Advances in the identification of molecular targets in tumor cells have enabled the development of more precise diagnostic and therapeutic approaches in oncology, through the use of radiopharmaceuticals. In this context, theranostics has gained relevance by integrating diagnosis and therapy within a single molecular platform. Among these agents, 68Ga-PSMA is widely used for prostate cancer imaging and has also demonstrated potential in other PSMA-expressing neoplasms, supporting diagnosis, treatment planning, and therapy response assessment. This study aims to optimize and standardize the in-house synthesis of 68Ga-PSMA radiopharmaceutical, ensuring reproducibility, safety, and technical feasibility, with a focus on its application in the theranostic model for non-prostatic neoplasms. This prospective study is being conducted at the Nuclear Medicine Service of the Hospital de Clínicas (NMS/HC) - Unicamp and was approved by the Research Ethics Committee (approval number 6,698,585/2024; CAAE 30476720.9.0000.5404). In an automated synthesis module, 68GaCl3 is eluted from a commercial 68Ge/68Ga generator and used for radiolabeling the PSMA-11 peptide. The reaction is performed in acetate buffer at 85°C for 5 minutes, followed by purification, sterilization, and dilution for clinical use. Quality control procedures are being implemented and optimized. To date, radiochemical purity of 68Ga-PSMA has been assessed by thin-layer chromatography (TLC) using TLC-SG and iTLC-SG as stationary phases, with 0.1M sodium citrate and ammonium acetate/methanol (1:1) as mobile phases, respectively. The pH of the final product has been determined. Current analyses include radiochemical yield and purity and chromatographic peak behavior expressed as retention factors (Rf), while stability studies are planned. In parallel, safety procedures and clinical protocols are being developed in collaboration with radiopharmacy and nuclear medicine specialists. Following optimization and standardization of the in-house synthesis methodology, 68Ga-PSMA will be implemented for clinical imaging in patients selected at NMS/Unicamp, supporting theranostic applications in accordance with ethical standards. Initial in-house 68Ga-PSMA syntheses were successfully performed, demonstrating consistent radiochemical performance across independent productions (n = 7). Radiochemical purity assessed by TLC showed a mean value of 92.5 ± 3.3% and was further confirmed by direct activity measurement of segmented TLC strips using a dose calibrator, with a mean of 99.2 ± 0.7%. The final radiolabeled product presented an appropriate pH of 5.2 ± 0.3. Chromatographic analysis demonstrated the expected migration profiles. Using ammonium acetate/methanol (1:1) as the mobile phase, 68Ga-PSMA migrated with the solvent front (Rf = 0.9‒1.0), whereas with 0.1M sodium citrate, free 68Ga remained near the origin (Rf = 0.3‒0.4). The optimization and standardization of in-house 68Ga-PSMA production represents an important step toward institutional autonomy, improving access to molecular imaging in oncology. This approach may extend PSMA-based theranostic applications beyond prostate cancer and contribute to the establishment of Unicamp’s radiopharmacy as a national reference center.
Torricelli et al. (Sun,) studied this question.