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                                                                   Exhibit 10.23

                         PHYSICIAN EMPLOYMENT AGREEMENT

         THIS PHYSICIAN EMPLOYMENT AGREEMENT ("Agreement") is made and entered
into as of April, 2004 by and between 21ST CENTURY ONCOLOGY, INC., a Florida
corporation ("21st Century") or its assignee and DANIEL E. DOSORETZ, M.D.
("Physician").

                                   WITNESSETH:

         WHEREAS, 21st Century is a Florida corporation that operates radiation
therapy centers ("Centers"); and

         WHEREAS, 21st Century is subsidiary of Radiation Therapy Services, Inc.
("RTSI"), a Florida corporation that has ownership interests in other
corporations (the "Affiliates") that operate Centers; and

         WHEREAS, Physician is a radiation oncologist who is licensed to
practice medicine in certain states in which 21st Century operates Centers;

         WHEREAS, Physician is concurrently herewith entering into an Executive
Employment Agreement (the "Executive Agreement") with RTSI; and

         WHEREAS, 21st Century wishes to engage Physician to provide medical
services as a radiation oncologist at certain of the Centers operated by 21st
Century according to the terms and conditions of this Agreement which is
conditioned upon closing of RTSI's initial public offering.

         NOW, THEREFORE, in consideration of the premises and of the promises
hereinafter contained, the parties agree as follows:

         1. TERM. Subject to the conditions set forth below, Physician agrees to
provide services as a radiation oncologist at the Centers specified pursuant to
this Agreement to such persons as are accepted by 21st Century as patients of
the Centers. Unless terminated earlier by either party as provided herein, this
Agreement shall be for three (3) years beginning the date hereof, and shall be
automatically renewed for consecutive two (2) year terms thereafter on the
anniversary date of this Agreement unless either party gives written notice to
the other party at least one hundred twenty (120) days in advance of the renewal
date of its intent not to renew the Agreement.

         2. ACCEPTANCE BY PHYSICIAN. Physician agrees to provide medical
services at the Centers on the terms and conditions herein set forth. Physician
shall practice at such Centers as are mutually agreed and it is contemplated
that Physician will work two (2) days per week under this Agreement while the
Executive Agreement is in effect. Throughout the term of this Agreement and any
renewal period hereof, Physician will be licensed to practice medicine in the
State of Florida and/or such other states as mutually agreed. Physician agrees
that in the rendition of such professional services at the Centers, Physician
will comply with the reasonable policies, standards and regulations of 21st
Century established from time to time. This Agreement is exclusive in favor of
21st Century and Physician may not perform services for other providers of
radiation therapy or oncology services without the prior written approval of
21st Century. Nothing in this Agreement shall be deemed to preclude Physician
from (i) serving or continuing to serve as an officer or on the Board of
Directors of entities that do not compete with 21st Century or (ii) serving or
continuing to serve on the board or advisory committees of medical, charitable
or other similar organizations.

         3. COMPENSATION. A. 21st Century agrees to pay Physician for the
services provided hereunder a base annual salary of Four Hundred Fifty Thousand
Dollars ($450,000) ("Base Salary").


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Physician shall be eligible for all fringe benefit plans, disability plan and
other health and welfare benefit plans of 21st Century. 21st Century shall pay
all medical malpractice insurance premiums related to Physician's employment
including "tail" coverage after termination or expiration of this Agreement. The
Medical Director or Board of Directors of the Company may provide a bonus to
Physician based upon a RVU formula.

         4. TERMINATION OTHER THAN FOR CAUSE. A. If Physician dies or becomes
disabled during any term of this Agreement, 21st Century agrees to pay to
Physician's designated beneficiary as salary continuation or to Physician one
(1) year of Physician's monthly Base Salary, plus such additional Base Salary as
Physician may have become entitled to pursuant to section 3 above, payable
monthly, beginning with the date of death or commencement of disability;
thereafter, in the case of disability and for the duration thereof, Physician
shall receive benefits to the extent provided under 21st Century's disability
plan (the "Disability Plan"). For purposes of this Agreement, "disability" shall
have the meaning given in the Disability Plan.

