EJNMMI Research最新文献

{"title":"PET pharmacokinetics of [¹⁸F]F-AraG as a marker of T cell activation during immunotherapy with a STING agonist with and without anti-PD-1.","authors":"J E E Pouw, M Stavenga, J E Wijngaarden, D E Oprea-Lager, P Schober, R C Schuit, S P P van Eeden, A D Windhorst, M M Murillo, P Galette, C A Parker, T A Bonasera, T D de Gruijl, M M Yaqub, C W Menke-van der Houven van Oordt Oordt, R Boellaard","doi":"10.1186/s13550-026-01503-y","DOIUrl":"10.1186/s13550-026-01503-y","url":null,"abstract":"<p><strong>Background: </strong>There is an urgent need for clinical biomarkers to monitor the mechanistic efficacy of immunotherapy in oncology. The [¹⁸F]F-AraG tracer, developed to image activated T cells, may provide the means to establish such a biomarker. This study extends previously reported pharmacokinetic findings in untreated NSCLC across additional tumor types undergoing immunotherapy, and examines [¹⁸F]F-AraG kinetics in various organs. Four patients with advanced solid tumors were included in this phase 1 trial investigating a stimulator of interferon genes agonist with anti-programmed cell death protein 1. Patients underwent a 90 min [¹⁸F]F-AraG PET/CT scan at baseline, one week and six weeks on-treatment. The tracer kinetics in tumors and organs were modeled using three compartment models. Model selection was based on the Akaike information criterion (AIC), visual assessment of the fit quality, and the reliability of estimated kinetic parameters. The relationship between the primary kinetic measures (influx rate (K_i), volume of distribution (V_T)) and the simplified uptake metrics (standardized uptake values (SUV), tumor-to-blood ratio (TBR) and tumor-to-plasma ratio (TPR)) were evaluated using scatter plots.</p><p><strong>Results: </strong>The kinetics of all tumors and most organs were adequately described with the two-tissue irreversible model (2T3K), which was identified as the preferred model based on the AIC in 40/55 tumor regions. For most organs, the 2T3K model was selected. We observed a consistent linear trend across all metrics for the relationship between primary kinetic parameters and simplified uptake metrics. However, a patient-specific bias can be observed for SUV and TBR, which was corrected for when using the TPR.</p><p><strong>Conclusion: </strong>This study confirms that [¹⁸F]F-AraG PET uptake in tumors is best described by a 2T3K model, with no treatment-induced effects observed. Quantification of [¹⁸F]F-AraG uptake in static scans is most reliable when normalized using the TPR.</p><p><strong>Trial registration: </strong>ClinicalTrials.gov at 14 February 2019, NCT03843359, https//clinicaltrials.gov/study/NCT03843359.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":"16 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13661840/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149180019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Matrix metalloproteinase imaging and survival prospects with aging in murine aortic aneurysm.","authors":"Mean Ghim, Onur Varli, Azmi A Ahmad, Afarin Neishabouri, Gunjan Kukreja, Zhengxing Zhang, Saalar Zarnegar, Nicholas Gangemi, Keshvad Hedayatyanfard, Jakub Toczek, Lingyun Wang, Jiasheng Zhang, Chi Liu, Yongjian Liu, Robert J Gropler, Mehran M Sadeghi","doi":"10.1186/s13550-026-01521-w","DOIUrl":"10.1186/s13550-026-01521-w","url":null,"abstract":"<p><strong>Background: </strong>Matrix metalloproteinases (MMPs) are elevated in aortic aneurysm (AA), where older age is a risk factor. The relationship among aging, aortic MMP activity, and AA development has not been systematically evaluated. This study leveraged MMP-targeted molecular imaging to investigate how aging affects aortic MMP activity, aneurysm development, and survival.</p><p><strong>Results: </strong>AA development and animal survival were monitored for 28 days after Angiotensin (Ang)-II infusion in 8-10-week-old (young) and > 51-week-old (old) apolipoprotein E (Apoe)^-/- mice. Old animals' survival at 28 days was significantly lower than that of young Ang-II-infused Apoe^-/- mice (P < 0.05). ⁶⁴Cu-RYM2 PET/CT showed significantly higher aortic MMP activation before and 1 week after Ang-II infusion in old compared to young Apoe^-/- mice. The ⁶⁴Cu-RYM2 signal was significantly higher in animals that did not survive 28 days than in those that did (P < 0.01). MMP activity significantly increased after Ang-II infusion and correlated with aortic macrophage infiltration. The increase in MMP activity preceded aortic dissection. Finally, MMP activity was heterogeneous along the aorta of control and Ang-II-infused young and old Apoe^-/- mice, and of old wild-type mice.