Dose calibrator manufacturer-dependent bias in assays of 123I

• Published in: Applied radiation and isotopes Vol. 90; pp. 79 - 83
• Main Authors: Bergeron, Denis E., Cessna, Jeffrey T., Golas, Daniel B., Young, Rheannan K., Zimmerman, Brian E.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-08-2014
• Subjects: Dose calibrator; I-123; Ionization chamber; Quantitative imaging; Secondary standard; Dose calibrator; Secondary standard; Ionization chamber; Quantitative imaging; I-123
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2014.03.018

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 established. The two major U.S. dose calibrator manufacturers recommend oppositely biased calibration factors, giving a spread of 11.3% in measured activities. With modern quantitative imaging techniques capable of ≤10% accuracy, this bias for a SPECT nuclide is highly significant.
•Dose calibrator calibration factors were determined for 123I.•The NIST standard was indirectly linked to the SIR.•Manufacturer-dependent biases result in a spread of 11.3 % in measured activity.