EJNMMI Radiopharmacy and Chemistry最新文献

{"title":"Cyclotron production of manganese-52: a promising avenue for multimodal PET/MRI imaging","authors":"Francesca Porto,&nbsp;Sara Cisternino,&nbsp;Emiliano Cazzola,&nbsp;Giorgia Speltri,&nbsp;Liliana Mou,&nbsp;Alessandra Boschi,&nbsp;Lorenza Marvelli,&nbsp;Giovanni Di Domenico,&nbsp;Antonella Pagnoni,&nbsp;Lucia De Dominicis,&nbsp;Irene Calliari,&nbsp;Claudio Gennari,&nbsp;Licia Uccelli,&nbsp;Gaia Pupillo,&nbsp;Giancarlo Gorgoni,&nbsp;Juan Esposito,&nbsp;Petra Martini","doi":"10.1186/s41181-024-00288-6","DOIUrl":"10.1186/s41181-024-00288-6","url":null,"abstract":"<div><h3>Background</h3><p>The integration of positron emission tomography (PET) and magnetic resonance imaging (MRI) holds promise for advancing diagnostic imaging capabilities. The METRICS project aims to develop cyclotron-driven production of ⁵²Mn for PET/MRI imaging.</p><h3>Results</h3><p>Using the ⁵²Cr(p,n)⁵²Mn reaction, we designed chromium metal targets via Spark Plasma Sintering and developed a separation procedure for isolating ⁵²Mn. Labeling tests were conducted with traditional chelators (i.e. S-2-(4-Isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane tetraacetic acid) and the 1.4-dioxa-8-azaspiro[4.5]decane-8- carbodithioate ligand to produce radioactive complexes suitable for PET/MRI applications. Our methodology yielded high-quality ⁵²Mn suitable for PET radiopharmaceuticals and PET/MRI imaging. Preliminary studies on phantom imaging using microPET and clinical MRI demonstrated the efficacy of our approach.</p><h3>Conclusions</h3><p>The developed technology offers a promising avenue for producing ⁵²Mn and enhancing PET/MRI imaging capabilities. Further in vivo investigations are warranted to evaluate the potential advantages of this hybrid imaging technique.</p></div>","PeriodicalId":534,"journal":{"name":"EJNMMI Radiopharmacy and Chemistry","volume":"9 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11297007/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141873849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The development of 177Lu-DOTA-CC-PSMA following a unified “Click Chemistry” protocol of synthesizing metal nuclide-conjugated radiopharmaceuticals","authors":"Xiaobei Zheng,&nbsp;Shuai Xue,&nbsp;Zhongqi Zhao,&nbsp;Shuxin Jin,&nbsp;Shuhua He,&nbsp;Lina Jia,&nbsp;Zheng Li,&nbsp;Christian Vanhove,&nbsp;Filip De Vos,&nbsp;Zijun Kuang,&nbsp;Tiantian Wang,&nbsp;Sara Neyt,&nbsp;Lan Zhang,&nbsp;Xiao Li","doi":"10.1186/s41181-024-00287-7","DOIUrl":"10.1186/s41181-024-00287-7","url":null,"abstract":"<div><h3>Background</h3><p>Currently, the synthesis pathway of metal nuclide-labeled radiopharmaceuticals is mainly divided into two steps: first, connecting the chelator with the target molecule, and second, labeling the metal nuclide to the chelator. However, the second step of the reaction to label the metal nuclide requires high temperature (90–100 °C), which tends to denature and inactivate the target molecule, leading to loss of biological activities, especially the targeting ability. A feasible solution may be the click chemistry labeling method, which consists of reacting a metal nuclide with a chelating agent to generate an intermediate and then synthesizing a radiopharmaceutical agent via the click chemistry intermediate and the target molecule-alkyne compound. In this study, through the click chemistry of ¹⁷⁷Lu-DOTA-N₃ with prostate-specific membrane antigen (PSMA)-alkyne compound, ¹⁷⁷Lu-labeled PSMA-targeted molecular probe was synthesized and evaluated for its potential to be cleared from the bloodstream and rapidly distributed to tissues and organs, achieving a high target/non-target ratio. ¹⁷⁷Lu-PSMA-617 was utilized as an analogue for comparison in terms of synthesizing efficiency and PSMA-targeting ability.