RT Journal Article
SR Electronic
T1 SIR-Spheres Activity Measurements Reveal Systematic Miscalibration
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1131
OP 1135
DO 10.2967/jnumed.121.262650
VO 63
IS 8
A1 Graves, Stephen A.
A1 Martin, Molly
A1 Tiwari, Ashok
A1 Merrick, Michael
A1 Sunderland, John
YR 2022
UL http://jnm.snmjournals.org/content/63/8/1131.abstract
AB The purpose of this work was to perform an independent and National Institute of Standards and Technology–traceable activity measurement of 90Y SIR-Spheres (Sirtex). γ-spectroscopic measurements of the 90Y internal pair production decay mode were made using a high-purity germanium detector. Methods: Measured annihilation radiation detection rates were corrected for radioactive decay during acquisition, dead time, source attenuation, and source geometry effects. Detection efficiency was determined by 2 independent and National Institute of Standards and Technology–traceable methods. Results: Measured SIR-Spheres vials (n = 5) contained more activity than specified by the manufacturer calibration; on average, the ratio of measured activity to calibrated was 1.233 ± 0.030. Activity measurements made using 2 distinct efficiency calibration methods agreed within 1%. Conclusion: The primary SIR-Spheres activity calibration appears to be a significant underestimate of true activity.