EJNMMI reports最新文献

{"title":"Effect of data-driven gating on the quantification of prostate cancer metastases in ⁶⁸Ga-PSMA- and ¹⁸F-DCFPyL-PSMA PET/CT.","authors":"Adam Farag, Cornel Felder, Douglas Hussey, Seyed Ali Mirshahvalad, Sara Harsini, Ur Metser, Patrick Veit-Haibach","doi":"10.1186/s41824-026-00328-1","DOIUrl":"https://doi.org/10.1186/s41824-026-00328-1","url":null,"abstract":"<p><strong>Background: </strong>PSMA PET/CT using ¹⁸F‑DCFPyL and ⁶⁸Ga‑labelled tracers is central to prostate cancer staging, but ⁶⁸Ga‑PSMA may show reduced sensitivity and quantitative accuracy, partly due to respiratory motion and lower spatial resolution. Device-based motion‑correction methods have limitations. Data‑driven gating (DDG) offers a hardware‑free alternative, though its impact on PSMA PET, especially ⁶⁸Ga‑PSMA has not been systematically evaluated. To evaluate the quantitative and qualitative performance of the DDG motion-correction method in ⁶⁸Ga-PSMA and ¹⁸F-DCFPyL-PSMA PET/CT, focusing on metastatic lymph node, lung, and bone lesions, and to assess its robustness across tracers.</p><p><strong>Methods: </strong>This retrospective study included patients with biopsy‑proven prostate cancer who underwent ⁶⁸Ga‑PSMA or ¹⁸F‑DCFPyL PSMA PET/CT for primary staging or biochemical recurrence and had metastatic disease. Motion correction was applied using the OncoFreeze AI™ data‑driven gating (OFAI‑DDG) method. Metastatic lesions were segmented semi‑automatically, and SUV metrics, image noise, and contrast‑to‑noise ratio were quantified by anatomical site in both OFAI-DDG and static images. Qualitative image quality was independently scored by two experienced readers. Statistical analyses included non‑parametric tests, Bland-Altman agreement, regression analyses, tracer comparison, and inter‑reader reliability assessment.</p><p><strong>Results: </strong>After exclusions, 23 ⁶⁸Ga‑PSMA and 40 ¹⁸F‑PSMA patients were analyzed, yielding 133 and 192 metastatic lesions, respectively. OFAI‑DDG reconstruction significantly increased SUV_mean and SUV_max compared with static imaging for both tracers across bone, lymph node, and lung lesions (p < 0.0001), with the largest gains in lung lesions. CNR improved for most lesion types, and image noise was significantly reduced. Qualitative analysis showed better image quality, sharpness, and noise with OFAI‑DDG, with high inter‑reader agreement. OFAI‑DDG performance was robust across tracers and largely independent of lesion location.</p><p><strong>Conclusions: </strong>This study demonstrates that OFAI‑DDG significantly improves PSMA PET/CT image quality and quantitative accuracy compared with standard static imaging. The improvements were observed for both ⁶⁸Ga‑PSMA and ¹⁸F‑PSMA tracers, indicating tracer‑independent robustness. The OFAI‑DDG simplified the workflow and reduced time used for patient set-up, while enhancing lesion visualization and quantitative reliability without altering lesion detection, supporting its clinical value for metastatic prostate cancer imaging.</p>","PeriodicalId":519909,"journal":{"name":"EJNMMI reports","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149248102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Expanding role of nuclear medicine in cardiac amyloidosis: insights from the EJNMMI collection.","authors":"Mahdi Zirakchian Zadeh, Medhat M Osman","doi":"10.1186/s41824-026-00326-3","DOIUrl":"10.1186/s41824-026-00326-3","url":null,"abstract":"<p><p>Recent advances in nuclear medicine are reshaping the evaluation of cardiac amyloidosis, as highlighted by the recent collection published in EJNMMI (collection link: https://link.springer.com/collections/igfdhcddjg). This commentary summarizes key insights from these studies, emphasizing the evolving shift from conventional diagnostic imaging toward a more integrated and comprehensive approach. Emerging developments include novel amyloid PET tracers, improved diagnostic accuracy with SPECT/CT, multimodality imaging strategies, and enhanced assessment of systemic disease burden extending beyond the left ventricle. There is also growing interest in longitudinal monitoring, pre-symptomatic detection, and the role of artificial intelligence. Together, these advances position nuclear medicine as an essential tool for disease characterization, risk stratification, and treatment assessment.