</p><h3>Results</h3><p>A novel ¹⁷⁷Lu-labeled PSMA radioligand was successfully synthesized through the click chemistry of ¹⁷⁷Lu-DOTA-N₃ with PSMA-alkyne compound, and abbreviated as ¹⁷⁷Lu-DOTA-CC-PSMA, achieving a radiochemical yield of 77.07% ± 0.03% (<i>n</i> = 6) and a radiochemical purity of 97.62% ± 1.49% (<i>n</i> = 6) when purified by SepPak C18 column. Notably, ¹⁷⁷Lu-DOTA-CC-PSMA was characterized as a hydrophilic compound that exhibited stability at room temperature and commendable pharmacokinetic properties, such as the superior uptake (19.75 ± 3.02%ID/g at 0.5 h) and retention (9.14 ± 3.16%ID/g at 24 h) within xenografts of 22Rv1 tumor-bearing mice. SPECT/CT imaging indicated that radioactivity in both kidneys and bladder was essentially eliminated after 24 h, while ¹⁷⁷Lu-DOTA-CC-PSMA was further enriched and retained in PSMA-expressing tumors, resulting in the high target/non-target ratio.</p><h3>Conclusion</h3><p>This study demonstrated the potential of click chemistry to unify the synthesis of metal radiopharmaceuticals, and ¹⁷⁷Lu-DOTA-CC-PSMA was found for rapid clearance and appropriate chemical stability as a PSMA-targeted radioligand.</p></div>","PeriodicalId":534,"journal":{"name":"EJNMMI Radiopharmacy and Chemistry","volume":"9 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11291776/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141854368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vitro and in vivo analyses of eFAP: a novel FAP-targeting small molecule for radionuclide theranostics and other oncological interventions","authors":"Circe D. van der Heide,&nbsp;Hanyue Ma,&nbsp;Mark W.H. Hoorens,&nbsp;Joana D. Campeiro,&nbsp;Debra C. Stuurman,&nbsp;Corrina M.A. de Ridder,&nbsp;Yann Seimbille,&nbsp;Simone U. Dalm","doi":"10.1186/s41181-024-00283-x","DOIUrl":"10.1186/s41181-024-00283-x","url":null,"abstract":"<div><h3>Background</h3><p>Fibroblast activation protein (FAP), a transmembrane serine protease overexpressed by cancer-associated fibroblasts in the tumor stroma, is an interesting biomarker for targeted radionuclide theranostics. FAP-targeting radiotracers have demonstrated to be superior to [¹⁸F]FDG PET/CT in various solid cancers. However, these radiotracers have suboptimal tumor retention for targeted radionuclide therapy (TRT). We aimed to develop a novel FAP-targeting pharmacophore with improved pharmacokinetics by introducing a substitution at the 8-position of (4-quinolinoyl)-glycyl-2-cyanopyrrolidine, which allows for conjugation of a chelator, dye, or other payloads.</p><h3>Results</h3><p>Here we showed the synthesis of DOTA-conjugated eFAP-6 and sulfo-Cyanine5-conjugated eFAP-7. After chemical characterization, the uptake and specificity of both tracers were determined on FAP-expressing cells. In vitro, [¹¹¹In]In-eFAP-6 demonstrated a superior affinity and a more rapid, although slightly lower, peak uptake than gold standard [¹¹¹In]In-FAPI-46. Confocal microscopy demonstrated a quick FAP-mediated internalization of eFAP-7. Studies with HT1080-huFAP xenografted mice confirmed a more rapid uptake of [¹⁷⁷Lu]Lu-eFAP-6 vs. [¹⁷⁷Lu]Lu-FAPI-46. However, tumor retention at 24 h post injection of [¹⁷⁷Lu]Lu-eFAP-6 was lower than that of [¹⁷⁷Lu]Lu-FAPI-46, hereby currently limiting its use for TRT.</p><h3>Conclusion</h3><p>The superior affinity and faster tumor accumulation of eFAP-6 over FAPI-46 makes it a suitable compound for radionuclide imaging. After further optimization, the eFAP series has great potential for various oncological interventions, including fluorescent-guided surgery and effective targeted radionuclide theranostics.</p></div>","PeriodicalId":534,"journal":{"name":"EJNMMI Radiopharmacy and Chemistry","volume":"9 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11286609/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141786981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generic semi-automated radiofluorination strategy for single domain antibodies: [18F]FB-labelled single domain antibodies for PET imaging of fibroblast activation protein-α or folate receptor-α overexpression in cancer","authors":"Herlinde Dierick,&nbsp;Laurent Navarro,&nbsp;Hannelore Ceuppens,&nbsp;Thomas Ertveldt,&nbsp;Ana Rita Pombo Antunes,&nbsp;Marleen