From:	Pomije, Brian D. (LCDR)
Sent:	Friday, August 12, 2005 11:16 AM
To:	Hodge, Jenny L. MSGT; Burke, Gerald; Casey, Richard W. LCDR; Clark, Dorothy M. (CIV); Ely, Karen D. (CIV); Fairchild Gregory R LT; Fong, Raynard K   CAPT; Giel, Daniel T. (CIV); Hecht, Sheila C , LCDR; Herrera, Mark E; Hope, Lawanda P. HM1; Johnson, Gabrielle M.; Kennemur, Lisa K LCDR; LaFontaine, Richard L CT; Loscocco, Michele F (CDR); Maher, John M CDR; Ozeroglu, Muhammed A  LT; Pomije, Brian D. (LCDR); Ruiz, Steven LCDR; Saylor, Tillman K (NNMC Contractor); Scott, John H., CIV.; Simays, Andrew E., CDR; Solanki, Haresh P; Swilley, Eugene A. (LT); Tu, Victor LT; Van Way, Rick L (LCDR); Younes, Georges  E LCDR
Cc:	Pomije, Brian D. (LCDR); Ely, Karen D. (CIV); Clark, Dorothy M. (CIV); Earles, Marvin R LCDR ; Glennon, Brendan K. CDR BUMED; Lino CDR Fragoso (E-mail) (Lino.Fragoso@navy.mil)
Subject:	NRMP - Cal. of Dose Calibrators for P-32 and other Beta Emitters or Low-Energy Photon Emitters
Calibration of Dose Calibrators for P-32 
and other Beta Emitters or Low-Energy Photon Emitters

To all Medical RSOs and NRMP Permittees:

The NRC has recently posted in their NMSS Quarterly Newsletter (July 2005), a warning about not properly calibrating a "dose calibrator" for use in measuring the activity of P-32 and other beta emitters or low-energy photon emitters.  Specifically, to properly calibrate a dose calibrator and accurately measure the activity of dosages, a licensee must, among other things, perform the geometric dependency test for the actual containers and volumes routinely used at a licensee’s facility and use the resulting data to obtain site specific correction factors.

[The excerpt from the NRC's newsletter has been pasted at the end of this message]  

Also, the NRC has previously published related guidance in NRC Information Notice 2002-19, “Medical Misadministrations Caused by Failure to Properly Perform Test on Dose Calibrators for Beta and Low-Energy Photon-Emitting Radionuclides”.  This Information Notice can be downloaded from the NRC's website at: http://www.nrc.gov/reading-rm/doc-collections/gen-comm/info-notices/2002/in02019.pdf.  The Navy Environmental Health Center had follow-up by publishing NRMP Information Notice 2003-02, which can be downloaded at: http://www-nehc.med.navy.mil/occmed/notice2003-02.doc.

Each NRMP Permittee shall review the contents of this message to determine applicability to their command, and verify that accurate procedures are in place to ensure that dose calibrator measurements of all radiopharmaceuticals are being conducted correctly.  No response to NEHC is required, unless a discrepancy has been identified at a command.

Very Respectfully,

LCDR Pomije

Brian D. Pomije, MS, DABR
Lieutenant Commander, Medical Service Corps, USN
Radiation Health Team Leader
Navy Environmental Health Center
620 John Paul Jones Circle (Suite 1100)
Portsmouth, VA 23708-2103

W: (757) 953-0766; DSN: 377-0766
Cell: (757) 651-2814
Fax: (757) 953-0685

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CALIBRATION of DOSE CALIBRATORS 
for P-32 and OTHER BETA EMITTERS 
or LOW-ENERGY PHOTON EMITTERS

During a recent inspection, a Nuclear Medicine licensee was measuring and adjusting Phosphorous-32 (P-32) radiopharmaceutical dosages using a dose calibrator that had only been calibrated using high-energy gamma-emitting sources and had not been calibrated specifically for P-32 use.  10 CFR 35.60, “Possession, use, and calibration of instruments used to measure the activity of unsealed byproduct material”, requires the licensee to calibrate instruments used for direct measurement of dosages before medical use.  In spite of this requirement, the licensee erroneously believed it was not required to calibrate the dose calibrator, but to “only perform periodic test following a nationally recognized standard”.  The standard cited was American National Standards Institute (ANSI) N42.13, “American National Standard Calibration and Usage of ‘Dose Calibrator’ Ionization Chambers for the Assay of Radionuclides”.  This standard describes required calibration procedures (i.e., initial calibration with standard sources for each radionuclide of interest, dependence of the assay on geometric configuration and composition of the source container, and energy range) and advisory calibration recommendations to be applied when practical (i.e., cover complete activity ranges used) to achieve acceptable accuracy and reproducibility limits.

The licensee did not perform the procedures required in ANSI N42.13.  Instead, the licensee used the dose calibrator manufacturer’s radionuclide calibration setting for P-32 without performing the geometry dependence test.  To properly calibrate the dose calibrator and accurately measure the activity of its P-32 dosages, the licensee needed, among other things, to perform the geometric dependency test for the actual containers and volumes routinely used at the licensee’s facility and use the resulting data to obtain a site specific correction factor for P-32.  This was important because the manufacturer’s table of radionuclides and calibration settings included the disclaimer “no warranty of any kind can be made as to their (calibration numbers) accuracy, since there were many uncontrollable factors (as well as the accuracy of the published data) involved in the overall accuracy of an assay” and further warned that the P-32 data was for “estimation use only”.

The NRC recognizes the difficulties associated with measuring and calibrating dose calibrators for pure beta-emitting radionuclides and discussed some of these difficulties in NRC Information Notice 2002-19, “Medical Misadministrations Caused by Failure to Properly Perform Test on Dose Calibrators for Beta and Low-Energy Photon-Emitting Radionuclides”.  An additional difficulty with beta calibrations is that lack of standard sources for certain radionuclides and, even if the standard sources were available, most medical use licensees do not have access to the NIST-prepared or traceable standard sources needed to perform the calibrations for beta-emitting radionuclides.  All these difficulties contributed to NRC giving medical use licensees the option in 10 CFR 35.63, “Determination of dosages of unsealed byproduct material for medical use”, of determining the proper dosages by using a combination of volumetric measurements and mathematical calculations, based on the activity per unit volume determination made by the manufacturer or preparer licensed under 10 CFR 32.72, “Manufacture, preparation, or transfer for commercial distribution of radioactive drugs containing byproduct material for medical use under Part 35”.  This option gives licensees a better method of determining activities without depending on dose calibrator reading from instruments that are not calibrated for the radionuclides being administered to humans.

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