Exhibit 10.19a**ADDENDUM TO****LEASE AGREEMENT FOR A GAMMA KNIFE UNIT**     This ADDENDUM TO LEASE AGREEMENT FOR A GAMMA KNIFE UNIT (the “Addendum”) is made effective asof October 25, 2005 (the “Effective Date”), and is entered into by and between YALE-NEW HAVENAMBULATORY SERVICES CORPORATION, a Connecticut corporation (“Yale”), and GK FINANCING, LLC, aCalifornia limited liability company (“GKF”), with reference to the following recitals.**RECITALS**     A.     On April 10, 1997, GKF and Yale entered into a Lease Agreement For A Gamma Knife Unit (the“Lease”).     B.     Section 15 of the Lease provides that the parties may discuss and mutually agree upon theupgrading or reloading of the Equipment.     C.     The parties have agreed to upgrade and reload the Equipment, and desire to amend the termsof the Lease to set forth the terms and conditions of such upgrading and reloading of theEquipment.     NOW, THEREFORE, in consideration of the mutual covenants and agreements set forth herein, andfor other good and valuable consideration, the receipt and sufficiency of which are herebyacknowledged, the parties agree as follows:**AGREEMENT**     1.     Defined Terms. Unless otherwise defined herein, the capitalized terms used hereinshall have the same meanings set forth in the Lease.     2.     Extension of Lease Term. Notwithstanding Section 15 of the Lease, in considerationfor the “Upgrade and Reload” (as defined below), the Term of the Lease is hereby extended to theearlier to occur of the following dates: (a) the date on which the Equipment is ready to beaccepted for installation at the new Yale-New Haven Cancer Center currently being planned forconstruction (which acceptance date is anticipated to be July 1, 2009); or (b) January 1, 2010;provided that in no event shall GKF have any obligation to remove, relocate and/orreinstall the Equipment and/or the leasehold improvements to or at the new Yale-New Haven CancerCenter and/or to repair or restore the existing Site. All references in the Lease to the “Term”shall be deemed to refer to the Term as extended hereby.     3.     Upgrade and Cobalt Reload of the Equipment. Subject to the terms and conditionsset forth below, GKF shall upgrade the Equipment to a Leksell Gamma Knife Model 4C (the “Model 4C”)and reload the Equipment (as upgraded) with new cobalt-60 (the “Upgrade and Reload”), which Upgradeand Reload shall be performed at the Site and shall include any required installation and rigging.The Upgrade and Reload shall be subject to the following:
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Exhibit 10.19a     a.     All actual costs and expenses (without markup or inclusion of administrativeoverhead) pertaining to the upgrade of the Equipment to the Model 4C shall be paid and/orreimbursed * as and when incurred, including, without limitation, any costs and expensespertaining to Site preparation, installation, rigging and/or obtaining of “Permits” (asdefined below), irrespective of whether incurred in connection with the upgrade and/or thereloading of the Equipment. Yale shall be solely responsible for obtaining all licenses,permits, approvals, consents and authorizations necessary and appropriate for the Upgradeand Reload, including, without limitation, the proper handling of the cobalt-60(collectively, the “Permits”). It is acknowledged that, as of October 13, 2005, *.     b.     Except as provided in subsection 3.a above, all actual costs and expenses incurredby the parties (without markup or inclusion of administrative overhead) pertaining to thereloading of the Equipment shall be borne by GKF and Yale as and when incurred, in the sameproportions as net technical revenues are currently allocated under the Lease as in effectimmediately prior to the execution of this Addendum, i.e.: *. It is acknowledgedthat, as of October 13, 2005, GKF and Yale have paid *, respectively, toward the costs ofreloading.     c.     If applicable, a party shall pay or reimburse any amount owed to the other party inaccordance with the foregoing allocations within ten (10) days following receipt of awritten statement from the other party. Each party shall have the right to inspect, auditand copy the other party’s books and records pertaining to the costs and expenses incurredin connection with the Upgrade and Reload.     d.     Yale, at Yale’s sole cost and expense, shall provide GKF with Yale personnel(including Yale physicists) and services upon request and as required by GKF, among otherthings, to oversee, supervise and assist with construction and compliance with local, stateand federal regulatory requirements and with nuclear regulatory compliance issues and thecalibration of the Model 4C.     e.     The Upgrade and Reload shall be performed by GKF as soon as practical after thePermits have been obtained. The timing and procedure for the Upgrade and Reload shall beas mutually agreed upon between the parties which is anticipated but not guaranteed to beperformed in or around December 2005.     f.     Immediately following the Upgrade and Reload, all references in the Lease to the“Equipment” shall be deemed to mean the Model 4C. Notwithstanding anything to the contrarycontained herein, GKF makes no representation or warranty to Yale concerning the Upgradeand Reload, and GKF shall have no obligation to pay any damages to Yale resultingtherefrom.     4.     Lease Payment to GKF.     a.     In consideration for the payment by Yale of * pertaining to the upgrade of the Equipment asset forth above, effective from and after the date on which
