AMENDED AND RESTATED NOTE AND EQUITY PURCHASE AGREEMENT by and among

Exhibit 10.4.3

AMENDMENT NO. 2

to the

AMENDED AND RESTATED

NOTE AND EQUITY PURCHASE AGREEMENT

by and among

GLOBAL DOSIMETRY SOLUTIONS, INC.,

AMERICAN CAPITAL FINANCIAL SERVICES, INC.,

AS AGENT

and

THE PURCHASERS IDENTIFIED ON

ANNEX A HERETO

Date of Amendment No. 2: February 1, 2006
Date of Amendment No. 1: October 14, 2005

AMENDMENT NO. 2
to the
AMENDED AND RESTATED
NOTE AND EQUITY PURCHASE AGREEMENT

          THIS AMENDMENT NO. 2, dated as of February 1, 2006 (this “ Amendment No. 2 ”), amends the Amended and Restated Note and Equity Purchase Agreement, dated November 10, 2004 (as amended to date, the “ Agreement ”), and is made by and among Global Dosimetry Solutions, Inc., a Delaware corporation (the “ Company ”), the securities purchasers that are now and hereafter at any time parties thereto and are listed in Annex A (or any amendment or supplement thereto) attached thereto (each a “ Purchaser ” and collectively, “ Purchasers ”), and American Capital Financial Services, Inc., a Delaware corporation (“ ACFS ”), as administrative agent for Purchasers (in such capacity “ Agent ”).

RECITALS

          A. The parties hereto were party to a Note and Equity Purchase Agreement, dated as of September 30, 2003 (the “ Original Purchase Agreement ”);

          B. The parties hereto are party to the Agreement, pursuant to which the Original Purchase Agreement was amended and restated;

          C. The Company, Purchasers and the Agent have agreed to enter into this Amendment No. 2 to amend certain terms of the Agreement.

          NOW, THEREFORE, the parties hereto, in consideration of the foregoing premises and their mutual covenants and agreements herein set forth and intending to be legally bound hereby, covenant and agree as follows:

1. Definitions . Capitalized terms used and not defined elsewhere in this Amendment are as defined in the Agreement.

2. Amendments . The Agreement is hereby amended as follows:

     (a) The following definition set forth in Section 1.1 of the Agreement is hereby amended and restated in its entirety:

“ LIBOR Period ” means each month commencing on the Closing Date, the Additional Closing Date, in the case of the Senior Term C Notes, or the Term D Closing Date, in the case of the Senior Term D Notes and the Revolving Notes (or if the Closing Date, the Additional Closing Date, or the Term D Closing Date is not a LIBOR Business Day, the next succeeding LIBOR Business Day) and ending one month thereafter; provided , that the foregoing provision relating to LIBOR Periods is subject to the following:

     (a) if any LIBOR Period would otherwise end on a day that is not a LIBOR Business Day, such LIBOR Period shall be extended to the next succeeding LIBOR Business Day unless the result of such extension would be to carry such LIBOR Period into another calendar month in which event such LIBOR Period shall end on the immediately preceding LIBOR Business Day;

     (b) any LIBOR Period that would otherwise extend beyond the maturity date of the Notes shall end on such date; and

     (c) any LIBOR Peri