the holders of Warrants, by their acceptance thereof, shall be
      bound:

     

    The
      Warrant Agent shall not be liable for or by reason of any of the statements
      of
      fact or recitals contained in this Agreement or in the Warrant Certificates
      (except its countersignature thereof and except such as describes the Warrant
      Agent or action taken or to be taken by it) or be required to verify the same,
      but all such statements and recitals are and shall be deemed to have been made
      by the Company only. The Warrant Agent shall not be under any responsibility
      in
      respect of the validity of this Agreement or the execution and delivery hereof
      or in respect of the validity or execution of any Warrant Certificate (except
      its countersignature thereof); nor shall it be responsible for any breach by
      the
      Company of any covenant or condition contained in this Agreement or in any
      Warrant Certificate to be complied with by the Company; nor shall it be
      responsible for the making of any adjustment in the Warrant Price or the number
      of shares issuable upon the exercise of a Warrant required under the provisions
      of Section 7 or responsible for the manner, method or amount of any such change
      or the ascertaining of the existence of facts that would require any such
      change; nor shall it by any act hereunder be deemed to make any representation
      or warranty as to the authorization or reservation of any shares to be issued
      pursuant to this Agreement or any Warrant or as to whether any shares will,
      when
      issued, be validly issued and fully paid and non-assessable.

     

    The
      Warrant Agent may execute and exercise any of the rights or powers hereby vested
      in it or perform any duty hereunder either itself or by or through its
      attorneys, agents or employees, and the Warrant Agent shall not be answerable
      or
      accountable for any act, default, neglect or misconduct of any such attorneys,
      agents or employees or for any loss to the Company resulting from such neglect
      or misconduct, provided reasonable care had been exercised in the selection
      and
      continued employment thereof.

     

    
      
         

      

      
        9

        
          

        

      

      
         

      

    

    The
      Warrant Agent may consult at any time with legal counsel satisfactory to it
      (who
      may be legal counsel for the Company) and the advice of such counsel shall
      be
      full and complete authorization and protection to the Warrant Agent as to any
      action taken or omitted by it in good faith and in accordance with such
      advice.

     

    The
      Warrant Agent shall incur no liability or responsibility to the Company or
      to
      any holder of a Warrant Certificate for any action taken in reliance on any
      notice, resolution, waiver, consent, order, certificate, or other paper,
      document or instrument believed by it to be genuine and to have been signed,
      sent or presented by the proper party or parties.

     

    The
      Company agrees to pay to the Warrant Agent reasonable compensation for all
      services rendered by the Warrant Agent in the execution of this Warrant
      Agreement, to reimburse the Warrant Agent for all expenses (including reasonable
      counsel fees), taxes and governmental charges and other charges of any kind
      and
      nature incurred by the Warrant Agent in the execution of this Warrant Agreement
      and to indemnify the Warrant Agent and save it harmless against any and all
      liabilities, including judgments, costs and reasonable counsel fees, for
      anything done or omitted by the Warrant Agent in the execution of this Warrant
      Agreement except as a result of the Warrant Agent's negligence, willful
      misconduct or bad faith.

     

    The
      Warrant Agent and any stockholder, director, officer or employee of the Warrant
      Agent may buy, sell, or deal in any of the Warrants or other securities of
      the
      Company or become pecuniarily interested in any transaction in which the Company
      may be interested, or contract with or lend money to the Company or otherwise
      act as fully and freely as though it were not Warrant Agent under this Warrant
      Agreement. Nothing herein shall preclude the Warrant Agent from acting in any
      other capacity for the Company or for any other legal entity.

     

    The
      Warrant Agent shall act hereunder solely as agent for the Company and in a
      ministerial capacity, and its duties shall be determined solely by the
      provisions hereof. The Warrant Agent shall not be liable for anything which
      it
      may do or refrain from doing in connection with this Agreement except for its
      own negligence, willful misconduct or bad faith.