</p>","PeriodicalId":519909,"journal":{"name":"EJNMMI reports","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13677663/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149221255","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":"DNA damage in thyroid cancer patients treated with radioactive iodine in Johannesburg, South Africa.","authors":"Shingirai Brenda Kagodora, Ans Baeyens, Anne Vral, Mboyo Di Tamba Willy Vangu","doi":"10.1186/s41824-026-00327-2","DOIUrl":"10.1186/s41824-026-00327-2","url":null,"abstract":"<p><strong>Background: </strong>Thyroid cancer is the most common endocrine cancer globally. The National Cancer Registry has estimated the prevalence of the disease to be higher in females than in the male population with a risk of 1 in 506 females and 1 in 1035 in males in South Africa. Thyroid cancer mostly develops in the thyroid nodules. If cancerous then the malignant cells can spread to the nearby lymph nodes or by the blood vessels to other organs. The aim of the study was to investigate the correlation between ¹³¹I emitted ionizing radiation and the induced and persistent DNA damage in patients treated with radioactive iodine. Patients suffering from thyroid cancer and treated with radioactive iodine face an increased risk of secondary cancers due to potential chromosomal damage from exposure to ionising radiation. We used the cytokinesis - block micronucleus assay to assess chromosomal damage at four time points.</p><p><strong>Results: </strong>We found that therapy induced micronuclei increased with the amount of radioactive iodine activity. There was a significant difference in the mean number of micronuclei in thyroid.</p><p><strong>Conclusion: </strong>Our results emphasize the need for ongoing monitoring of chromosomal damage in thyroid cancer patients to understand the long-term implications of radioactive iodine therapy. We anticipate that further research exploring the effects of treatment intervals on genetic stability and the potential risks of retreatment, may elucidate the true impact of this routinely used treatment on DNA damage, particularly in patients who may receive consecutive radioiodine therapies.</p>","PeriodicalId":519909,"journal":{"name":"EJNMMI reports","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13672718/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149198725","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":"Pregnancy testing prior to iodine-131 thyroid therapy: a literature review of current recommendations.","authors":"Stephen J Sozio, David Cohen, William Y Raynor, Jeffrey S Kempf","doi":"10.1186/s41824-026-00313-8","DOIUrl":"10.1186/s41824-026-00313-8","url":null,"abstract":"<p><strong>Purpose: </strong>Iodine-131 (I-131) thyroid ablation is strictly contraindicated during pregnancy due to the risk of fetal thyroid damage after 10 weeks of gestation. Current society guidelines lack consistency regarding the best timing and method for pregnancy testing. This review aims to consolidate current recommendations and propose a standardized testing algorithm.</p><p><strong>Methods: </strong>A literature review was conducted using the PubMed/MEDLINE database over a 55-year period to identify peer-reviewed publications on professional society guidelines for pre-radioiodine therapy pregnancy testing, as well as performance characteristics of serum and urine pregnancy tests.</p><p><strong>Results: </strong>Fetal susceptibility to radioiodine begins around 8-10 weeks of gestation. While serum hCG tests are approximately 2.5 times more sensitive than standard urine tests, they still have a \"biological window\" during which early pregnancy might be undetectable. Current guidelines differ on testing timelines, ranging from 24 to 72 h before therapy.</p><p><strong>Conclusion: </strong>Patients should be advised to abstain from sexual activity for at least two weeks before therapy and provide a written attestation on the day of treatment confirming they completed this abstinence period. Serum pregnancy testing is preferred because of its higher sensitivity and should be performed within 72 h prior to therapy, ideally within 24 h.</p>","PeriodicalId":519909,"journal":{"name":"EJNMMI reports","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13654911/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149169257","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":"Detection rate of PSMA PET MRI (18 F-Flotufolastat) at the onset of biochemical recurrence following radical prostatectomy.","authors":"Herbert Lepor, Hebert Alberto Vargas, Majlinda Tafa, James S Wysock, Wei Phin Tan, Madhur Nayan","doi":"10.1186/s41824-026-00325-4","DOIUrl":"10.1186/s41824-026-00325-4","url":null,"abstract":"<p><strong>Purpose: </strong>The optimal timing to obtain the initial PET-PSMA imaging study when disease recurrence is suspected following RP is controversial.