EJNMMI Research最新文献

{"title":"Acute complications of nuclear medicine: an emergency medicine perspective.","authors":"Mehmet Necmeddin Sutaşır, Banu Arslan, Mohamed Mukhtar Mohamed, Nihat Müjdat Hökenek","doi":"10.1186/s13550-026-01464-2","DOIUrl":"10.1186/s13550-026-01464-2","url":null,"abstract":"<p><strong>Background: </strong>Nuclear medicine procedures are increasingly integrated into routine clinical practice worldwide, including in low- and middle-income settings. Although radiopharmaceuticals have a well-established safety profile, the growing volume of diagnostic and therapeutic procedures means that acute adverse events, while uncommon, are encountered with sufficient frequency to present to emergency departments. Emergency physicians are often the first clinicians to assess patients with post-procedural symptoms, yet guidance tailored to emergency care remains limited. This review aims to provide an emergency medicine-focused synthesis of the incidence, clinical presentation, and acute management of adverse events associated with nuclear medicine procedures.We conducted a narrative review using a systematic search strategy across PubMed/MEDLINE, Embase, Scopus, and the Cochrane Library, covering publications from January 2020 to December 2024. Studies reporting acute events related to radiopharmaceutical administration, including extravasation, allergic reactions, maladministration, and radiation contamination, were included. Evidence from cohort studies, surveillance registries, systematic reviews, and relevant case reports was synthesized narratively due to methodological heterogeneity.</p><p><strong>Main body: </strong>Sixty-eight studies encompassing over two million radiopharmaceutical administrations were included. Diagnostic radiopharmaceutical extravasation was common when systematically assessed but rarely resulted in clinically significant harm. Severe allergic reactions and anaphylaxis were exceedingly rare. Maladministration events occurred infrequently and were predominantly associated with diagnostic procedures, with minimal patient harm in most cases. In contrast, extravasation and toxicity related to therapeutic radiopharmaceuticals, particularly high-energy beta emitters, carried greater clinical significance. Newer agents such as lutetium-177-labelled therapies demonstrated predictable toxicity profiles, with hematologic adverse events representing the primary emergency care concern.Emerging alpha-emitting theranostic agents such as actinium-225-PSMA-617 demonstrate promising efficacy but may be associated with clinically relevant xerostomia and hematologic toxicity.</p><p><strong>Conclusion: </strong>Acute events related to nuclear medicine procedures are uncommon but clinically relevant in emergency practice. Diagnostic radiopharmaceuticals are generally safe and require supportive management, whereas therapeutic radiopharmaceutical complications warrant heightened vigilance and specialist consultation. Familiarity with these presentations can support timely, appropriate emergency care, particularly in settings with limited on-site nuclear medicine expertise.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13473028/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148162051","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":"Head to head comparison of [⁶⁸Ga]Ga-FAPI-04 and [¹⁸F]FDG PET/CT in the diagnosis and staging of pancreatic cancer: a prospective study.","authors":"Ruoxi Yang, Yuhan Sun, Ran An, Xiaolin Chen, Xiao Pang, Jingmian Zhang, Jianfang Wang, Jingya Han, Tuo Ma, Mengjiao Wang, Fangyu Shi, Bin Guo, Xinming Zhao","doi":"10.1186/s13550-026-01456-2","DOIUrl":"10.1186/s13550-026-01456-2","url":null,"abstract":"<p><strong>Background: </strong>[⁶⁸Ga]Ga-FAPI-04 targets FAP overexpressed in pancreatic cancer microenvironment. This study compared diagnostic efficacy and clinical impact with [¹⁸F]FDG PET/CT in pancreatic cancer.