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Purpose: To explore the feasibility of [68Ga]Ga-DOTATATE positron emission tomography/computed tomography (PET/CT) in patients with non-keratinizing nasopharyngeal carcinoma (NPC) and to evaluate whether [68Ga]Ga-DOTATATE PET/CT could be used for non-invasive determination of somatostatin receptor 2 (SSTR2) expression in NPC. Methods: This prospective study included patients with NPC who underwent [68Ga]Ga-DOTATATE PET/CT between February and May 2021. The [68Ga]Ga-DOTATATE and [18F]FDG uptakes in primary and metastatic NPC lesions were calculated and compared, and the [68Ga]Ga-DOTATATE uptake between SSTR2 score groups was analysed. Results: A total of 36 participants (25 patients, initial staging; 11 patients, recurrence detection) were included; 33 patients also underwent [18F]FDG PET/CT for staging/restaging as a part of their routine diagnostic workup. [68Ga]Ga-DOTATATE PET/CT showed an intense tracer uptake in primary and metastatic NPC lesions. The radiotracer uptake was higher with [68Ga]Ga-DOTATATE than with [18F]FDG PET in primary NPC lesions (SUVmax: 12.03 vs. 10.07, P = 0.048; tumour-to-brain ratio: 36.16 vs. 0.86, P < 0.001) and regional lymph node metastases (median SUVmax: 9.11 vs. 6.12, P < 0.001) and comparable in bone and visceral metastases. Importantly, most NPC lesions showed intense SSTR2 expression (85.7%), which was strongly correlated with the [68Ga]Ga-DOTATATE uptake. The SUVmax of SSTR2-negative lesions was significantly lower than that of SSTR2-positive lesions (SUVmax: 4.95 vs. 12.61, P = 0.013). Conclusion: [68Ga]Ga-DOTATATE PET/CT is a promising imaging modality for detecting primary and metastatic NPC, with favourable image contrast and comparable diagnostic efficacy when compared to [18F]FDG PET/CT. An intense SSTR2 expression was observed in most NPCs, and this expression was significantly correlated with the [68Ga]Ga-DOTATATE uptake. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate the diagnostic performance of [68Ga]Ga-FAPI PET/CT for primary and metastatic pancreatic carcinoma lesions and compare the results with those of [18F]-fluorodeoxyglucose ([18F]FDG) PET/CT. Methods: Patients with suspected or diagnosed pancreatic malignancy, who underwent contemporaneous [18F]FDG and [68Ga]Ga-FAPI PET/CT between June 2020 and January 2021, were retrospectively analyzed. Routine contrast-enhanced CT (CE-CT) is performed in all patients as standardized care. Findings were confirmed by histopathology or radiographic follow-up. We compared radiotracer uptake, diagnostic performance, and TNM (tumor-node-metastasis) classifications. Results: We evaluated 36 participants (25/36 men; median age, 60 years), including 26 patients with pancreatic malignancies and ten patients with pancreatic benign lesions. [68Ga]Ga-FAPI PET/CT showed higher radiotracer uptake and higher sensitivity than [18F]FDG PET/CT in evaluating primary tumors (SUVmax, 21.4 vs. 4.8; sensitivity, 100% vs. 73.1%), involved lymph nodes (SUVmax, 8.6 vs. 2.7; sensitivity, 81.8% vs. 59.1%), and metastases (SUVmax, 7.9 vs. 3.5; sensitivity, 91.5% vs. 44.0%); Compared with [18F]FDG, [68Ga]Ga-FAPI PET/CT upstaged six patients' TNM staging (6/23, 26.1%) and changed two patients' clinical management (2/23, 8.7%). Compared with CE-CT, [68Ga]Ga-FAPI PET/CT upgraded TNM staging in five patients (5/23, 21.7%) and changed the therapeutic regimen in only one patient (1/23, 4.3%). Intense [68Ga]Ga-FAPI uptake was observed throughout the pancreas in 12/26 pancreatic malignancies; dual-time point [68Ga]Ga-FAPI PET/CT may differentiate pancreatitis from malignancy. Conclusions: Compared with [18F]FDG PET/CT, [68Ga]Ga-FAPI PET/CT shows higher sensitivity in detecting primary pancreatic tumors, involved lymph nodes, and metastases and is superior in terms of TNM staging. Prospective trials with larger patient population are needed to evaluate whether [68Ga]Ga-FAPI PET/CT could elicit treatment modification in pancreatic cancer when compared with standard of care imaging. