Insulinoma is a rare pancreatic neuroendocrine tumour characterised by inappropriate insulin secretion and recurrent hypoglycaemia. Owing to their small size and intrapancreatic localisation, insulinomas are frequently difficult to detect using conventional anatomical imaging techniques. Functional imaging based on positron emission tomography has therefore gained increasing interest, particularly through targeting of the glucagon-like peptide-1 receptor, which is highly overexpressed in most insulinomas. Among available tracers, gallium-68-labelled NODAGA-exendin-4 has demonstrated excellent diagnostic performance. However, its routine clinical implementation remains limited by the absence of a harmonised, robust and transferable radiosynthesis protocol compatible with hospital radiopharmacy practice. The aim of this work was to optimise and harmonise the automated preparation of gallium-68-labelled NODAGA-exendin-4 by systematically evaluating critical synthesis parameters and validating the optimised process across multiple commercially available gallium-68 generators. Using an automated synthesis module, key variables including precursor amount, labelling temperature and duration, formulation additives, workflow sequence and quality control conditions were investigated. The optimised protocol was subsequently validated using generators from three different manufacturers. Optimisation studies demonstrated that formulation-related parameters, particularly the post-labelling addition of polysorbate 20, resulted in improved radiochemical conversion and reduced residual activity within the synthesis cassette. An optimal precursor amount of 20 µg was identified as a compromise between radiochemical yield and clinical injectability constraints. Radiolabelling at 95 °C for 12 min ensured high conversion while reducing overall synthesis time. Validation runs showed excellent reproducibility, with non-decay-corrected yields ranging from 60 to 73

Fibroblast activation protein inhibitor (FAPI)-based positron emission tomography (PET) radiopharmaceuticals have shown promise for imaging cancer-associated fibroblasts (CAFs), a key component of the tumor microenvironment. FAPI radiopharmaceuticals offer high tumor-to-background contrast and are not influenced by hyperglycemia. Among these, [18F]AlF-FAPI-74, labeled using the Al18F-method, offers logistical advantages over 68Ga-labeled radiopharmaceuticals, including a longer physical half-life and suitability for large-scale, centralized production. This study reports a fully automated, efficient, and GMP-compliant synthesis of [18F]AlF-FAPI-74 using the Trasis AllInOne® platform, alongside a refined isocratic radio-HPLC method that enhances fluorine-18 recovery and impurity resolution. Additionally, the impact of molar dose on [18F]AlF-FAPI-74 biodistribution is evaluated in a preclinical model and a clinical case-study highlighting the performance of [18F]AlF-FAPI-74 produced at high apparent molar activity is provided. The automated GMP-compliant production was validated in three independent runs, with an average decay-corrected yield and apparent molar activity of 50 ± 10

[68 Ga]Ga-PentixaFor is a frequently used radiotracer to image the CXCR4/CXCL12 axis in various malignancies, infections, and cardiovascular diseases. To answer increasing clinical needs, an automatized synthesis process ensuring efficient and reproducible production and improving operator's radioprotection is needed. [68 Ga]Ga-PentixaFor synthesis has been described on other synthesizers but not on the miniAiO. In this work, we defined automated synthesis process and an analytical method for the quality control of [68 Ga]Ga-PentixaFor. Validation batches were performed under aseptic conditions in a class A hotcell. All the quality controls required by the European Pharmacopea (Eur. Ph) were performed. The analytical methods were validated according to the International Conference Harmonization (ICH) recommendations. Validation batches were performed with a radiochemical yield of 94.8 ± 2.6%. All the quality controls were in conformity with the Eur. Ph, and the validation of the analytical method complied with the ICH. The environmental monitoring performed during the synthesis process showed that the aseptic conditions were ensured. [68 Ga]Ga-PentixaFor was successfully synthesized with the miniAiO by a fully automated process. This robust production mode and the quality control have been validated in this study allowing to increase the access of patients to this new promising radiopharmaceutical.

Corentin Warnier, Thibault Gendron, Muhammad Otabashi, Charles Vriamont and Alex Jackson were not included as authors in the original publication [...].

