(1) Includes 603,077 shares issuable upon exercise of options exercisable within 60 days of October 19, 2007.

2

(1) Includes 603,077 shares issuable upon exercise of options exercisable within 60 days of October 19, 2007.

3

(1) Includes 603,077 shares issuable upon exercise of options exercisable within 60 days of October 19, 2007.

4

(1) Includes 603,077 shares issuable upon exercise of options exercisable within 60 days of October 19, 2007.

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(2) Includes 403,077 shares issuable upon exercise of options exercisable within 60 days of October 19, 2007.

6

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(3) Includes 200,000 shares issuable upon exercise of options exercisable within 60 days of October 19, 2007.

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THIS AMENDMENT NO. 1 RELATES TO THE SCHEDULE 13D ORIGINALLY FILED ON BEHALF OF THE REPORTING PERSONS WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 29, 2007.  THE SAID SCHEDULE 13D IS HEREBY AMENDED TO ADD CERTAIN DISCLOSURE REGARDING A MANAGEMENT AGREEMENT UNDER “ITEM 6 — CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH RESPECT TO SECURITIES OF THE ISSUER” AND “ITEM 7 — MATERIALS TO BE FILED AS EXHIBITS”.

Item 6.                    Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer.

The information contained in Item 6 of the Statement is hereby amended and restated as follows:

SUPPORT AND VOTING AGREEMENTS

The information set forth under Item 4 is hereby incorporated by reference.

ROLLOVER SUBSCRIPTION AGREEMENTS, LLC AGREEMENT AND SECURITYHOLDERS AGREEMENT

Pursuant to the Support Agreements, each Management Holder has agreed to enter into a Management Stock Contribution and Unit Subscription Agreement substantially in the form attached hereto within Exhibit 99.8, 99.9, 99.10 or 99.11, respectively (collectively, the “Rollover Subscription Agreements”), pursuant to which each such holder will contribution a portion of his shares of Common Stock to RTI immediately prior to the effective time of the Merger in exchange for units of limited liability company interest in RTI.  Each Rollover Subscription Agreement contains, among other provisions, certain call options as more fully described within Exhibits 99.8 through 99.11.  In addition, the Rollover Subscription Agreement with Dr. Daniel E. Dosoretz gives Dr. Dosoretz a put option, exercisable after the third anniversary of the closing date of the Merger, with respect to an amount of equity in RTI not to exceed the value of the shares of Common Stock contributed by him in connection with the Merger in the event his employment with the Issuer (as the surviving corporation in the Merger) is terminated by the Issuer without “cause” (as defined in the Rollover Subscription Agreement) or by Dr. Dosoretz for “good reason” (as defined in the Rollover Subscription Agreement) and, at the time of such termination, the Issuer meets certain performance targets, as more fully described within Exhibit 99.8.

In connection with the Management Holders’ subscription for equity interest in RTI, each such holder will also execute an amended and restated limited liability company agreement of RTI substantially in the form attached hereto as Exhibit 99.5 (the “LLC Agreement”), and a securityholders agreement substantially in the form attached hereto as Exhibit 99.6 (the “Securityholders Agreement”).  The LLC Agreement will set forth certain terms of limited liability interests in RTI, including, without limitation, the right of members to receive distributions from distributable assets of RTI, as more fully described in Exhibit 99.5.  The Securityholders Agreement will set forth, among other things, the composition of the board of managers of RTI, restrictions on the transfer of securities owned by Vestar or the Management Holders (in each case subject to certain exemptions), registration rights, “tag-along” rights, “drag-along” rights and preemptive rights, in each case as more fully described in Exhibit 99.6.