</p><p><strong>Methods: </strong>24 subjects with new onset of BCR following RP were enrolled. The initial PET MRI (study #1) was performed within 2 months of signing informed consent. Salvage treatment was offered only if site(s) of disease recurrence were identified by study #1. A second PSMA PET MRI (study #2) was performed 1 year following Study 1, or sooner if the 6-month PSA was > 0.5 ng/ml. PET/MR was performed in a dedicated scanner which allows simultaneous acquisition of PET and MR images following the IV administration of 8 m Ci of ¹⁸F-Flotufolastat (18F-rH PSMA, Blue Earth Diagnostics, UK).</p><p><strong>Results: </strong>Disease recurrence was identified in 25% and 40% of subjects by study #1 and study #2, respectively. PSA doubling time with and without disease recurrence on study #2 was 12.8 months (IQR 4.0-17.2) and 20.8 months (20.8 months (IQR 9.1-51.7), respectively (p = 0.27). PSA prior to RP but not age, pathological grade, stage margin status or time to recurrence were significantly different between subjects with and without localization of disease recurrence.</p><p><strong>Conclusions: </strong>The 25% disease detection and localizations justify performing PSMA PET MRI imaging at the onset of BCR. If the initial PSMA PET MRI does not identify site(s) of disease, our study supports repeating a PSMA PET study when the PSA is > 0.5 ng/ml or if the PSA doubling time is < 1 year.</p><p><strong>Clinical trial record: </strong>The study is registered on ClinicalTrials.gov with study number NCT05678322.- Registration date 12/28/2022 URL of trial registry record: https://clinicaltrials.gov/study/NCT05678322.</p>","PeriodicalId":519909,"journal":{"name":"EJNMMI reports","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13650233/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149140096","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":"Glucagon-like peptide-1 receptor PET/CT in gastrinomas: a case series demonstrating the precise characterization to guide surgical and medical treatment.","authors":"Junyan Xu, Yun Liang, Jie Chen, Shaoli Song","doi":"10.1186/s41824-026-00320-9","DOIUrl":"10.1186/s41824-026-00320-9","url":null,"abstract":"<p><p>Gastrinoma is a rare type of neuroendocrine tumor with ectopic secretion of gastrin causing Zollinger-Ellison syndrome (ZES). Accurate localization of gastrinomas and their metastases is important for developing precise treatment strategies. We reported three cases of metastatic gastrinomas evaluated with ⁶⁸Ga-exendin-4 and ⁶⁸Ga-DOTANOC PET/CT. Despite most gastrinomas highly expressing somatostatin receptor (SSTR), these patients showed no or heterogeneous uptake on ⁶⁸Ga-DOTANOC PET/CT, whereas ⁶⁸Ga-exendin-4 PET/CT sensitively detected the primary tumor, lymph node metastasis, liver metastasis, and bone metastasis, facilitating accurate tumor assessment and supporting clinical decision-making. The findings were correlated with enhanced CT and MRI and confirmed the location of the hormone-related tumors. This highlights the potential utility of ⁶⁸Ga-exendin-4 PET/CT as a promising imaging modality for evaluating gastrinomas with no or heterogeneous SSTR expression and guiding precise treatment strategies.</p>","PeriodicalId":519909,"journal":{"name":"EJNMMI reports","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13638915/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149121869","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":"Infected von Meyenburg complex causing recurrent gram‑negative septicaemia: the critical diagnostic role of FDG‑PET/CT in a patient with hidradenitis suppurativa.","authors":"Chi Lai Ho, Sirong Chen, Yuet Hung Wong, Kwan Kit Wu, Yu Yip, Wai Chi Lin, Shing Kee Cheung","doi":"10.1186/s41824-026-00324-5","DOIUrl":"https://doi.org/10.1186/s41824-026-00324-5","url":null,"abstract":"<p><strong>Background: </strong>von Meyenburg complex (VMC) is a rare ductal plate malformation, typically presenting as asymptomatic benign intrahepatic biliary microhamartomas. However, when secondarily infected, VMC can become the source of cryptic recurrent septicaemia, posing a substantial diagnostic challenge, particularly in patients with a known history of chronic source of comorbid infection.