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to explore the role of [68Ga]Ga-DOTA-FAPI-04 positron emission tomography/computed tomography (PET/CT), compared with 18F-fluorodeoxyglucose [18F]-FDG PET/CT, for evaluating peritoneal carcinomatosis in patients with various types of cancer. Methods: Patients with suspected peritoneal malignancy, who underwent both [18F]-FDG and [68Ga]Ga-DOTA-FAPI-04 PET/CT between October 2019 and August 2020, were retrospectively analysed. The radiotracer uptake, peritoneal cancer index (PCI) score, and diagnostic performance of [18F]-FDG and [68Ga]Ga-DOTA-FAPI-04 PET/CT were evaluated and compared. Results: Our cohort consisted of 46 patients, including 16 patients with diffuse-type peritoneal carcinomatosis, 27 with nodular-type peritoneal carcinomatosis, and 3 true-negative patients. A significant difference in standard uptake values (SUV) of lesions between [18F]-FDG and [68Ga]Ga-DOTA-FAPI-04 PET/CT examination was observed (median SUV: 3.48 vs. 9.82; P < 0.001), particularly in peritoneal carcinomatosis from gastric cancer (median SUV: 3.44 vs. 8.05; P = 0.001). Moreover, [68Ga]Ga-DOTA-FAPI-04 PET/CT showed a higher PCI score and better sensitivity than [18F]-FDG PET/CT for the detection of peritoneal carcinomatosis (6 vs. 18; P < 0.001; 72.09% vs. 97.67%; P = 0.002). Conclusion: [68Ga]Ga-DOTA-FAPI-04 PET/CT demonstrated superior sensitivity over [18F]-FDG PET/CT for the detection of peritoneal carcinomatosis in patients with various types of cancer, particularly gastric cancer. Furthermore, the uptake of [68Ga]Ga-DOTA-FAPI-04 in peritoneal carcinomatosis was significantly higher than that of [18F]-FDG, demonstrating a larger extent of the lesions and yielding a higher PCI score. This could help enhance the image contrast, improve physicians' diagnostic confidence, and reduce the proportion of missed diagnoses. [ABSTRACT FROM AUTHOR]

Objective: Programmed death-ligand 1 (PD-L1) expression status is a crucial index for identifying patients who will benefit from anti-programmed cell death protein 1 (PD-1)/PD-L1 therapy for non-small cell lung cancer (NSCLC). However, the concordance of Tumor Proportion Score (TPS) between biopsies and matched surgical specimens remains controversial. This study aims to evaluate the concordance of PD-L1 expression between image-guided percutaneous biopsies and matched surgical specimens. Method: We evaluated 157 patients diagnosed with operable NSCLC on both surgical tissue sections and matched lung biopsies retrospectively. The patients underwent either regular computed tomography (CT)-guided biopsy (n = 82) or positron emission tomography (PET)/CT-guided biopsy (n = 75). The concordance between surgical specimens and lung biopsies for PD-L1 TPS was evaluated using Cohen's kappa (κ) coefficient. Results: Immunohistochemical expression of PD-L1 was evaluated in both surgical resected specimens and matched biopsies in the eligible 138 patients. The concordance rate of PD-L1 expression between surgical tissue sections and matched biopsies was fairly high at 84.1% (116/138), and the κ value was 0.73 (95% CI: 0.63–0.83, P < 0.001). The concordance rate was higher for tissue sections from PET/CT-guided biopsy than for tissue sections from CT-guided biopsy [88.6% (62/70, κ value: 0.81) vs 79.4% (54/68, κ value: 0.66)]. Conclusion: PD-L1 TPS was strongly concordant between surgical specimens and matched lung biopsies. Thus, the routine evaluation of PD-L1 expression in diagnostic percutaneous biopsies could be reliable for identifying patients who will benefit from anti-PD-1/PD-L1 immunotherapy. [ABSTRACT FROM AUTHOR]

Purpose: This prospective study aimed to evaluate the potential usefulness of [68Ga]Ga-DOTA-FAPI-04 positron emission tomography/computed tomography (PET/CT) in the oncological evaluation of patients presenting with inconclusive [18F]FDG PET/CT findings. Methods: [68Ga]Ga-DOTA-FAPI-04 was performed in patients presenting with inconclusive [18F]FDG PET/CT findings. Tumour uptake was quantified by the maximum standard uptake value (SUV). Histopathology or follow-up imaging served as the standard for the final diagnosis. Results: A total of 68 patients with inconclusive [18F]FDG PET/CT findings underwent additional [68Ga]Ga-DOTA-FAPI-04 PET/CT. Of them, 18 (26.5%) were for discrimination of mass lesions detected on conventional imaging, 6 (8.8%) for detection of the unknown primary site in biopsy-proven metastatic malignancy, 21 (30.9%) for the staging of cancer, and the other 23 (33.8%) for evaluation of suspected disease recurrence. Most of the primary and metastatic lesions demonstrated higher uptake of [68Ga]Ga-DOTA-FAPI-04 than did [18F]FDG, which resulted in favourable tumour-to-background contrast in various types of cancer. As a result, [68Ga]Ga-DOTA-FAPI-04 PET/CT identified suspicious mass lesions with an accuracy of 12/18 (66.7%), detected the primary site in 4/6 patients (66.7%) with unknown malignancy, upgraded tumour staging in 7/21 patients (33.3%), and detected disease recurrence in 20/23 patients (87.0%). Conclusions: In patients undergoing oncological evaluation with inconclusive [18F]FDG PET/CT findings, [68Ga]Ga-DOTA-FAPI-04 may have a complementary role in discriminating mass lesions on conventional imaging, locating the primary site of unknown malignancy, modifying tumour staging, and detecting suspected disease recurrence. Nevertheless, careful attention should be paid when reading the [68Ga]Ga-DOTA-FAPI-04 PET/CT images in tumours complicated with inflammation. [ABSTRACT FROM AUTHOR]