     

    SECTION
      19. Change
      of Warrant Agent.
      The
      Warrant Agent may resign and be discharged from its duties under this Agreement
      upon 30 days’ notice in writing mailed to the Company by registered or certified
      mail and the Company shall subsequently mail such notice to the holders of
      the
      Warrant Certificates by first-class mail. The Company may remove the Warrant
      Agent or any successor Warrant Agent upon 30 days’ notice in writing, mailed to
      the Warrant Agent or successor Warrant Agent, as the case may be, and to each
      transfer agent of the Common Stock by registered or certified mail, and to
      the
      holders of the Warrant Certificates by first-class mail. If the Warrant Agent
      shall resign or be removed or shall otherwise become incapable of acting, the
      Company shall appoint a successor to the Warrant Agent. If the Company shall
      fail to make such appointment within a period of 30 days after such removal
      or
      after it has been notified in writing of such resignation or incapacity by
      the
      resigning or incapacitated Warrant Agent or by the holder of a Warrant
      Certificate (who shall, with such notice, submit such holder's Warrant
      Certificate for inspection by the Company), then the registered holder of any
      Warrant Certificate may apply to any court of competent jurisdiction for the
      appointment of a new Warrant Agent. Any successor Warrant 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 the States of
      California or New York, in good standing, having its principal office in the
      City of New York, New York or the City of Los Angeles, California, which is
      authorized under such laws to exercise corporate trust powers and is subject
      to
      supervision or examination by federal or state authority and which has at the
      time of its appointment as Warrant Agent a combined capital and surplus of
      at
      least $5,000,000. After appointment, the successor Warrant Agent shall be vested
      with the same powers, rights, duties and responsibilities as if it had been
      originally named as Warrant Agent without further act or deed; but the
      predecessor Warrant Agent shall deliver and transfer to the successor Warrant
      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 such appointment the Company shall file notice
      thereof in writing with the predecessor Warrant Agent and each transfer agent
      of
      the Common Stock, and mail a notice thereof in writing to the registered holders
      of the Warrant Certificates. Failure to give any notice provided for in this
      Section 19, however, or any defect therein, shall not affect the legality or
      validity of the resignation or removal of the Warrant Agent or the appointment
      of the successor Warrant Agent, as the case may be.

     

    
      
         

      

      
        10

        
          

        

      

      
         

      

    

    SECTION
      20. Identity
      of Transfer Agent.
      Forthwith upon the appointment of any subsequent Transfer Agent for shares
      of
      the Common Stock, the Company will file with the Warrant Agent a statement
      setting forth the name and address of such Transfer Agent.

     

    SECTION
      21. Notices.
      Any
      notice pursuant to this Agreement to be given by the Warrant Agent or by the
      registered holder of any Warrant to the Company shall be sufficiently given
      if
      sent by first-class mail, postage prepaid, addressed (until another address
      is
      filed in writing by the Company with the Warrant Agent) as follows:

     

    North
      American Scientific, Inc.

    20200
      Sunburst Street

    Chatsworth,
      California 91311

    Attention:
      James Klingler

    Telephone
      No.: (818) 734-8600

    Telecopy
      No.: (818) 734-5224

    


    with
      a
      copy to:

    


    Seyfarth
      Shaw LLP

    131
      South
      Dearborn Street, Ste. 2400

    Chicago,
      Illinois 60603

    Attention:
      Allan Reich

    Telephone
      No.: (312) 460-5000

    Telecopy
      No.: (312) 460-7000

    


    
      
         

      

      
        11

        
          

        

      

      
         

      

    

    Any
      notice pursuant to this Agreement to be given by the Company or by the
      registered holder of any Warrant to the Warrant Agent shall be sufficiently
      given if sent by first-class mail, postage prepaid, addressed (until another
      address is filed in writing by the Warrant Agent with the Company) as
      follows:

     

    [Computershare
      Investor Services

    1745
      Garden Avenue

    Glendale,
      California

    Attention:
      Syed Hussaini]

    


    SECTION
      22. Successors.
      All the
      covenants and provisions of this Agreement by or for the benefit of the Company
      or the Warrant Agent shall bind and inure to the benefit of their respective
      successors and assigns hereunder.

     

    SECTION
      23. Governing
      Law.
      This
      Agreement and each Warrant issued hereunder shall be deemed to be a contract
      made under the laws of the State of New York, and for all purposes shall be
      construed in accordance with the laws of the State of New York, without regard
      to principles of conflict of laws.

