To characterize the systemic and organ-specific pharmacokinetics (PK) of a novel bis-boron tracer, [18F]BBPA, using total-body PET imaging in comparison with conventional blood sampling. Ten healthy volunteers underwent 60-minute dynamic total-body [18F]BBPA PET, followed by three static scans (up to 240 min p.i.), alongside 11 venous blood sampling. Regions of interest were drawn on PET in their right atrium, superior vena cava (SVC), and inferior vena cava (IVC) to obtain image-derived blood time-activity curves (TACs), as well as in major organs to obtain tissue TACs. PK parameters of [18F]BBPA were assessed using both blood samples and image-derived blood TACs. Additionally, tissue TACs were analyzed for organ-specific PK and fitted with an tissue-compartment models for kinetic rates of [18F]BBPA. [18F]BBPA exhibited rapid clearance (6.58 ± 0.57 L/h, a short elimination half-life (186.48 ± 30.29 min), and a volume of distribution of 29.22 ± 3.52 L. Image-derived PK results were comparable to those obtained from blood sampling, with the relative differences < 13 www.chinadrugtrials.org.cn (CTR20233997).

To investigate the association of amygdalar activity with disease activity, inflammatory markers, cerebrovascular events, and structural vascular injury in patients with Takayasu arteritis (TAK). A total of 303 TAK patients underwent 18F-fluorodexoyglucose positron emission tomography/computed tomography (¹⁸F-PET/CT). Amygdalar, bone marrow, and vessel wall SUV were quantified. Clinical, laboratory, and imaging data were collected. The median follow-up duration was 27 months, during which adverse events were recorded. No significant association was found between amygdalar SUV and cerebrovascular events in the overall cohort. However, among treatment-naïve patients, those with cerebrovascular events had significantly lower amygdalar SUVmax (9.3±2.0 v.s. 10.3±2.0, p=0.011) and SUVmean (6.6±1.2 v.s. 7.4±1.5, p=0.003) than event-free patients. The low SUV group had a higher proportion of cerebrovascular events (24.3

Abstract Background Myocardial bridging (MB) is often considered a benign anatomical variant, yet deep or long bridges can result in dynamic coronary compression and ischemia. In rare instances, MB may lead to myocardial infarction with nonobstructive coronary arteries (MINOCA), posing a diagnostic challenge. Case summary We report the case of a 59-year-old man who presented with chest pain and elevated cardiac troponin following exertion. Coronary angiography showed no obstructive coronary artery disease but revealed a myocardial bridge in the mid-left anterior descending (LAD) artery with complete systolic compression. Intravascular ultrasound (IVUS) confirmed the presence of MB without underlying atherosclerosis. Functional assessment using resting full-cycle ratio (RFR) demonstrated a value of 0.91. Single-photon emission computed tomography (SPECT) revealed no perfusion defects, supporting the absence of significant ischemia. The patient was diagnosed with MINOCA secondary to myocardial bridging and treated conservatively with beta-blockers. He remained free of recurrent myocardial infarction and the exertional chest pain was markedly improved. Discussion This case highlights the potential of severe MB to cause infarction in the absence of fixed coronary lesions. It also underscores the diagnostic utility of RFR in assessing MB physiology and its concordance with perfusion imaging.

Lutetium-177(177Lu)-prostate specific membrane antigen(PSMA)-617 is a small-molecule radioligand therapy(RLT)drug targeting PSMA.By selectively delivering the β-radiation emitted by 177Lu to PSMA-positive prostate cancer cells,it induces tumor cell death.The agent has been approved in multiple nations and regions for the treatment of PSMA-positive metastatic castration-resistant prostate cancer,thereby expanding therapeutic options for this patient population.This review outlines the development,pharmacological properties,and current clinical applications of 177Lu-PSMA-617,aiming to provide a theoretical basis for the clinical practice of RLT in prostate cancer treatment.

