Comparative assessment of the diagnostic efficacy of [18F]AlF-NOTA-FAPI-04 and [18F]FDG PET/CT imaging for detecting postoperative recurrence in gastric cancer patients: a pilot study.

Purpose: This study aimed to compare the efficacy of [18F]AlF-NOTA-FAPI-04 PET/CT with that of [18F]FDG PET/CT for detecting postoperative recurrence in patients with gastric cancer. Methods: This single-center retrospective clinical study was performed at Hunan Cancer Hospital between December 2020 and June 2022. The participants underwent both [18F]AlF-NOTA-FAPI-04 and [18F]FDG within 14 days. Histopathologic examination, morphological imaging, and/or follow-up imaging were used as a reference for the final diagnosis. We recorded the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of [18F]AlF-NOTA-FAPI-04 and [18F]FDG PET/CT for detecting local recurrence, lymph node metastasis and distant metastasis. The SUVmax and background ratio (TBR) of local recurrence and metastases between [18F]FDG and [18F]AlF-NOTA-FAPI-04 PET/CT were compared using paired-sample t tests. Results: Forty-seven patients (27 males, aged 25-68 years) with gastric cancer after curative resection (27 with adenocarcinoma, 17 with signet ring cell carcinoma and 4 with mucinous adenocarcinoma) were included in the study. [18F]AlF-NOTA-FAPI-04 accumulation was significantly greater than that of [18F]FDG in terms of local recurrence (SUVmax, 11.65 vs 3.48, p< 0.0001; TBR, 12.93 vs 2.94, p< 0.0001), lymph node metastasis (SUVmax, 13.45 vs 3.05, p=0.003875; TBR, 12.43 vs 2.21, p=0.001661), and distant metastasis (SUVmax, 11.89 vs 2.96, p < 0.0001; TBR, 13.32 vs 2.32, p< 0.0001). Despite no statistical comparison was made with [18F]FDG, [18F]AlF-NOTA-FAPI-04 imaging exhibited high levels of sensitivity, specificity, PPV, NPV, and accuracy for detecting postoperative local recurrence, lymph node metastasis, and distant metastasis in patients with gastric cancer. Conclusion: [18F]AlF-NOTA-FAPI-04 has demonstrated potential for more accurate tumor re-evaluation in GC, thus enhancing treatment decision-making.

The diagnostic value of 68Ga-NOTA-MAL-Cys-MZHER2:342 PET/CT imaging for HER2-positive lung adenocarcinoma.

Background: The human epidermal growth factor receptor 2 gene (HER2) has been identified as a potential therapeutic target in lung adenocarcinoma (LUAD). Non-invasive positron emission tomography (PET) imaging provides a reliable strategy for in vivo determination of HER2 expression through whole-body detection of abnormalities. The PET tracer 68Ga-NOTA-MAL-Cys-MZHER2:342 has shown promising results for HER2-positive breast and gastric cancers. This study aims to evaluate the performance of 68Ga-NOTA-MAL-Cys-MZHER2:342 in vitro and in vivo models and in clinical patients with HER2-positive LUAD. Methods: NOTA-MAL-Cys-MZHER2:342 was synthesized and labeled with 68Ga. Cell uptake, cell binding ability, and stability studies of 68Ga-NOTA-MAL-Cys-MZHER2:342 were assessed both in the Calu-3 lung cancer (LC) cell line and normal mice. In vivo assessment in tumor-bearing mice was conducted using microPET imaging and biodistribution experiments. Additionally, preliminary PET/CT imaging analysis was performed on HER2-positive LC patients. Results: 68Ga-NOTA-MAL-Cys-MZHER2:342 was prepared with a radiochemical purity (RCP) exceeding 95%. The tracer demonstrated high cell uptake in HER2-overexpressing Calu-3 cells, with an IC50 of 158.9, an adequate 1.73 nM. Good stability was exhibited both in vitro and in vivo. MicroPET imaging of Calu-3-bearing mice revealed high tumor uptake and notable tumor-to-background ratios. Positive outcomes were also observed in two HER2-positive LUAD patients. Conclusion: 68Ga-NOTA-MAL-Cys-MZHER2:342 demonstrated satisfactory stability, sensitivity, and specificity. These findings suggest that 68Ga-NOTA-MAL-Cys-MZHER2:342 PET/CT imaging provides a novel tool for non-invasive visual assessment of HER2 expression in LUAD patients.

Perception and knowledge of general practitioners on COPD management according to the GOLD23 document and reimbursement criteria for drugs prescription: an e-Delphi study.

BACKGROUND: COPD management and therapy have been periodically revised to support a more patient-specific approach. Several concerns remain in primary care, such as the proper choice of initial treatment, medication adherence, and missing values for spirometry investigations. These concerns may be exacerbated by inconsistencies between the GOLD23 report and reimbursement criteria, as per the Italian NOTA99, especially for what concerns the assessment of disease severity and related treatment choice. We therefore examined the perception and knowledge of general practitioners (GPs) on COPD management and treatment. METHODS: We conducted an exploratory e-Delphi study among 600 GPs. The study examined the COPD-related GP's access to spirometry evaluations in primary care clinics; knowledge on early recognition of COPD and related clinical concerns; perception of the clinical application of the NOTA99; the place in therapy of the triple LABA/LAMA/ICS combination. RESULTS: Among 466 participating GPs (response rate: 70.3%; mean age 52, SD: 14.2; mean years of experience: 21.3, SD: 15) had a good level of knowledge about the GOLD 2023 document and the reimbursement criteria for COPD medications. Nevertheless, a low (34%) direct access to spirometry was reported, along with absence of consensus on the proper choice of initial treatment (especially of use of LABA/LAMA combination), and the re-evaluation of free-triple therapy LABA/LAMA/ICS through specialist's referral. CONCLUSIONS: This study captured the domains on which further training for GPs might be implemented to improve the management and treatment of COPD. An extension of this e-Delphi to a larger GPs' panel might further confirm these findings.

