EJNMMI Research最新文献

Background: Although molecular tumor-targeting peptides modified with albumin-binding domains can enhance tumor probe uptake and prolong tumor retention time, the prolonged systemic circulation resulting from this modification also increases radiation exposure to normal tissues. This study aims to validate that peptide nucleic acid (PNA)-mediated pretargeted ¹⁶¹Tb radionuclide therapy can slow tumor growth and reduce systemic radiation exposure.

Results: ⁶⁸Ga-EB-RGD, ⁶⁸Ga-cPNA-PNA-EB-RGD, ¹⁶¹Tb-EB-RGD, and ¹⁶¹Tb-cPNA-PNA-EB-RGD all demonstrated labeling efficiencies exceeding 80% and exhibited high stability in phosphate-buffered saline. ¹⁶¹Tb-EB-RGD and ¹⁶¹Tb-cPNA-PNA-EB-RGD showed comparable tumor cell uptake and apoptosis induction (0.95-fold). The binding capability between the pretargeting receptor PNA-EB-RGD and the ligand cPNA reached 80%. The blood biodistribution of the pretargeting group (¹⁶¹Tb-cPNA-PNA-EB-RGD) was 32-fold lower than that of the conventional group (¹⁶¹Tb-EB-RGD) (0.37 ± 0.05%ID/g vs. 11.93 ± 0.62%ID/g, P < 0.05). The biodistribution of ¹⁶¹Tb-EB-RGD and ¹⁶¹Tb-cPNA-PNA-EB-RGD in 4T1 tumor cells was 8.77 ± 0.16%ID/g and 3.86 ± 0.21%ID/g, respectively. The conventional treatment group (¹⁶¹Tb-EB-RGD) showed superior therapeutic efficacy compared to the pretargeting group (¹⁶¹Tb-cPNA-PNA-EB-RGD), which in turn outperformed the control group (345.09 ± 4.93 vs. 100.76 ± 12.20 vs. 183.02 ± 12.94 mm³, P < 0.05). No significant pathological changes were detected in the vital organs of treated animals. Ex vivo tumor analysis supported the treatment trends.

Conclusions: Compared to conventional non-pretargeted radionuclide therapy, PNA-based pretargeted ¹⁶¹Tb radionuclide therapy reduced systemic radiation exposure, significantly decreased hematotoxicity, and suppressed tumor growth in tumor-bearing mice.

Background: Graves' ophthalmopathy (GO) is a challenging autoimmune manifestation of Graves' disease, whose management relies on accurate assessment of inflammatory activity in the extraocular muscles (EOMs). The Clinical Activity Score (CAS), the current gold standard for assessing disease activity, is based on subjective clinical signs. Consequently, objective imaging biomarkers are urgently needed as a complement orbital ^99mTc-DTPA SPECT/CT imaging holds potential, but its quantitative methodology lacks standardization. This study aimed to evaluate the utility of four SPECT/CT-derived quantitative indices for quantifying EOM inflammatory activity in GO.

Results: Group Differences: EOM uptake values for all four indices were significantly higher in the active GO group than in both the inactive and control groups (all P ＜ 0.001). No significant differences were found between the inactive and control groups.

Clinical correlation: All quantitative parameters showed significant positive correlations with the CAS (all p ＜ 0.001).

Diagnostic performance: ROC curve analysis confirmed that all indices effectively differentiated active from inactive GO, with SUV_mean yielding the superior diagnostic efficacy (AUC = 0.887).

Conclusions: In summary, this study confirms that quantitative indices from orbital ^99mTc-DTPA SPECT/CT, particularly SUV_mean-3D, effectively quantify EOMs inflammatory activity in GO. Parameters derived using CT-based 3D VOI delineation (SUV_mean-3D and SUV_max-3D) demonstrated superior reliability over traditional methods. Among all indices, SUV_mean-3D demonstrated superior diagnostic efficacy (AUC = 0.887) for differentiating active from inactive disease. These indices provide an objective tool for quantifying GO severity and monitoring disease changes during patient follow-up. This capability is vital for monitoring treatment response, guiding therapeutic decisions, and serving as a potential endpoint in clinical trials.

Background: [¹⁸F]F-FDG PET/CT is an established imaging modality for diagnosing cardiac sarcoidosis (CS). While a 90-minute uptake time is commonly recommended to enhance target-to-background ratio, its added diagnostic value remains unclear. This study aimed to compare the diagnostic performance of 60-minute versus 90-minute uptake times. Eighty-seven patients (45 females, 42 males) with suspected CS underwent whole-body FDG PET/CT at 60 min post-injection (p.i.), followed by an additional chest scan at 90 min p.i. Patient preparation included a low-carbohydrate diet, prolonged fasting, and weight-based heparin administration. Three blinded readers with varying experience independently assessed the scans using binary classification for typical sarcoidosis-related FDG uptake, provided adequate myocardial glucose suppression was achieved. Inter- and intrarater agreement were analyzed using Fleiss' and Cohen's κ, respectively. Diagnostic accuracy was determined by majority vote, using Japanese Circulation Society (JCS) criteria as the reference standard.

Results: Interrater agreement was substantial (Fleiss' κ = 0.690-0.693), and intrarater agreement ranged from substantial to almost perfect (Cohen's κ = 0.703-0.899). Among patients with sufficient myocardial suppression, diagnostic accuracy was 97% (n = 62) at 60 min and 92% (n = 65) at 90 min. No statistically significant differences were observed between the two time points (p = 0.22).

Conclusion: FDG PET/CT with a 60-minute uptake time offers diagnostic accuracy comparable to that of a 90-minute uptake for CS detection, provided adequate myocardial suppression is achieved. Shorter uptake protocols may streamline workflow and improve patient comfort without compromising diagnostic integrity.

Background: Hyperparathyroidism-jaw tumor (HPT-JT) syndrome is a rare autosomal dominant disorder caused by CDC73 gene mutations, predisposing individuals to primary hyperparathyroidism (pHPT), cemento-ossifying fibromas, and other neoplastic conditions. [18F]Fluorocholine PET/CT has emerged as a tool for localizing hyperfunctioning parathyroid glands in pHPT, but its application in HPT-JT syndrome remains unreported.

Case presentation: We describe the case of a 15-year-old male presenting with severe hypercalcemia, increased PTH serum levels, and a history of cemento-ossifying fibroma removal. Standard imaging, including [99mTc]Tc-MIBI scintigraphy, was inconclusive. [18F]Fluorocholine PET/CT successfully identified a hyperfunctioning parathyroid gland, identified as parathyroid atypical adenoma at subsequent histology, and a recurrent maxillary cemento-ossifying fibroma. Genetic testing confirmed a CDC73 mutation, leading to the diagnosis of HPT-JT syndrome.

Conclusions: To our knowledge, this is the first reported case utilizing [18F]Fluorocholine PET/CT for the evaluation and management of HPT-JT syndrome with active presence of a maxillary cemento-ossifying fibroma. Given its superior sensitivity compared to conventional imaging, [18F]Fluorocholine PET/CT provided critical information for surgical planning and it might be a useful diagnostic tool for long-term disease monitoring. This case highlights the potential role of [18F]Fluorocholine PET/CT in detecting both parathyroid and jaw manifestations of HPT-JT syndrome, emphasizing the need for further research into its application in hereditary endocrine disorders.