     

    SECTION
      24. Benefits
      of this Agreement.
      Nothing
      in this Agreement shall be construed to give to any person or entity other
      than
      the Company, the Warrant Agent and the registered holders of the Warrant
      Certificates any legal or equitable right, remedy or claim under this Agreement;
      but this Agreement shall be for the sole and exclusive benefit of the Company,
      the Warrant Agent and the registered holders of the Warrant Certificates. None
      of this Warrant Agreement, the Warrants Certificates nor the Warrants shall
      entitle the holders of the Warrant Certificates to any voting rights or any
      rights as a stockholder of the Company. The rights and obligations of the
      Company, the Warrant Agent, the holder and any holder of shares of Common Stock
      issuable hereunder shall survive the exercise of this Warrant.

     

    SECTION
      25. Counterparts.
      This
      Agreement may be executed in any number of counterparts and each of such
      counterparts shall for all purposes be deemed to be an original, and all such
      counterparts shall together constitute but one and the same
      instrument.

     

    SECTION
      26. Registration
      of Shares of Common Stock.
      The
      Company will furnish to the Warrant Agent (i) if a registration statement filed
      under the Securities Act of 1933, as amended, has been declared effective with
      respect to the shares issuable upon exercise of the Warrant (the “Registration
      Statement”),
      within 10 days after the Registration Statement has been declared effective,
      an
      opinion of counsel to the effect that a Registration Statement is then in effect
      with respect to the Warrant Shares and the prospectuses hereinafter referred
      to
      comply as to form in all material respects with the requirements of the
      Securities Act of 1933, as amended, and the rules and regulations of the
      Securities and Exchange Commission thereunder; or (ii) within 10 days of such
      time as a Registration Statement with respect to the shares of Warrant Common
      Stock issuable upon the exercise of the Warrants is not required under the
      Securities Act of 1933, as amended, an opinion of counsel to the effect that
      a
      Registration Statement is not required under the Securities Act of 1933, as
      amended, and the rules and regulations of the Securities and Exchange Commission
      thereunder. In the event that said opinion states that such a Registration
      Statement is in effect, the Company will, within 10 days of after the
      Registration Statement has been declared effective, furnish the Warrant Agent
      with current prospectuses meeting the requirements of said Act and all rules
      and
      regulations thereunder in sufficient quantity to permit the Warrant Agent to
      deliver a prospectus to each transferee of a Warrant Certificate and each holder
      of a Warrant Certificate upon exercise or conversion thereof. The Company
      further agrees to pay all fees, costs and expenses in connection with the
      preparation and delivery to the Warrant Agent of the foregoing opinions and
      prospectuses.

     

    
      
         

      

      
        12

        
          

        

      

      
         

      

    

    If
      any
      shares of Warrant Common Stock issuable upon the exercise of the Warrants or
      the
      issuance thereof requires registration or approval of any governmental
      authority, including, without limitation, the filing of necessary amendments,
      supplements or post-effective amendments to a Registration Statement of the
      Company under the Securities Act of 1933, or the taking of any other action
      under the laws of the United States of America or any political subdivision
      hereof or under the laws of any state of the United States of America before
      such shares may be validly and legally issued, then the Company covenants that
      it will in good faith and as expeditiously as possible endeavor to secure and
      keep effective such registration or approval or to take such other action,
      as
      the case may be.

     

    SECTION
      27. Entire
      Agreement.
      This
      Agreement (together with the Exhibits attached hereto) and the Securities
      Purchase Agreements between certain purchasers and the Company set forth the
      entire agreement of the Company and the holder of the Common Stock issuable
      upon
      the exercise of this Warrant with respect to the rights of the holder and the
      Common Stock issuable upon the exercise of this Warrant.

     

    
      
         

      

      
        13

        
          

        

      

      
         

      

    

    IN
      WITNESS WHEREOF, the parties hereto have caused this Warrant Agreement to be
      executed and delivered as of the day and year first above written.

     

    
      	 	 	 
	 	NORTH
              AMERICAN
              SCIENTIFIC, INC.
	 
 	 
 	 
 
	 	By:  	 
	 	
              
Name:
	 	Title:


    

    
       

      
        	 	 	 
	 	[COMPUTERSHARE
                INVESTOR SERVICES]
	 	as Warrant Agent
	 
 	 
 	 
 
	 	By:  	 
	 	
                
Name:
	 	Title:


      

       

      
        
           

        

        
          14

          
            

          

        

        
           

        

      

    

    EXHIBIT
      A

    Form
      of Warrant

     

    EXERCISABLE
      AT ANY TIME AFTER [__], 2008 AND AT OR PRIOR TO 12:30 P.M. PACIFIC TIME ON
      [__],
      2014

     

    WARRANT
      CERTIFICATE

    NORTH
      AMERICAN SCIENTIFIC, INC.

