POWER OF ATTORNEY

Know all by these presents that the undersigned hereby constitutes
and appoints each of William J. O'Shaughnessy, Jr., Michael E. Prevoznik
and Elena H. Radine, signing singly, his true and lawful attorney-in-fact to:

(1)    execute for and on behalf of the undersigned Forms 3, 4 and 5 in
accordance with Section 16(a) of the Securities Exchange Act of 1934 and the
rules thereunder;

(2)    do and perform any and all acts for and on behalf of the undersigned
which may be necessary or desirable to complete the execution of any such
Form 3, 4 or 5 and the timely filing of such form with the United States
Securities and Exchange Commission and any other authority; and

(3) take any other action of any type whatsoever in connection with the
foregoing which, in the opinion of such attorney-in-fact, may be of benefit
to, in the best interest of, or legally required by, the undersigned, it
being understood that the document executed to this Power of Attorney shall
be in such form and shall contain such terms and conditions as such
ttorney-in-fact may approve in his/her discretion.

The undersigned hereby grants to each such attorney-in-fact full power and
authority to do and perform all and every act and thing whatsoever requisite,
necessary and proper to be done in the exercise of any of the rights and
powers herein granted, as fully to all intents and purposes as the undersigned
might or could do if personally present, with full power of substitution or
revocation, hereby ratifying and confirming all that such attorney-in-fact,
or such attorney-in-fact's substitute or substitutes shall lawfully do or
cause to be done by virtue of this power of attorney and the rights and powers
herein granted.  The undersigned acknowledges that the foregoing
attorneys-in-fact, in serving in such capacity at the request of the undersigned,
are not assuming any of the undersigned's responsibilities to comply with
Section 16 of the Securities Exchange Act of 1934.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of this 25th day of January, 2017


/s/ Jeffrey M. Leiden, M.D., Ph.D.
JEFFREY M. LEIDEN, M.D., PH.D.

STATE OF Massachusetts    )
            ) ss.
COUNTY OF Suffolk    )

On this 25th day of January, 2017, before me, SUSAN M. BYRNE, the undersigned
notary public, personally appeared JEFFREY M. LEIDEN, M.D., PH.D., proved to me on the basis
of satisfactory evidence to be the person whose name is subscribed to the within
instrument, and acknowledged to me that he executed the same for the purposes
therein stated.



/s/ Susan M. Byrne
Notary Public
My Commission Expires: February 20, 2020