                (a) If Physician voluntarily gives written notice at least
ninety (90) days in advance of the last day of any term hereunder to terminate
this Agreement at the expiration of such term and continues to render services
as provided herein until at the end of the term, 21st Century agrees to pay to
Physician as severance pay two (2) months of Physician's monthly Base Salary for
the immediately preceding twelve month period, plus such additional Base Salary
as Physician may have become entitled to pursuant to section 3 above, payable
monthly, beginning with the date of actual termination of this Agreement. Said
severance pay shall be in addition to the compensation earned by Physician
during the notice period required herein. Physician must render services as
provided hereunder during the 90 day period. The required notice and continued
service is of the essence, and if Physician does not give the required notice
and continue to be available for full-time exclusive service to 21st Century
pursuant to this Agreement during the notice period, Physician shall not be
entitled to any severance pay.

                (b) If Physician voluntarily terminates his employment for any
reason prior to the end of a term or without giving notice in accordance with
section 1 of this Agreement, 21st Century shall have no liability to Physician
other than for accrued and unpaid Base Salary prior to the date of termination.

                (c) If 21st Century terminates Physician without "cause" (as
defined in section 5 below), 21st Century shall pay Physician all compensation
provided for in section 3 above until the end of the then-current term of this
Agreement.

                (d) If the Executive Agreement is terminated for any reason,
but this Agreement is not terminated, this Agreement shall continue in full
force and effect, except that the annual Base Salary shall be increased to an
amount that is no less than the amount of annual compensation of the highest
paid physician then employed by or associated with 21st Century, and Physician
shall be expected to devote full time and attention to the rendition of
professional services pursuant to this Agreement.

                (e) If this Agreement is terminated for any reason, but the
Executive Agreement is not terminated, Physician shall not receive the
post-termination or severance benefits set forth in subsections (a) and (b)
above so long as his annual base salary under the Executive Agreement is
increased pursuant to the upward adjustment clause under Section 5 of the
Executive Agreement.

         5. TERMINATION FOR CAUSE. This Agreement shall be deemed to be
terminated for "cause" by 21st Century, and the relationship of 21st Century and
Physician existing between the parties shall be deemed severed without any
liability on the part of 21st Century to Physician for further compensation or
remuneration (other than for accrued and unpaid Base Salary prior to the date of
termination) upon the occurrence of any of the following events:


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                (a) A final and unappealable suspension, revocation, or
cancellation of Physician's license or right to perform medical services in the
State of Florida;

                (b) The final and unappealable placing or imposing of any
restrictions or limitations, by any governmental authority having jurisdiction
over Physician, upon Physician so that Physician cannot engage in the medical
services contemplated hereunder;

                (c) Physician shall willfully or with gross negligence fail or
refuse to materially comply after reasonable notice with the reasonable
policies, standards, and regulations of 21st Century from time to time
established or engage in gross misconduct resulting in material economic harm to
21st Century;

                (d) Physician is convicted of a felony;

                (e) Physician is convicted of a crime or offense committed in
connection with his duties hereunder; or

                (f) Physician is excluded from the Medicare or Medicaid program
as a participating physician.

         No termination shall be treated as a termination for "cause" unless the
Physician is given a minimum of one hundred and twenty (120) days or such longer
period as is reasonably necessary to cure an alleged breach.

         6. NON-COMPETITIVE AND RESTRICTIVE AGREEMENTS.

                (a) During the term of this Agreement and any renewal period,
Physician shall not undertake any professional service except as directed and
authorized by 21st Century and shall not engage in any profession other than the
rendition of the professional services as directed by 21st Century.

                (b) In the event of the termination of this Agreement for any
reason, Physician agrees not to directly or indirectly engage in the practice of
radiation therapy or oncology, or otherwise compete with 21st Century, or any of
its physician providers, by practicing as a radiation therapist or oncologist
(i) at any hospital in which physician providers of 21st Century regularly admit
patients, (ii) within any county in which 21st Century or any of its Affiliates
operate a Center, or (iii) or within a radius of twenty-five (25) miles of any
Center of 21st Century or any of its Affiliates, for a period of two (2) years
after the date of such actual termination of this Agreement. The purpose of this
covenant is to protect 21st Century from the irreparable harm it will suffer if
Physician competes with 21st Century after having participated in the initial
public offering of RTSI, and having been introduced to 21st Century's personnel
and patients and after learning special medical procedures used by 21st
Century's physician providers, 21st Century's business procedures, office and
practice policies, and the special and confidential professional procedures
developed by 21st Century.