</p><p><strong>Results: </strong>Of 97 suspected pancreatic cancer patients (58 males; mean age 63.0 ± 10.1 years), 88 were confirmed as pancreatic cancer (57 by pathology, 31 by imaging follow‑up). [⁶⁸Ga]Ga-FAPI-04 PET/CT showed significantly higher SUVmax than [¹⁸F]FDG PET/CT in primary lesions (10.2 ± 3.5, 95%CI: 9.320-11.126 vs. 6.1 ± 3.8, 95%CI: 5.092-7.152; p = 0.001) and lymph node metastases (4.1 ± 2.4, 95%CI: 3.718-4.559 vs. 3.3 ± 2.3, 95%CI: 2.845-3.714; p = 0.001), with superior AUCs for primary tumors and lymph nodes(0.851, 95% CI: 0.735-0.981 vs. 0.802, 95% CI: 0.354-0.803; p = 0.001) (0.867, 95% CI: 0.827-0.907 vs. 0.701, 95% CI: 0.641-0.761; p = 0.001). The T/B ratio of bone and visceral metastases was higher in [⁶⁸Ga]Ga-FAPI-04 PET/CT than [¹⁸F]FDG PET/CT(4.7 ± 3.1, 95%CI: 4.108-5.245 vs. 2.5 ± 1.6, 95%CI: 2.231-2.835; p = 0.001) with superior AUC(0.938, 95% CI: 0.912-0.964 vs. 0.919, 95% CI: 0.886-0.951; p = 0.040), as were liver (5.0 ± 4.0, 95%CI: 3.706-6.284 vs. 2.7 ± 1.3, 95%CI: 2.211-3.131; p = 0.001), peritoneal (5.4 ± 3.3, 95%CI: 4.318-6.482 vs. 3.0 ± 2.1. 95%CI: 2.211-3.745; p = 0.001) and other organ metastases (4.4 ± 2.5, 95%CI: 3.756-5.035 vs. 2.7 ± 1.7, 95%CI: 1.379-2.254; p = 0.001). [⁶⁸Ga]Ga‑FAPI‑04 SUVmax and TBR were positive predictors for primary tumors (SUVmax: OR = 1.951, 95%CI: 1.286-2.960, p = 0.004) and nodal metastases (SUVmax: OR = 4.199, 95%CI: 2.970-5.939, p = 0.001; TBR: OR = 14.502, 95%CI: 7.228-29.095, p = 0.001). For bone and visceral metastases, both tracers were positive predictors, but [⁶⁸Ga]Ga‑FAPI‑04 SUVmax (OR = 2.925, 95%CI: 2.048-4.177, p = 0.003) and T/B ratio (OR = 3.520, 95%CI: 2.311-5.362, p = 0.001) outperformed [¹⁸F]FDG (SUVmax: OR = 1.901, 95%CI: 1.308-2.761, p = 0.003; T/B ratio: OR = 2.480, 95%CI: 1.488-4.136, p = 0.001). Furthermore, [⁶⁸Ga]Ga-FAPI-04 achieved higher accuracy (93.2% vs. 72.7%, p = 0.007), revised the staging of 7 patients and altered the treatment (surgical resection to unresectable) in 6 patients. Limitations include single‑center, short follow‑up, small subgroups (e.g., recurrent lesions) and incomplete pathologically confirmation.</p><p><strong>Conclusion: </strong>[⁶⁸Ga]Ga-FAPI-04 PET/CT suggested potentially better diagnostic performance to [¹⁸F]FDG PET/CT and improves staging and clinical decision-making in pancreatic cancer, suggesting potential clinical value.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13457526/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148175664","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":"GWAS from a multicenter prospective study of radium-223 in bone-metastatic castration-resistant prostate cancer.","authors":"Tokiyoshi Tanegashima, Masaki Shiota, Atsushi Doi, Shuichi Tatarano, Tomomi Kamba, Tsukasa Igawa, Naoya Masumori, Hirotsugu Uemura, Toshiyuki Kamoto, Katsuyoshi Higashijima, Kensuke Mitsunari, Hiroji Uemura, Takayuki Sumiyoshi, Takuro Isoda, Kousei Ishigami, Shoji Tokunaga, Masatoshi Eto","doi":"10.1186/s13550-026-01463-3","DOIUrl":"10.1186/s13550-026-01463-3","url":null,"abstract":"<p><strong>Background: </strong>Radium-223 dichloride improves survival and delays symptomatic skeletal events in patients with bone-metastatic castration-resistant prostate cancer; however, therapeutic responses vary considerably among individuals, and predictive germline biomarkers remain undefined. We conducted a prospective multicenter genome-wide association study within the KYUCOG-1901 cohort to identify germline single-nucleotide polymorphisms associated with the clinical efficacy of radium-223.</p><p><strong>Results: </strong>Among 93 patients with bone-predominant castration-resistant prostate cancer treated with up to six cycles of radium-223, the intronic variant rs1568679 in MEIS2 reached genome-wide significance for association with ≥ 30% decline in prostate-specific antigen (P < 5.0 × 10⁻⁸). Patients carrying the rs1568679 CC genotype exhibited significantly greater prostate-specific antigen decline and significantly longer symptomatic skeletal event-free survival, radiographic progression-free survival, and overall survival compared with those with TT/TC genotypes. In multivariate analyses adjusting for established clinical prognostic factors, the rs1568679 CC genotype remained independently associated with favorable clinical outcomes. Although rs1568679 showed no significant expression quantitative trait loci effect on MEIS2 expression, pathway enrichment analysis of MEIS2-associated regulatory networks revealed strong enrichment of genes involved in DNA repair and genomic stability.