Objective To explore the feasibility and image quality of respiratory-gated total-body 18F-FDG PET/CT imaging with a 4-minute acquisition in patients with malignant tumors.Methods Sixty-two patients with pathologically confirmed malignant tumors(118 lesions measured)who underwent total-body 18F-FDG PET/CT examination were consecutively enrolled at the Department of Nuclear Medicine,Zhongshan Hospital,Fudan University,from September 23,2021 to November 23,2021,and their clinical and imaging data were retrospectively collected.PET data was acquired over 12 minutes with simultaneous respiratory waveform recorded.The data were reconstructed into four image sets:gated-12 group and gated-4 group(using all counts and the first 4-minute counts,respectively)and ungated-12 group and ungated-6 group(using all counts and the first 6-minute counts,respectively)reconstructed with respiratory gating that retained counts corresponding to the half respiratory window near end-expiration.Image quality assessment and quantitative analysis of lesions were performed and compared among the four image sets,and subgroup analyses were performed according to lesion location,size,and metabolic activity.Results The effective counts of 4 sets of PET images were highest in ungated-12 group,followed by ungated-6 group and gated-12 group,and lowest in gated-4 group(P＜0.001).Regardless of the metabolic level and size of the lesions,compared with the ungated-12 group and the ungated-6 group,the lesions in the gated-12 group showed higher maximum,average,and peak standardized uptake values(SUVmax,SUVmean,and SUVpeak),tumor liver uptake ratio,tumor blood pool uptake ratio,and smaller metabolic volume(P＜0.05);There was no statistically significant difference in the above indicators between the gate-12 group and the gate-4 group.The background noise of gate-4 group images is slightly higher than that of gate-12 group images(Liver SUVSD:[0.17+0.05]vs[0.14+0.04]);Blood pool SUVSD:(0.08±0.03)vs(0.06±0.03).There was a statistically significant difference in subjective scores of PET image quality among the four groups(P＜0.001).The subjective scores of image quality in the gated-12 group(4.79±0.41)were not significantly different from those in the non gated-12 group(4.97±0.17)and non gated-6 group(4.79±0.45),but were higher than those in the gated-4 group([4.17±0.45],P＜0.001),And the scores have good consistency(Kappa＞0.75).Conclusion In total-body PET/CT imaging for malignant tumors,4-minute respiratory-gated acquisition can achieve comparable quantitative performance to longer respiratory gating imaging while significantly shortening acquisition time.This approach demonstrates promising potential for clinical application.

To investigate the feasibility of 2-h-delayed total-body [18F]FDG PET/CT for detecting vascular inflammation after concurrent chemoradiotherapy (CCRT) in head-and-neck-cancer (HNC) patients and to exploratorily assess its association with cardiovascular-related events (CVRE). Twenty-four HNC patients underwent 2-h total-body [18F]FDG PET/CT before and 3 months after CCRT and were followed for CVRE. Vascular inflammation was evaluated across eleven arterial segments. Slice-based mean standardized uptake values (SUVmean) were normalized to the superior vena cava (SVC) to derive the target-to-background ratio (TBRmean), and segmental averages (avgTBRmean) were calculated. Pre- and post-CCRT avgTBRmean were compared, and the relative difference (RD-avgTBRmean) was analyzed for association with radiation dose and CVRE. Post-CCRT PET demonstrated increased avgTBRmean in all arterial segments, with significant increases in the carotid arteries (left: 1.32 vs 1.20, P < 0.001; right: 1.34 vs 1.24, P = 0.018), subclavian arteries (left: 1.20 vs 1.14, P = 0.022; right: 1.18 vs 1.10, P = 0.019), and infrarenal abdominal aorta (1.08 vs 0.96, P < 0.001). Mean radiotherapy dose correlated with both post-CCRT avgTBRmean (r = 0.289, P = 0.002) and RD-avgTBRmean (r = 0.251, P = 0.008). Patient-based average RD-avgTBRmean was higher in patients with CVRE (12.1