Synthesis and Preclinical Evaluation of [18F]AlF-NOTA-Asp2-PEG2-Folate as a Novel Folate-Receptor-Targeted Tracer for PET Imaging.

Recently, the folate receptor (FR) has become an exciting target for the diagnosis of FR-positive malignancies. Nevertheless, suboptimal in vivo pharmacokinetic properties, particularly high uptake in the renal and hepatobiliary systems, are important limiting factors for the clinical translation of most FR-based radiotracers. In this study, we developed a novel 18F-labeled FR-targeted positron emission tomography (PET) tracer [18F]AlF-NOTA-Asp2-PEG2-Folate modified with a hydrophilic linker (-Asp2-PEG2) to optimize its pharmacokinetic properties and conducted a comprehensive preclinical assessment. The [18F]AlF-NOTA-Asp2-PEG2-Folate was manually synthesized within 30 min with a non-decay-corrected radiochemical yield of 16.3 ± 2.0% (n = 5). Among KB cells, [18F]AlF-NOTA-Asp2-PEG2-Folate exhibited high specificity and affinity for FR. PET/CT imaging and biodistribution experiments in KB tumor-bearing mice showed decent tumor uptake (1.7 ± 0.3% ID/g) and significantly decreased uptake in kidneys and liver (22.2 ± 2.1 and 0.3 ± 0.1% ID/g at 60 min p.i., respectively) of [18F]AlF-NOTA-Asp2-PEG2-Folate, compared to the known tracer [18F]AlF-NOTA-Folate (78.6 ± 5.1 and 5.3 ± 0.5 % ID/g at 90 min p.i., respectively). The favorable properties of [18F]AlF-NOTA-Asp2-PEG2-Folate, including its efficient synthesis, decent tumor uptake, relatively low renal uptake, and rapid clearance from most normal organs, portray it as a promising PET tracer for FR-positive tumors.

Ultrasensitive detection of uveal melanoma using [18F]AlF-NOTA-PRGD2 PET imaging.

BACKGROUND: Uveal melanoma (UM) is the most common primary intraocular tumor in adults, and early detection is critical to improve the clinical outcome of this disease. In this study, the diagnostic effectiveness of [18F]AlF-NOTA-PRGD2 (an investigational medicinal product) positron emission tomography (PET) imaging in UM xenografts and UM patients were evaluated. The cell uptake, cell binding ability and in vitro stability of [18F]AlF-NOTA-PRGD2 were evaluated in 92-1 UM cell line. MicroPET imaging and biodistribution study of [18F]AlF-NOTA-PRGD2 were conducted in 92-1 UM xenografts. Then, UM patients were further recruited for evaluating the diagnostic effectiveness of [18F]AlF-NOTA-PRGD2 PET imaging (approval no. NCT02441972 in clinicaltrials.gov). In addition, comparison of [18F]AlF-NOTA-PRGD2 and 18F-labelled fluorodeoxyglucose ([18F]FDG) PET imaging in UM xenografts and UM patients were conducted. RESULTS: The in vitro data showed that [18F]AlF-NOTA-PRGD2 had a high cell uptake, cell binding ability and in vitro stability in 92-1 UM cell line. The in vivo data indicated that 92-1 UM tumors were clearly visualized with the [18F]AlF-NOTA-PRGD2 tracer in the subcutaneous and ocular primary UM xenografts model at 60 min post-injection. And the tumor uptake of the tracer was 2.55 ± 0.44%ID/g and 1.73 ± 0.15%ID/g at these two tissue locations respectively, at 7 days after animal model construction. The clinical data showed that tumors in UM patients were clearly visualized with the [18F]AlF-NOTA-PRGD2 tracer at 60 min post-injection. In addition, [18F]AlF-NOTA-PRGD2 tracer showed higher sensitivity and specificity for PET imaging in UM xenografts and UM patients compared to [18F]FDG tracer. CONCLUSION: [18F]AlF-NOTA-PRGD2 PET imaging may be a more preferred approach in the diagnosis of primary UM compared to [18F]FDG PET imaging. Additionally, due to the high tumor-to-background ratio, [18F]AlF-NOTA-PRGD2 PET imaging seems also to be applicable for the diagnosis of UM patients with liver metastasis. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02441972, Registered 1 January 2012, https://clinicaltrials.gov/study/NCT02441972 .

Evaluation of the safety, biodistribution, dosimetry of [18F]AlF-NOTA-LM3 and head-to-head comparison with [68Ga]Ga-DOTATATE in patients with well-differentiated neuroendocrine tumors: an interim analysis of a prospective trial.