     

    No.
      W-             
      

     

    This
      certifies that _____________________________ or registered assigns is the
      registered holder of the number of Warrants set forth above, and is entitled,
      upon surrender of this Warrant Certificate at the office of [Computershare
      Investor Services], Warrant Agent (or any successor as such Warrant Agent),
      in
      the [City of Glendale, California], at any time 180 after the date hereof and
      at
      or prior to 12:30 p.m. Pacific Time on [__], 2014, to purchase one share of
      Common Stock, par value $0.01, of North American Scientific, Inc., a Delaware
      corporation (the “Company”),
      per
      Warrant, at the price equal to $0.246 per share.

     

    The
      applicable per share purchase price shown above and the number of shares
      issuable upon exercise of the Warrants represented by this Warrant Certificate
      are subject to adjustment for the occurrence of certain events, including stock
      dividends and split-ups, combinations, reorganizations, reclassifications,
      consolidations, mergers or sales of properties and assets and upon the issuance
      of certain rights or warrants to holders of Common Stock, as set forth in the
      Warrant Agreement hereinafter referred to. A complete statement with respect
      to
      such adjustments and to other terms and conditions pertaining to the Warrants
      is
      contained in the Warrant Agreement, dated as of [__], 2007, between the Company
      and [Computershare Investor Services], Warrant Agent, a copy of which may be
      examined by the registered holder hereof at the office of the Warrant
      Agent.

     

    To
      exercise the Warrants represented by this Warrant Certificate the form of
      election to purchase on the reverse hereof must be duly executed and the
      accompanying instructions for the registration and delivery of the stock must
      be
      filled in.

     

    The
      Warrants represented by this Warrant Certificate are transferable (subject
      to
      the conditions set forth in the preceding paragraphs) at the office in the
      [City
      of Glendale, California] of the Warrant Agent (or of its successor as Warrant
      Agent) by the registered holder thereof in person or by attorney duly authorized
      in writing, upon surrender of this Warrant Certificate. Upon any such transfer,
      a new Warrant Certificate, representing the right to purchase a like number
      of
      shares of the Company's Common Stock, will be issued to the transferee in
      exchange for this Warrant Certificate.

     

    This
      Warrant Certificate and similar Warrant Certificates when surrendered at the
      office in the [City of Glendale, California] of the Warrant Agent (or of its
      successor as Warrant Agent) by the registered holder hereof in person or by
      attorney duly authorized in writing may be exchanged for another Warrant
      Certificate or Warrant Certificates, representing in the aggregate the right
      to
      purchase a like number of shares of the Company's Common Stock.

     

    
      
         

      

      
        A-1

        
          

        

      

      
         

      

    

    If
      the
      Warrants evidenced by this Warrant Certificate remain outstanding at the
      expiration of the period during which Warrants are exercisable, as set forth
      in
      the first paragraph of this Warrant Certificate, such Warrants shall thereupon
      be deemed null and void.

     

    No
      fractional shares of Common Stock will be issued upon the exercise of any
      Warrant or Warrants evidenced hereby, but in lieu thereof, a cash payment will
      be made, as provided in the Warrant Agreement.

     

    No
      holder
      of this Warrant Certificate shall be entitled to vote or receive dividends
      or be
      deemed for any purpose the holder of Common Stock or of any other securities
      of
      the Company which may at any time be issuable on the exercise hereof, nor shall
      anything contained in the Warrant Agreement or herein be construed to confer
      upon the holder hereof, as such, any of the rights of a stockholder of the
      Company or any right to vote upon any matter submitted to stockholders at any
      meeting thereof, or to give or withhold consent to any corporate action (whether
      upon any recapitalization, issue of stock, reclassification of stock, change
      of
      par value, consolidation, merger, conveyance, or otherwise) or, except as
      provided in the Warrant Agreement, to receive notice of meetings, or to receive
      dividends or subscription rights or otherwise, until the Warrant or Warrants
      evidenced by this Warrant Certificate shall have been exercised as provided
      in
      the Warrant Agreement.

