Document:

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                                                                   EXHIBIT 10.36

                                 PROMISSORY NOTE

$80,000.00                                                   Fort Myers, Florida
                                                             November 10, 1993

         FOR VALUE RECEIVED, SOUTHWEST FLORIDA EQUIPMENT, INC. a Florida
Corporation, promises to pay to the order of HOWARD M. SHERIDAN, as Trustee
under the Will of Henry Sheridan, the principal sum of EIGHTY THOUSAND
($80,000.00) DOLLARS, plus interest thereon at the prime rate, said principal
and interest being payable in lawful money of the United States to Howard M.
Sheridan, as Trustee under the Will of Henry Sheridan, at 842 Cal Cove Drive,
Fort Myers, Florida 33919, or at such other place as the holder thereof may
designate in writing.

         This is a Demand Note.

         If Holder of the note demands payment of the note, holder must notify
Southwest Florida Equipment, Inc. at 1419 S.E. 8th Terrace, Cape Coral, Florida
33904 by certified mail, return receipt requested, that the entire remaining
unpaid principal balance plus any accrued interest must be paid in full within
sixty (60) days from the date of the letter demanding full payment. Only
interest payments will be required at the prime rate of interest which shall be
paid on December 10, 1993 and on the 10th day of each month thereafter until a
demand is made for the payment of the remaining unpaid principal balance and
accrued interest. Interest shall be paid at the prime rate established by
Nations Bank of Florida, N.A. in Tampa, Florida.

         1. Prime Rate: For purposes hereof, "Prime Rate" means the fluctuating
rate of interest per annum established by Nations Bank of Florida, N.A. ("Bank")
in Tampa, Florida as its prime lending rate in effect from time to time whether
or not such rate shall be otherwise published. Such Prime Rate is established by
Bank as an index or base rate.

         2. Interest: The outstanding loan principal balance shall bear interest
at a variable rate per annum, equal to the Prime Rate. The interest rate
hereunder shall be adjusted daily in accordance with fluctuations in the Prime
Rate. Interest shall be computed on the basis of a daily amount of interest
accruing on the daily outstanding principal balance during a 360 day year
multiplied by the actual number of days the principal is outstanding during such
applicable interest period.

         The maker may pay all or part of the principal balance outstanding plus
accrued interest, before due, without payment of any penalty.

         Each maker and endorser severally waives demand, protest and notice of
maturity, nonpayment or protest and all requirements necessary to hold each of
them liable as makers and endorsers.

         Each maker and endorser further agrees, jointly and severally, to pay
all costs of collection, including a reasonable attorneys fee in case the
principal and interest of this note or any payment on the principal and interest
thereon is not paid at the respective maturity thereof, or in case it becomes
necessary to protect the security hereof, whether suit be brought or not.

         If any installment of principal or interest is not made within 15 days
from the date it is due, the entire remaining unpaid principal balance, plus
accrued interest shall become immediately due and payable in full, at the option
of the holder of the note. Holder of note has the right to accelerate the
remaining unpaid principal balance and accrued interest.

         This note is governed by the Laws of the State of Florida.

         This note is binding on the heirs, personal representatives, assigns,
transferees of the parties hereto.

Address of Maker:                          SOUTHWEST FLORIDA EQUIPMENT, INC.
1419 S.E. 8th Terrace
Cape Coral, FL 33904                       by: /s/ Daniel E. Dosoretz
                                               ------------------------------
                                           DANIEL E. DOSORETZ, M.D.
                                           Secretary, Treasurer<PAGE>

                                                                   EXHIBIT 10.37

                                 PROMISSORY NOTE

$99,000.00                                                   Fort Myers, Florida
                                                             April 15, 1994

         FOR VALUE RECEIVED, KATIN, DOSORETZ RADIATION THERAPY ASSOCIATES, P.A.,
a Florida Professional Association, promises to pay to the order of HOWARD M.
SHERIDAN, as Trustee under the Will of Henry Sheridan, the principal sum of
NINETY NINE THOUSAND ($99,000.00) DOLLARS, plus interest thereon at the prime
rate, said principal and interest being payable in lawful money of the United
States to Howard M. Sheridan, as Trustee under the Will of Henry Sheridan, at
842 Cal Cove Drive, Fort Myers, Florida 33919, or at such other place as the
holder thereof may designate in writing.

         This is a Demand Note.

         If Holder of the note demands payment of the note, holder must notify
Katin, Dosoretz Radiation Therapy Associates, P.A. at 1419 S.E. 8th Terrace,
Cape Coral, Florida 33904 by certified mail, return receipt requested, that the
entire remaining unpaid principal balance plus any accrued interest must be paid
in full within sixty (60) days from the date of the letter demanding full
payment. Only interest payments will be required at the prime rate of interest
which shall be paid on May 15, 1994, and on the 15th day of each month
thereafter until a demand is made for the payment of the remaining unpaid
principal balance and accrued interest. Interest shall be paid at the prime rate
established by Nations Bank of Florida, N.A. in Tampa, Florida.

         1. Prime Rate: For purposes hereof, "Prime Rate" means the fluctuating
rate of interest per annum established by Nations Bank of Florida, N.A. ("Bank")
in Tampa, Florida as its prime lending rate in effect from time to time whether
or not such rate shall be otherwise published. Such Prime Rate is established by
Bank as an index or base rate.