PURPOSE: 18F-labelled somatostatin receptor (SSTR) analogs offer several advantages over 68Ga in terms of yield, cost, spatial resolution and detection rate. This study presents an interim analysis of a prospective trial designed to assess the safety, biodistribution and dosimetry of [18F]AlF-NOTA-LM3, and compare its diagnostic efficacy and clinical management outcomes with [68Ga]Ga-DOTATATE or [68Ga]Ga-NODAGA-LM3 in patients with well-differentiated NETs. METHODS: Twenty-one patients with histologically confirmed well-differentiated neuroendocrine tumors (G1 and G2) were prospectively recruited. The first eight patients underwent serial PET scans at 5, 15, 30, 45, 60, and 120 min after [18F]AlF-NOTA-LM3 injection to assess biodistribution and dosimetry. The remaining patients underwent whole-body PET/CT scans. [18F]AlF-NOTA-LM3 and [68Ga]Ga-DOTATATE PET/CT were done within a week, with a minimum 24-hour interval between the two scans. Focal uptake above the surrounding background activity and could not be explained by physiologic uptake was considered lesions of NETs. Lesion number, tumor uptake, and tumor-to-background ratio (TBR) were compared. In patients with discrepant findings, the size of the smallest lesions (measured on coregistered CT) detected on [68Ga]Ga-DOTATATE and [18F]AlF-NOTA-LM3 was compared. RESULTS: [18F]AlF-NOTA-LM3 was safe and well-tolerated. Physiological uptake of [18F]AlF-NOTA-LM3 was significantly lower than that of [68Ga]Ga-DOTATATE in abdominal organs and bone marrow, but higher in blood pool and lung. The mean effective dose was 0.024 ± 0.014 mSv/MBq. [18F]AlF-NOTA-LM3 detected significantly more liver lesions (457 vs. 291, P = 0.006) and lymph node lesions (30 vs. 22, P = 0.011) compared to [68Ga]Ga-DOTATATE. The tumor uptake was comparable, but TBR was significantly higher with [18F]AlF-NOTA-LM3 for lesions from all sites except for the duodenum. The size of the minimum liver lesions (0.54 ± 0.15 vs. 1.01 ± 0.49, P<0.001) and lymph node lesions (0.50 ± 0.19 vs. 1.26 ± 0.86, P = 0.024) detected on [18F]ALF-NOTA-LM3 were significantly smaller than those detected on [68Ga]Ga-DOTATATE. CONCLUSION: [18F]AlF-NOTA-LM3 shows favorable biodistribution, higher spatial resolution and superior performance than [68Ga]Ga-DOTATATE in detecting liver and lymph node metastases, with higher TBR. Notably, it is the first SSTR analog to show superiority in detecting lymph node lesions when compared to [68Ga]Ga-DOTATATE. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT06056362.

Clinical impact of using [18F]AlF-NOTA-octreotide PET/CT instead of [68Ga]Ga-DOTA-SSA PET/CT: Secondary endpoint analysis of a multicenter, prospective trial.

[18F]AlF-NOTA-octreotide ([18F]AlF-OC) is a promising alternative for [68Ga]Ga-DOTA-somatostatin analogs (SSAs) in positron emission tomography (PET) imaging of the somatostatin receptor (SSTR). Our aim is to assess changes in TNM staging and differences in patient management between [18F]AlF-OC PET/CT and [68Ga]Ga-DOTA-SSA PET/CT in the work-up of neuroendocrine tumor (NET) patients. Patients who underwent both [18F]AlF-OC and [68Ga]Ga-DOTA-TATE or [68Ga]Ga-DOTA-NOC PET/CT in our multicenter study (Pauwels et al., J Nucl Med.2023;63:632-638) with a NET were included for analysis. TNM staging was determined and compared for both tracers. For each patient, the blinded [68Ga]Ga-DOTA-SSA or [18F]AlF-OC PET/CT images were presented in random order at a multidisciplinary team board. The images were presented together with clinical information and compared with previous SSTR and [18F]FDG PET/CT imaging. After a consensus decision for patient management was recorded, the board was presented with the PET/CT images from the other SSTR tracer and a decision was made for the second tracer. Differences in management were classified as major if it entailed an intermodality change and minor if it led to an intramodality change. Compared with [68Ga]Ga-DOTA-SSA, the use of [18F]AlF-OC led to a change in 16/75 patients: TNM staging changes in 10/75 patients (13.3%; downstaging in 3/10, upstaging in 7/10) and differences in clinical management were seen in 10/75 patients (13.3%), leading to a major difference in 7/10 cases and a minor change in 3/10 cases. All 10 cases with a difference in patient management between both PET tracers were caused by additional lesion detection by [18F]AlF-OC. The use of [18F]AlF-OC did not impact TNM staging or clinical management in the large majority of the patients (86.7%), further validating the potential for routine clinical use of [18F]AlF-OC PET/CT as an alternative for [68Ga]Ga-DOTA-SSA PET/CT. The trial is registered under ClinicalTrials.gov identifier NCT04552847 and EudraCT 2020-000549-15.

18F-AlF-NOTA-octreotide PET/CT in the localization of tumor-induced osteomalacia: case series and literature review.

Introduction: This study explores tumor-induced osteomalacia (TIO) through a case series and literature review, assessing the diagnostic potential of 18F-AlF-NOTA-octreotide (18F-OC) positron emission tomography/computed tomography (PET/CT). Methods: We analyzed TIO patients who underwent 18F-OC PET/CT. Parameters such as tumor dimension, the maximum standardized uptake value (SUVmax), the mean standardized uptake value (SUVmean) and metabolic tumor volume (MTV) were meticulously assessed. Clinical features and imaging characteristics pertinent to TIO were reviewed. Results: 6 patients with clinical suspicion of TIO exhibited hypophosphatemia (0.25 to 0.64 mmol/L), elevated alkaline phosphatase (ALP) levels (142 to 506 U/L), and increased parathyroid hormone (PTH) levels (92.9 to 281.7 pg/mL). Of these patients, two underwent FGF-23 testing, with results of 3185.00 pg/ml and 17.56 pg/ml, respectively. Conventional imaging modalities depicted widespread osteoporosis, with several cases demonstrating fractures indicative of osteomalacic and associated pathological fractures. Subsequent 18F-OC PET/CT facilitated the accurate localization of causative tumors, with histopathological examination confirming the diagnosis of phosphaturic mesenchymal tumor (PMT). The interval from initial clinical presentation to definitive TIO diagnosis spanned approximately 2.5 years (range: 1 - 4 years), with tumors varying in size (maximum diameter: 7.8 to 40.0 mm), SUVmax (5.47 to 25.69), SUVmean (3.43 to 7.26), and MTV (1.27 to 18.59 cm3). Conclusion: The implementation of whole-body 18F-OC PET/CT imaging emerges as a critical tool in the identification of occult tumors causing TIO. Future investigations incorporating a broader cohort are imperative to further delineate the diagnostic and therapeutic implications of 18F-OC PET/CT in managing TIO.