</p><p><strong>Case presentation: </strong>A 73-year-old man with long-standing hidradenitis suppurativa presented with over ten episodes of recurrent gram-negative septicaemia. Extensive conventional imaging, including a ⁶⁷Gallium scintigraphy in another hospital, failed to identify an infectious source. Due to persistent diagnostic uncertainty, ¹⁸F-FDG PET/CT was performed. The scan revealed an enlarged liver with heterogeneously increased ¹⁸F-FDG uptake exhibiting an \"inverted pyramidal\" metabolic configuration: a wide base of activity along the subcapsular dome of superior hepatic segments converged centripetally towards the porta hepatis, thereby casting a tree-like three-dimensional anatomy of the biliary radicles. CT findings were non-specific, showing vaguely scattered mixed densities, greatly outnumbered by the hypermetabolic foci. Constellation of these findings suggests a non-dilated ductal infectious process, leading to the presumptive diagnosis of infected VMC with micro-abscesses. Subsequent MRI/MRCP confirmed numerous tiny T2‑weighted bright signals of varying sizes and intensities in agreement with the \"starry sky\" pattern of biliary hamartomas. Targeted levofloxacin therapy based on susceptibility testing resulted in resolution of fever and septic parameters. A follow-up ¹⁸F-FDG PET/CT scan three weeks after treatment demonstrated complete metabolic quiescence and resolution of previously documented intrahepatic hypermetabolic foci.</p><p><strong>Conclusion: </strong>¹⁸F-FDG PET/CT has proven value in investigation for fever of unknown origin. This case illustrates the value of this imaging not only in precise localization of the infectious source but also provides a suggestive metabolic pattern leading to the diagnosis of a rare congenital biliary condition, VMC, as a hidden source of infection otherwise masked by other comorbid infectious foci. Revealing the true source of loculated infection and its mechanism of spread leads to appropriate antibiotic therapy and treatment monitoring.</p>","PeriodicalId":519909,"journal":{"name":"EJNMMI reports","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13633229/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149121895","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":"Subtle hypometabolism on [¹⁸F]FDG-PET, yet absent [¹²³I]FP-CIT SPECT binding in a patient with spastic paraplegia type 7.","authors":"Dylan Henssen, Danique L M Radder, Anke H Snijders, Anne I J Arens","doi":"10.1186/s41824-026-00323-6","DOIUrl":"10.1186/s41824-026-00323-6","url":null,"abstract":"<p><p>Nuclear medicine neuroimaging is becoming increasingly important for the diagnosis and differential diagnosis of Parkinson's disease, atypical parkinsonian syndromes and more rare neurological (movement) disorders. We report on a 46-year-old woman presented with frequent falls, a gradually progressive bipyramidal syndrome with gait ataxia, dysphagia, urinary urgency and -incontinence, low mood with disturbed emotional regulation and a mild asymmetric hypokinetic rigid syndrome. Additionally, she had a blurry vision, asymmetrical ptosis and abnormal vertical saccades. [¹⁸F]FDG PET/CT of the brain showed unspecific pattern of regional cortical hypometabolism and, more pronounced, striatal hypometabolism. [¹²³I]FP-CIT SPECT showed a complete absence of on-target binding. Subsequent genetic testing revealed two variants in SPG7. The patient showed a modest favourable response on levodopa. This case illustrates profound neurodegeneration of the presynaptic dopaminergic nigrostriatal neurons in SPG7.</p>","PeriodicalId":519909,"journal":{"name":"EJNMMI reports","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13620053/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149077090","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":"Future scenarios of radioligand therapy in pheochromocytomas and paragangliomas.","authors":"S Pacella, F Elisei, M V Mattoli, L S Airò Farulla, G Aliberti, A Rizzo, M Maccauro","doi":"10.1186/s41824-026-00318-3","DOIUrl":"10.1186/s41824-026-00318-3","url":null,"abstract":"<p><strong>Background: </strong>Pheochromocytomas and paragangliomas (PPGL) are rare and heterogeneous neuroendocrine tumors for which therapeutic options remain limited, particularly in the metastatic or progressive setting. Radioligand therapy (RLT) has emerged as a promising strategy, leveraging tumor-specific molecular targets to deliver cytotoxic radiation.</p><p><strong>Objective: </strong>This review provides a structured and updated overview of RLT in PPGL, critically comparing the two main therapeutic radiopharmaceuticals-[¹³¹I]mIBG and [¹⁷⁷Lu]Lu DOTATATE-and discussing their clinical evidence, safety profiles, patient selection criteria, and positioning within current guidelines. Emerging approaches, including alpha emitter-based therapies and novel theranostic targets, are also explored.