To investigate the feasibility of early dynamic 2-[18F]-fluoro-2-deoxy-d-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) imaging in predicting epidermal growth factor receptor (EGFR) and tumor protein 53 (TP53) mutation status in lung adenocarcinoma (AC). In total, 81 patients with lung nodules underwent early dynamic PET (10 min after injection) and late static PET (60 min after injection), and 41 (18 male, 23 female; mean age 64 ± 10 years) with confirmed AC were included in the final analysis. Dynamic images were reconstructed into 25 frames, and time-to-activity curves were generated. An irreversible two-tissue compartment model was used to derive kinetic parameters (K1, k2, k3, Ki, and MRFDG). EGFR and TP53 mutation statuses were determined via histological analysis. Statistical tests, including the Wilcoxon rank-sum test, Kruskal–Wallis H test, and Spearman’s correlation, were used to assess differences and associations among groups. Receiver operating characteristic (ROC) curve analysis was conducted to evaluate the predictive performance. In patients with AC, k3, Ki, and MRFDG were strongly correlated with SUVmax (r = 0.821, 0.862, and 0.778, respectively; all P < 0.001). SUVmax, k3, Ki, and MRFDG differed significantly between patients with AC and SCC, as well as across TNM and pathological stage subgroups (P < 0.05). SUVmax and k3 were significantly lower in the EGFR-positive group, while Ki was higher in the TP53-positive group (P < 0.05). AUCs for predicting EGFR mutation were 0.718 (SUVmax) and 0.776 (k3), and 0.703 (Ki) for TP53 mutation. Early dynamic 18F-FDG PET/CT may serve as a valuable non-invasive tool for predicting EGFR and TP53 mutation status in AC, for screening patients for targeted therapy.

The study aims to maximize clinical scan efficiency for Total-body (TB) 18F-FDG PET/CT systems by optimizing scan strategies based on theoretical models and clinical experience from a single center. This prospective study include two parts. The first part involved simulation experiments using theoretical models to maximize patient throughput and/or minimizing radiotracer activity across four clinical scanning scenarios: fixed working time, predetermined radiotracer activity, integration of various injection activity regimens for a fixed number of patients, and incorporation of dynamic scans into routine static scans within a fixed working time. The optimal scan strategies for these scenarios were then proposed. The second part validated the estimated throughput results through high-throughput tests performed in the real clinical settings with an fixed working time of 8 h. Under a fixed working time of 8 h, the theoretical patient throughput for full-activity, half-activity, 1/3-activity, and 1/10-activity injection regimens was 60, 48, 43, 30 patients, respectively. The corresponding real clinical throughput achieved was 60, 49, 48, 28 patients. For a total 18F-FDG activity of 37,000 to 148,000 MBq (1 to 4 Ci), the 1/3-activity injection regimen yielded the highest patient throughput, ranging 52 to 72 patients. Strategically combining various injection activity regimens could reduce radiotracer activity consumption. Additionally, placing full-activity dynamic scans after routine static scans for full-activity, half-activity, and 1/3-activity, and before 1/10 activity, proved to ba more economical strategies. Optimized scan strategies for typical clinical scenarios of TB 18F-FDG PET/CT systems were proposed, which could promote clinical scan efficiency and accommodate diverse clinical requirements. These strategies enable centers to balance throughput and activity efficiency while maintaining diagnostic quality.

This study explored a hybrid curve-fitting method optimized for radiation dosimetry evaluation in total-body dynamic positron emission tomography/computed tomography (PET/CT) imaging, compared to conventional methods reliant on multi-time-point static acquisition protocols, and evaluated the radiation dosimetry results and organ biodistribution of [68Ga]Ga-NOTA-SNA002. A total of 16 patients with solid tumors underwent a 60-min dynamic PET acquisition immediately after administration of [68Ga]Ga-NOTA-SNA002, followed by a 20-min static PET scan at about 120 min post-injection. Volumes of interest (VOIs) were manually delineated on the CT images for subsequent radiation dosimetry estimation and biodistribution analysis. Two datasets were created to generate organ time-activity curves (TACs): (1) two PET frames reconstructed at 15–35 min and 40–60 min from the dynamic PET dataset, and one frame from static PET acquisition, thereby simulating a conventional multi-time-point static protocol; (2) 55 frames from the dynamic PET dataset and a frame from static PET. To calculate the time-integrated activity coefficients (TIACs) for the tracer in source organs, two methods were used: a routine method (RM) that fitted Dataset 1 by using a conventional bi-exponential curve fitting approach, and a hybrid method (HM) that fitted Dataset 2 by combining rectangular integration for the early phase of TACs with exponential fitting for the later phase. Absorbed and effective radiation doses were subsequently estimated using OLINDA/EXM version 1.1. The [68Ga]Ga-NOTA-SNA002 primarily accumulated in the urinary system, with relatively low overall uptake levels in other source organs. Analysis of tumor-to-organ standardized uptake value (SUV) ratios revealed that all ratios reached their highest values at 120 min post-injection. The TIACs derived from the HM were consistently higher than those obtained using the RM method, while preserving a similar rank order of distribution across organs. In both methods, the kidneys, liver, and lungs exhibited the largest TIACs. The bladder wall, kidneys, and spleen received the highest absorbed doses. The total effective dosimetry calculated with RM and HM were 20.47 ± 3.08 µSv/MBq and 36.33 ± 6.18 µSv/MBq, respectively. The radiation dosimetry results obtained from both the RM and the HM consistently support the safety and feasibility of total-body PET/CT imaging using [68Ga]Ga-NOTA-SNA002. Meanwhile, the HM provides theoretically more accurate results compared to the RM, and is therefore recommended for radiation dosimetry evaluation of other novel tracers.