[18F] AlF-NOTA-FAPI-04 PET/CT for non-invasive assessment of tubular injury in kidney diseases.

Background: [18F] AlF-NOTA-FAPI-04 is a novel positron emission tomography (PET) ligand, which specifically targets fibroblast activation protein (FAP) expression as a FAP inhibitor (FAPI). We analysed the diagnostic value of [18F] AlF-NOTA-FAPI-04 PET/CT for the non-invasive assessment of kidney interstitial inflammation and fibrosis in different renal pathologies. Methods: Twenty-six patients (14 males and 12 females; mean age, 50.5 ± 16.5 years) with a wide range of kidney diseases and 10 patients (six males and four females; mean age, 55.4 ± 8.6 years) without known evidence of renal disease as disease controls underwent [18F] AlF-NOTA-FAPI-04 PET/CT imaging. Kidney tissues obtained from kidney biopsies were stained with haematoxylin and eosin, periodic acid-Schiff, Masson's trichome, and periodic acid-silver methenamine. Immunohistochemical staining was also performed to assess the expression of α-smooth muscle actin (αSMA) and FAP. Renal parenchymal FAPI uptake reflected by maximum standardized uptake value (SUVmax) and mean standardized uptake value (SUVmean) measurements on PET/CT was analysed against pathohistological findings. Results: We found that renal parenchymal FAPI uptake was significantly higher in patients with various kidney diseases than in control patients in this study (SUVmax = 4.3 ± 1.8 vs 1.9 ± 0.4, SUVmean=3.9 ± 1.7 vs 1.5 ± 0.4, respectively; all P < 0.001). All kidney diseases, both in acute and chronic kidney disease, had increased renal parenchymal uptake to varying degrees. The correlation analysis indicated a positive association between the SUVmax and the tubulointerstitial inflammation (TII), interstitial fibrosis and tubular atrophy (IF/TA), and TII + IF/TA scores (r = 0.612, 0.681, and 0.754, all P < 0.05), and between the SUVmean and the TII, IF/TA, and TII + IF/TA scores (r = 0.603, 0.700, and 0.748, all P < 0.05). Furthermore, we found significant positive correlations between both SUVmax and the SUVmean with SMA and FAP staining scores (r = 0.686 and 0.732, r = 0.667 and 0.739, respectively; both P < 0.001). Conclusions: [18F] AlF-NOTA-FAPI-04 PET/CT is clinically available for the comprehensive and non-invasive assessment of tubular injury in various kidney diseases.

Granzyme B PET Imaging for Assessment of Disease Activity in Inflammatory Bowel Disease.

Developing a noninvasive imaging method to detect immune system activation with a high temporal resolution is key to improving inflammatory bowel disease (IBD) management. In this study, granzyme B (GZMB), typically released from cytotoxic T and natural killer cells, was targeted using PET with 68Ga-NOTA-GZP (where GZP is ß-Ala-Gly-Gly-Ile-Glu-Phe-Asp-CHO) to detect early intestinal inflammation in murine models of colitis. Methods: Bioinformatic analysis was used to assess the potential of GZMB as a biomarker for detecting IBD and predicting response to treatment. Human active and quiescent Crohn disease and ulcerative colitis tissues were stained for GZMB. We used IL-10-/- mice treated with dextran sulfate sodium (DSS) as an IBD model, wild-type C57BL/6J mice as a control, and anti-tumor necrosis factor as therapy. We used a murine GZMB-binding peptide conjugated to a NOTA chelator (NOTA-GZP) labeled with 68Ga as the PET tracer. PET imaging was conducted at 1, 3, and 4 wk after colitis induction to evaluate temporal changes. Results: Bioinformatic analysis showed that GZMB gene expression is significantly upregulated in human ulcerative colitis and Crohn disease compared with the noninflamed bowel by 2.98-fold and 1.92-fold, respectively; its expression is lower by 2.16-fold in treatment responders than in nonresponders. Immunofluorescence staining of human tissues demonstrated a significantly higher GZMB in patients with active than with quiescent IBD (P = 0.032).68Ga-NOTA-GZP PET imaging showed significantly increased bowel uptake in IL-10-/- mice with DSS-induced colitis compared with vehicle-treated IL-10-/- mice (SUVmean, 0.75 vs. 0.24; P < 0.001) and both vehicle- and DSS-treated wild-type mice (SUVmean, 0.26 and 0.37; P < 0.001). In the IL-10-/- DSS-induced colitis model, the bowel PET probe uptake decreased in response to treatment with tumor necrosis factor-α (SUVmean, 0.32; P < 0.001). There was a 4-fold increase in colonic uptake of 68Ga-NOTA-GZP in the colitis model compared with the control 1 wk after colitis induction. The uptake gradually decreased to approximately 2-fold by 4 wk after IBD induction; however, the inflamed bowel uptake remained significantly higher than control at all time points (week 4 SUVmean, 0.23 vs. 0.08; P = 0.001). Conclusion: GZMB is a promising biomarker to detect active IBD and predict response to treatment. This study provides compelling evidence to translate GZMB PET for imaging IBD activity in clinical settings.

