1
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549


                                  SCHEDULE 13G
                    Under the Securities Exchange Act of 1934
                            (Amendment No. ________)*


                       American Shared Hospital Services
- --------------------------------------------------------------------------------
                                (Name of Issuer)


                      Common Stock, no par value per share
- --------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                  029595 10 5
                  ---------------------------------------------
                                 (CUSIP Number)

                               December 31, 1998
- --------------------------------------------------------------------------------
            (Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

     [X] Rule 13d-1(b)

     [X] Rule 13d-1(c)

     [ ] Rule 13d-1(d)


         *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 disclosure provided in a prior cover page.


         The information required on 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, as amended ("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 11 pages


   2
CUSIP NO. 029595 10 5
- --------------------------------------------------------------------------------
1.      NAME OF REPORTING PERSONS
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

       American International Group, Inc.
       I.R.S. Identification No. 13-2592361
- --------------------------------------------------------------------------------
2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                    (a)      [ ]
                                                    (b)      [ ]
- --------------------------------------------------------------------------------
3.    SEC USE ONLY

- --------------------------------------------------------------------------------
4.    CITIZENSHIP OR PLACE OF ORGANIZATION

      Incorporated under the laws of the State of Delaware
- --------------------------------------------------------------------------------
                        5.    SOLE VOTING POWER
  NUMBER OF                            0
   SHARES                     --------------------------------------------------
BENEFICIALLY            6.    SHARED VOTING POWER
  OWNED BY                     423,758
    EACH                      --------------------------------------------------
 REPORTING              7.    SOLE DISPOSITIVE POWER
   PERSON                              0
    WITH                      --------------------------------------------------
                        8.    SHARED DISPOSITIVE POWER
                               423,758
- --------------------------------------------------------------------------------
  9.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING
       PERSON
                                            423,758
- --------------------------------------------------------------------------------
10.   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES
      CERTAIN SHARES
                                                     [ ]
- --------------------------------------------------------------------------------
11.   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW  (9)
                                            9.0%
- --------------------------------------------------------------------------------
12.   TYPE OF REPORTING PERSON

                                       HC


                                   Page 2 of 11


   3
CUSIP NO. 029595 10 5
- --------------------------------------------------------------------------------
1.      NAME OF REPORTING PERSONS
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON


       SunAmerica Inc.
       I.R.S. Identification No. 95-4715639  
- --------------------------------------------------------------------------------
2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                             (a)      [ ]
                                             (b)      [ ]
- --------------------------------------------------------------------------------
3.    SEC USE ONLY

- --------------------------------------------------------------------------------
4.    CITIZENSHIP OR PLACE OF ORGANIZATION

       Organized under the laws of the State of Delaware
- --------------------------------------------------------------------------------
                        5.    SOLE VOTING POWER
  NUMBER OF                            0
   SHARES                     --------------------------------------------------
BENEFICIALLY            6.    SHARED VOTING POWER
  OWNED BY                     423,758
    EACH                      --------------------------------------------------
 REPORTING              7.    SOLE DISPOSITIVE POWER
   PERSON                              0
    WITH                      --------------------------------------------------
                        8.    SHARED DISPOSITIVE POWER
                               423,758
- --------------------------------------------------------------------------------
  9.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING
       PERSON
                                            423,758
- --------------------------------------------------------------------------------
10.   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES
      CERTAIN SHARES
                                                     [ ]
- --------------------------------------------------------------------------------
11.   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW  (9)
                                            7.2%
- --------------------------------------------------------------------------------
12.   TYPE OF REPORTING PERSON
                                       OO


                                   Page 3 of 11


   4
CUSIP NO. 029595 10 5
- --------------------------------------------------------------------------------
1.      NAME OF REPORTING PERSONS
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

       SunAmerica Life Insurance Company
       I.R.S. Identification No. 52-0502540
- --------------------------------------------------------------------------------
2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                    (a)      [ ]
                                                    (b)      [ ]
- --------------------------------------------------------------------------------
3.    SEC USE ONLY

- --------------------------------------------------------------------------------
4.    CITIZENSHIP OR PLACE OF ORGANIZATION

      Incorporated under the laws of the State of Arizona
- --------------------------------------------------------------------------------
                        5.    SOLE VOTING POWER
  NUMBER OF                            0
   SHARES                     --------------------------------------------------
BENEFICIALLY            6.    SHARED VOTING POWER
  OWNED BY                     214,326
    EACH                      --------------------------------------------------
 REPORTING              7.    SOLE DISPOSITIVE POWER
   PERSON                              0
    WITH                      --------------------------------------------------
                        8.    SHARED DISPOSITIVE POWER
                               214,326
- --------------------------------------------------------------------------------
  9.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING
       PERSON
                                            214,326
- --------------------------------------------------------------------------------
10.   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES
      CERTAIN SHARES
                                                     [ ]
- --------------------------------------------------------------------------------
11.   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW  (9)
                                            4.5%
- --------------------------------------------------------------------------------
12.   TYPE OF REPORTING PERSON

