Personalized lung dosimetry evaluated by 90Y PET/CT in radioembolization: dosimetric correlations and exploratory observations on radiation pneumonitis
摘要
To evaluate whether personalized lung mass improves pre-treatment lung dose estimation accuracy compared to the 1000-g lung model, using post-treatment 90Y PET/CT as the reference. Sex-specific anatomical differences and dosimetric factors associated with radiation pneumonitis (RP) were also explored.
Materials and methodsA retrospective analysis was conducted on 100 patients treated with 90Y radioembolization from 2018 to 2025. Pre-treatment lung dose estimates were derived using both the standard 1000-g lung mass model and CT-based personalized lung mass. Post-treatment lung absorbed doses were quantified via 90Y PET/CT. Dosimetric and clinical variables were compared between patients with and without RP, and sex-specific differences in lung anatomy and dose distribution were evaluated.
ResultsThe mean lung mass (760.11 ± 144.89 g) was significantly lower than the 1000-g model (P < 0.001). Two patients (2%) developed RP, and both had baseline lung metastases (28% overall). Although limited by the small number of events, the RP group showed a trend toward higher median administered activity (4425 MBq [range, 3000–5800 MBq] vs. 1300 MBq [range, 400–4900 MBq]) and lung absorbed dose, whereas no similar trend was observed for lung shunt fraction (LSF) (7.6% [range, 5.1–10.0%] vs. 4.3% [range, 1.0–14.5%]). Personalized lung dose showed a stronger correlation with 90Y PET/CT than the 1000-g model (r = 0.678 vs. r = 0.612; P = 0.009), while LSF showed no correlation (r = 0.150). Sex-based dose differences seen with the 1000-g model were absent with personalized lung mass, which showed significantly lower lung mass in females (810.78 ± 126.21 g vs. 636.05 ± 109.33 g, P < 0.001).
ConclusionPersonalized dosimetry improves predictive accuracy and mitigates sex-related dosimetric bias, suggesting CT-derived lung mass should be considered to optimize 90Y radioembolization precision. Given our limited sample size, the association between pre-existing lung metastases and RP warrants further investigation.