In Vivo Imaging of Acute Hindlimb Ischaemia in Rat Model: A Pre-Clinical PET Study.

BACKGROUND: To better understand ischaemia-related molecular alterations, temporal changes in angiogenic Aminopeptidase N (APN/CD13) expression and glucose metabolism were assessed with PET using a rat model of peripheral arterial disease (PAD). METHODS: The mechanical occlusion of the base of the left hindlimb triggered using a tourniquet was applied to establish the ischaemia/reperfusion injury model in Fischer-344 rats. 2-[18F]FDG and [68Ga]Ga-NOTA-c(NGR) PET imaging performed 1, 3, 5, 7, and 10 days post-ischaemia induction was followed by Western blotting and immunohistochemical staining for APN/CD13 in ischaemic and control muscle tissue extracts. RESULTS: Due to a cellular adaptation to hypoxia, a gradual increase in [68Ga]Ga-NOTA-c(NGR) and 2-[18F]FDG uptake was observed from post-intervention day 1 to 7 in the ischaemic hindlimbs, which was followed by a drop on day 10. Conforming pronounced angiogenic recovery, the NGR accretion of the ischaemic extremities differed significantly from the controls 5, 7, and 10 days after ischaemia induction (p ≤ 0.05), which correlated with the Western blot and immunohistochemical results. No remarkable radioactivity was depicted between the normally perfused hindlimbs of either the ischaemic or the control groups. CONCLUSIONS: The PET-based longitudinal assessment of angiogenesis-associated APN/CD13 expression and glucose metabolism during ischaemia may continue to broaden our knowledge on the pathophysiology of PAD.

Synthesis and Evaluation of [18F]AlF-NOTA-c-DVAP: A Novel PET Probe for Imaging GRP78 in Cancer.

GRP78, a member of the HSP70 superfamily, is an endoplasmic reticulum chaperone protein overexpressed in various cancers, making it a promising target for cancer imaging and therapy. Positron emission tomography (PET) imaging offers unique advantages in real time, noninvasive tumor imaging, rendering it a suitable tool for targeting GRP78 in tumor imaging to guide targeted therapy. Several studies have reported successful tumor imaging using PET probes targeting GRP78. However, existing PET probes face challenges such as low tumor uptake, inadequate in vivo distribution, and high abdominal background signal. Therefore, this study introduces a novel peptide PET probe, [18F]AlF-NOTA-c-DVAP, for targeted tumor imaging of GRP78. [18F]AlF-NOTA-c-DVAP was radiolabeled with fluoride-18 using the aluminum-[18F]fluoride ([18F]AlF) method. The study assessed the partition coefficients, stability in vitro, and metabolic stability of [18F]AlF-NOTA-c-DVAP. Micro-PET imaging, pharmacokinetic analysis, and biodistribution studies were carried out in tumor-bearing mice to evaluate the probe's performance. Docking studies and pharmacokinetic analyses of [18F]AlF-NOTA-c-DVAP were also performed. Immunohistochemical and immunofluorescence analyses were conducted to confirm GRP78 expression in tumor tissues. The probe's binding affinity to GRP78 was analyzed by molecular docking simulation. [18F]AlF-NOTA-c-DVAP was radiolabeled in just 25 min with a high yield of 51 ± 16%, a radiochemical purity of 99%, and molar activity within the range of 20-50 GBq/µmol. [18F]AlF-NOTA-c-DVAP demonstrated high stability in vitro and in vivo, with a logD value of -3.41 ± 0.03. Dynamic PET imaging of [18F]AlF-NOTA-c-DVAP in tumors showed rapid uptake and sustained retention, with minimal background uptake. Biodistribution studies revealed rapid blood clearance and excretion through the kidneys following a single-compartment reversible metabolic model. In PET imaging, the T/M ratios for A549 tumors (high GRP78 expression), MDA-MB-231 tumors (medium expression), and HepG2 tumors (low expression) at 60 min postintravenous injection were 10.48 ± 1.39, 6.25 ± 0.47, and 3.15 ± 1.15% ID/g, respectively, indicating a positive correlation with GRP78 expression. This study demonstrates the feasibility of using [18F]AlF-NOTA-c-DVAP as a PET tracer for imaging GRP78 in tumors. The probe shows promising results in terms of stability, specificity, and tumor targeting. Further research may explore the clinical utility and potential therapeutic applications of this PET tracer for cancer diagnosis.

Synthesis, Quality Control, and Bench-to-Bed Translation of a New [68Ga]Ga-Labeled NOTA-Conjugated Bisphosphonate for Imaging Skeletal Metastases by Positron Emission Tomography.