Abstract Background Flumazenil (FMZ) is a functionally silent imidazobenzodiazepine which binds to the benzodiazepine binding site of approximately 75% of the brain γ-aminobutyric acid-A receptors (GABAARs). Positron Emission Tomography (PET) imaging of the GABAARs with [11C]FMZ has been used to evidence alterations in neuronal density, to assess target engagement of novel pharmacological agents, and to study disorders such as epilepsy and Huntington’s disease. Despite the potential of FMZ PET imaging the short half-life (t 1/2) of carbon-11 (20 min) has limited the more widespread clinical use of [11C]FMZ. The fluorine-18 (18F) isotopologue with a longer t 1/2 (110 min) is ideally suited to address this drawback. However, the majority of current radiochemical methods for the synthesis of [18F]FMZ are non-trivial and low yielding. We report a robust, automated protocol that is good manufacturing practice (GMP) compatible, and yields multi-patient doses of [18F]FMZ. Results The fully automated synthesis was developed on the Trasis AllinOne (AIO) platform using a single-use cassette. [18F]FMZ was synthesized in a one-step procedure from [18F]fluoride, via a copper-mediated 18F-fluorination of a boronate ester precursor. Purification was performed by semi-preparative radio-HPLC and the collected fraction formulated directly into the final product vial. The overall process from start of synthesis to delivery of product is approximately 55 min. Starting with an initial activity of 23.6 ± 5.8 GBq (n = 3) activity yields of [18F]FMZ were 8.0 ± 1 GBq (n = 3). The synthesis was successfully reproduced at two independent sites, where the product passed quality control release criteria in line with the European Pharmacopoeia standards and ICH Q3D(R1) guidelines to be suitable for human use. Conclusion Reported is a fully automated cassette-based synthesis of [18F]FMZ that is Good Manufacturing Practice (GMP) compatible and produces multi-patient doses of [18F]FMZ.

Lung PET/CT is a promising imaging modality for regional lung function assessment. Our aim was to develop and validate a fast, simple, and fully automated GMP compliant [68Ga]Ga-MAA labeling procedure, using a commercially available [99mTc]Tc-MAA kit, a direct gallium-68 eluate and including a purification of the [68Ga]Ga-MAA. Method: The synthesis parameters (pH, heating temperature) were manually determined. Automated 68Ga-labeling of MAA was then developed on a miniAIO (Trasis®, Ans, Belgium) module. An innovative automated process was developed for the purification. The process was then optimized and adapted to automate both the [68Ga]Ga-MAA synthesis and the isolation of gallium-68 eluate required for the pulmonary ventilation PET/CT. Results: The 15-min process demonstrated high reliability and reproducibility, with high synthesis yield (>95 %). Mean [68Ga]Ga-MAA radiochemical purity was 99 % ± 0.6 %. The 68Ga-labeled MAA particles size and morphology remained unchanged. Conclusion: A fast, user friendly, and fully automated process to produce GMP [68Ga]Ga-MAA for clinical use was developed. This automated process combining the advantages of using a non-modified MAA commercial kit, a gallium-68 eluate without pre-purification and an efficient final purification of the [68Ga]Ga-MAA may facilitate the implementation of lung PET/CT imaging in nuclear medicine departments.

This preclinical study aims to evaluate the extent to which a change in prostate-specific membrane antigen (PSMA) expression of castration-resistant prostate cancer (CRPC) following standard treatment is reflected in [18F]JK-PSMA-7 PET/CT. Castrated mice supplemented with testosterone implant were xenografted with human LNCaP CRPC. After appropriate tumour growth, androgen deprivation therapy (ADT) was carried out by the removal of the implant followed by a single injection of docetaxel (400 μg/20-g mouse) 2 weeks later. [18F]JK-PSMA-7 PET/CT were performed before ADT, then before and at days 12, 26, 47 and 69 after docetaxel administration. The [18F]JK-PSMA-7 PET data were compared to corresponding unspecific metabolic [18F]FDG PET/CT and ex vivo quantification of PSMA expression estimated by flow cytometry on repeated tumour biopsies. ADT alone had no early effect on LNCaP tumours that pursued their progression. Until day 12 post-docetaxel, the [18F]JK-PSMA7 uptake was significantly higher than that of [18F]FDG, indicating the persistence of PSMA expression at those time points. From day 26 onwards when the tumours were rapidly expanding, both [18F]JK-PSMA7 and [18F]FDG uptake continuously decreased although the decrease in [18F]JK-PSMA uptake was markedly faster. The fraction of PSMA-positive cells in tumour biopsies decreased similarly over time to reach a non-specific level after the same time period. Applying PSMA-based imaging for therapy monitoring in patients with CRPC should be considered with caution since a reduction in [18F]JK-PSMA-7 PET uptake after successive ADT and chemotherapy may be related to downregulation of PSMA expression in dedifferentiated and rapidly proliferating tumour cells.