Purpose: We evaluated the potential usefulness of [68Ga]Ga-DOTA-FAPI-04 positron emission tomography/computed tomography (PET/CT) for the diagnosis of primary and metastatic lesions in various types of cancer, compared with [18F] FDG PET/CT. Methods: A total of 75 patients with various types of cancer underwent contemporaneous [68Ga]Ga-DOTA-FAPI-04 and [18F] FDG PET/CT either for an initial assessment or for recurrence detection. Tumour uptake was quantified by the maximum standard uptake value (SUVmax). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of [18F] FDG and [68Ga]Ga-DOTA-FAPI-04 PET/CT were calculated and compared to evaluate the diagnostic efficacy. Results: The study cohort consisted of 75 patients (47 males and 28 females; median age, 61.5 years; age range, 32–85 years). Fifty-four patients with 12 different tumour entities underwent paired [68Ga]Ga-DOTA-FAPI-04 and [18F] FDG PET/CT for initial assessment, while the other 21 patients underwent paired scans for recurrence detection. [68Ga]Ga-DOTA-FAPI-04 PET/CT was able to clearly identify 12 types of malignant tumours with favourable tumour-to-background contrast, which resulted in a higher detection rate of primary tumours than did [18F] FDG PET/CT (98.2% vs. 82.1%, P = 0.021). Meanwhile, [68Ga]Ga-DOTA-FAPI-04 PET/CT showed a better sensitivity than [18F] FDG PET/CT in the detection of lymph nodes (86.4% vs. 45.5%, P = 0.004) and bone and visceral metastases (83.8% vs. 59.5%, P = 0.004). Conclusion: [68Ga]Ga-DOTA-FAPI-04 PET/CT showed a superior diagnostic efficacy than [18F] FDG PET/CT for the diagnosis of primary and metastatic lesions in patients with various types of cancer, especially in identifying liver metastases, peritoneal carcinomatosis, and brain tumours. [ABSTRACT FROM AUTHOR]

• 68Ga-FAPI PET/CT showed favourable tumour-to-background contrast compared to 18F-FDG PET/CT in oesophageal cancer. • SUV thresholds of FAPI ×20%, 30%, 40%, and FDG ×40% showed similar lesion lengths compared with endoscopic examination. • 68Ga-FAPI PET/CT may provide additional information for target volume delineation to avoid tumour geographic misses. To compare 68Ga-fibroblast activation protein inhibitor (FAPI) and 18F-FDG PET/CT in imaging locally advanced oesophageal cancer, and evaluate the potential usefulness of 68Ga-FAPI PET/CT on gross target volume (GTV) delineation aimed at radiotherapy planning for oesophageal cancer as compared with contrast-enhanced CT (CE-CT) and 18F-FDG PET/CT. Twenty-one patients with newly diagnosed oesophageal cancer who underwent both 18F-FDG and 68Ga-FAPI PET/CT scans were selected. GTVs of the primary tumours based on CE-CT (GTV CT), PET/CT, and CE-CT plus PET/CT were delineated. Gross tumour lengths were measured by GTVs and endoscopy and recorded. The 68Ga-FAPI PET showed significantly higher radiotracer uptake than 18F-FDG PET (median SUVmax 16.71 vs. 11.23; P = 0.002) in the primary tumours. SUV thresholds of FAPI ×20%, 30%, 40%, and FDG ×40% showed similar lesion lengths compared with that in endoscopic examination (P > 0.05). GTV CT demonstrated the largest volume (median: 48.80 mm3, range: 14.83–162.23 mm3) than PET-based GTVs. For PET/CT-guided complementary contouring of GTV CT , four patients (19%) were increased by FAPI ×20% and 30%, two patients (9.5%) were increased by FAPI ×40%, and only one patient was increased by FDG ×40%. Furthermore, the volume of GTV based on CE-CT plus FAPI ×20%, 30%, and 40% showed no significant difference with GTV CT and planning target volume based CE-CT plus FAPI-PET and meets the organ at risk standard. The 68Ga-FAPI PET/CT methodology showed favourable tumour-to-background contrast in oesophageal cancer and might provide additional information for target volume delineation and help avoid tumour geographic misses. [ABSTRACT FROM AUTHOR]