Background: Early detection of skeletal metastasis is of great interest to determine the prognosis of cancer. Positron emission tomography-computed tomography (PET-CT) imaging provides a better temporal and spectral resolution than single photon emission computed tomography-computed tomography (SPECT-CT) imaging, and hence is more suitable to detect small metastatic lesions. Although [18F]NaF has been approved by U.S. FDA for a similar purpose, requirement of a medical cyclotron for its regular formulation restricts its extensive utilization. Efforts have been made to find suitable alternative molecules that can be labeled with 68Ga and used in PET-CT imaging. Objective: The main objective of this study is to synthesize and evaluate a new [68Ga]Ga-labeled NOTA-conjugated geminal bisphosphonate for its potential use in early detection of skeletal metastases using PET-CT. Methods: The authors performed a multistep synthesis of a new NOTA-conjugated bisphosphonic acid using thiourea linker and radiolabeled the molecule with 68Ga. The radiolabeled formulation was evaluated for its in vitro stability, affinity for hydroxyapatite (HA) particles, preclinical biodistribution in animal models, and PET-CT imaging in patients. Results: The bifunctional chelator (NOTA)-conjugated bisphosphonate was synthesized with 97.8% purity and radiolabeled with 68Ga in high yield (>98%). The radiolabeled formulation was found to retain its stability in vitro to the extent of >95% up to 4 h in physiological saline and human serum. The formulation also showed high affinity for HA particles in vitro with Kd = 907 ± 14 mL/g. Preclinical biodistribution studies in normal Wistar rats demonstrated rapid and almost exclusive skeletal accumulation of the complex. PET-CT imaging in a patient confirmed its ability to detect small metastatic skeletal lesions. Conclusions: The newly synthesized [68Ga]Ga-labeled NOTA-conjugated bisphosphonate is a promising radiotracer for PET-CT imaging for skeletal metastases.

Effectiveness of [67Cu]Cu-trastuzumab as a theranostic against HER2-positive breast cancer.

PURPOSE: To evaluate the imaging and therapeutic properties (theranostic) of 67Cu-labeled anti-human epidermal growth factor receptor II (HER2) monoclonal antibody trastuzumab against HER2-positive breast cancer (BC). METHODS: We conjugated trastuzumab with p-SCN-Bn-NOTA, 3p-C-NETA-NCS, or p-SCN-Bn-DOTA, and radiolabeled with [67Cu]CuCl2. Immunoconjugate internalization was evaluated in BT-474, JIMT-1 and MCF-7 BC cells. In vitro stability was studied in human serum (HS) and Phosphate Buffered Saline (PBS). Flow cytometry, radioligand binding and immunoreactive fraction assays were carried out. ImmunoSPECT imaging of [67Cu]Cu-NOTA-trastuzumab was done in mice bearing BT-474, JIMT-1 and MCF-7 xenografts. Pharmacokinetic was studied in healthy Balb/c mice while dosimetry was done in both healthy Balb/c and in athymic nude mice bearing JIMT-1 xenograft. The therapeutic effectiveness of [67Cu]Cu-NOTA-trastuzumab was evaluated in mice bearing BT-474 and JIMT-1 xenografts after a single intravenous (i.v.) injection of ~ 16.8 MBq. RESULTS: Pure immunoconjugates and radioimmunoconjugates (> 95%) were obtained. Internalization was HER2 density-dependent with highest internalization observed with NOTA-trastuzumab. After 5 days, in vitro stabilities were 97 ± 1.7%, 31 ± 6.2%, and 28 ± 4% in HS, and 79 ± 3.5%, 94 ± 1.2%, and 86 ± 2.3% in PBS for [67Cu]Cu-NOTA-trastuzumab, [67Cu]Cu-3p-C-NETA-trastuzumab and [67Cu]Cu-DOTA-trastuzumab, respectively. [67Cu]Cu-NOTA-trastuzumab was chosen for further evaluation. BT-474 flow cytometry showed low KD, 8.2 ± 0.2 nM for trastuzumab vs 26.5 ± 1.6 nM for NOTA-trastuzumab. There were 2.9 NOTA molecules per trastuzumab molecule. Radioligand binding assay showed a low KD of 2.1 ± 0.4 nM and immunoreactive fraction of 69.3 ± 0.9. Highest uptake of [67Cu]Cu-NOTA-trastuzumab was observed in JIMT-1 (33.9 ± 5.5% IA/g) and BT-474 (33.1 ± 10.6% IA/g) xenograft at 120 h post injection (p.i.). Effectiveness of the radioimmunoconjugate was also expressed as percent tumor growth inhibition (%TGI). [67Cu]Cu-NOTA-trastuzumab was more effective than trastuzumab against BT-474 xenografts (78% vs 54% TGI after 28 days), and JIMT-1 xenografts (90% vs 23% TGI after 19 days). Mean survival of [67Cu]Cu-NOTA-trastuzumab, trastuzumab and saline treated groups were > 90, 77 and 72 days for BT-474 xenografts, while that of JIMT-1 were 78, 24, and 20 days, respectively. CONCLUSION: [67Cu]Cu-NOTA-trastuzumab is a promising theranostic agent against HER2-positive BC.

Clinical value of [18F]AlF-NOTA-FAPI-04 PET/CT for assessing early-stage liver fibrosis in adult liver transplantation recipients compared with chronic HBV patients.

AIMS: To investigate the clinical value and performance of [18F]AlF-NOTA-FAPI-04 PET/CT in assessing early-stage liver fibrosis in liver transplantation (LT) recipients. METHODS: A prospective study including 17 LT recipients and 12 chronic Hepatitis B (CHB) patients was conducted. All patients received liver biopsy, transient elastography (TE), and [18F]AlF-NOTA-FAPI-04 PET/CT. On [18F]AlF-NOTA-FAPI-04 PET/CT scans, the liver parenchyma's maximum standardized uptake values (SUVmax) were measured. The receiver operating characteristic (ROC) curve analysis was applied to determine the diagnostic efficacy of [18F]AlF-NOTA-FAPI-04 PET/CT in early-stage liver fibrosis (S1-S2) compared with the diagnostic performance of TE. RESULTS: Among those 29 patients enrolled in this study, 15(51.7%) had fibrosis S0, 10(34.5%) had S1, and 4(13.8%) had S2, respectively. The SUVmax of patients with early-stage liver fibrosis was significantly higher than those without liver fibrosis in LT recipients and CHB patients (P = 0.004, P = 0.02). In LT recipients, a SUVmax cut-off value of 2.0 detected early-stage liver fibrosis with an AUROC of 0.92 (P = 0.006), and a liver stiffness measurements (LSM) score cut-off value of 8.2 kPa diagnosed early-stage liver fibrosis with an AUROC of 0.80 (P = 0.012). In CHB patients, a SUVmax cut-off value of 2.7 detected early-stage liver fibrosis with an AUROC of 0.94 (P < 0.001) and an LSM scores cut-off value of 8.4 kPa diagnosed early-stage liver fibrosis with an AUROC of 0.91 (P < 0.001). CONCLUSION: [18F]AlF-NOTA-FAPI-04 PET/CT could be applied to evaluate early-stage liver fibrosis in LT recipients and CHB patients properly, with the potential additional advantages in monitoring and predicting complications after LT.