</p><p><strong>Conclusions: </strong>The germline variant rs1568679 in MEIS2 may represent a potential biomarker associated with favorable response to radium-223 in metastatic castration-resistant prostate cancer. These findings suggest that MEIS2-related DNA repair regulation may influence susceptibility to α-particle-induced cytotoxicity and may facilitate biomarker-driven treatment strategies for optimizing Ra-223 therapy.</p><p><strong>Trial registration: </strong>University Hospital Medical Information Network (UMIN), UMIN000040358, registered 11 May 2020, https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000045641 .</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13442763/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148148935","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":"The test-retest reproducibility of [¹¹C]PK11195 positron emission tomography using Biograph Vision Quadra scanner.","authors":"Tanja Sjöros, Markus Matilainen, Virva Saunavaara, Saara Wahlroos, Johan Rajander, Mikko Koivumäki, Eveliina Honkonen, Amelie Luoma, Laura Airas","doi":"10.1186/s13550-026-01460-6","DOIUrl":"10.1186/s13550-026-01460-6","url":null,"abstract":"<p><strong>Background: </strong>Positron emission tomography (PET) imaging of the 18 kDa translocator protein (TSPO) is a method to quantify central inflammation and particularly microglial activation, which is increased in progressive multiple sclerosis (MS) among other neurodegenerative diseases. We evaluated the test-retest reproducibility of TSPO-PET imaging using Biograph Vision Quadra and [¹¹C]PK11195 radioligand. Three healthy volunteers and three people with progressive MS underwent two [¹¹C]PK11195-PET scans with a 1-3 day interval. TSPO binding was quantified as distribution volume ratios (DVR) using the supervised clustering algorithm. To evaluate the reproducibility of repeated [¹¹C]PK11195-PET scans, repeatability coefficients (RC) and intraclass correlation coefficients (ICC) were calculated.</p><p><strong>Results: </strong>The ICCs indicated excellent test-retest reproducibility in distinct cortical regions (0.933-0.985) and white matter (0.980), and good to excellent test-retest reproducibility in deep grey matter structures (0.867-0.988). Additionally, the reproducibility was evaluated lesion-wise in the ≥50mm³ MS lesions (n=59). The test-retest reproducibility was good both at the lesion core (ICC 0.869) and rim (ICC 0.846).</p><p><strong>Conclusion: </strong>The test-retest reproducibility of [¹¹C]PK11195-PET using Biograph Vision Quadra is good to excellent among people with MS. This supports the usability of the ligand in longitudinal studies, including treatment trials.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13442786/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148148885","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":"Reconstruction matters: influence of EARL standards and BSREM in [¹⁸F]FET PET for distinguishing glioma progression from treatment-related changes.","authors":"J de Jong, M Segbers, A A Harteveld, W J Bron, R Valkema, R Boellaard, S E M Veldhuijzen van Zanten","doi":"10.1186/s13550-026-01458-0","DOIUrl":"10.1186/s13550-026-01458-0","url":null,"abstract":"<p><strong>Background: </strong>Differentiating progressive disease (PD) from treatment-related changes (TRC) in glioma remains challenging using magnetic resonance imaging (MRI) alone. Amino acid positron-emission tomography (PET) with O-(2-[¹⁸F]fluoroethyl)-L-tyrosine ([¹⁸F]FET) is increasingly applied in clinical practice, and the first guideline for PET-based Response Assessment in Neuro-Oncology (PET-RANO) has recently been developed. However, quantitative PET metrics are sensitive to image reconstruction, which may directly influence response classification and clinical interpretation. This study aimed to investigate how different reconstruction standards affect quantitative [¹⁸F]FET PET metrics and to what extent these differences impact clinical interpretation.