Background:It remains unclear how rapidly the collateral circulation regresses after percutaneous coronary intervention (PCI) of chronic total occlusion (CTO). This study aimed to investigate the short-term changes of myocardial perfusion in the predominant donor vessel after successful CTO PCI. Methods:A total of 68 patients who underwent single-photon emission computerized tomography (SPECT) assessment before and within 24-72 hours after successful CTO PCI were retrospectively included into this study. The coronary flow reserve (CFR) in the CTO territory and the predominant donor vessel territory were analyzed. Results:The average age of the included patients was 57.1±12.5 years old, and 88.2% were male. In the CTO territory, the CFR increased from 1.80±0.99 at baseline to 2.13±1.02 after PCI (P=0.018). In the predominant donor territory, the CFR at baseline did not significantly differ from that of after PCI (baseline: 2.12±1.09; after-PCI: 2.27±0.78; P=0.214). However, the change in CFR (ΔCFR) of the predominant donor territory was correlated with that in the CTO territory (P<0.001). The target vessel of CTO [left anterior descending artery (LAD) vs. left circumflex artery (LCX); P=0.022] and diabetes mellitus (P=0.011) were other independent factors associated with ΔCFR in the predominant donor territory. In the those treated with CTO of the LAD, CFR in the predominant donor territory increased from 1.65±0.61 at baseline to 2.30±0.75 after PCI (P=0.003). In contrast, no significant ΔCFR was not observed in those treated with CTO of the LCX or right coronary artery (RCA). Conclusions:The myocardial perfusion in the predominant donor territory was positively associated with that in the CTO territory. The myocardial perfusion in the predominant donor territory increased within a short-term period after CTO PCI, specifically in those patients with CTO of the LAD.

To explore the feasibility of a low-dose 18F-FDG protocol for the 30-cm standard axial field of view (SAFOV) PET/CT imaging in pediatric patients. A retrospective analysis was conducted on 112 pediatric patients who underwent a full-dose (3.7 MBq/kg) 18F-FDG PET/CT imaging, and a prospective analysis was performed on 55 patients who received a low-dose (2.5 MBq/kg) imaging. PET images were reconstructed at 1.0-min/bed intervals, and labeled as G1.0, G2.0, G3.0 for the full-dose imaging and G1.0', G2.0', G3.0' for the low-dose imaging. Patients were categorized into three age groups, and the image quality was assessed using the Likert scale and signal-to-noise ratio (SNR); Lesion detectability was evaluated using lesion detection rates and the target-to-liver ratio (TLR). In G2.0 and G3.0, all cases (112/112) achieved an image score of ≥ 3 and a lesion detection rate of 100