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Exhibit 10.19athe first billed Procedure is performed using the Model 4C (as reloaded) (the “New FirstProcedure Date”) through the duration of the Term of the Lease (as extended), GKF’s pro-rata shareof net technical component revenues associated with Gamma Knife treatment less Direct OperatingExpenses associated with providing Gamma Knife treatment (the “GKF Percentage”), as set forth inSection 7 of the Lease, shall be amended to equal approximately *, subject to adjustment for actualinstallation costs incurred by Yale in connection with the upgrade of the Equipment (without markupor inclusion of administrative overhead), as reasonably approved by both parties.     b.     Notwithstanding the New Procedure Date, the compensation payable to GKF for the lease ofthe Equipment pertaining to Procedures performed prior to the New First Procedure Date, shall becalculated and paid in accordance with the same GKF Percentage in effect immediately prior to thisAddendum *, irrespective of whether the technical component revenues or Direct Operating Expensespertaining to such Procedures are collected or paid after the New First Procedure Date.     c.     Notwithstanding anything to the contrary set forth in the Lease, following the terminationor expiration of the Lease, and within ten (10) days following the end of each month (or portionthereof) thereafter, Yale shall continue to pay compensation to GKF for Procedures performed duringthe Term of the Lease until all technical fees billed for all such Procedures have been collectedby Yale, its agents, representatives or affiliates or until the date that is eighteen (18) monthsfollowing the termination or expiration of the Lease (as extended), whichever occurs first (the“Post-Termination Period”); provided that, for purposes of calculating the compensation tobe paid to GKF during the Post-Termination Period, no Direct Operating Expenses shall be deemed tohave been incurred by either party during such period.     5.     No Responsibility for Additional Upgrades or Reloading. It is understood by theparties that GKF is not responsible for any additional upgrades, hardware, cobalt reloading,software changes and/or other modifications to the Model 4C except as expressly set forth herein orotherwise agreed upon in writing by Yale and GKF.     6.     Option To Purchase GKF’s Ownership Interest In The Equipment.     a.     Upon the expiration of the Term of the Lease (as extended), Yale shall have the option topurchase GKF’s ownership interest in the Equipment (the “Purchase Option”) for a purchase price of* (the “Option Purchase Price”). The Option Purchase Price shall be paid in full in cash to GKFupon the expiration of the Term of the Lease (as extended), upon which GKF shall quitclaim all ofits right, title and interest to Yale, on an “as is, where is” basis, without representation orwarranty, with all faults. Upon the expiration or termination of the Lease, it is understood thatGKF shall have no obligation with respect to the removal, relocation, reinstallation and/or repairof the Equipment and/or the leasehold improvements.     b.     The Purchase Option may be exercised by Yale by giving GKF written notice thereof, whichnotice shall be received by GKF not less than ninety (90) days prior to the expiration of the Termof the Lease (as extended). Such written notice
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Exhibit 10.19amay be delivered by hand or sent by certified mail, return receipt requested to GKF at thefollowing address: GK Financing, LLC, Four Embarcadero Center, Suite 3700, San Francisco, CA94111, Attn: Mr. Craig K. Tagawa, Chief Executive Officer.     c.     Concurrently with the execution of this Addendum, Yale shall deposit with GKF the sum of *(the “Deposit”), which Deposit shall be credited towards the payment of the Option Purchase Price,if applicable. If the Purchase Option is not exercised by Yale, then, within ten (10) daysfollowing the expiration of the Lease, GKF shall return the Deposit to Yale. The Deposit shall notbear interest and may be commingled with GKF’s general funds.     7.     Captions. The captions and paragraph headings used herein are for convenience onlyand shall not be used in construing or interpreting this Addendum.     8.     Full Force and Effect. Except as amended and/or supplemented by this Addendum, allof the terms and provisions of the Lease shall remain in full force and effect.     IN WITNESS WHEREOF, the parties have executed this Addendum effective as of the date firstwritten above.     **GK FINANCING, LLC** **YALE-NEW HAVEN AMBULATORY**