</p><p><strong>Results: </strong>Thirty-three patients with 42 lesions were analysed. In lesion‑based comparisons, both EANM Research Ltd. harmonization standard version 2.0 (EARL2) and block-sequential regularized expectation maximization using a β-value of 150 (BSREM150) yielded significantly higher standardized uptake values (SUV), tumour‑to‑background ratios (TBR), and biological tumour volumes (BTV) than EANM Research Ltd. harmonization standard version 1.0 (EARL1), and identified a greater number of lesions as measurable disease (MD). BTV differed across reconstructions; adapting the BSREM150 segmentation threshold to SUV ≥ 1.7 x mean background activity improved BTV concordance while preserving superior MD detection. Excellent discrimination between PD and TRC was observed for TBRmax across all reconstructions (area under the curve ≥ 0.94), although optimal thresholds were reconstruction‑specific (EARL1: 1.67; EARL2: 1.84; BSREM150: 2.39). At the patient level, EARL1 failed to identify three PD cases, whereas BSREM150 misclassified one TRC case as PD.</p><p><strong>Conclusion: </strong>Reconstruction standards substantially influence quantitative [¹⁸F]FET PET metrics and clinical interpretation. Applying universal thresholds across reconstructions risks misclassification, with EARL1 potentially underestimating tumour extent and BSREM150 increasing false-positive findings. Reconstruction-specific thresholds and neuro-oncology-specific harmonization frameworks are therefore essential for reliable [¹⁸F]FET PET assessment in routine clinical practice and PET-RANO implementation in multicentre trials.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13421519/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148053467","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 is a quantitative tool to probe vascular inflammation and immune system metabolic activation in atherosclerotic nonhuman primates.","authors":"Hee-Jeong Yang, Hui Wang, Russell Byrum, Christopher Bartos, Philip J Sayre, Gabriella Worwa, Anya Crane, Thomas C Friedrich, David H O'Connor, Ian Crozier, Jens H Kuhn, Venkatesh Mani, Claudia Calcagno","doi":"10.1186/s13550-026-01449-1","DOIUrl":"10.1186/s13550-026-01449-1","url":null,"abstract":"<p><strong>Background: </strong>Atherosclerosis is a major global health concern, necessitating advanced research models to better understand pathophysiology and inform potential interventions. Due to their physiological similarities to humans, nonhuman primates (NHPs), particularly crab-eating macaques, are valuable models to study the development and progression of atherosclerosis. This retrospective study utilized quantitative 2-deoxy-2-[fluorine-18]fluoro-D-glucose ([¹⁸F]FDG) positron emission tomography-computed tomography (PET/CT) to characterize a cohort of crab-eating macaques with diet-induced atherosclerosis. We evaluated [¹⁸F]FDG uptake in the vasculature, bone marrow, spleen, and adipose tissues from macaques fed an atherogenic diet compared with those fed a regular chow diet.</p><p><strong>Results: </strong>[¹⁸F]FDG uptake was significantly higher in the vasculature, bone marrow, and adipose tissues of macaques on the atherogenic diet, along with increased vascular calcification. Correlation analyses demonstrated moderate to strong associations among vascular inflammation, calcification, and metabolic activity in the bone marrow and adipose tissues.</p><p><strong>Conclusions: </strong>We provide a robust methodology for quantitative PET/CT imaging analysis of atherosclerosis in an established NHP model. Our work adds to the research toolkit and highlights the translational potential of imaging in NHP models to investigate systemic cardiovascular disease, including of fundamental pathobiology and of targeted interventions.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13437869/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148053493","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":"Toward reproducible metabolic tumor volume quantification in endometrial cancer: optimizing [¹⁸F]FDG PET/CT tumor segmentation methods.","authors":"Kristine Eldevik Fasmer, Sunniva Lindås, Ankush Gulati, Julie Andrea Dybvik, Erlend Hodneland, Camilla Krakstad, Ingfrid Salvesen Haldorsen","doi":"10.1186/s13550-026-01412-0","DOIUrl":"10.1186/s13550-026-01412-0","url":null,"abstract":"<p><strong>Background: </strong>Metabolic tumor volume (MTV) derived from [¹⁸F]FDG PET/CT has shown promise in improving preoperative staging and prognostication in endometrial cancer, both as a standalone biomarker and as a foundation for PET-based tumor radiomics. Despite its potential, standardized segmentation methods are lacking. This study aimed to (1) evaluate interobserver agreement in MTV delineation, (2) compare MTVs obtained through various thresholding approaches by examining their correlation with anatomical tumor volume (ATV) from MRI, and (3) assess their value for predicting aggressive disease.