The translocator protein (TSPO) positron emission tomography (PET) can noninvasively detect neuroinflammation associated with epileptogenesis and epilepsy. This study explored the role of the TSPO-targeting radioligand [18F]F-TFQC, an m-trifluoromethyl ER176 analog, in the PET neuroimaging of epileptic rats. Initially, [18F]F-TFQC was synthesized with a radiochemical yield of 8%–10% (EOS), a radiochemical purity of over 99%, and a specific activity of 38.21 ± 1.73 MBq/nmol (EOS). After determining that [18F]F-TFQC exhibited good biochemical properties, [18F]F-TFQC PET neuroimaging was performed in epileptic rats at multiple time points in various stages of disease progression. PET imaging showed specific [18F]F-TFQC uptake in the right hippocampus (KA-injected site, i.e., epileptogenic zone), which was most pronounced at 1 week (T/NT 1.63 ± 0.21) and 1 month (T/NT 1.66 ± 0.20). The PET results were further validated using autoradiography and pathological analysis. Thus, [18F]F-TFQC can reflect the TSPO levels and localize the epileptogenic zone, thereby offering the potential for monitoring neuroinflammation and guiding anti-inflammatory treatment in patients with epilepsy.

Background:Apoptosis plays a critical role in the development and progression of atherosclerotic plaques. [18F] fluoride 2-(5-fluoro-pentyl)-2-methylmalonic acid (18F-ML-10), a positron emission tomography (PET) radiotracer, selectively targets cells undergoing apoptosis by binding to apoptosis-associated membrane alterations. This study evaluated the efficacy of 18F-ML-10 PET/computed tomography (CT) in visualizing apoptotic activity in atherosclerotic plaques. Methods:Apolipoprotein E knockout (ApoE-/-) mice were fed a high-fat diet to induce atherosclerosis, and imaged at 20 and 32 weeks, with C57BL/6J (C57) mice serving as controls. 18F-ML-10 was synthesized using a standard conjugation protocol and subsequently used for the in-vivo PET/CT imaging of the atherosclerotic plaques in this animal model. Oil-red-O staining, hematoxylin and eosin (H&E) staining, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL), and caspase-3 staining were performed to evaluate the deposition of lipids and amount of apoptosis in the lesions where focal intensity was positively correlated with the uptake of 18F-ML-10. Results:18F-ML-10 was synthesized with a high radiochemical purity (>99%), a quick clearance rate, and a favorable biodistribution. In the 18F-ML-10 PET/CT imaging, the plaque-to-background (P/B) ratio of the ApoE-/- mice at 32 weeks was significantly higher than that of the ApoE-/- mice at 20 weeks. Specifically, the P/B ratio values of the ApoE-/- mice were 2.28±0.20 at 32 weeks, and 1.69±0.22 at 20 weeks (P=0.002, n=5). No plaque was found in the PET images of the control mice. Further, oil-red-O staining revealed a significant increase in lipid deposition in the ApoE-/- mice from 20 to 32 weeks, which was consistent with the 18F-ML-10 PET/CT findings. Immunohistochemically, the apoptosis index (AI) on TUNEL (r=0.950, P<0.001) and the integrated optic density (IOD)/area on caspase-3 staining (r=0.955, P<0.001) were significantly correlated with the P/B ratio of the lesions on 18F-ML-10 PET/CT in the corresponding area. Conclusions:The 18F-ML-10 PET/CT imaging technique enables the visualization of atherosclerotic plaques that are rich in apoptotic cells.

