Measure of 90Y-glass microspheres residue post-TARE using PET/CT and potential impact on tumor absorbed dose in comparison 99mTc-MAA SPECT/CT dosimetry

Abstract

BackgroundTransarterial radio-embolization (TARE) became a routine procedure for non-resectable liver tumor mainly hepatocellular carcinoma (HCC). Personalized dosimetry to the index lesion increased tumor response rate. However, there is no requirement to measure the precise activity injected during TARE. We measured 90Y-glass microspheres residue (90Y-Res) in the application system after TARE and assessed its potential impact on the tumor absorbed dose (AD) previously planned with 99mTc MAA SPECT/CT.MethodsWe measured 90Y-Res using PET/CT in all patients that underwent TARE using 90Y-glass-microspheres for non-resectable liver tumors over one year.Results90Y-Res was measured in 34 patients (HCC n = 22) with 61 injections, 93.1 ± 94.6 MBq [2–437] that was 4.8 ± 3.5% [0.2–13.7] in comparison to the activity measured in the sealed TheraSphere™ vial (ρ = 0.697; p < 0.001).ConclusionWe reported an average of 5% 90Y-Res using PET/CT after TARE with the strongest association to the activity in the TheraSphere™ vial. Therefore, when a high 90Y-Res is suspected on the survey meter, a 90Y-PET/CT scan of 90Y-Res might be useful as a first step to estimate if the target lesion received the recommended AD, especially in HCC patients with borderline tumor dosimetry on the pre-treatment 99mTc-MAA SPECT/CT.