EXHIBIT 3.15

                                                                     FILED
                                                                  MAY 1 1984
                                                                    2:45 PM
                                                                /s/ [ILLEGIBLE]
                                                              SECRETARY OF STATE

      8401220230

                          CERTIFICATE OF INCORPORATION

                                       OF

                        MEDIQ MOBILE X-RAY SERVICES, INC.

1.    The name of the Corporation is MEDIQ Mobile X-Ray Services, 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 Thousand (1,000) shares of Common Stock; all of
      such shares shall have One Dollar ($1.00) par value.

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

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

      George P. Warren, Jr.               103 Springer Building
                                          3411 Silverside Road
                                          Wilmington, Delaware 19810

      Judith P. Dolan                     103 Springer Building
                                          3411 Silverside Road
                                          Wilmington, Delaware 19810

5b.   The name and mailing address of each person who is to serve as director
      until the first annual meeting of the stockholders or until a successor is
      elected and qualified is as follows:

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

      Robert E. Matthews                  0ne MEDIQ Plaza
                                          Pennsauken, New Jersey 08110

      Bernard J. Korman                   0ne MEDIQ Plaza
                                          Pennsauken, New Jersey 08110

      Eugene M. Schloss, Jr.              0ne MEDIQ Plaza
                                          Pennsauken, New Jersey 08110

6.    The corporation is to have perpetual existence. 



7.    In furtherance and not in limitation of the powers conferred by statute,
      the Board of Directors 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 1st day of May, 1984.

                                        /s/ George P. Warren, Jr.
                                        -------------------------
                                        George P. Warren, Jr.


                                        /s/ Judith F. Dolan
                                        -------------------------
                                        Judith F. Dolan