1039 Objectives: Tau PET tracers are well known radioactive probes designed for imaging of the accumulation and regional spread of brain neurofibrillary tangles (NFTs). NFTs are characteristic of neurodegenerative disorders known as tauopathies, Alzheimer’s disease (AD) being the most common. Second generation Tau tracers, such as [18F]MK-6240, have recently been developed to improve their binding properties and lower the off-target binding. First in human studies with [18F]MK-6240 underlined it as a promising PET radioligand for in vivo imaging of neurofibrillary tau aggregates in AD with minimal off-target binding in the human brain. The purpose of this work is to develop the automation of [18F]MK-6240 production on a cassette-based platform and enable its routine production and distribution at large scale. Methods: The production of [18F]MK-6240 is performed along the synthesis method described hereafter (Figure 1) and performed with an AllinONe with HPLC following the cassette layout depicted below (Figure 2). The 18F- produced in the cyclotron is separated from the aqueous solvent by trapping on an anion-exchange cartridge followed by elution with a solution of tetrabutylammonium hydrogen bicarbonate (TBAHCO3) to give the intermediate (2). The precursor (1) is added to the intermediate (2). Heating the reaction to 160°C in DMF allows, in addition to the radiolabelling , the thermal to afford the crude [18F]MK-6240 radiotracer in one single step (3). [18F]MK-6240 (3) is purified by a reversed phase semi-preparative HPLC. The fraction of interest is collected and reformulated on a SPE cartridge. The product is ready for QC and dispensing. Results: [18F]MK-6240 was produced on the Trasis AllinOne unit- in 65 minutes (from start of the synthesis to the collection in the final vial) - with a typical average yield of 30 +- 5 % non-decay-corrected (NDC) (53 +-7 % decay corrected) The HPLC purification was performed on the integrated HPLC unit and allows to selectively collect the [18F]MK-6240 peak, as depicted below on the chromatogram (Figure 3). Stability of the final product was tested up to ~ 30 GBq and demonstrated >98% RCP at 8 hours post EOS. [18F]MK-6240 Synthesis have been performed on different Trasis synthesizers, at different facilities and with several operators and gave similar results, highlighting the robustness of the process. Conclusions: The automation of the 18F]MK-6240 PET tracer synthesis on the AllinOne platform afford a reliable cassette-based synthesis, providing high yields (30+-5% NDC) and a stable product over time.

Prostate-specific membrane antigen (PSMA)-based radioligands for positron emission tomography (PET)/computed tomography (CT) studies represent the gold standard for detection of recurrent prostate cancer (PCa). [Ga-68]PSMA-HBED-CC is a PET radiotracer suitable for detection of PCa, and its clinical use has become widespread over the last few years. In this contribution, we detail our GMP-compliant production of [Ga-68]PSMA-HBED-CC using the Trasis miniAllinOne radiosynthesizer and report synthetic and clinical data for the first 100 productions of 2019. Additionally, we detail our efforts towards a GMP-compliant production of the radiotherapeutic [Lu-177]PSMA-I&T using the same synthesis module. PSMA-based radioligand therapy (RLT) offers a possible future treatment in cases of metastatic castration-resistant PCa, and GMP-compliant routine production methods are therefore called for. This report highlights how PSMA-based agents for theranostic purposes can be conveniently produced at a single radiochemistry Good Manufacturing Practice (GMP) site, thereby facilitating optimized detection and treatment of PCa.

Prostate-specific membrane antigen (PSMA)-based radioligands for positron emission tomography (PET)/computed tomography (CT) studies represent the gold standard for detection of recurrent prostate cancer (PCa). [68 Ga]PSMA-HBED-CC is a PET radiotracer suitable for detection of PCa, and its clinical use has become widespread over the last few years. In this contribution, we detail our GMP-compliant production of [68 Ga]PSMA-HBED-CC using the Trasis miniAllinOne radiosynthesizer and report synthetic and clinical data for the first 100 productions of 2019. Additionally, we detail our efforts towards a GMP-compliant production of the radiotherapeutic [177 Lu]PSMA-I&T using the same synthesis module. PSMA-based radioligand therapy (RLT) offers a possible future treatment in cases of metastatic castration-resistant PCa, and GMP-compliant routine production methods are therefore called for. This report highlights how PSMA-based agents for theranostic purposes can be conveniently produced at a single radiochemistry Good Manufacturing Practice (GMP) site, thereby facilitating optimized detection and treatment of PCa.

The synaptic vesicle glycoprotein 2A (SV2A), a protein essential to the proper nervous system function, is found in presynaptic vesicles. Thus, SV2A targeting, using dedicated radiotracers combined with positron emission tomography (PET), allows the assessment of synaptic density in the living brain. The first-in-class fluorinated SV2A specific radioligand, [18F]UCB-H, is now available at high activity through an efficient radiosynthesis compliant with current good manufacturing practices (cGMP). We report here a noninvasive method to quantify [18F]UCB-H binding in rat brain with microPET. Validation study in rats confirmed the need of high enantiomeric purity to target SV2A in vivo. We demonstrated the reliability of a population-based input function to quantify SV2A in preclinical microPET setting. Finally, we investigated the in vivo metabolism of [18F]UCB-H and confirmed the negligible amount of radiometabolites in the rat brain. Hence, the in vivo quantification of SV2A using [18F]UCB-H microPET seems a promising tool for the assessment of the synaptic density in the rat brain, and opens the way for longitudinal follow-up in neurodegenerative disease rodent models.