Diagnostic Value of Preoperative uPAR-PET/CT in Regional Lymph Node Staging of Oral and Oropharyngeal Squamous Cell Carcinoma: A Prospective Phase II Trial.

The detection of lymph node metastases is a major challenge in oral and oropharyngeal squamous cell carcinoma (OSCC and OPSCC). 68Ga-NOTA-AE105 is a novel positron emission tomography (PET) radioligand with high affinity to urokinase-type plasminogen activator receptor (uPAR), a receptor expressed on the surfaces of tumor cells. The aim of this study was to investigate the diagnostic value of uPAR-PET/CT (computerized tomography) in detecting regional metastatic disease in patients with OSCC and OPSCC compared to the current imaging work-up. In this phase II trial, patients with OSCC and OPSCC referred for surgical treatment were prospectively enrolled. Before surgery, 68Ga-NOTA-AE105 uPAR-PET/CT was conducted, and SUVmax values were obtained from the primary tumor and the suspected lymph nodes. Histology results from lymph nodes were used as the standard of truth of metastatic disease. The diagnostic values of 68Ga-uPAR-PET/CT were compared to conventional routine preoperative imaging results (CT and/or MRI). The uPAR expression in resected primary tumors and metastases was determined by immunohistochemistry and quantified digitally (H-score). A total of 61 patients underwent uPAR-PET/CT. Of the 25 patients with histologically verified lymph node metastases, uPAR-PET/CT correctly identified regional metastatic disease in 14 patients, with a median lymph node metastasis size of 14 mm (range 3-27 mm). A significant correlation was found between SUVmax and the product of the H-score and tumor depth (r = 0.67; p = 0.003). The sensitivity and specificity of uPAR-PET/CT in detecting regional metastatic disease were 56% and 100%, respectively. When added to CT/MRI, uPAR-PET was able to upstage 2/11 (18%) of patients with occult metastases and increase the sensitivity to 64%. The sensitivity and specificity of 68Ga-NOTA-AE105 uPAR-PET/CT were equivalent to those of CT/MRI. The significant correlation between SUVmax and uPAR expression verified the target specificity of 68Ga-NOTA-AE105. Despite the target specificity, the sensitivity of imaging is too low for nodal staging and it cannot replace neck dissection.

Superiority of FAPI-PET/CT for examining multiple malignant tumors: a retrospective study.

To compare the diagnostic value of [18F]-AlF-NOTA-FAPI-04 PET/CT and [18F]-FDG PET/CT for primary and metastatic lesions in different types of tumors. A retrospective analysis was conducted on 51 patients with 11 different types of tumors. Among them, 20 patients underwent PET/CT, and 31 patients underwent restaging. The patients were diagnosed using [18F]-AlF-NOTA-FAPI-04 PET/CT and [18F]-FDG PET/CT scan techniques, and adverse reactions were recorded. Thickness of primary lesions, metastasis, and lymph node involvement were analyzed and confirmed by histological analysis. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of [18F]-AlF-NOTA-FAPI-04 PET/CT and [18F]-FDG PET/CT were calculated. Neither [18F]-AlF-NOTA-FAPI-04 PET/CT nor [18F]-FDG PET/CT scan techniques caused adverse reactions in the patients. [18F]-AlF-NOTA-FAPI-04 PET/CT performed well in detecting recurrence, with a positive rate of 100%, higher than 71.0% of [18F]-FDG PET/CT. Compared with [18F]-FDG PET/CT, [18F]-AlF-NOTA-FAPI-04 PET/CT identified 6 types of malignant tumors more clearly, and could improve the detection rate of primary and metastatic tumors (97.0% vs. 84.8%, P<0.001). [18F]-AlF-NOTA-FAPI-04 PET/CT exhibited a higher sensitivity for detecting lymph node (81.8% vs. 50.0%, P<0.05) than [18F]-FDG PET/CT. Additionally, [18F]-AlF-NOTA-FAPI-04 PET/CT demonstrated higher diagnostic sensitivity (67.39% vs. 58.7%, P=0.387) and accuracy (82.14% vs. 60.71%, P=0.377) for detecting metastatic lesions compared to [18F]-FDG PET/CT. [18F]-AlF-NOTA-FAPI-04 PET/CT outperforms [18F]-FDG PET/CT in diagnosing primary and metastatic lesions across various types of tumors, especially in identifying lymph node, visceral, and peritoneal metastases. It can improve diagnostic efficiency and accuracy, thereby positively influencing clinical decision-making for optimal patient management.

Typical Zollinger-Ellison syndrome-atypical location of gastrinoma and absence of hypergastrinemia: A case report and review of literature.