</p><p><strong>Conclusions: </strong>Aging is associated with increased MMP activity along the aorta and worse AA survival. MMP-targeted molecular imaging provides insights regarding aneurysm survival prospects in this exploratory cohort. Combining MMP inhibitors and tracers may help prevent and track aneurysm growth, dissection, and rupture.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":"16 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13675461/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149206591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correlation of apparent diffusion coefficient, FAP expression in IHC and [⁶⁸Ga]Ga‑FAPI‑46 uptake using integrated PET/MRI in high-grade soft tissue sarcoma: initial exploratory results.","authors":"Madelaine Hettler, Franka Menge, Johannes Ludwig, Dominik Nörenberg, Stefan O Schönberg, Anna Hinterberger, Björn Wängler, Carmen Wängler, Henning Rudolf, Güllü Davarci, Patrick Cieslik, Cristina L Cotarelo, Melissa Harbrücker, Christoph Reißfelder, Jens Jakob, Wolfgang G Kunz, Freba Grawe","doi":"10.1186/s13550-026-01517-6","DOIUrl":"10.1186/s13550-026-01517-6","url":null,"abstract":"<p><strong>Background: </strong>Fibroblast activation protein inhibitor (FAPI)-targeted positron emission tomography (PET) has emerged as a promising imaging approach in soft tissue sarcomas (STS), whereas magnetic resonance imaging (MRI) remains the diagnostic standard. We evaluated integrated [⁶⁸Ga]Ga‑FAPI‑46 PET/MRI including maximum standard uptake value (SUV_max), diffusion-weighted imaging, apparent diffusion coefficient (ADC), and contrast-enhanced sequences compared to FAP expression in immunohistochemistry for tumor assessment in high-grade STS.</p><p><strong>Results: </strong>Thirteen [⁶⁸Ga]Ga‑FAPI‑46 PET/MRI examinations from 9 patients were included, of which 4 were follow-up scans after therapy. All STS showed distinct FAPI uptake (median SUV_max 8.4; range 2.9-33). Mean SUV_max was 13 (2.9-33) for G2 and 8.4 (7.5-8.4) for G3 tumors. Neither SUV_max (P = 0.196) nor ADC (P = 0.895) differentiated between FNCLCC Grade 2 and Grade 3. A significant inverse correlation was observed between ADC_mean and SUV_max (Spearman's ρ = -0.70, 95% CI: -0.93 to - 0.07, P = 0.035). Immunohistochemistry demonstrated positive FAP expression in 4 of 9 patients, with significantly higher SUV_max in FAP-positive vs. negative tumors in immunohistochemistry (17.7 vs. 6.4; P = 0.047). High concordance of [⁶⁸Ga]Ga-FAPI-46 uptake and contrast enhancement was observed. Treatment responders showed marked reductions in SUV_max (40-70%) and increased ADC without significant changes in tumor size.</p><p><strong>Conclusion: </strong>In this exploratory pilot study, [68Ga]Ga-FAPI-46 PET/MRI provided complementary functional information in high-grade STS. Although no correlation with grading was observed either using SUVmax or ADC, a significant inverse correlation between ADCmean and SUVmax was identified within this cohort. Preliminary observations regarding treatment monitoring suggested that early changes in tracer uptake and ADC may reflect treatment-related changes, however, these findings were derived from a small pilot cohort. Larger prospective studies are required to validate these observations and to further define the potential role of [68Ga]Ga-FAPI-46 PET/MRI in treatment monitoring and response assessment.