US-guided percutaneous ablation of thyroid nodules with 177LU-MAA (LUTMA) - Feasibility study

Purpose The main purpose is to evaluate the safety, and efficacy of 177Lutetium labeled macroaggregated albumin (LUTMA) ablation of thyroid nodules. Materials and methods Patients with confirmed benign nodules who were not candidate or did not accept surgery were enrolled. Under ultrasonography (USG) guidance, LUTMA which was produced in our department, was administered into the nodules. Nodule volumes were assessed via USG before the injection and at 1-week, 1-month, and 3-months post-treatment. We calculated the volume reduction rates (VRRs) for these intervals. To detect extranodular activity leakage, patients underwent SPECT/CT imaging at one hour, 24 hours, and one week post-injection. Results Fifteen patients (male: 12, female: 3) with benign thyroid nodules were eligible to join this study. These nodules were categorized as cystic (n = 9), solid (n = 3), or mixed (n = 3). Median nodules volume was 6.59 ml (range: 0.56-55 ml). Predicted absorbed dosee to the nodules varied between 10 to 1036 Gy. The VRRs at 3. months was 85% for all nodule types with gradual increases over time: 0-92%, 20-97%, and 28-98% at 1. week, 1. month, and 3-months, respectively. The median VRR of cystic nodules was 89% (range: 81%-98%) at 3-months. It is significantly higher than solid ones (p = 0.009). None of the patients experienced adverse reactions or discomfort during the injection or follow-up. Conclusion LUTMA treatment significantly reduces the volume of benign thyroid nodules, offering relief from disease-associated symptoms and cosmetic concerns. It emerges as a promising alternative to surgical and other local treatments for benign thyroid nodule ablation. Clinical signification LUTMA is a novel theranostic radiopharmaceutical which is promising in local ablative treatment of benign thyroid nodules.