</p><p><strong>Methods: </strong>A comprehensive literature search was conducted across PubMed, Scopus, and Web of Science (updated to August 2024), focusing on studies evaluating RLT in PPGL. Due to heterogeneity in study design, protocols, and outcome measures, a metaanalysis was not feasible.</p><p><strong>Results: </strong>Evidence derives predominantly from small retrospective studies and a limited number of prospective cohorts. Both [¹³¹ I]mIBG and [¹⁷⁷ Lu]LuDOTATATE demonstrate favorable safety profiles and high disease control rates, although with substantial variability in protocols and patient populations. Comparative analyses suggest longer progressionfree survival with PRRT in selected patients, particularly those with high somatostatin receptor expression.</p><p><strong>Conclusions: </strong>RLT represents a valuable therapeutic option for patients with progressive or symptomatic PPGL. Advances in molecular imaging, alphaemitter therapies, and personalized dosimetry are expected to further refine treatment selection and improve outcomes. Larger prospective studies are needed to define optimal sequencing and integration into clinical practice.</p>","PeriodicalId":519909,"journal":{"name":"EJNMMI reports","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13590459/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149013531","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":"Cannabinoid type 1 receptor availability imaging in attention-deficit/hyperactivity disorder using [¹⁸F]MK-9470 positron emission tomography: study protocol of the CB1-ADHD study.","authors":"Isabelle Miederer, Marina Louise Schofer, Christian Ruckes, Wolfgang Retz, Mathias Schreckenberger, Alexandra Sebastian","doi":"10.1186/s41824-026-00322-7","DOIUrl":"10.1186/s41824-026-00322-7","url":null,"abstract":"<p><strong>Background: </strong>Attention deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by attentional deficits, hyperactivity and impulsivity that often persists into adulthood. While dysfunction of dopaminergic neurotransmitter systems has been observed, underlying mechanisms remain incompletely understood. Current treatments with methylphenidate and amphetamines show limited long-term effectiveness and do not address broader clinical needs. The endocannabinoid system represents a promising therapeutic target. Cannabinoid type 1 (CB1) receptors are highly concentrated in the prefrontal cortex and striatum, brain regions central to ADHD pathophysiology. The \"dual pathway model of ADHD\" describes deficits in inhibition-related executive functions and reward-related functions, both mediated by fronto-striatal networks. Striatal CB1 receptor availability correlates negatively with impulsivity. Given the interaction between dopaminergic and endocannabinoid systems, CB1 receptors may play a key role in ADHD pathogenesis.</p><p><strong>Methods: </strong>This controlled study will investigate CB1 receptor availability in ADHD using positron emission tomography (PET) with the CB1-selective radiotracer [¹⁸F]MK-9470. The primary outcome is the CB1 receptor distribution volume (V_T) in the striatum. Secondary outcomes include CB1 receptor availability in prefrontal cortex and other ADHD-relevant brain regions, plasma concentrations of endocannabinoids (anandamide, 2-arachidonoylglycerol), and validated neuropsychological assessments of attention and impulsivity. We will compare three groups (n = 34 each): medication-naïve participants with ADHD, methylphenidate-treated participants with ADHD, and healthy controls. Statistical analysis will employ ANOVA with post-hoc comparisons and correlation analyses between neuroimaging and behavioral measures.</p><p><strong>Results: </strong>N/A, as this is a study protocol.</p><p><strong>Conclusions: </strong>This first investigation of the endocannabinoid system in ADHD will provide crucial insights into disease mechanisms and identify potential therapeutic targets. Results may inform development of novel cannabinoid-based treatments and improve evidence-based therapeutic strategies for ADHD management.</p><p><strong>Trial registration: </strong>German Clinical Trials Register (DRKS-ID: DRKS00037526, Registration date: 25 September 2025).</p>","PeriodicalId":519909,"journal":{"name":"EJNMMI reports","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13569728/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148957747","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}