         2. Interest: The outstanding loan principal balance shall bear interest
at a variable rate per annum, equal to the Prime Rate. The interest rate
hereunder shall be adjusted daily in accordance with fluctuations in the Prime
Rate. Interest shall be computed on the basis of a daily amount of interest
accruing on the daily outstanding principal balance during a 360 day year
multiplied by the actual number of days the principal is outstanding during such
applicable interest period.

         The maker may pay all or part of the principal balance outstanding plus
accrued interest, before due, without payment of any penalty.

         Each maker and endorser severally waives demand, protest and notice of
maturity, nonpayment or protest and all requirements necessary to hold each of
them liable as makers and endorsers.

         Each maker and endorser further agrees, jointly and severally, to pay
all costs of collection, including a reasonable attorneys fee in case the
principal and interest of this note or any payment on the principal and interest
thereon is not paid at the respective maturity thereof, or in case it becomes
necessary to protect the security hereof, whether suit be brought or not.

         If any installment of principal or interest is not made within 15 days
from the date it is due, the entire remaining unpaid principal balance, plus
accrued interest shall become immediately due and payable in full, at the option
of the holder of the note. Holder of note has the right to accelerate the
remaining unpaid principal balance and accrued interest.

         This note is governed by the Laws of the State of Florida.

         This note is binding on the heirs, personal representatives, assigns,
transferees of the parties hereto.

Address of Maker:                            KATIN, DOSORETZ RADIATION
1419 S.E. 8th Terrace,                       THERAPY ASSOCIATES, P.A.
Cape Coral, FL 33904
                                             by: /s/ Daniel E. Dosoretz
                                                 --------------------------
                                             DANIEL E. DOSORETZ, M.D.
                                             Secretary<PAGE>

                                                                   EXHIBIT 10.38

                                 PROMISSORY NOTE

$200,000.00                                                  Fort Myers, Florida
                                                             February 8, 1993

         FOR VALUE RECEIVED, KATIN, DOSORETZ, RADIATION THERAPY ASSOCIATES,
P.A., a Florida Professional Association, premises to pay to the order of
MILDRED SHERIDAN the principal sum of TWO HUNDRED THOUSAND ($200,000.00)
DOLLARS, plus interest thereon at the prime rate, said principal and interest
being payable in lawful money of the United States to Mildred Sheridan, in care
of Howard M. Sheridan, M.D., at 842 Cal Cove Drive, Fort Myers, Florida 33919,
or at such other place as the holder thereof my designate in writing.

         This is a Demand Note.

         If Holder of the note demands payment of the note, holder must notify
Katin, Dosoretz, Radiation Therapy Associates, P.A. at 3680 Broadway, Fort
Myers, Florida 33901, by certified mail, return receipt requested, that the
entire remaining unpaid principal balance plus any accrued interest trust be
paid in full within sixty (60) days from the date of the letter demanding full
payment. Only interest payments will be required at the prime rate of interest
which shall be paid on March 8, 1993 and on the 8th day of each month thereafter
until a demand is made for the payment of the remaining unpaid principal balance
and accrued interest. Interest shall be paid at the prime rate established by
Nations Bank of Florida, N.A. in Tampa, Florida.

         1. Prime Rate: For purposes hereof, "Prime Rate" means the fluctuating
rate of interest per annum established by Nations Bank of Florida, N.A. ("Bank")
in Tampa, Florida as its prime lending rate in effect from time to time whether
or not such rate shall be otherwise published. Such Prime Rate is established by
Bank as an index or base rate.

         2. Interest: The outstanding loan principal balance shall bear interest
at a variable rate per annum, equal to the Prime Rate. The interest rate
hereunder shall be adjusted daily in accordance with fluctuations in the Prime
Rate. Interest shall be computed on the basis of a daily amount of interest
accruing on the daily outstanding principal balance during a 360 day year
multiplied by the actual number of days the principal is outstanding during such
applicable interest period.

         The maker may pay all or part of the principal balance outstanding plus
accrued interest, before due, without payment of any penalty.

         Each maker and endorser severally waives demand, protest and notice of
maturity, nonpayment or protest and all requirements necessary to hold each of
them liable as makers and endorsers.

         Each maker and endorser further agrees, jointly and severally, to pay
all costs of collection, including a reasonable attorneys fee in case the
principal and interest of this note or any payment on the principal and interest
thereon is not paid at the respective maturity thereof, or in case it becomes
necessary to protect the security hereof, whether suit bo brought or not.

         If any installment of principal or interest is not made within 15 days
from the date it is due, the entire remaining unpaid principal balance, plus
accrued interest shall become immediately due and payable in full, at the option
of the holder of the note. Holder of note has the right to accelerate the
remaining unpaid principal balance and accrued interest.

         This note is governed by the Laws of the State of Florida.

         This note is binding on the heirs, personal representatives, assigns,
transferees of the parties hereto.

Address of Maker:                              KATIN, DOSORETZ RADIATION
3680 Broadway                                  THERAPY, ASSOCIATES, P.A.
Fort Myers, FL 33901
                                               BY: /s/ Daniel E. Dosoretz
                                                   ---------------------------
                                               DANIEL E. DOSORETZ, M.D.
                                               Secretary and Chief Executive
                                               Officer

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