Keyaerts,&nbsp;Nick Devoogdt,&nbsp;Karine Breckpot,&nbsp;Matthias D’Huyvetter,&nbsp;Tony Lahoutte,&nbsp;Vicky Caveliers,&nbsp;Jessica Bridoux","doi":"10.1186/s41181-024-00286-8","DOIUrl":"10.1186/s41181-024-00286-8","url":null,"abstract":"<div><h3>Background</h3><p>Radiofluorination of single domain antibodies (sdAbs) via <i>N</i>-succinimidyl-4-[¹⁸F]fluorobenzoate ([¹⁸F]SFB) has shown to be a promising strategy in the development of sdAb-based PET tracers. While automation of the prosthetic group (PG) [¹⁸F]SFB production, has been successfully reported, no practical method for large scale sdAb labelling has been reported. Therefore, we optimized and automated the PG production, enabling a subsequently efficient manual conjugation reaction to an anti-fibroblast activation protein (FAP)-α sdAb (4AH29) and an anti-folate receptor (FR)-α sdAb (2BD42). Both the alpha isoform of FAP and the FR are established tumour markers. FAP-α is known to be overexpressed mainly by cancer-associated fibroblasts in breast, ovarian, and other cancers, while its expression in normal tissues is low or undetectable. FR-α has an elevated expression in epithelial cancers, such as ovarian, brain and lung cancers. Non-invasive imaging techniques, such as PET-imaging, using tracers targeting specific tumour markers can provide molecular information over both the tumour and its environment, which aides in the diagnosis, therapy selection and assessment of the cancer treatment.</p><h3>Results</h3><p>[¹⁸F]SFB was synthesized using a fully automated three-step, one-pot reaction. The total procedure time was 54 min and results in [¹⁸F]SFB with a RCP &gt; 90% and a RCY d.c. of 44 ± 4% (n = 13). The manual conjugation reaction after purification produced [¹⁸F]FB-sdAbs with a RCP &gt; 95%, an end of synthesis activity &gt; 600 MBq and an apparent molar activity &gt; 10 GBq/µmol. Overall RCY d.c., corrected to the trapping of [¹⁸F]F⁻ on the QMA, were 9% (n = 1) and 5 ± 2% (n = 3) for [¹⁸F]FB-2BD42 and [¹⁸F]FB-4AH29, respectively.</p><h3>Conclusion</h3><p>[¹⁸F]SFB synthesis was successfully automated and upscaled on a Trasis AllInOne module. The anti-hFAP-α and anti-hFR-α sdAbs were radiofluorinated, yielding similar RCYs d.c. and RCPs, showing the potential of this method as a generic radiofluorination strategy for sdAbs. The radiofluorinated sdAbs showed a favourable biodistribution pattern and are attractive for further characterization as new PET tracers for FAP-α and FR-α imaging.</p></div>","PeriodicalId":534,"journal":{"name":"EJNMMI Radiopharmacy and Chemistry","volume":"9 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11269545/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141756419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Process validation and preclinical development of a new PET cerebral blood flow tracer [11C]MMP for initial clinical trials","authors":"Jun Toyohara,&nbsp;Tetsuro Tago,&nbsp;Muneyuki Sakata","doi":"10.1186/s41181-024-00285-9","DOIUrl":"10.1186/s41181-024-00285-9","url":null,"abstract":"<div><h3>Background</h3><p>2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) is commonly used for diagnosis of dementia because brain glucose metabolism reflects neuronal activity. However, as [¹⁸F]FDG is an analogue of glucose, accumulation of tracer in the brain is affected by plasma glucose levels. In contrast, cerebral blood flow (CBF) tracers are theoretically unaffected by plasma glucose levels and are therefore expected to be useful alternatives for the diagnosis of dementia in patients with diabetes. The techniques currently used for CBF imaging using single photon emission computed tomography (SPECT) and [¹⁵O]H₂O positron emission tomography (PET), but these are limited by their insufficient resolution and sensitivity for regional brain imaging, especially in patients with brain atrophy. <i>N</i>-isopropyl-4-[¹¹C]methylamphetamine ([¹¹C]MMP) is a possible CBF tracer with high resolution and sensitivity that exhibits comparable performance to that of [¹⁵O]H₂O in conscious monkey brains. We performed process validation of the radiosynthesis and preclinical development of [¹¹C]MMP prior to clinical translation.