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Publications

Search Publications by Brian E. Zimmerman

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Displaying 1 - 25 of 66

Ra-224 activity, half-life, and 241 keV gamma ray absolute emission intensity: a NIST-NPL bilateral comparison

December 31, 2020
Author(s)
Denis E. Bergeron, Sean Collins, Leticia Pibida, Jeffrey T. Cessna, Ryan P. Fitzgerald, Brian E. Zimmerman, Peter Ivanov, John Keightley, Elisa Napoli
The national metrology institutes for the United Kingdom and the United States have compared activity standards for 224Ra, an -particle emitter of interest as the basis for therapeutic radiopharmaceuticals. Solutions of 224RaCl2 were assayed by absolute

Primary standardization of Ra-224 activity by liquid scintillation counting

October 11, 2019
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Ryan P. Fitzgerald, Brian E. Zimmerman, Lizbeth Laureano-Perez, Ronald Colle, Leticia S. Pibida, Elisa Napoli
A standard for 224Ra activity has been developed, based on triple-to-double coincidence ratio (TDCR) liquid scintillation (LS) counting. The standard was confirmed by efficiency tracing and 4παβ(LS)-γ(NaI(Tl)) anticoincidence counting, as well as by 4πγ

Standardization of I-124 by three liquid scintillation-based methods

August 9, 2019
Author(s)
Denis E. Bergeron, Leticia S. Pibida, Brian E. Zimmerman, Jeffrey T. Cessna, Ryan P. Fitzgerald
A solution of 124I was standardized for activity by 4πβ(LS)-γ(NaI) live-timed anticoincidence (LTAC) counting, with confirmatory measurements by triple-to-double coincidence ratio (TDCR) and CIEMAT-NIST efficiency tracing (CNET) liquid scintillation

Standardization of 64Cu activity

May 25, 2018
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Ryan P. Fitzgerald, Leticia S. Pibida, Brian E. Zimmerman
The complex decay scheme that makes 64Cu promising as both an imaging and therapeutic agent in medicine also makes the absolute measurement of its activity challenging. The National Institute of Standards and Technology (NIST) has completed a primary

Activity measurements of the radionuclides 18F and 64Cu for the NIST, USA in the ongoing comparisons BIPM.RI(II)-K4.F-18 and BIPM.RI(II)-K4.Cu-64

January 1, 2018
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Ryan P. Fitzgerald, Leticia S. Pibida, Brian E. Zimmerman, Carine Michotte, Manuel Nonis, Andrew Fenwick, Kelly Ferreira, John Keightley
In 2016, comparisons of activity measurements of 18F and 64Cu using the Transfer Instrument of the International Reference System (SIRTI) took place at the National Institute of Standards and Technology (NIST, USA). This is the first SIRTI comparison for

Natural Uranium Radioactivity Solution Standard: SRM 4321d

December 27, 2017
Author(s)
Ronald Colle, Lizbeth Laureano-Perez, Svetlana Nour, Jerome J. LaRosa, Brian E. Zimmerman, Leticia S. Pibida, Denis E. Bergeron
A new natural uranium solution standard has been produced and will be disseminated by the National Institute of Standards and Technology (NIST) as Standard Reference Material 4321d. The standard is certified for the massic activities of 234U, 235U, and

Results of an International Comparison of Activity Measurements of 68Ge

November 7, 2017
Author(s)
Jeffrey T. Cessna, Ryan P. Fitzgerald, Brian E. Zimmerman, Lizbeth Laureano-Perez, Denis E. Bergeron
An international key comparison, identifier CCRI(II)-K2.Ge-68, has been performed. The National Institute of Standards and Technology (NIST) served as the pilot laboratory, distributing aliquots of a 68Ge/68Ga solution. Results for the activity

Two determinations of the Ge-68 half-life

October 19, 2017
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Brian E. Zimmerman
In nuclear medicine, 68Ge is used to generate 68Ga for imaging by positron emission tomography (PET) and sealed sources containing 68Ge/68Ga in equilibrium have been adopted as long-lived calibration surrogates for the more common PET nuclide, 18F. We

Comparison of C-14 liquid scintillation counting at NIST and NRC Canada

March 1, 2016
Author(s)
Denis E. Bergeron, Raphael Galea, Lizbeth Laureano-Perez, Brian E. Zimmerman
An informal bilateral comparison of 14C liquid scintillation (LS) counting at the National Research Council of Canada (NRC) and the National Institute of Standards and Technology (NIST) has been completed. Two solutions, one containing 14C-labeled sodium

Long-term stability of carrier-added Ge-68 standardized solutions

March 1, 2016
Author(s)
Brian E. Zimmerman, Denis E. Bergeron, Ryan P. Fitzgerald, Jeffrey T. Cessna
Tests for chemical stability were carried out on carrier-added 68Ge solutions prepared and calibrated in 2007 and 2011 to evaluate the suitability of the specific composition as a potential Standard Reference Material. Massic count rates of the stored

Determination of photon emission probabilities for the main gamma-rays of 223Ra in equilibrium with its progeny

March 11, 2015
Author(s)
Leticia S. Pibida, Brian E. Zimmerman, Ryan P. Fitzgerald, Lynne E. King, Jeffrey T. Cessna, Denis E. Bergeron
The currently published 223Ra gamma-ray emission probabilities display a wide variation in the values depending on the source of the data. The National Institute of Standards and Technology performed activity measurements on a 223Ra solution that was used

Secondary standards for 223Ra revised

March 5, 2015
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Brian E. Zimmerman
Dose calibrator dial settings reported by NIST in 2010 (ARI v. 68, p. 1367) are now known to give erroneously low (by 10 %) activity readings. The original determinations were based on a chain of calibrations; a broken link in this chain was recently

A review of NIST primary activity standards for 18F: 1982 to 2013

August 27, 2014
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Bert M. Coursey, Ryan P. Fitzgerald, Brian E. Zimmerman
The new NIST activity standardization for 18F differs from results obtained between 1998 and 2008 by 4 %. The new results are considered to be very reliable; they are based on a battery of robust primary measurement techniques and bring the NIST standard

Dose calibrator manufacturer-dependent bias in assays of 123I

March 26, 2014
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Daniel B. Golas, Rheannan K. Young, Brian E. Zimmerman
Calibration factors for commercial ionization chambers (i.e. dose calibrators) were determined for a solution of 123I; the activity was based on the 1976 NBS standard. A link between the NIST standard and the International Reference System (SIR) was

A New NIST Primary Standardization of 18F

February 1, 2014
Author(s)
Ryan P. Fitzgerald, Brian E. Zimmerman, Denis E. Bergeron, Jeffrey T. Cessna, Leticia S. Pibida, Denise S. Moreira
A new primary standardization of 18F by NIST is reported. The standard is based on live-timed beta- gamma anticoincidence counting with confirmatory measurements by three other methods: (i) liquid scintillation (LS) counting using CIEMAT/NIST 3H efficiency

Results of an international comparison for the activity measurement of 177Lu

March 6, 2012
Author(s)
Brian E. Zimmerman, Denis E. Bergeron, Jeffrey T. Cessna
An international Key Comparison of 177Lu has recently been carried out. Twelve laboratories performed assays for radioactivity content on aliquots of a common master solution of 177Lu, leading to eleven results submitted for entry into the Key Comparison

TDCR Measurements on Pu-241 at NIST

December 21, 2010
Author(s)
Denis E. Bergeron, Brian E. Zimmerman
We have performed a series of measurements on a Pu-241 solution using the triple-to-double coincidence ratio (TDCR) liquid scintillation technique. A similar series of measurements in 2007 revealed significant discord between activity values determined via