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":"16 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13598007/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149024345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correlation of [¹⁸F]SiTATE-PET-tracer with somatostatin receptor expression in meningiomas: an exploratory ex vivo histological pilot study.","authors":"Rieke Gerdes, Jens Schittenhelm, Stephan Singer, Gerald Reischl, Hannes Becker, Marcos Tatagiba, Salvador G Castaneda-Vega, Christian la Fougère, Benjamin Bender, Nils F Trautwein","doi":"10.1186/s13550-026-01505-w","DOIUrl":"10.1186/s13550-026-01505-w","url":null,"abstract":"<p><strong>Background: </strong>Radioactively labeled somatostatin analogs (SSAs) are used in PET imaging of meningiomas due to the high expression of somatostatin receptor (SSTR) subtype 2. ¹⁸F-labeled SSTR-tracers offer several economic and logistical advantages over ⁶⁸Ga-labeled tracers, such as a cyclotron-based production, higher activities per synthesis, a lower positron energy resulting in improved spatial resolution, and a longer half-life. Owing to the advantages over the most commonly used ⁶⁸Ga-labeled SSAs, [¹⁸F]SiTATE - although not yet approved by FDA or EMA - is currently in clinical use. The study compares [¹⁸F]SiTATE PET uptake with histological SSTR2-expression in meningiomas.</p><p><strong>Results: </strong>A correlation of SUV values and immunohistochemical SSTR2-expression was performed in 12 patients (42% female, mean age 68.8 ± 7.2 years). This study demonstrates a strong and significant correlation between [¹⁸F]SiTATE uptake (SUV_mean) and histological SSTR2-immune-reactivity-score (SSTR2-IRS) values (r = 0.80; p = 0.002). In addition, a significant difference in [¹⁸F]SiTATE uptake (SUV_mean) was observed between low SSTR-expressing lesions (scores 0-1) and high SSTR-expressing lesions (scores 2-3; p = 0.006). Furthermore, it was noted that in four cases, the molecular tumor volume (MTV) was underestimated using a threshold value of SUV_min 4, presumably caused by a low SUV_max, while the application of a 50% isocontour threshold led to an underestimation of the MTV in two lesions that showed high SUV_max values.</p><p><strong>Conclusions: </strong>[¹⁸F]SiTATE PET shows a strong and significant correlation with SSTR2-expression in meningiomas. However, neither of the two threshold methods yielded MTVs comparable to MRI volumes in all cases. Further studies are necessary to identify the conditions under which each threshold value yields the best MTV.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":"16 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13542035/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148886768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"TSPO PET selectively detects the denervated skeletal muscle district remodeling after experimental peripheral nerve injury.","authors":"Serena Losacco, Irene Di Patrizi, Edoardo Dighero, Maddalena Ghelardoni, Mattia Riondato, Roberta Resaz, Laura Emionite, Sabrina Chiesa, Matteo Bauckneht, Mattia Camera, Giovanna Capodivento, Francesca Vitale, Sonia Carta, Luca Sofia, Roberta Piva, Anna Maria Orengo, Mehrnaz Hamedani, Federico Zaottini, Carlo Martinoli, Lucilla Nobbio, Angelo Schenone, Gianmario Sambuceti, Cecilia Marini","doi":"10.1186/s13550-026-01497-7","DOIUrl":"10.1186/s13550-026-01497-7","url":null,"abstract":"<p><strong>Background: </strong>Peripheral nerve injury induces inflammatory and stress-related remodeling in downstream skeletal muscle before overt atrophy develops, yet non-invasive approaches capable of detecting and anatomically localizing early muscle involvement remain limited. The 18-kDa translocator protein (TSPO), a marker of inflammatory activation and mitochondrial stress, is a molecular target for PET imaging with [¹⁸F]DPA-714. This study aimed to determine whether TSPO-targeted PET imaging enables early and spatially resolved detection of denervation-induced skeletal muscle injury distal to a peripheral nerve lesion.</p><p><strong>Results: </strong>Adult mice underwent unilateral sciatic nerve crush. One-week post-injury, static [¹⁸F]DPA-714 PET imaging was performed to assess tracer uptake in hindlimb skeletal muscle. Uptake was quantified and compared between injured and contralateral limbs as well as with sham-operated mice. Ex vivo validation included CD68 immunofluorescence, Western blot analysis of TSPO expression, and laminin-based muscle fiber morphometry. [¹⁸F]DPA-714 uptake was significantly increased in distal hindlimb of crush-injured mice compared with contralateral and sham models. PET signal was selectively confined to denervated muscle distal to the lesion. Tracer uptake ratio between injured and contralateral hindlimb clearly discriminated crush-injured from sham animals without overlap. Immunofluorescence demonstrated marked macrophage infiltration, Western blot confirmed increased TSPO protein levels, and laminin morphometry revealed reduced muscle fiber size consistent with early atrophic remodeling.