Develop a universal lesion recognition algorithm for PET/CT and PET/MRI, validate it, and explore factors affecting performance. The 2022 AutoPet Challenge's 1014 PET/CT dataset was used to train the lesion detection model based on 2D and 3D fractional-residual (F-Res) models. To extend this to PET/MRI, a network for converting MR images to synthetic CT (sCT) was developed, using 41 sets of whole-body MR and corresponding CT data. 38 patients' PET/CT and PET/MRI data were used to verify the universal lesion recognition algorithm. Image quality was assessed using signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Total lesion glycolysis (TLG), metabolic tumor volume (MTV), and lesion count were calculated from the resultant lesion masks. Experienced physicians reviewed and corrected the model's outputs, establishing the ground truth. The performance of the lesion detection deep-learning model on different PET images was assessed by detection accuracy, precision, recall, and dice coefficients. Data with a detection accuracy score (DAS) less than 1 was used for analysis of outliers. Compared to PET/CT, PET/MRI scans had a significantly longer delay time (135 ± 45 min vs 61 ± 12 min) and lower SNR (6.17 ± 1.11 vs 9.27 ± 2.77). However, CNR values were similar (7.37 ± 5.40 vs 5.86 ± 6.69). PET/MRI detected more lesions (with a mean difference of -3.184). TLG and MTV showed no significant differences between PET/CT and PET/MRI (TLG: 119.18 ± 203.15 vs 123.57 ± 151.58, p = 0.41; MTV: 36.58 ± 57.00 vs 39.16 ± 48.34, p = 0.33). A total of 12 PET/CT and 14 PET/MRI datasets were included in the analysis of outliers. Outlier analysis revealed PET/CT anomalies in intestines, ureters, and muscles, while PET/MRI anomalies were in intestines, testicles, and low tracer uptake regions, with false positives in ureters (PET/CT) and intestines/testicles (PET/MRI). The deep learning lesion detection model performs well with both PET/CT and PET/MRI. SNR, CNR and reconstruction parameters minimally impact recognition accuracy, but delay time post-injection is significant.

There has been developed a clinical dynamic total-body 68Ga-DOTATATE PET/CT imaging protocol that allows quantitative imaging of net influx rate (Ki). Using qualitative and quantitative analyses of clinical studies, this retrospective study aims to assess whether parametric Ki images improve lesion detectability. Using a 194-cm axial field-of-view PET/CT scanner, 52 patients with neuroendocrine tumors underwent a 60-min dynamic total-body 68Ga-DOTATATE scan. Parametric Ki images and static standardized uptake value (SUV) images were generated. In addition to visual inspection of both sets of images, a quantitative analysis of 249 individual lesions was conducted using the target-to-background (TBR) metric. There were 52 patients who underwent dynamic total-body 68Ga-DOTATATE PET/CT scans. A total of 249 lesions were evaluated, of which 66 lesions were biopsy-proven and 183 lesions were unproven. Ki images produced two fewer false positives than the SUV images. Overall, our results from 66 proven NET lesions suggested similar sensitivity (98.5

Objective Recurrence is the leading cause of tumor-related death in retroperitoneal liposarcoma (RPLPS). Variant subtypes of RPLPS determine different recurrence 18 F]-fluoro-2-deoxy-D-glucose ( 18 F-FDG) PET/computed tomography (PET/CT). This study analyzed the characteristics of different histologic subtypes of 18 F-FDG PET/CT and their associations with recurrence and prognosis. Methods Clinical-pathological information, 18 F-FDG PET/CT data, recurrence, and progression-free survivals (PFS) of 83 patients with RPLPS were collected. Maximum and peak standardized uptake values (SUV max and SUV peak , respectively) and mean CT value (CT mean ) of tumors were measured and correlated with histologic subtype. Receiver operating characteristics (ROC) curves were used to analyze the predictability for subtype and recurrence. Kaplan-Meier analysis examined SUV max and SUV peak as recurrence risk factors. Results Studied patients with different types of liposarcomas. Dedifferentiated liposarcomas (DDLPS) had higher SUV max and SUV peak than well-differentiated (WDLPS) and myxoid/round cell (MLPS) types. WDLPS had lower CT mean values compared to MLPS and DDLPS. Using ROC curves, determined cut-off values for SUV max (5.1) to differentiate DDLPS, SUV peak (3.0) for WDLPS, and CT mean (12.3 Hu) for WDLPS. These cut-offs were found to be best for predicting recurrence. Kaplan–Meier analysis showed that histologic subtype, SUV max , and SUV peak were all linked to recurrence-free survival. Conclusions The use of SUV and CT features on 18 F-FDG PET/CT imaging may increase confidence in subtype diagnosis. Patients with SUV max > 5.1 or SUV peak > 3.0 suggest a poor prognosis.

177Lu- prostate specific membrane antigen (PSMA) radio-ligand therapy has been approved abroad for advanced prostate cancer and has been in several clinical trials in China. Based on domestic clinical practice and experimental data and referred to international experience and viewpoints, the expert group forms a consensus on the clinical application of 177Lu-PSMA radio-ligand therapy in prostate cancer to guide clinical practice.