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Calibration of traceable solid mock I-131 phantoms used in an international SPECT image quantification comparison



Brian E. Zimmerman, Leticia S. Pibida, Lynne E. King, Denis E. Bergeron, Jeffrey T. Cessna, Matthew M. Mille


The International Atomic Energy Agency (IAEA) has organized an international comparison to assess Single Photon Emission Computed Tomography (SPECT) image quantification capabilities in 12 countries. Iodine-131 was chosen as the radionuclide for the comparison because of its wide use around the world, but for logistical reasons solid 133Ba sources were used as a long-lived surrogate for 131I. For this study, we designed a set of solid cylindrical sources so that each site could have a set of phantoms (having nominal volumes of 2 mL, 4 mL, 6 mL, and 23 mL) with traceable activity calibrations so that the results could be properly compared. We also developed a technique using two different detection methods for individually calibrating the sources for 133Ba activity based on a National standard. This methodology allows for the activity calibration of each 133Ba source with a standard uncertainty on the activity of 1.4 % for the high-level 2-, 4-, and 6-mL sources and 1.7 % for the lower-level 23 mL cylinders. This level of uncertainty allows for these sources to be used for the intended comparison exercise, as well as in other SPECT image quantification studies.
Journal of Research (NIST JRES) - 118.017
Report Number


barium-133, iodine-131, SPECT, standards, traceability


Zimmerman, B. , Pibida, L. , King, L. , Bergeron, D. , Cessna, J. and Mille, M. (2013), Calibration of traceable solid mock I-131 phantoms used in an international SPECT image quantification comparison, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed June 17, 2024)


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Created August 15, 2013, Updated November 10, 2018