</p><h3>Results</h3><p>The decay-corrected yields of [¹¹C]MMP at the end of synthesis were 41.4 ± 6.5%, with 99.7 ± 0.3% radiochemical purity, and 192.3 ± 22.5 MBq/nmol molar activity. All process validation batches complied with the product specifications. The acute toxicity of MMP was evaluated at a dose of 3.55 mg/kg body weight, which is 10,000 times the potential maximum clinical dose of [¹¹C]MMP. The acute toxicity of [¹¹C]MMP injection at 150 or 200 times, to administer a postulated dose of 740 MBq of [¹¹C]MMP, was also evaluated after the decay-out of ¹¹C. No acute toxicity of MMP and [¹¹C]MMP injection was found. No mutagenic activity was observed for MMP. The effective dose calculated according to the Medical Internal Radiation Dose (MIRD) method was 5.4 µSv/MBq, and the maximum absorbed dose to the bladder wall was 57.6 µGy/MBq. MMP, a derivative of phenylalkylamine, showed binding to the sigma receptor, but had approximately 1/100 of the affinity of existing sigma receptor imaging agents. The affinity for other brain neuroreceptors was low.</p><h3>Conclusions</h3><p>[¹¹C]MMP shows acceptable pharmacological safety at the dose required for adequate PET imaging. The potential risk associated with [¹¹C]MMP PET imaging is well within the acceptable dose limit.</p></div>","PeriodicalId":534,"journal":{"name":"EJNMMI Radiopharmacy and Chemistry","volume":"9 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11266321/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141747106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preclinical evaluation of CXCR4 peptides for targeted radionuclide therapy in glioblastoma","authors":"Anthony Waked,&nbsp;Melissa Crabbé,&nbsp;Virginie Neirinckx,&nbsp;Sunay Rodriguez Pérez,&nbsp;Jasmien Wellens,&nbsp;Bernard Rogister,&nbsp;M. Abderrafi Benotmane,&nbsp;Koen Vermeulen","doi":"10.1186/s41181-024-00282-y","DOIUrl":"10.1186/s41181-024-00282-y","url":null,"abstract":"<div><h3>Background</h3><p>Glioblastoma (GBM), is the most fatal form of brain cancer, with a high tendency for recurrence despite combined treatments including surgery, radiotherapy, and chemotherapy with temozolomide. The C-X-C chemokine receptor 4 (CXCR4) plays an important role in tumour radioresistance and recurrence, and is considered as an interesting GBM target. TRT holds untapped potential for GBM treatment, with CXCR4-TRT being a promising strategy for recurrent GBM treatment. Our study focuses on the preclinical assessment of different ¹⁷⁷Lu-labelled CXCR4-targeting peptides, CTCE-9908, DV1-K-DV3, and POL3026 for GBM treatment and exploring some of the radiobiological mechanisms underlying these therapies.</p><h3>Results</h3><p>All three DOTA-conjugated peptides could be radiolabelled with ¹⁷⁷Lu with &gt; 95% radiochemical yield. Binding studies show high specific binding of [¹⁷⁷Lu]Lu-DOTA-POL3026 to U87-CXCR4 + cells, with 42% of the added activity binding to the membrane at 1 nM, and 6.5% internalised into the cells. In the presence of the heterologous CXCR4 blocking agent, AMD11070, membrane binding was reduced by 95%, a result confirmed by quantitative in vitro autoradiography of orthotopic GBM xenograft sections. An activity-dependent decrease in cell viability was observed for [¹⁷⁷Lu]Lu-DOTA-DV1-K-DV3 and [¹⁷⁷Lu]Lu-DOTA-POL3026, along with a slight increase in the induction of apoptotic markers. Additionally, the expression of γH2AX increased in a time-and activity-dependent manner. Ex vivo biodistribution studies with [¹⁷⁷Lu]Lu-DOTA-POL3026 show uptake in the tumour reaching a SUV of 1.9 at 24 h post-injection, with higher uptake in the kidneys, lungs, spleen, and liver. Dosimetry estimations show an absorbed dose of 0.93 Gy/MBq in the tumour. A blocking study with AMD11070 showed a 38% reduction in tumour uptake, with no significant reduction observed in µSPECT imaging. Although no brain uptake was observed in the ex vivo biodistribution study, autoradiography on U87-CXCR4 + tumour inoculated mouse brain slices shows non-specific binding in the brain, next to high specific binding to the tumour.