</p><p><strong>Conclusions: </strong>TSPO-targeted PET with [¹⁸F]DPA-714 enables an early and anatomically selective detection of denervation-induced skeletal muscle injury distal to the nerve lesion, supporting its role as a translational imaging biomarker of peripheral nerve-muscle interaction during acute reversible nerve damage.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":"16 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13624233/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149080229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[¹⁸F]FDG PET/CT as an endpoint marker in drug interventional studies in atherosclerosis - a structured review.","authors":"Casper E W Gijsen, Felix M Mottaghy, Ahmed Tawakol, Joachim E Wildberger, Jan Bucerius","doi":"10.1186/s13550-026-01489-7","DOIUrl":"10.1186/s13550-026-01489-7","url":null,"abstract":"<p><strong>Background: </strong>Inflammation plays a central role in the initiation, progression, and destabilization of atherosclerotic plaques. Persistent vascular inflammation despite therapeutic intervention may contribute substantially to residual cardiovascular risk. In this context, [¹⁸F]fluorodeoxyglucose-positron-emission-tomography ([¹⁸F]FDG PET) imaging has emerged as a non-invasive imaging biomarker capable of visualizing and quantifying vascular inflammatory activity in vivo. Previously published studies showed that the use of [¹⁸F]FDG PET may provide a non-invasive assessment of arterial inflammation. Accordingly, we aimed to systematically summarize treatment studies using [¹⁸F]FDG PET as an endpoint marker.</p><p><strong>Main body: </strong>18 studies were considered to be eligible for data extraction. Of these 22 articles, 10 investigated vascular inflammation reduction after trials with lipid-lowering therapies, the other 12 were considering the effect of novel anti-inflammatory drugs on vascular inflammation.</p><p><strong>Conclusion: </strong>This review provides an overview of the additional value that [¹⁸F]FDG PET can provide as an endpoint marker in clinical intervention trials. Overall, statin therapies demonstrated a more consistent reduction in vascular [¹⁸F]FDG uptake compared to novel anti-inflammatory therapies.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":"16 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13542030/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148886694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biodistribution and dosimetry of the carbon-11 labelled PARP1-selective PET radiopharmaceutical [¹¹C]AZ14193391.","authors":"Anders Törnblom, Cecilia He, Martin Bolin, Antonios Tzortzakakis, Josefin Fernebro, Chunde Li, Susanne Fridsten, Renske Altena, Rimma Axelsson, Jonathan Siikanen, Cecilia Hindorf","doi":"10.1186/s13550-026-01481-1","DOIUrl":"10.1186/s13550-026-01481-1","url":null,"abstract":"<p><strong>Background: </strong>Poly (ADP-ribose) polymerase-1 (PARP1) inhibitors are used for treatment of advanced breast, ovarian, and prostate cancer with germline or somatic BRCA1/2 mutations. However, not all patients respond to these drugs, and therapy-predictive biomarkers are needed to optimise the benefit-risk balance. The ¹¹C-labelled PARP1-selective radiopharmaceutical [¹¹C]AZ14193391 has emerged as a promising radioligand to identify eligible patients. The aim of this study was to investigate the safety and to determine the biodistribution and dosimetry of [¹¹C]AZ14193391. A secondary aim was to investigate the parametric bootstrap method to determine time-integrated activity coefficients (TIACs), absorbed doses, and effective dose.