     

    
      	 	 	 
	 	NORTH
              AMERICAN
              SCIENTIFIC, INC.
	 
 	 
 	 
 
	 	By:  	 
	 	Its: 	
              
 
	 	
              

            


    

     

    This
      Warrant Certificate is not valid until countersigned by the Warrant
      Agent.

    
       

      
        	 	 	 
	Dated:	Countersigned:
	 	 
	 	[COMPUTERSHARE INVESTOR
                SERVICES],
	 	as Warrant Agent,
	 
 	 
 	 
 
	 	By:  	 
	 	 	
                
Authorized
                Officer


      

       

      
        
           

        

        
          A-2

          
            

          

        

        
           

        

      

    

    FORM
      OF EXERCISE

     

    (Form
      of exercise to be executed by the Warrant

    Holder
      at the time of exercise)

     

    To
      [Computershare Investor Services] or its successor as Warrant
      Agent:

     

    The
      undersigned holder of the within Warrant Certificate hereby elects to (check
      one
      box only):

     

    
      	 	
              q

            	
              irrevocably
                exercise the undersigned’s right to purchase _________ shares of Common
                Stock, par value $0.01 per share, of North American Scientific, Inc.
                (the
                “Company”)
                which the undersigned is entitled to purchase under the terms of
                the
                within Warrant Certificate, or such other securities as the undersigned
                shall be entitled to purchase under the terms of the Warrant Agreement
                referred to in such Warrant Certificate by reason of the occurrence
                of
                certain events specified therein, and to make payment in full for
                the
                number of shares of Common Stock so purchased by payment of $______
                in
                wire transfer in immediately available funds, cash or by certified
                or
                official bank check.

            


    

     

    
      	 	
              q

            	
              irrevocably
                exercise the undersigned’s right to purchase ______________ shares of
                Common Stock, par value $0.01 per share, of the Company by cashless
                exercise pursuant to Section 9(b) of the Warrant Agreement by surrendering
                Warrant Certificates relating to _________
                shares.

            


    

     

    Please
      issue the certificate for shares of Common Stock in the name of, and pay any
      cash for any fractional share to:

     

    
       

        
          

        

      

    

    Print
      or
      type name

     

     

    
      
 Social
      Security or other Identifying Number

     

     

    
      
 Street
      Address

     

     

    
      
 City State Zip
      Code

     

    
      
         

      

      
        A-3

        
          

        

      

      
         

      

    

    If
      such
      number of shares shall not be all the shares purchasable upon the exercise
      of
      the Warrants evidenced by this Warrant Certificate, a new Warrant Certificate
      for the balance of such Warrants remaining unexercised shall be registered
      in
      the name of and delivered to:

     

    Please
      insert social security or other identifying number:
      ___________________

     

    
      
        

      

    

    (Please
      print name and address)

     

    
      

    

     

    
      	Dated:
              ___________, _______	 	       
	 	 	
              Signature

            
	 	 	
              (Signature
                must conform in all respects to name
                of holder as
                specified on the face of the Warrant
                Certificate)

            


    

     

    (Signature
      Medallion Guaranteed): ___________________________  Date:
      ___________________

     

    (If
      the
      Common Stock, cash in lieu of fractional shares, or Warrants for any unexercised
      balance are to be issued or paid to a person other than the person in whose
      name
      the within Warrant is registered, or if otherwise requested by the Company
      or
      the Warrant Agent, a signature Medallion guarantee is required.)

     

    
      
         

      

      
        A-4

        
          

        

      

      
         

      

    

    ASSIGNMENT

     

    (Form
      of assignment to be executed if Warrant

    Holder
      desires to transfer Warrant)

     

    FOR
      VALUE RECEIVED,
      __________________________________ hereby sells, assigns, and transfer unto
      ____________________ this Warrant Certificate together with all right, title
      or
      interest therein and does hereby irrevocably appoint ___________________
      attorney to transfer the within Warrant Certificate on the books of the Warrant
      Agent with full power of substitution in the premises.

     

    
      
        	Dated:
                ___________, _______	 	       
	 	 	
                Signature

              
	 	 	
                (Signature
                  must conform in all respects to name
                  of holder as
                  specified on the face of the Warrant
                  Certificate)

              


      

       

      (Signature
        Medallion Guaranteed): ___________________________  Date:
        ___________________

    

     

    
      
         

      

        A-5