                (c) The parties agree that in the event of any breach or
attempted breach of any of the covenants set out in section 6(b) (the "Covenant
Not to Compete"), 21st Century will be entitled to equitable relief by way of
injunction or otherwise, in addition to any remedy at law which may be
available. The parties agree that any violation or threatened violation by
Physician of the Covenant Not to Compete will cause 21st Century to suffer
irreparable harm. The parties agree that 21st Century's remedy of an injunction
is not the exclusive remedy for breach of the Covenant Not to Compete and that a
court may grant such additional relief as is reasonable.

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                (d) In the event the Covenant Not to Compete shall be determined
by a court of competent jurisdiction to be unenforceable by reason of its
geographic or temporal restrictions being too great, or by reason that the range
of activities covered is too great, or for any other reason, this Section 6
shall be interpreted to extend over the maximum geographic area, period of time,
range of activities or other restrictions as to which it may be enforceable.

                (e) RTSI shall be a third party beneficiary of this Section 6 to
the extent permitted by law.

         7. 21ST CENTURY'S RIGHT TO INCOME. All fees, compensation, monies, and
other things of value charged by 21st Century and received or realized as a
result of the rendition of medical services by Physician pursuant to this
Agreement shall belong to and be paid and delivered to 21st Century.

         8. PHYSICIAN EXPENSES. 21st Century shall pay the reasonable business
expenses as are incurred by Physician upon presentation by Physician of an
itemized account of such expenditures.

         9. VACATION AND TIME AWAY. Physician shall be entitled to no less than
four (4) weeks vacation with pay during each year of this Agreement. Physician
may take additional time away from the practice to attend professional meetings
and seminars with the reasonable expenses paid for by 21st Century with the
prior approval of 21st Century. All time away from practice, including time for
vacation and continuing medical education, shall be scheduled with 21st Century.
Physician shall be responsible for arranging coverage during Physician's
absences for vacation and continuing medical education and shall inform 21st
Century of such coverage arrangements.

         10. NOTICES. Any notice required or permitted to be given pursuant to
this Agreement shall be sufficient if in writing and if sent by registered mail
to either party at its last known residence.

         11. GOVERNING LAW. This Agreement shall be governed by the laws of the
State of Florida.

         12. ENTIRE AGREEMENT. This instrument contains the entire agreement of
the parties regarding Physician's provision of medical services at the Centers
and supersedes all previous negotiations, discussions, and agreements between
the parties. Any amendments or modifications to this Agreement shall be made in
writing only and shall be by agreement of 21st Century and Physician.

         13. ASSIGNMENT. This Agreement may not be assigned without the written
consent of the parties.

         14. SEVERABILITY. In the event that any paragraph or clause of this
Agreement is held or declared by a final and unappealable decision to be void,
illegal, or unenforceable for any reason, the offending paragraph or clause
shall, if possible, be reformed by the authority making such decision in such
manner as will implement, to the fullest extent legally permissible, the
expressed intentions of the parties hereto without illegality or
unenforceability. If such reformation is not possible, the offending paragraph
or clause shall be stricken and all other paragraphs and clauses of this
Agreement shall nevertheless remain in full force and effect; provided, however,
that if striking such offending clause or paragraph would result in a
substantial change in the contractual relationship between the parties, thereby
depriving either or both of the parties of the benefit of the fundamental
economic bargain herein set forth, this Agreement shall become voidable upon
demand of the party whose interests are thus impaired.

         15. HEADINGS. The headings contained in this Agreement are included for
convenience only and no such heading shall in any way alter the meaning of any
provision.


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         16. WAIVER. The failure of either party to insist upon strict adherence
to any obligation of this Agreement shall not be considered a waiver or deprive
that party of the right thereafter to insist upon strict adherence to that term
or any other term of this Agreement. Any waiver must be in writing.

         17. COUNTERPARTS. This Agreement may be executed in two (2)
counterparts, each of which shall be considered an original.


         IN WITNESS WHEREOF, the parties have set their hands and seals the day
and year first above written.


                                   21ST CENTURY ONCOLOGY, INC.

                                   By:
                                      -----------------------------------------

                                   Title:
                                          -------------------------------------


                                   "PHYSICIAN"

                                   /s/ Daniel E. Dosortez, M.D.
                                   --------------------------------------------
                                   Daniel E. Dosortez, M.D.