</p><p><strong>Results: </strong>Ten participants (5 breast, 3 ovarian, 2 prostate cancer) were injected with 5.7 MBq/kg [¹¹C]AZ14193391. Participants underwent five positron emission tomography (PET) acquisitions, ranging from the base of the skull to the proximal femur, at approximately 0, 10, 20, 30, and 45 min post-injection. Participants were monitored for changes in vital signs and were contacted 24 h after injection. No adverse events occurred. Visual evaluation of PET images showed high activity concentrations in the gastrointestinal tract, liver, kidneys, red marrow, pancreas, salivary glands, and spleen. Organs were segmented on a low-dose computed tomography image with an automatic segmentation tool (TotalSegmentator extension in 3D Slicer). The segmentations were reviewed and corrected based on the PET images. Time-activity curve (TAC) fits were determined with two TAC fit methods: 1) individual and 2) parametric bootstrap, to calculate TIACs. Absorbed doses and effective dose were determined with IDAC-Dose 2.1 from eleven source organs. Mean effective dose was estimated to be 5.0 (SD = 0.3) µSv/MBq with individual TAC fits and 5.0 (SE = 0.1) µSv/MBq with parametric bootstrap TAC fits. The organs receiving the highest mean absorbed doses per injected activity were liver, kidneys, and spleen. Gallbladder, red marrow, salivary glands, and spleen showed continued accumulation during the PET acquisitions.</p><p><strong>Conclusions: </strong>Imaging with [¹¹C]AZ14193391 is feasible and safe. Our results suggest that the radiation-induced risk is low, warranting further studies to evaluate the potential benefits of this diagnostic approach. The parametric bootstrap method estimated the population variability in the effective dose, but not in the TIACs.</p><p><strong>Clinical trial registry: </strong>Ongoing recruitment Human Pharmacology (phase I) trial in Sweden including cancer patients in the age range (18-64) years.</p><p><strong>Sponsor: </strong>Karolinska University Hospital. https://euclinicaltrials.eu/ctis-public/view/2022-502918-87-00 : Registry identifier: EU CT 2022-502918-87-00; Date of registration: 2023-08-17.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":"16 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13504008/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148812357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the biodistribution of [^99mTc]Tc-PSMA-GCK01 SPECT/CT in a prospective, intraindividual comparison with [⁶⁸Ga]PSMA-11 PET/CT for phenotyping in mCRPC prior to PSMA-targeted radioligand therapy.","authors":"Emil Novruzov, Eduards Mamlins, Joseph Kabunda, Jens Cardinale, Milani Qebetu, Clemens Kratochwil, Anna Feisthauer, Stefan Martlbauer, Chimbabantu Alexis Kaoma, Sandile Sibiya, Tertia de Bruin, Sipho Mdanda, Mbongeni Shungube, Cindy Davis, Liani Smith, Yonwaba Mzizi, Kgomotso Mokoala, Honest Ndlovu, Keamogetswe Ramonaheng, Frederik L Giesel, Mike M Sathekge","doi":"10.1186/s13550-026-01501-0","DOIUrl":"https://doi.org/10.1186/s13550-026-01501-0","url":null,"abstract":"<p><strong>Background: </strong>PSMA-PET/CT became an important means for prostate cancer management. The high-resolution and signal-to-noise ratio of PET is mandatory in primary staging or biochemical relapse that often present with tiny lesions. PSMA-PET is also used to select patients for PSMA-targeted radioligand-therapy, but scanner availability increasingly becomes a bottleneck. The resolution of PSMA-SPECT/CT might be sufficient to tailor PSMA positive vs. negative disease and would help overcome supply limitations. This prospective, monocentric study evaluates the biodistribution and tumor uptake of [^99mTc]Tc-PSMA-GCK01 in an intra-individual head-to-head comparison with [⁶⁸Ga]PSMA-11 to assess its suitability for phenotyping prior to RLT.</p><p><strong>Results: </strong>A cohort of ten patients (median age, 68 y; range, 56-85 y) with advanced-stage, metastatic prostate cancer underwent both unenhanced [⁶⁸Ga]PSMA-11 PET/CT and [^99mTc]Tc-PSMA-GCK01 SPECT/CT scans with a mean time interval of 6 days (± 1). The tracer uptake in malignant lesions and normal organs was assessed visually and semi-quantitatively using spherical VOIs by two nuclear medicine physicians in consensus. Compared to [^99mTc]Tc-PSMA-GCK01, [⁶⁸Ga]PSMA-11 displayed a trend toward higher uptake in normal organs. Renal tracer uptake was significantly higher with [⁶⁸Ga]PSMA-11 than with [^99mTc]Tc-PSMA-GCK01. In the salivary glands and liver, there was no statistically significant difference in uptake between the two tracers, although [^99mTc]Tc-PSMA-GCK01 displayed a trend toward lower uptake.