MANAGEMENT AGREEMENT

The Issuer, Holdings and RTI have agreed to enter into a management agreement (the “Management Agreement”) with Vestar Capital Partners relating to certain advisory and consulting services Vestar Capital Partners will render to the Issuer, Holdings and RTI after the consummation of the Merger. Under the Management Agreement, Vestar Capital Partners will receive a $10 million transaction fee upon the closing of the Merger for services rendered in connection with the consummation of Merger and be reimbursed for its reasonable out of pocket expenses. The Management Agreement also provides for

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Vestar Capital Partners to receive an annual management fee equal to the greater of (i) $850,000 or (ii) an amount equal to 1.0% of the Issuer’s consolidated EBITDA, which fee will be payable quarterly. Holdings, RTI and the Issuer will indemnify Vestar Capital Partners and its affiliates against all losses, claims, damages and liabilities arising out of the performance by Vestar Capital Partners of its services pursuant to the Management Agreement, other than those that have resulted primarily from the gross negligence or willful misconduct of Vestar Capital Partners and/or its affiliates.  A complete copy of the Management Agreement is filed as Exhibit 99.12 hereto.

EMPLOYMENT AGREEMENTS

Pursuant to the Support Agreements, the Management Holders have also agreed to enter into certain employment agreements with Holdings, the Issuer (as the surviving corporation in the Merger), and/or 21st Century Oncology, Inc., a wholly-owned subsidiary of the Issuer (“21st Century”), which employment agreements are attached hereto within Exhibit 99.8 through 99.11 (collectively, the “Employment Agreements”).  The Employment Agreement (or Employment Agreements) for each Management Holder sets forth the terms and conditions of such person’s employment as an officer of the Issuer and/or a physician of 21st Century after the consummation of the Merger, including, without limitation, compensation, severance benefits and covenant-not-to-compete, in each case as more fully described within Exhibits 99.8 through 99.11.  In addition, the Employment Agreement with Dr. Dosoretz provides that in consideration of Dr. Dosoretz agreement not to engage in certain competitive activities until the later of (x) the fifth anniversary of the closing date of the Merger and (y) three years after the termination of his employment with the Issuer, the Issuer shall pay Dr. Dosoretz $6,000,000 in cash, payable in three equal installments on the closing date of the Merger and the first and second anniversary of the closing date, provided that the Issuer will have no further obligation to make any such payment if Dr. Dosoretz materially breaches his covenant-not-to-compete.

EQUITY INCENTIVE PLAN AND INCENTIVE UNIT SUBSCRIPTION AGREEMENTS

Pursuant to the Support Agreements, the Management Holders have also agreed to accept certain incentive equity arrangements.  The Management Holders will be eligible to participate in a unit award plan substantially in the form attached hereto as Exhibit 99.7 (the “Equity Incentive Plan”), pursuant to which the board of managers of RTI will be authorized to issue units of limited liability company interests to the Management Holders.  The units granted under the Equity Incentive Plan will be subject to both time-based and performance-based vesting.  The Management Holders will subscribe for the units granted under the Equity Incentive Plan pursuant to a Management Unit Subscription Agreement substantially in the form attached within Exhibits 99.8 through 99.11 (collectively, the “Incentive Unit Subscription Agreements”).

The descriptions of the Support Agreements and the forms of the Rollover Subscription Agreement, the LLC Agreement, the Securityholders Agreement, the Management Agreement, the Employment Agreements, the Incentive Unit Plan and the Incentive Unit Subscription Agreements do not purport to be complete and are qualified in their entirety by reference to the complete text of such agreements, copies of which are filed as Exhibits hereto and incorporated herein by reference.

Except for the agreements described above or in response to Items 3 and 4 of this Schedule 13D, which are hereby incorporated herein by reference, to the best knowledge of the Reporting Persons, there are no contracts, arrangements, understandings or relationships (legal or otherwise) between the persons enumerated in Item 2 of this Schedule 13D, and any other person, with respect to any securities of the Issuer, including, but not limited to, transfer or voting of any of the securities, finder’s fees, joint ventures, loan or option agreements, puts or calls, guarantees of profits, divisions of profits or loss, or the giving or withholding of proxies.

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Item 7.                    Material to Be Filed as Exhibits.

* Incorporated by reference to the corresponding exhibits to the Schedule 13D filed by the filing persons with the Securities and Exchange Commission on October 29, 2007.

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SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

December 21, 2007

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Index of Exhibits

* Incorporated by reference to the corresponding exhibits to the Schedule 13D filed by the filing persons with the Securities and Exchange Commission on October 29, 2007.

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