</p><h3>Conclusions</h3><p>In conclusion, we compared different ¹⁷⁷Lu-radiolabelled CXCR4-targeting peptides for their binding potential in GBM, and demonstrated their varied cytotoxic action against GBM cells in vitro, with POL3026 being the most promising, causing considerable DNA damage. Though the peptide’s systemic biodistribution remains to be improved, our data demonstrate the potential of [¹⁷⁷Lu]Lu-DOTA-POL3026 for CXCR4-TRT in the context of GBM.</p></div>","PeriodicalId":534,"journal":{"name":"EJNMMI Radiopharmacy and Chemistry","volume":"9 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ejnmmipharmchem.springeropen.com/counter/pdf/10.1186/s41181-024-00282-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141615517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"cGMP compliant one-step, one-pot automated [18F]FBnTP production for clinical imaging of mitochondrial activity","authors":"Mai Lin,&nbsp;Cong-Dat Pham,&nbsp;Robert T. Ta,&nbsp;H. Charles Manning","doi":"10.1186/s41181-024-00274-y","DOIUrl":"10.1186/s41181-024-00274-y","url":null,"abstract":"<div><h3>Background</h3><p>4-[¹⁸F]fluorobenzyl-triphenylphosphonium ([¹⁸F]FBnTP) is a lipophilic cation PET tracer. The cellular uptake of [¹⁸F]FBnTP is correlated with oxidative phosphorylation by mitochondria, which has been associated with multiple critical diseases. To date, [¹⁸F]FBnTP has been successfully applied for imaging myocardial perfusion, assessment of severity of coronary artery stenosis, delineation of the ischemic area after transient coronary occlusion, and detection/quantification of apoptosis in various animal models. Recent preclinical and clinical studies have also expanded the possibilities of using [¹⁸F]FBnTP in oncological diagnosis and therapeutic monitoring. However, [¹⁸F]FBnTP is typically prepared through a tediously lengthy four-step, three-pot reaction and required multiple synthesizer modules; Thus, such an approach remains a challenge for this promising radiopharmaceutical to be implemented for routine clinical studies. Herein, we report an optimized one-step, one-pot automated approach to produce [¹⁸F]FBnTP through a single standard commercially-available radiosynthesizer that enables centralized production for clinical use.</p><h3>Results</h3><p>The fully automated production of [¹⁸F]FBnTP took less than 55 min with radiochemical yields ranging from 28.33 ± 13.92% (non-decay corrected), apparent molar activity of 69.23 ± 45.62 GBq/µmol, and radiochemical purities of 99.79 ± 0.41%. The formulated [¹⁸F]FBnTP solution was determined to be sterile and colorless with a pH of 4.0–6.0. Our data has indicated no observable radiolysis after 8 h from the time of final product formulation and maximum assay of 7.88 GBq.</p><h3>Conclusions</h3><p>A simplified and cGMP-compliant radiosynthesis of [¹⁸F]FBnTP has been established on the commercially available synthesizer in high activity concentration and radiochemical purity. While the preclinical and clinical studies using [¹⁸F]FBnTP PET are currently underway, the automated approaches reported herein facilitate clinical adoption of this radiotracer and warrant centralized production of [¹⁸F]FBnTP for imaging multiple patients.</p></div>","PeriodicalId":534,"journal":{"name":"EJNMMI Radiopharmacy and Chemistry","volume":"9 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11211300/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141454428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automated radiosynthesis and preclinical evaluation of two new PSMA-617 derivatives radiolabelled via [18F]AlF2+ method","authors":"Marco Nicola Iannone,&nbsp;Silvia Valtorta,&nbsp;Stefano Stucchi,&nbsp;Stefano Altomonte,&nbsp;Elia Anna Turolla,&nbsp;Elisa Vino,&nbsp;Paolo Rainone,&nbsp;Valentina Zecca,&nbsp;Alessia Lo Dico,&nbsp;Marco Maspero,&nbsp;Mariangela