</p><p><strong>Conclusion: </strong>Our study demonstrates intraindividual comparability of [^99mTc]Tc-PSMA-GCK01 and [⁶⁸Ga]PSMA-11 with respect to normal-organ distribution including typical reference organs such as the liver or salivary glands. If only lesions > 2 cm are considered, [^99mTc]Tc-PSMA-GCK01 PSMA-SPECT seems to be a viable, cost-effective alternative to [⁶⁸Ga]PSMA-11 to stratify patients toward or against PSMA-RLT in certain clinical settings.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":"16 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13486452/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148789725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[¹⁶¹Tb]Tb-DOTATATE as a potential treatment option for neuroblastoma.","authors":"Saloni Chopra, Tianqi Xu, Hanna Berglund, Amanda Gustafsson, Marika Nestor","doi":"10.1186/s13550-026-01487-9","DOIUrl":"10.1186/s13550-026-01487-9","url":null,"abstract":"<p><strong>Background: </strong>Neuroblastoma is an aggressive paediatric malignancy with poor outcomes in high-risk patients despite multimodal therapy. [¹⁷⁷Lu]Lu-DOTATATE, targeting somatostatin receptor 2 (SSTR2), is under clinical investigation for neuroblastoma. Terbium-161 (¹⁶¹Tb) shares chemical characteristics and a similar half-life with lutetium-177 (¹⁷⁷Lu) but offers advantages through its higher emission of Auger and conversion electrons, which may enhance therapeutic efficacy especially for micrometastases and recurrent disease. This study investigates [¹⁶¹Tb]Tb-DOTATATE as a potential complement for treatment of SSTR2-expressing neuroblastoma.</p><p><strong>Results: </strong>DOTATATE was successfully radiolabelled with ¹⁶¹Tb, achieving high radiochemical yield and stability. [¹⁶¹Tb]Tb-DOTATATE demonstrated clear SSTR2-specific binding in vitro, as well as biodistribution and tumour uptake comparable to [¹⁷⁷Lu]Lu-DOTATATE in vivo. Treatment with [¹⁶¹Tb]Tb-DOTATATE reduced tumour growth in an activity-dependent manner, and demonstrated stronger early tumour control compared to [¹⁷⁷Lu]Lu-DOTATATE at comparable administered activities (**p < 0.01 at day 9). Tumour doubling times were longest in the 6 MBq [¹⁶¹Tb]Tb-DOTATATE group (29 vs. 18 days in controls), while the 3 MBq [¹⁶¹Tb]Tb-DOTATATE group showed similar doubling times to 4 MBq [¹⁷⁷Lu]Lu-DOTATATE (21 vs. 22 days). This was also reflected in survival, where 6 MBq [¹⁶¹Tb]Tb-DOTATATE achieved the greatest effect (50% increase in median survival), followed by 4 MBq [¹⁶¹Tb]Tb-DOTATATE (36%), while 3 MBq [¹⁶¹Tb]Tb-DOTATATE and 4 MBq [¹⁷⁷Lu]Lu-DOTATATE showed more modest improvements (23%). All treatment regimens were well tolerated, and no signs of treatment-related toxicity were observed.</p><p><strong>Conclusion: </strong>[¹⁶¹Tb]Tb-DOTATATE demonstrates favourable targeting properties and activity-dependent therapeutic efficacy in preclinical neuroblastoma models without detectable toxicity. These findings encourage us to explore its potential as a complement to [¹⁷⁷Lu]Lu-DOTATATE, particularly for targeting minimal residual disease and micrometastases, and warrant further preclinical and clinical evaluation.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":"16 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13415435/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148600776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Early detection and localization of recurrent prostate cancer using [Formula: see text]F-DCFPyL PET/CT in patients with low and ultra-low PSA levels.","authors":"Ida Sonni, Alexandra Gulpe, Nicholas G Nickols, Derace Schaffer, Louis Montagut, Gholam R Berenji, Matthew B Rettig","doi":"10.1186/s13550-026-01490-0","DOIUrl":"10.1186/s13550-026-01490-0","url":null,"abstract":"","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":"16 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13407815/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148600806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}