Tumoral fibrosis effect on the radiation absorbed dose of ¹⁷⁷Lu–Tyr³-octreotate and ¹⁷⁷Lu–Tyr³-octreotate conjugated to gold nanoparticles

The aim of this work was to evaluate the tumoral fibrosis effect on the radiation absorbed dose of the radiopharmaceuticals ¹⁷⁷Lu–Tyr³-octreotate (monomeric) and ¹⁷⁷Lu–Tyr³-octreotate–gold nanoparticles (multimeric) using an experimental HeLa cells tumoral model and the Monte Carlo PENELOPE code. Experimental and computer micro-environment models with or without fibrosis were constructed. Results showed that fibrosis increases up to 33% the tumor radiation absorbed dose, although the major effect on the dose was produced by the type of radiopharmaceutical (112 Gy-multimeric vs. 43 Gy-monomeric). - Highlights: • Fibrosis increases the radiation absorbed dose to the tumor. • Fibrosis increases the radiopharmaceutical residence time in the tumor. • The multimeric nature of the radiopharmaceuticals enhances the radiopharmaceutical retention