**Exhibit 10.35****ADDENDUM****TO LEASE AGREEMENT FOR A GAMMA KNIFE UNIT**     This ADDENDUM TWO TO LEASE AGREEMENT FOR A GAMMA KNIFE UNIT (this “Addendum”) is datedeffective as of April 13, 2007, and is entered into between GK FINANCING, LLC, a California limitedliability company (“GKF”) or its wholly owned subsidiary whose obligation under this Agreementshall be guaranteed by GKF, and OSF Healthcare System, an Illinois not for profit corporation,owner and operator of St. Francis Medical Center (“Medical Center”), with reference to thefollowing recitals:**Recitals****:**     WHEREAS, on February 18, 2000, GKF and Medical Center executed a Lease Agreement for a GammaKnife Unit (the “Lease”); and     WHEREAS, the parties desire to amend the terms and provisions of the Lease as set forthherein.     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**.          a. It is acknowledged that the Commencement Date of the Lease is May 14, 2001. In view of theprovisions set forth below in this Section, Section 18 of the Lease is hereby deleted in itsentirety.          b. In consideration of the “Upgrade and First Reload” described below, the Term of the Leaseas set forth in Section 6 of the Lease is hereby extended for an additional five (5) years(collectively, the “First Extension”). The First Extension shall commence on May 14, 2011 (whichis the expiration date of the initial Term of the Lease).          c. If the “Second Reload” is performed as described below, then, in consideration thereof, theTerm of the Lease (as extended by the First Extension) shall be automatically extended for anadditional three (3) years (collectively, the “Second Extension”). The Second Extension shallcommence on May 14, 2016 (which is the expiration date of the First Extension).          d. All references in the Lease to the “Term” shall be deemed to refer to the Term, as extendedby the First Extension and the Second Extension, as applicable.
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     3. **Upgrade and Cobalt Reload of the Equipment****.**Section 15 of the Lease is herebydeleted in its entirety and replaced with the following:     “15.1 Upgrade and First Reload. Subject to the terms and conditionsset forth below, (a) GKF, at GKF’s cost and expense, shall replace and upgrade theEquipment to a Leksell Gamma Knife Perfexion model (the “Perfexion Model”) andreload the Equipment (as upgraded) with new cobalt-60 (the “Upgrade and FirstReload”), which Upgrade and First Reload shall be performed at the Site; and (b) GKFshall use its commercially reasonable efforts to perform the Upgrade and FirstReload during summer/fall 2007, subject to availability of the Perfexion Model fromthe equipment manufacturer. It is anticipated that the Equipment will beunavailable to perform procedures for approximately four to five weeks due to theUpgrade and First Reload process. Medical Center agrees to be responsible for allinsurance, rigging, site modifications and installation costs related to the Upgradeand First Reload, and the de-installation and removal of the existing Equipment.     “15.2 Second Reload. Subject to the terms and conditions set forthbelow, (a) GKF may elect, at its sole option and at its cost and expense, to reloadthe Perfexion Model with new cobalt-60 (the “Second Reload”), which Second Reloadshall be performed at the Site; and (b) if GKF has elected to do so, GKF shall useits commercially reasonable efforts to perform the Second Reload during the13th year of the Lease. Medical Center agrees to be responsible for allinsurance, rigging, site modifications and installation costs related to the SecondReload.     “15.3 Medical Center Support. In connection with both the Upgrade andFirst Reload and the Second Reload, Medical Center, at Medical Center’s cost andexpense, shall provide GKF with Medical Center personnel (including Medical Centerphysicists) and services upon request and as required by GKF, among other things, tooversee, supervise and assist with construction and compliance with local, state andfederal regulatory requirements and with nuclear regulatory compliance issues andthe calibration of the Perfexion Model.     “15.4 Permits. Notwithstanding the foregoing, the Upgrade and FirstReload and the Second Reload (if applicable) shall be performed by GKF only afterall necessary and appropriate licenses, permits, approvals, consents andauthorizations, including, without limitation, the proper handling of the cobalt-60(collectively, the “Permits”), have been obtained by Medical Center at MedicalCenter’s sole cost and expense (other than any filing or registration fees whichshall be paid for by GKF). The timing and procedure for such Upgrade and FirstReload and the Second Reload (if applicable) shall be as mutually agreed uponbetween the parties. Notwithstanding anything to the contrary contained in thisAgreement, GKF makes no representation or warranty to Medical Center concerning theUpgrade and First Reload and/or the Second Reload (if applicable), and GKF shallhave no obligation or liability to pay any damages to Medical Center resultingtherefrom.
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     “15.5 All references in this Agreement to (a) “Installation” shall be deemed torefer to the Upgrade and First Reload and the Second Reload, as applicable; and (b)“Equipment” shall be deemed, immediately following its upgrade, to mean thePerfexion Model.”     4. **Per Procedure Payment****.**          a. Notwithstanding the provisions of Section 7 of the Lease, commencing from and after thefirst day of the first month after installation of the Perfexion Model, the per procedure paymentset forth in Section 7 of the Lease shall be amended to equal * per procedure, and no furtheradjustment to such per procedure payment shall be made based on the number of procedures performedduring any year or other time period under the Lease. As used in the Lease, the term “procedure”shall mean each individual treatment session (fraction), whether performed on an inpatient oroutpatient basis, during which a patient receives treatment, imaging or other procedures,including, without limitation, treatment planning and delivery, imaging and other ancillaryservices, using the Equipment and/or any other equipment or devices that are used in lieu of, or asan alternative to, the Equipment.     5. **No Responsibility for Additional Upgrades or Reloading****.**Notwithstanding anythingto the contrary contained herein or in the Lease, it is understood by the parties that GKF is notresponsible for any additional upgrades, hardware, cobalt reloading, software changes and/or othermodifications to the Perfexion Model, except as expressly set forth herein or otherwise agreed uponin writing by Medical Center and GKF.     6. **Captions****.**The captions and paragraph headings used herein are for convenience onlyand shall not be used in construing or interpreting this Addendum.     7. **Full Force and Effect****.**Except as amended by this Addendum, all of the terms andprovisions 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**   **OSF HEALTHCARE SYSTEM**, owner andoperator of Saint Francis Medical Center             By: