Caracterización de lesiones oncológicas prostáticas a través de la farmacocinética de 18F-PSMA mediante cuantificación con modelos compartimentales

Abstract

The Simplified Reference Tissue Model (SRTM) is presented as a promising alternative for the evaluation of prostate oncological lesions through the use of the 18F-PSMA-1007 tracer, addressing the problem of the need for arterial entry curves that conventional methods require. The main objective of the study was to evaluate the efficacy of SRTM and analyze the behavior of its pharmacokinetic constants in the prostate oncological context. In the adopted methodology, six patients diagnosed with prostate cancer were administered a mean dose of 4.53 mCi of 18F-PSMA-1007, and imaging was performed using PET-CT and PET-MR scanners with 45-minute dynamic protocols. Volumes of interest were outlined in areas with different pathologies and gluteal tissue was used as a reference for the SRTM. By analyzing temporal activity curves and applying the Monte Carlo model to minimize noise errors, the pharmacokinetic constants R1, BPnd, k2, k2', and k2a were derived. Preliminary results show that, in patients with confirmed recurrence, ligand uptake (R1) was significantly higher and the clearance rate (k2) was considerably lower compared to patients with undifferentiated pathology, indicating greater ligand retention and receptor density increased. These findings highlight important pharmacokinetic differences between the patients studied, reflecting variations in ligand dynamics that are crucial for the characterization of prostatic pathological states and subsequent therapeutic management. The utility of SRTM, demonstrated in this study, establishes its value in the non-invasive evaluation of ligand dynamics in prostate tissue.