In vivo preclinical evaluation of YntraDose™ in pig's lung: A pilot study of a 90Y-microsphere device implantation

Background YntraDose™ is a novel injectable radiotherapeutic formulation combining BioGlue® (bovine serum albumin–glutaraldehyde polymer) with Yttrium-90 resin microspheres. This pilot preclinical feasibility study represents the first in vivo evaluation of YntraDose™ administration into lung tissue and was designed to assess its injectability, polymerization performance, biodistribution, dosimetry, and tissue response. Methods Seven healthy female Landrace pigs were enrolled and received ultrasound-guided percutaneous injections of YntraDose™ in two lung lobes (5 mL and 10 mL syringes targeting 150–185 MBq). Pigs were euthanized at 24 h, 7-, 14-, and 21 days post-injection for necropsy, PET/CT imaging, dosimetry, and histological evaluation. Immunohistochemistry for IL-1β, IL-6, and IL-8 was performed on lung biopsies to assess inflammatory activity. Results YntraDose™ administration was feasible and resulted in localized polymerization within the injection site, with no evidence of radioactivity spread to other organs. Histological analysis revealed areas of necrosis extending up to 1–1.5 cm from the main deposition site and diffuse inflammatory cell infiltration. IL-1β, IL-6, and IL-8–positive cells were identified throughout the tissue, indicating a strong inflammatory response. Conclusions This first in vivo preclinical investigation demonstrates that YntraDose™ can be successfully injected and polymerized in lung tissue, even at high radioactivity levels. Despite the intense inflammatory reaction observed, the results support further preclinical studies with optimized, clinically relevant 90 Y activities to evaluate the potential of YntraDose™ for localized lung tumor ablation.