EXHIBIT 3.7

                                   8601350020

                                                                    FILED
                                                               MAY 15 1986 9 AM


                                                               /s/ [ILLEGIBLE]
                                                              SECRETARY OF STATE

                          CERTIFICATE OF INCORPORATION

                                       OF

                  MEDIQ Diagnostic & Treatment Centers - I Inc.

1.    The name of the Corporation is MEDIQ Diagnostic & Treatment Centers - I
      Inc.

2.    The address of its registered office is 103 Springer Building, 3411
      Silverside Road, Wilmington, County of New Castle, Delaware 19810. The
      name of its registered agent at such address is Organization Services,
      Inc.

3.    The nature of the business to be conducted or promoted is to engage in any
      lawful act or activity for which corporations may be organized under the
      General Corporation Law of Delaware.

4.    The total number of shares of stock which the Corporation shall have
      authority to issue is One hundred (100) shares of common stock; each such
      share shall have Ten Dollars ($10.00) par value.

5.    The name and mailing address of each incorporator is as follows:


                NAME                       ADDRESS
                ----                       -------

      Lee Lieberman                      103 Springer Building
                                         3411 Silverside Road
                                         Wilmington, Delaware 19810

      Harold F. Kalbach, Jr.             103 Springer Building
                                         3411 Silverside Road
                                         Wilmington, Delaware 19810

6.    The corporation is to have perpetual existence.

7.    In furtherance and not in limitation of the powers conferred by statute,
      the Board of Director is expressly authorized to make, alter or repeal the
      By-Laws of the Corporation.

8.    Meetings of stockholders may be held within or without the State of
      Delaware as the By-Laws may provide. The books of the Corporation may be
      kept (subject to any provisions contained in the statutes) outside the
      State of Delaware at such place or places as may be designated from time
      to time by the Board of Directors or in the By-Laws of the Corporation.
      Elections of Directors need not be by written ballot unless the By-Laws of
      the Corporation shall so provide.



9.    The Corporation reserves the right to amend, alter, change or repeal any
      provision contained in this Certificate of Incorporation, in the manner
      now or hereinafter prescribed by statute, and all rights conferred upon
      stockholders herein are granted subject to this reservation.

      WE THE UNDERSIGNED, being each of the incorporators hereinbefore named,
for the purpose of forming a corporation pursuant to the General Corporation Law
of the State of Delaware, do make this certificate, hereby declaring and
certifying that this is our act and deed and the facts herein stated are true,
and accordingly have hereunto set our hands this 14th day of May, 1986.


                                                  /s/ Lee Lieberman
                                                  --------------------------
                                                  Lee Lieberman

                                                  /s/ Harold F. Kalbach, Jr.
                                                  --------------------------
                                                  Harold F. Kalbach, Jr.



     STATE OF DELAWARE
    SECRETARY OF STATE
 DIVISION OF CORPORATIONS
FILED 10:00 AM 10/30/1992
    923095023 - 2091201

                            CERTIFICATE OF AMENDMENT

                                       OF

                          CERTIFICATE OF INCORPORATION

                                    * * * * *

      MEDIQ Diagnostic & Treatment Centers - I Inc. a corporation organized and
existing under and by virtue of the General Corporation Law of the State of
Delaware,

      DOES HEREBY CERTIFY:

      FIRST: That the Board of Directors of said Corporation, by the unanimous
written consent of its members, filed with the minutes of the Board adopted a
resolution proposing and declaring advisable the following amendment to the
Certificate of Incorporation of said corporation:

            RESOLVED, that the Certificate of Incorporation of MEDIQ Diagnostic
& Treatment Centers - I Inc. be amended by changing the First Article thereof so
that, as amended, said Article shall be and read as follows:

      "The name of the corporation is MEDIQ Diagnostic Centers - I Inc."

      SECOND: That in lieu of a meeting and vote of stockholders, the
stockholders have given unanimous written consent to said amendment in
accordance with the provisions of Section 228 of the General Corporation Law of
the State of Delaware.

      THIRD: That the aforesaid amendment was duly adopted in accordance with
the applicable provisions of Sections 242 and 228 of the General Corporation Law
of the State of Delaware.



            IN WITNESS WHEREOF, said MEDIQ Diagnostic & Treatment Centers - I
Inc. has caused this certificate to be signed by James F. Corey, its
Vice-President and attested by Alan S. Einhorn, its Assistant Secretary, this
27th day of October, 1992.


                              MEDIQ Diagnostic & Treatment Centers - I Inc.


                              By /s/ James F. Corey
                                 ----------------------------------------- 
                                 James F. Corey
                                 Vice-President


ATTEST:


By /s/ Alan S. Einhorn
   ------------------------------------------
   Alan S. Einhorn
   Assistant Secretary