18F-GP1 is a novel positron emission tomography (PET) tracer that targets glycoprotein IIb/IIIa receptors on activated platelets. The study objective was to explore the feasibility of directly imaging acute arterial thrombosis (AAT) with 18F-GP1 PET/computed tomography (PET/CT) and to quantitatively assess 18F-GP1 uptake. Safety, biodistribution, pharmacokinetics and metabolism were also evaluated. Adult patients who had signs or symptoms of AAT or had recently undergone arterial intervention or surgery within 14 days prior to 18F-GP1 PET/CT were eligible for inclusion. The AAT focus was demonstrated by conventional imaging within the 5 days prior to 18F-GP1 administration. Whole-body dynamic 18F-GP1 PET/CT images were acquired for up to 140 min after injection of 250 MBq of 18F-GP1. Venous plasma samples were analysed to determine 18F-GP1 clearance and metabolite formation. Among the ten eligible patients assessed, underlying diseases were abdominal aortic aneurysm with endovascular repair (n = 6), bypass surgery and stent placement (n = 1), endarterectomy (n = 1), arterial dissection (n = 1) and acute cerebral infarction (n = 1). 18F-GP1 administration and PET/CT procedures were well tolerated, with no drug-related adverse events. All patients showed high initial 18F-GP1 uptake in the spleen, kidney and blood pool, followed by rapid clearance. Unmetabolised plasma 18F-GP1 levels peaked at 4 min post-injection and decreased over time until 120 min. The overall image quality was sufficient for diagnosis in all patients and AAT foci were detected in all participants. The 18F-GP1 uptake in AAT foci remained constant from 7 min after injection and began to separate from the blood pool after 20 min. The median standardised uptake value of AAT was 5.0 (range 2.4–7.9) at 120 min post-injection. The median ratio of standardised uptake value of AAT foci to the mean blood pool activity was 3.4 (range 2.0–6.3) at 120 min. 18F-GP1 is a safe and promising novel PET tracer for imaging AAT with a favourable biodistribution and pharmacokinetic profile. ClinicalTrials.gov identifier: NCT02864810 , Registered August 3, 2016.

Patients with inflammatory bowel disease (IBD) are usually hospitalized because of aggravated gastrointestinal symptoms. Many clinicians empirically advise these patients to fast once they are admitted. However, there has been no evidence that maintaining a complete bowel rest improves the disease course. Therefore, we aimed to investigate the effects of fasting on disease course in admitted patients with IBD or intestinal Behçet's disease. A total of 222 patients with IBD or intestinal Behçet's disease, who were admitted for disease-related symptoms, were retrospectively analyzed. We divided them into 2 groups: fasting group (allowed to take sips of water but no food at the time of admission) and dietary group (received liquid, soft, or general diet). On admission, 124 patients (55.9%) started fasting and 98 patients (44.1%) started diet immediately. Among patients hospitalized through the emergency room, a significantly higher proportion underwent fasting (63.7% vs. 21.4%, P<0.001); however, 96.0% of the patients experienced dietary changes. Corticosteroid use (P<0.001; hazard ratio, 2.445; 95% confidence interval, 1.506-3.969) was significantly associated with a reduction in the disease activity score, although there was no significant difference between the fasting group and the dietary group in disease activity reduction (P=0.111) on multivariate analysis. In terms of disease activity reduction, there was no significant difference between the fasting and dietary groups in admitted patients with IBD, suggesting that imprudent fasting is not helpful in improving the disease course. Therefore, peroral diet should not be avoided unless not tolerated by the patient.

Primary bone tumors encompass a heterogeneous spectrum ranging from benign entities to highly aggressive sarcomas. This review aims to summarize the current role and future perspectives of nuclear medicine in the diagnosis, staging, and management of primary bone tumors. Accurate diagnosis and staging are critical yet challenging due to histologic heterogeneity and overlapping imaging features. While radiographs, computed tomography (CT), and magnetic resonance imaging (MRI) remain essential, nuclear medicine provides a complementary functional perspective by assessing bone turnover, vascularity, and glucose metabolism. Bone scintigraphy is highly sensitive for skeletal lesions and useful for detecting skip lesions or multifocal disease, although its specificity is limited. Hybrid single-photon emission computed tomography (SPECT)/CT enhances diagnostic confidence through precise anatomic localization and quantitation. [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography (PET)/CT, by directly visualizing tumor metabolism, has become a cornerstone in osteosarcoma and Ewing sarcoma management, demonstrating superiority over bone scintigraphy for detecting skeletal metastases. In chondrosarcoma, [¹⁸F]FDG uptake correlates with histologic grade, although overlap with benign cartilage tumors complicates interpretation. Future directions include the integration of quantitative SPECT, artificial intelligence, and novel tracers such as [¹⁸F]sodium fluoride and [⁶⁸Ga]Ga-fibroblast activation protein inhibitor (FAPI). Collectively, nuclear medicine imaging is becoming a key element in musculoskeletal oncology, offering unique biological insights that complement anatomic imaging and contribute to improved patient management.

Objectives: This study aimed to evaluate the consistency of Centiloid (CL) values calculated using three commercially available software platforms: BTXBrain (v1.1.2), MIM (v7.3.7), and SCALE PET (v2.0.1). Methods: A total of 239 patients who underwent amyloid PET/CT with either F-18 flutemetamol (FMM) or F-18 florbetaben (FBB) were retrospectively analyzed. CL values were calculated using BTXBrain, MIM, and SCALE PET. Linear regression, Passing–Bablok regression, and Bland–Altman analysis were performed to assess the agreement between CL values. Subgroup analyses were conducted for each radiotracer. CL values were compared according to visual interpretation status. Results: Strong correlations were observed between CL values derived from the three software platforms (R² > 0.95). However, Passing–Bablok regression revealed significant proportional bias, with CL values from BTXBrain being lower than others, and CL values from SCALE PET being higher than others as CL values increased. Bland–Altman plots visualized the proportional bias, particularly between BTXBrain and SCALE PET. Subgroup analyses by radiotracer showed similar results. CL values in visually positive scans were significantly higher than those in visually negative scans across all platforms. Conclusions: The three commercial software programs demonstrated high consistency in CL quantification. However, a notable systematic bias was observed. Further evaluation of various scanner effects and CL calculation methods is warranted to improve the consistency and reproducibility of CL quantification in clinical practice.