<PAGE>
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(AMENDMENT NO. 1)*
North American Scientific, Inc.
-------------------------------
(Name of Issuer)
Common Stock
------------
(Title of Class of Securities)
65715D100
---------
(CUSIP Number)
*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.
The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).
Page 1 of 4 pages
<PAGE>
SCHEDULE 13G
CUSIP NO. 65715D100 PAGE 2 OF 4 PAGES
- ----------------------------------- --------------------------
- --------------------------------------------------------------------------------
1 NAME OF REPORTING PERSON
S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Irwin J. Gruverman
- --------------------------------------------------------------------------------
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
(a) / /
(b) /X/
- --------------------------------------------------------------------------------
3 SEC USE ONLY
- --------------------------------------------------------------------------------
4 CITIZENSHIP OR PLACE OF ORGANIZATION
U.S.A.
- --------------------------------------------------------------------------------
5 SOLE VOTING POWER
319,000**
--------------------------------------------------------------
6 SHARED VOTING POWER
NUMBER OF
SHARES 0
BENEFICIALLY
OWNED BY --------------------------------------------------------------
EACH
REPORTING 7 SOLE DISPOSITIVE POWER
PERSON
WITH 319,000**
--------------------------------------------------------------
8 SHARED DISPOSITIVE POWER
0
- --------------------------------------------------------------------------------
9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING
PERSON
319,000**
- --------------------------------------------------------------------------------
10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES
CERTAIN SHARES* / /
N/A
- --------------------------------------------------------------------------------
11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
10.3%
- --------------------------------------------------------------------------------
12 TYPE OF REPORTING PERSON*
IN
- --------------------------------------------------------------------------------
**Includes 19,000 shares held in a fund of which the reporting person is
general partner and 40,000 shares subject to outstanding options which are
immediately exercisable.
<PAGE>
ITEM 1 (a) Name of Issuer:
North American Scientific, Inc.
ITEM 1 (b) Address of Issuer's Principal Executive Offices:
7435 Greenbush Avenue
North Hollywood, CA 91605
ITEM 2 (a) Name of Person Filing:
Irwin J. Gruverman
ITEM 2 (b) Address of Principal Business Office, or, if none, Residence:
30 Ossipee Road
Newton, MA 02464
ITEM 2 (c) Citizenship:
U.S.A.
ITEM 2 (d) Title of Class of Securities:
Common Stock, par value $0.01 per share
ITEM 2 (e) CUSIP Number:
65715D100
ITEM 3 Not Applicable.
ITEM 4 Ownership:
The following information is provided as of December 31, 1996:
(a) Amount Beneficially Owned: 319,000*
(b) Percent of Class: 10.3%
(c) Number of shares as to which such person has:
(i) sole power to vote or to direct the vote: 319,000*
(ii) shared power to vote or to direct the vote: 0
(iii) sole power to dispose or to direct the disposition of:
319,000*
(iv) shared power to dispose or to direct the disposition
of: 0
ITEM 5 Ownership of Five Percent or Less of a Class: Not Applicable
ITEM 6 Ownership of More than Five Percent on Behalf of Another Person:
Not Applicable
ITEM 7 Identification and Classification of the Subsidiary Which
Acquired the Security Being Reported on By the Parent Holding
Company: Not Applicable
* Includes 19,000 shares held in a fund of which the reporting person is general
partner and 40,000 shares subject to outstanding options which are immediately
exercisable.
<PAGE>
ITEM 8 Identification and Classification of Members of the Group: Not
Applicable
ITEM 9 Notice of Dissolution of Group: Not Applicable
ITEM 10 Certification: Not Applicable
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.
2/5/97
--------------------------------------------------
Date
/s/ Irwin J. Gruverman
--------------------------------------------------
Signature
Irwin J. Gruverman
--------------------------------------------------
Name/Title
ATTENTION: INTENTIONAL MISSTATEMENTS OR OMISSIONS OF FACT CONSTITUTE FEDERAL
CRIMINAL VIOLATIONS
(SEE 18 U.S.C. 1001).