BACKGROUND: Zollinger-Ellison syndrome (ZES) results from hypersecretion of gastrin from pancreatic or duodenal neuroendocrine tumors, commonly referred to as gastrinomas. The high levels of gastrin lead to a typical presentation involving watery diarrhea and multiple ulcers in the duodenum. Here, we have presented the rare case of a patient with ZES and absence of hypergastrinemia as well as an atypical location of gastrinoma. CASE SUMMARY: A 72-year-old woman presented with the typical clinical manifestations of ZES, including upper abdominal pain, significant watery diarrhea, and acidic liquid vomitus. Surprisingly, however, she did not have an increased level of serum gastrin. In addition, there was no evidence of gastrinoma or any other ulcerogenic tumor. Esophagogastroduodenoscopy was conducted to examine the upper digestive tract. Revised diagnoses were considered, and an individualized treatment plan was developed. The patient responded to antacid medication while experiencing intermittent, recurring bouts of ZES. 18F-AlF-NOTA-octreotide positron emission tomography (18F-OC PET)/computed tomography (CT) helped locate the tumor. Postoperative pathology and immunohistochemistry results suggested that the tumor was a gastrinoma located at an unconventional site. CONCLUSION: This present case study demonstrates the possibility of ZES-like manifestation in patients with absence of hypergastrinemia. 18F-OC PET/CT is a relatively new imaging technique that can be applied for diagnosing even tiny gastrinomas that are atypical in terms of location.

Clinical application of Al18F-NOTA-FAPI PET/CT in diagnosis and TNM staging of pancreatic adenocarcinoma, compared to 18F-FDG.

PURPOSE: This study aimed to investigate the ability of Al18F-NOTA-FAPI PET/CT to diagnose pancreatic carcinoma and tumor-associated inflammation with the comparison of 18F-FDG PET/CT. METHODS: Prospective analysis of Al18F-NOTA-FAPI PET/CT and 18F-FDG PET/CT scans of 31 patients from 05/2021 to 05/2022 were analyzed. Al18F-NOTA-FAPI imaging was performed in patients who had Ce-CT and FDG PET/CT and the diagnosis was still unclear. Follow-up histopathology or radiographic examination confirmed the findings. Radiotracer uptake, diagnostic performance, and TNM (tumor-node-metastasis) classifications were compared. RESULTS: A total of 31 patients with pancreatic carcinoma (all were adenocarcinoma) underwent Al18F-NOTA-FAPI-04 PET/CT, including 20 male and 11 female patients, with a mean age of 58.2 ± 8.5 years. FAPI-04 PET/CT imaging showed a higher value of SUVmax-15min/30min/60min, SUVmean-15min/30min/60min, TBR1, and TBR2 in pancreatic carcinoma than FDG (all P < 0.01). The mean level of Al18F-NOTA FAPI-04 uptake values of the pancreatic ductal adenocarcinoma was higher than that of pancreatitis in both SUVmax-30min (P < 0.01), SUVmean-30min (P < 0.05), SUVmax-60min (P < 0.01), and SUVmean-60min (P < 0.01). The FAPI △SUVmax-1, △SUVmax-2, and △SUVmean-2 uptake values of pancreatic carcinoma were higher than tumor-associated inflammation (all P < 0.01). TNM staging of 16/31 patients changed after Al18F-NOTA FAPI-04 PET/CT examination with all upstaging changes. CONCLUSION: Al18F-NOTA-FAPI-04 PET/CT at 15 and 30 min also demonstrated an equivalent detection ability of pancreatic lesion to 18F-FDG PET/CT. Delayed-phase Al18F-NOTA-FAPI-04 PET/CT can help differentiate pancreatic carcinoma and tumor-associated inflammation. Al18F-NOTA FAPI-04 PET/CT also performed better than FDG PET/CT in TNM staging. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR2100051406. Registered 23 September 2021, https://www.chictr.org.cn/showproj.html?proj=133033.

Comparison of the Effects of DOTA and NOTA Chelators on 64Cu-Cudotadipep and 64Cu-Cunotadipep for Prostate Cancer.

BACKGROUND: This study compared the effects of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) and 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) as 64Cu-chelating agents in newly developed prostate-specific membrane antigen (PSMA) target compounds, 64Cu-cudotadipep and 64Cu-cunotadipep, on pharmacokinetics. METHODS: The in vitro stability of the chelators was evaluated using human and mouse serum. In vitro PSMA-binding affinity and cell uptake were compared using human 22Rv1 cells. To evaluate specific PSMA-expressing tumor-targeting efficiency, micro-positron emission tomography (mcroPET)/computed tomography (CT) and biodistribution analysis were performed using PSMA+ PC3-PIP and PSMA- PC3-flu tumor xenografts. RESULTS: The serum stability of DOTA- or NOTA-conjugated 64Cu-cudotadipep and 64Cu-cunotadipep was >97%. The Ki value of the NOTA derivative, cunotadipep, in the in vitro affinity binding analysis was higher (2.17 ± 0.25 nM) than that of the DOTA derivative, cudotadipep (6.75 ± 0.42 nM). The cunotadipep exhibited a higher cellular uptake (6.02 ± 0.05%/1 × 106 cells) compared with the cudotadipep (2.93 ± 0.06%/1 × 106 cells). In the biodistribution analysis and microPET/CT imaging, the 64Cu-labeled NOTA derivative, 64Cu-cunotadipep, demonstrated a greater tumor uptake and lower liver uptake than the DOTA derivative. CONCLUSIONS: This study indicates that the PSMA-targeted 64Cu-cunotadipep can be applied in clinical practice owing to its high diagnostic power for prostate cancer.