Iudicello Antonella, Boschi Stefano, Ghedini Pietro, Lohr Frank, Panareo Stefano
Pharmaceutical Department, Azienda USL di Modena, Largo del Pozzo 71, 41121 Modena, Italy.
Nuclear Medicine Unit, Department of Oncology and Hematology, Azienda Ospedaliero-Universitaria di Modena, Largo del Pozzo 71, 41124 Modena, Italy.
Pharmaceuticals (Basel). 2022 Mar 11;15(3):343. doi: 10.3390/ph15030343.
[Ga]Ga-PSMA-11 PET/CT plays a pivotal role in the diagnosis and staging of prostate cancer because of its higher sensitivity and detection rate compared with traditional choline PET/CT. A highly reproducible radiochemical yield of the radiopharmaceutical to be used in the clinical routine is an important parameter for planning and optimization of clinical activity. During radiometallation of PSMA-11, the presence of metal ion contaminants in the peptide precursor may cause a decrease in the [Ga]Ga-PSMA-11 radiochemical yield because of metal ion contaminants competition with gallium-68. To optimize the radiochemical yield of [Ga]Ga-PSMA-11 radiosynthesis, data obtained by preparing the solution of the PSMA-11 precursor with three different methods (A, B, and C) were compared. Methods A and B consisted of the reconstitution of different quantities of precursor (1000 µg and 30 µg, respectively) to obtain a 1 µg/mL solution. In Method A, the precursor solution was aliquoted and stored frozen, while the precursor solution obtained with Method B was entirely used. Method C consisted of the reconstitution of 1000 µg of precursor taking into account net peptide content as described in European Pharmacopoeia. Radiosynthesis data demonstrated that reconstitution methods B and C gave a consistently higher and reproducible radiochemical yield, highlighting the role of metals and precursor storage conditions on the synthesis performance.
[镓]镓-PSMA-11 PET/CT在前列腺癌的诊断和分期中发挥着关键作用，因为与传统的胆碱PET/CT相比，它具有更高的灵敏度和检测率。临床常规使用的放射性药物具有高度可重复的放射化学产率，是规划和优化临床活动的一个重要参数。在PSMA-11的放射性金属化过程中，肽前体中金属离子污染物的存在可能会导致[镓]镓-PSMA-11放射化学产率下降，这是由于金属离子污染物与镓-68竞争。为了优化[镓]镓-PSMA-11放射性合成的放射化学产率，比较了用三种不同方法（A、B和C）制备PSMA-11前体溶液所获得的数据。方法A和B包括重构不同量的前体（分别为1000微克和30微克）以获得1微克/毫升的溶液。在方法A中，前体溶液被等分并冷冻保存，而用方法B获得的前体溶液则全部使用。方法C包括按照欧洲药典所述考虑净肽含量重构1000微克前体。放射性合成数据表明，重构方法B和C产生的放射化学产率始终更高且可重复，突出了金属和前体储存条件对合成性能的作用。