                                       IC


                                   Page 4 of 11


   5
CUSIP NO. 029595 10 5
- --------------------------------------------------------------------------------
1.      NAME OF REPORTING PERSONS
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON


       Anchor National Life Insurance Company
       I.R.S. Identification No.  86-0198983
- --------------------------------------------------------------------------------
2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                             (a)      [ ]
                                             (b)      [ ]
- --------------------------------------------------------------------------------
3.    SEC USE ONLY

- --------------------------------------------------------------------------------
4.    CITIZENSHIP OR PLACE OF ORGANIZATION

       Organized under the laws of the State of Arizona
- --------------------------------------------------------------------------------
                        5.    SOLE VOTING POWER
  NUMBER OF                            0
   SHARES                     --------------------------------------------------
BENEFICIALLY            6.    SHARED VOTING POWER
  OWNED BY                     84,766
    EACH                      --------------------------------------------------
 REPORTING              7.    SOLE DISPOSITIVE POWER
   PERSON                              0
    WITH                      --------------------------------------------------
                        8.    SHARED DISPOSITIVE POWER
                               84,766
- --------------------------------------------------------------------------------
  9.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING
       PERSON
                                            84,766
- --------------------------------------------------------------------------------
10.   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES
      CERTAIN SHARES
                                                     [ ]
- --------------------------------------------------------------------------------
11.   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW  (9)
                                            1.8%
- --------------------------------------------------------------------------------
12.   TYPE OF REPORTING PERSON
                                       IC


                                   Page 5 of 11


   6
ITEM 1 (a).       NAME OF ISSUER:

                  American Shared Hospital Services

ITEM 1 (b).       ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES:
                                Four Embarcadero Center
                                Suite 3620
                                San Francisco, California 94111
ITEM 2 (a).       NAME OF PERSON(S) FILING:

                  American International Group, Inc.

                  SunAmerica Inc.

                  SunAmerica Life Insurance Company

                  Anchor National Life Insurance Company

ITEM 2 (b).       ADDRESS OF PRINCIPAL BUSINESS OFFICE(S):

                  American International Group, Inc.
                  70 Pine Street
                  New York, New York  10270

                  SunAmerica Inc.
                  1 SunAmerica Center
                  Century City
                  Los Angeles, California 90067
                  
                  SunAmerica Life Insurance Company
                  1 SunAmerica Center
                  Century City
                  Los Angeles, California 90067

                  Anchor National Life Insurance Company
                  1 SunAmerica Center
                  Century City
                  Los Angeles, California 90067

ITEM 2 (c).       CITIZENSHIP:

                  The information requested hereunder is set forth
                  under Item 4 of the cover pages to this Schedule 13G.

ITEM 2 (d).       TITLE OF CLASS OF SECURITIES:

                  Common Stock, no par value per share

ITEM 2 (e).       CUSIP NUMBER:  029595 10 5


                                  Page 6 of 11

   7
ITEM 3.       TYPE OF PERSONS FILING:

                       American International Group, Inc.*:

                       (g)      Parent Holding Company, in accordance with
                                Rule 13d-1(b) (ii) (G) promulgated under the
                                Securities Exchange Act of 1934, as amended
                                (the "Act")

                       SunAmerica, Inc.:

                       Passive Investor pursuant to Rule 13d-1(c)

                       SunAmerica Life Insurance Company and Anchor National 
                       Life Insurance Company:

                       (c)       Insurance Company as defined in Section
                                 3 (a) (19) of the Act

                       *This filing gives effect to the acquisition of
                        SunAmerica Inc. and its subsidiaries by American
                        International Group, Inc., which acquisition resulted
                        from the merger of SunAmerica Inc., a Maryland
                        corporation, into American International Group, Inc.
                        effective January 1, 1999. American International Group,
                        Inc. is making this filing as successor in interest to
                        SunAmerica, Inc., the Maryland Corporation.

 ITEM 4.               OWNERSHIP.

                       (a) through (c). The information requested hereunder
                       is set forth, as of December 31, 1998, under Items 5
                       through 9 and Item 11 of the cover pages to this
                       Schedule 13G.

ITEM 5.       OWNERSHIP OF FIVE PERCENT OR LESS OF 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.

                       See Exhibit 1 attached hereto for the information
                       requested hereunder with respect to the relevant
                       subsidiaries of American International Group, Inc.

ITEM 8.       IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE
                       GROUP.

                       Not applicable.

