Abstract
Dosimetry-guided treatment planning in selective internal radiation therapy relies on accurate and reproducible measurement of administrated activity. This multi-center (ncenter=4), multi-device (nPET=5) study compared the manufacturer-declared 90Y activity in vials with quantitative 90Y PET/CT-assessment of the same vials. We compared 90Y PET-measured activity (APET) for 90Y-labeled glass (ng=56) and resin (nr=18) microsphere vials with the calibrated activity specified by the manufacturer (AM). Additionally, the same analysis was performed for 90Y-chloride vials (ncl=4). The mean APET/AM ratio for glass microspheres was 0.79±0.04 [range: 0.71–0.89] and for resin microspheres was 1.15±0.06 [range: 1.05–1.25]. Mean APET/AM ratio for 90Y-chloride vials was 1.00±0.04 [range: 0.96–1.06]. Thus, we found an average difference of 46% between glass and resin microsphere activity calibrations while a close agreement was found for chloride solutions. We expect the reported discrepancies will promote further investigations to establish reliable and accurate patient dosimetry and dose-effect assessments.
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