Transarterial 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 ⁹⁰ Y-glass microspheres residue ( ⁹⁰ Y-Res) in the application system after TARE and assessed its potential impact on the tumor absorbed dose (AD) previously planned with ^99m Tc MAA SPECT/CT.
We measured ⁹⁰ Y-Res using PET/CT in all patients that underwent TARE using ⁹⁰ Y-glass-microspheres for non-resectable liver tumors over one year.
⁹⁰ Y-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).
We reported an average of 5% ⁹⁰ Y-Res using PET/CT after TARE with the strongest association to the activity in the TheraSphere™ vial. Therefore, when a high ⁹⁰ Y-Res is suspected on the survey meter, a ⁹⁰ Y-PET/CT scan of ⁹⁰ Y-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 ^99m Tc-MAA SPECT/CT.