ITEM 9.       NOTICE OF DISSOLUTION OF GROUP.

                       Not applicable.


                                  Page 7 of 11


   8
ITEM 10.      CERTIFICATION.

                  (a) By signing below I certify that, to the best of my 
knowledge and belief, the securities referred to above were acquired in the
ordinary course of business and were not acquired for the purpose of and do not
have the effect of changing or influencing the control of the issuer of such
securities and were not acquired in connection with or as a participant in any
transaction having such purpose or effect.

                  (b) By signing below I certify that, to the best of my 
knowledge and belief, the securities referred to above were not required and 
are not held for the purpose of or with the effect of changing or influencing 
the control of the issuer of the securities and were not acquired and are not 
held in connection with or as a participant in any transaction having that 
purpose or effect.

                                    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.

Date:  February 16, 1999

                          AMERICAN INTERNATIONAL GROUP, INC.


                          By /s/ Kathleen E. Shannon
                          ------------------------------------
                          Name: Kathleen E. Shannon
                          Title:    Vice President and 
                                    Secretary


                          SUNAMERICA INC.


                          By /s/ Jay S. Wintrob
                          ------------------------------------
                          Name: Jay S. Wintrob
                          Title:    Vice Chairman


                          SUNAMERICA LIFE INSURANCE COMPANY


                          By /s/ Jay S. Wintrob
                          ------------------------------------
                          Name: Jay S. Wintrob
                          Title:    Executive Vice President


                          ANCHOR NATIONAL LIFE INSURANCE  COMPANY


                          By /s/ Jay S. Wintrob
                          ------------------------------------
                          Name: Jay S. Wintrob
                          Title:    Executive Vice President




                                  Page 8 of 11


   9
                                  EXHIBIT INDEX



Exhibit 1     Identification and Classification of the Subsidiaries Which
              Acquired the Security Being Reported on by the Parent Holding
              Company

Exhibit 2     Agreement of Joint Filing


                                  Page 9 of 11


   1
                                                                       Exhibit 1

IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY
BEING REPORTED ON BY THE PARENT HOLDING COMPANY.


          American International Group, Inc. -- Subsidiary Information


SunAmerica Inc

          Passive Investor pursuant to Rule 13d-1(c)

           Category Symbol:           OO




SunAmerica Life Insurance Company:

      (c)   Insurance Company as defined in Section 3(a)(19) of the
            Act

           Category Symbol:           IC


Anchor National Life Insurance Company

      (c)   Insurance Company as defined in Section 3(a)(19) of the
            Act

           Category Symbol:           IC


                                  Page 10 of 11


   1
                                                                       Exhibit 2

                            AGREEMENT OF JOINT FILING

                  In accordance with Rule 13d-1(f), promulgated under the
Securities Exchange Act of 1934, as amended, each of the undersigned hereby
agrees to the joint filing on behalf of each of them of a Statement on Schedule
13G, and any amendments thereto, with respect to the Common Stock, no par
value per share, of American Shared Hospital Services and that this Agreement
may be included as an Exhibit to such filing.

                  Each of the undersigned parties represents and warrants to the
other that the information contained in any amendment thereto about it will be,
true, correct and complete in all material respects and in accordance with all
applicable laws. Each of the undersigned parties agrees to inform the other of
any changes in such information or of any additional information which would
require any amendment to the Schedule 13G and to promptly file such amendment.

                  Each of the undersigned parties agrees to indemnify the other
for any losses, claims, liabilities or expenses (including reasonable legal fees
and expenses) resulting from, or arising in connection with, the breach by such
party of any representations, warranties or agreements in this Agreement.

                  This Agreement may be executed in any number of counterparts,
each of which shall be deemed to be an original and all of which together shall
be deemed to constitute one and the same Agreement.

                  IN WITNESS WHEREOF, each of the undersigned hereby executes
this Agreement as of February 16, 1999.

                          AMERICAN INTERNATIONAL GROUP, INC.


                          By /s/ Kathleen E. Shannon
                          ------------------------------------
                          Name: Kathleen E. Shannon
                          Title:    Vice President and 
                                    Secretary


                          SUNAMERICA INC.


                          By /s/ Jay S. Wintrob
                          ------------------------------------
                          Name: Jay S. Wintrob
                          Title:    Vice Chairman



                          SUNAMERICA LIFE INSURANCE COMPANY


                          By /s/ Jay S. Wintrob
                          ------------------------------------
                          Name: Jay S. Wintrob
                          Title:    Executive Vice President


                          ANCHOR NATIONAL LIFE INSURANCE COMPANY


                          By /s/ Jay S. Wintrob
                          ------------------------------------
                          Name: Jay S. Wintrob
                          Title:    Executive Vice President


                                 Page 11 of 11