</p><p><strong>Results: </strong>This study included 146 patients with histologically confirmed endometrial cancer who underwent preoperative PET/CT imaging on a Siemens TruePoint (n = 67) or a Siemens Biograph Vision scanner (n = 79). MTV_2.5 defined by a standardized uptake value (SUV) threshold larger than 2.5, demonstrated excellent reproducibility between readers, with an intraclass correlation coefficient (95% confidence interval (CI)) of 0.97 (0.96, 0.98). MTV_40%, defined by SUV > 40% of SUV_max, yielded an ICC (95% CI) of 0.91 (0.87, 0.93). Both the fixed 2.5 threshold and all relative SUV_max-based thresholds (20-60% SUV_max) produced MTVs with strong correlation to ATV, with Spearman's rank correlation coefficients ranging from 0.806 to 0.874 (p < 0.001). The closest volumetric match to ATV was observed for MTV_30%, with a median difference (95% CI) of -4% (-11%, 2%). In terms of predictive performance, MTV_2.5 and MTV_20-50% yielded comparable results for predicting lymph node metastases, advanced FIGO stage (III-IV), and 3-year disease specific survival, with area under receiver operating characteristic curve (AUC) values (95% CI) ranging from 0.68 (0.53, 0.82) to 0.77 (0.65, 0.88). MTV_60% showed slightly lower prediction values across all outcomes, with AUCs (95% CI) between 0.64 (0.49, 0.80) and 0.72 (0.63, 0.82).</p><p><strong>Conclusion: </strong>MTV_2.5 has excellent reproducibility and correlates well with anatomical volume. Both MTV_2.5 and MTV_20-50% thresholds yield similar performances for predicting aggressive disease features, supporting their potential for clinical implementation in preoperative assessment of endometrial cancer.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13230389/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148053486","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":"Fully automatic left ventricle segmentation in [Formula: see text]Rb PET/CT Using a semi-supervised nnU-net.","authors":"Mohammadreza Amirian, Arthur Chevalley, María Martín Asiain, Ran Klein, Robert DeKemp, Eric Moulton, John O Prior, Christel H Kamani, Mario Jreige, Adrien Depeursinge","doi":"10.1186/s13550-026-01455-3","DOIUrl":"10.1186/s13550-026-01455-3","url":null,"abstract":"<p><strong>Background: </strong>Quantification of myocardial blood flow (MBF) with [Formula: see text]Rb PET/CT requires accurate delineation of the left ventricle (LV). Manual or semi-automated contouring remains time-consuming and error-prone, particularly in hypoperfused myocardium. We developed and validated a fully automatic LV segmentation pipeline using nnU-Net applied to [Formula: see text]Rb PET/CT. A manual, multimodal segmentation protocol integrating dynamic PET and CT was established in a single-center cohort of 40 non-gated PET/CT series (20 patients, rest & stress), including challenging cases with extensive necrosis (median 21%). The resulting ground truth masks were used for five-fold cross-validation, and semi-supervised learning incorporated 805 additional unlabeled dynamic PET series (504 patients). Model performance was compared with an optimized semi-automatic thresholding baseline (35% [Formula: see text]).</p><p><strong>Results: </strong>The nnU-Net significantly outperformed the baseline, achieving a mean Dice of 87.8[85.6, 89.2]% vs 75.1[72.9, 76.9]%, recall 89.1[86.1, 91.4]% vs 82.6[79.1, 85.4]%, and precision 88.1[84.2, 90.4]% vs 70.2[67.2, 73.0]%. The improvement was most pronounced in hypoperfused regions, where recall increased by 20-30% compared to thresholding. Semi-supervised learning modestly enhanced model robustness across both rest and stress acquisitions.