FORM 4

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue.
See Instruction 1(b).

(Print or Type Responses)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section
17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the
Investment Company Act of 1940

OMB APPROVAL

OMB Number: 3235-0287
Expires: January 31, 2005
Estimated average burden
hours per response. . . 0.5

1. Name and Address of Reporting Person *

Lebowitz Elliot

(Last) (First) (Middle)

143 Gardner Road

(Street)

Brookline MA 02445

(City) (State) (Zip)

2. Issuer Name and Ticker
or Trading Symbol

North American Scientific, Inc.
NASI

3. I.R.S. Identification
    Number of Reporting
    Person, if an entity
    (voluntary)

4. Statement for
(Month/Day/Year)

2/24/2003

5. If Amendment, Date of
Original (Month/Day/Year)

6. Relationship of Reporting Person(s) to Issuer

(Check all applicable)

Director

10% Owner

Officer (give title below)

X Other (specify below)
President, Theseus Imaging Corp.

7. Individual or Joint/Group
Filing (Check Applicable Line)

X Form filed by One Reporting Person

Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/ Year)	2A. Deemed Execution Date, if any (Month/Day/ Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/ Year)	2A. Deemed Execution Date, if any (Month/Day/ Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date
(Month/Day/
Year)

3A. Deemed Execution Date, if any (Month/Day/
Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)

6. Date Exercisable and Expiration Date
(Month/Day/Year)

7. Title and Amount of Underlying Securities
(Instr. 3 and 4)

8. Price of Derivative Security
(Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)

10. Ownership Form of Derivative Securities: Direct (D) or Indirect (I)
(Instr. 4)

11. Nature of Indirect Beneficial Ownership
(Instr. 4)

Code

(A)

(D)

Date
Exercisable

Expiration
Date

Title

Amount or Number of Shares

Incentive Stock Option

7.21

2/20/03

40,000

2/20/13

Common Stock

40,000

Explanation of Responses:

/s/ Elliot Lebowitz

** Signature of Reporting Person

2/21/03

Date

Elliot Lebowitz

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations.
See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

http://www.sec.gov/divisions/corpfin/forms/form4.htm

Last update: 09/05/2002

LEBOWITZ ELLIOT 4