Figini,&nbsp;Matteo Bellone,&nbsp;Samuele Ciceri,&nbsp;Diego Colombo,&nbsp;Clizia Chinello,&nbsp;Lisa Pagani,&nbsp;Rosa Maria Moresco,&nbsp;Sergio Todde,&nbsp;Patrizia Ferraboschi","doi":"10.1186/s41181-024-00280-0","DOIUrl":"10.1186/s41181-024-00280-0","url":null,"abstract":"<div><h3>Background</h3><p>In the last decade the development of new PSMA-ligand based radiopharmaceuticals for the imaging and therapy of prostate cancer has been a highly active and important area of research. The most promising derivative in terms of interaction with the antigen and clinical properties has been found to be “PSMA-617”, and its lutetium-177 radiolabelled version has recently been approved by EU and USA regulatory agencies for therapeutic purposes. For the above reasons, the development of new derivatives of PSMA-617 radiolabelled with fluorine-18 may still be of great interest. This paper proposes the comparison of two different PSMA-617 derivatives functionalized with NODA and RESCA chelators, respectively, radiolabelled via [¹⁸F]AlF²⁺ complexation.</p><h3>Results</h3><p>The organic synthesis of two PSMA-617 derivatives and their radiolabelling via [¹⁸F]AlF²⁺ complexation resulted to proceed efficiently and successfully. Moreover, stability in solution and in plasma has been evaluated. The whole radiosynthesis procedure has been fully automated, and the final products have been obtained with radiochemical yield and purity potentially suitable for clinical studies. The biodistribution of the two derivatives was performed both in prostate cancer and glioma tumour models. Compared with the reference [¹⁸F]F-PSMA-1007 and [¹⁸F]F-PSMA-617-RESCA, [¹⁸F]F-PSMA-617-NODA derivative showed a higher uptake in both tumors, faster clearance in non-target organs, and lower uptake in salivary glands.</p><h3>Conclusion</h3><p>PSMA-617 NODA and RESCA derivatives were radiolabelled successfully via [¹⁸F]AlF²⁺ chelation, the former being more stable in solution and human plasma. Moreover, preclinical biodistribution studies showed that [¹⁸F]F-PSMA-617-NODA might be of potential interest for clinical applications.</p></div>","PeriodicalId":534,"journal":{"name":"EJNMMI Radiopharmacy and Chemistry","volume":"9 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ejnmmipharmchem.springeropen.com/counter/pdf/10.1186/s41181-024-00280-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141431065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recently developed radiopharmaceuticals for bacterial infection imaging","authors":"Maryke Kahts,&nbsp;Beverley Summers,&nbsp;Aadil Gutta,&nbsp;Wilfrid Pilloy,&nbsp;Thomas Ebenhan","doi":"10.1186/s41181-024-00279-7","DOIUrl":"10.1186/s41181-024-00279-7","url":null,"abstract":"<div><h3>Background</h3><p>Infection remains a major cause of morbidity and mortality, regardless of advances in antimicrobial therapy and improved knowledge of microorganisms. With the major global threat posed by antimicrobial resistance, fast and accurate diagnosis of infections, and the reliable identification of intractable infection, are becoming more crucial for effective treatment and the application of antibiotic stewardship. Molecular imaging with the use of nuclear medicine allows early detection and localisation of infection and inflammatory processes, as well as accurate monitoring of treatment response. There has been a continuous search for more specific radiopharmaceuticals to be utilised for infection imaging. This review summarises the most prominent discoveries in specifically bacterial infection imaging agents over the last five years, since 2019.</p><h3>Main body</h3><p>Some promising new radiopharmaceuticals evaluated in patient studies are reported here, including radiolabelled bacterial siderophores like [⁶⁸Ga]Ga-DFO-B, radiolabelled antimicrobial peptide/peptide fragments like [⁶⁸Ga]Ga-NOTA-UBI29-41, and agents that target bacterial synthesis pathways (folic acid and peptidoglycan) like [¹¹C]para-aminobenzoic acid and D-methyl-[¹¹C]-methionine, with clinical trials underway for [¹⁸F]fluorodeoxy-sorbitol, as well as for ¹¹C- and ¹⁸F-labelled trimethoprim.