</p><p><strong>Conclusions: </strong>A deep-learning-based approach enables fully automatic LV segmentation in [Formula: see text]Rb PET/CT with near-expert accuracy. This framework eliminates manual interaction, supports large-scale MBF quantification, and paves the way for reproducible, high-throughput cardiac PET analysis in clinical and research workflows.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13407406/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148041624","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":"Dialysis-related amyloidosis mimicking metastatic bone disease: a scintigraphic pitfall of non-MDP-avid osteolytic lesions on bone SPECT/CT.","authors":"Tzyy-Ling Chuang, Chih-En Tseng, Po-Hsun Lin, Yuh-Feng Wang","doi":"10.1186/s13550-026-01453-5","DOIUrl":"10.1186/s13550-026-01453-5","url":null,"abstract":"<p><strong>Background: </strong>Dialysis-related amyloidosis (DRA) is a recognized complication of long-term dialysis caused by progressive deposition of β2-microglobulin amyloid in osteoarticular and periarticular tissues. Although its musculoskeletal manifestations are well described, bone lesions from DRA may be misidentified as malignant disease on imaging, posing a diagnostic challenge.</p><p><strong>Case presentation: </strong>We describe a 70-year-old woman on long-term dialysis who presented with a pathologic femoral neck fracture and adjacent osteolytic lesions initially suspicious for metastatic disease or brown tumor. Bone SPECT/CT showed uptake only at the fracture site with background activity in the lytic lesions. Histopathological examination confirmed the diagnosis of amyloidosis by Congo red staining.</p><p><strong>Conclusions: </strong>This case illustrates that DRA may present as non-MDP-avid osteolytic lesions on bone scintigraphy, potentially mimicking malignant bone disease. Awareness of this scintigraphic pitfall is essential when evaluating dialysis patients with atypical skeletal lesions.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13402274/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148041684","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":"Noninvasive tracking of myocardial fibrosis in pressure-overload heart failure with [⁶⁸Ga]Ga-FAPI-04 PET/CT.","authors":"Shanshan Liu, Hui Wen, Bingqing Han, Fei Wang, Xiangyang Gao, Yi Luo, Hao Zhang, Xiaoyan Hao, Chao Fu, Zhaohui Xie, Xiaojun Zhang, Qiang Zeng","doi":"10.1186/s13550-026-01461-5","DOIUrl":"10.1186/s13550-026-01461-5","url":null,"abstract":"<p><strong>Background: </strong>Myocardial fibrosis is a major driver of heart failure progression, yet noninvasive tools to track its activity are limited. We evaluated fibroblast activation protein (FAP)-targeted [⁶⁸Ga]Ga-FAPI-04 (FAPI = FAP inhibitor) positron emission tomography/computed tomography (PET/CT) in C57BL/6J mice subjected to transverse aortic constriction (TAC).</p><p><strong>Results: </strong>PET/CT and echocardiography were performed at 2, 4, and 8 weeks post-surgery. Compared to the sham group, TAC mice exhibited significantly elevated myocardial [⁶⁸Ga]Ga-FAPI-04 uptake at week 2, with progressive intensification at weeks 4 and 8. Although cardiac function remained preserved at week 2, pronounced systolic and diastolic dysfunction (decreased left ventricular ejection fraction [LVEF] and elevated E/A ratio) developed by week 4, deteriorating further by week 8. Correspondingly, histological (wheat germ agglutinin [WGA], Sirius Red, Masson's) and autoradiographic analyses revealed progressive cardiomyocyte hypertrophy, accompanied by time-dependent increases in collagen deposition and FAP-specific signals. Importantly, a blocking experiment significantly suppressed myocardial uptake, confirming targeting specificity.</p><p><strong>Conclusions: </strong>[⁶⁸Ga]Ga-FAPI-04 PET/CT provides a specific, noninvasive method to track the progression of myocardial fibrosis. Crucially, increased FAPI uptake precedes the manifestation of cardiac dysfunction, highlighting its significant potential as a promising imaging tool for the early detection and longitudinal monitoring of heart failure.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13219577/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148028407","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}