</p><h3>Conclusion</h3><p>It is evident that a great deal of effort has gone into the development of new radiopharmaceuticals for infection imaging over the last few years, with remarkable progress in preclinical investigations. However, translation to clinical trials, and eventually clinical Nuclear Medicine practice, is apparently slow. It is the authors’ opinion that a more structured and harmonised preclinical setting and well-designed clinical investigations are the key to reliably evaluate the true potential of the newly proposed infection imaging agents.</p></div>","PeriodicalId":534,"journal":{"name":"EJNMMI Radiopharmacy and Chemistry","volume":"9 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ejnmmipharmchem.springeropen.com/counter/pdf/10.1186/s41181-024-00279-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141417132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vivo stable 211At-labeled prostate-specific membrane antigen-targeted tracer using a neopentyl glycol structure","authors":"Hiroyuki Suzuki,&nbsp;Kento Kannaka,&nbsp;Mizuki Hirayama,&nbsp;Tomoki Yamashita,&nbsp;Yuta Kaizuka,&nbsp;Ryota Kobayashi,&nbsp;Takahiro Yasuda,&nbsp;Kazuhiro Takahashi,&nbsp;Tomoya Uehara","doi":"10.1186/s41181-024-00278-8","DOIUrl":"10.1186/s41181-024-00278-8","url":null,"abstract":"<div><h3>Background</h3><p>Prostate cancer is a common cancer among men worldwide that has a very poor prognosis, especially when it progresses to metastatic castration-resistant prostate cancer (mCRPC). Therefore, novel therapeutic agents for mCRPC are urgently required. Because prostate-specific membrane antigen (PSMA) is overexpressed in mCRPC, targeted alpha therapy (TAT) for PSMA is a promising treatment for mCRPC. Astatine-211 (²¹¹At) is a versatile α-emitting radionuclide that can be produced using a cyclotron. Therefore, ²¹¹At-labeled PSMA compounds could be useful for TAT; however, ²¹¹At-labeled compounds are unstable against deastatination in vivo. In this study, to develop in vivo stable ²¹¹At-labeled PSMA derivatives, we designed and synthesized ²¹¹At-labeled PSMA derivatives using a neopentyl glycol (NpG) structure that can stably retain ²¹¹At in vivo. We also evaluated their biodistribution in normal and tumor-bearing mice.</p><h3>Results</h3><p>We designed and synthesized ²¹¹At-labeled PSMA derivatives containing two glutamic acid (Glu) linkers between the NpG structure and asymmetric urea (NpG-L-PSMA ((L-Glu)₂ linker used) and NpG-D-PSMA ((D-Glu)₂ linker used)). First, we evaluated the characteristics of ¹²⁵I-labeled NpG derivatives because ¹²⁵I was readily available. [¹²⁵I]I-NpG-L-PSMA and [¹²⁵I]I-NpG-D-PSMA showed low accumulation in the stomach and thyroid, indicating their high in vivo stability against deiodination. [¹²⁵I]I-NpG-L-PSMA was excreted in urine as hydrophilic radiometabolites in addition to the intact form. Meanwhile, [¹²⁵I]I-NpG-D-PSMA was excreted in urine in an intact form. In both cases, no radioactivity was observed in the free iodine fraction. [¹²⁵I]I-NpG-D-PSMA showed higher tumor accumulation than [¹²⁵I]I-NpG-L-PSMA. We then developed ²¹¹At-labeled PSMA using the NpG-D-PSMA structure. [²¹¹At]At-NpG-D-PSMA showed low accumulation in the stomach and thyroid in normal mice, indicating its high stability against deastatination in vivo. Moreover, [²¹¹At]At-NpG-D-PSMA showed high accumulation in tumor similar to that of [¹²⁵I]I-NpG-D-PSMA.</p><h3>Conclusions</h3><p>[²¹¹At]At-NpG-D-PSMA showed high in vivo stability against deastatination and high tumor accumulation. [²¹¹At]At-NpG-D-PSMA should be considered as a potential new TAT for mCRPC.</p></div>","PeriodicalId":534,"journal":{"name":"EJNMMI Radiopharmacy and Chemistry","volume":"9 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ejnmmipharmchem.springeropen.com/counter/pdf/10.1186/s41181-024-00278-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141330008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}