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Purpose: To compare the detection ability of 68Ga-labelled DOTA-l-Nal3-octreotide ([68Ga]Ga-DOTA-NOC) and 6-[18F]fluoro-L-3,4-dihydroxyphenylalanine ([18F]DOPA) in patients with phaeochromocytomas and paragangliomas (PPGLs) of different origins and gene mutations, such as germline succinate dehydrogenase complex genes (SDHx). Methods: Eighty-five patients with histopathologically confirmed PPGLs who underwent both [68Ga]Ga-DOTA-NOC and [18F]DOPA PET/CT from March 2017 to June 2023 were enrolled in this retrospective study. For comparative analyses, PPGLs were classified as phaeochromocytoma (PCC), sympathetic paraganglioma (sPGL), and head/neck paraganglioma (HNPGL). Detection rates were analyzed on per-patient and per-lesion bases and compared using the Chi-square/Fischer's exact test. Results: Among 85 patients with PPGLs (48 males; 43 years ± 17 [SD]), the patient-based detection rates of [68Ga]Ga-DOTA-NOC and [18F]DOPA PET/CT were 87.1% (74/85) and 89.4% (76/85), respectively (p = 0.634), and the lesion-based detection rates were 80.8% (479/593) and 71.2% (422/593), respectively (p < 0.001). Only one patient with a recurrent PCC presented double-negative imaging, while 66 patients exhibited double-positive imaging. The remaining patients were either [68Ga]Ga-DOTA-NOC-negative/[18F]DOPA-positive (n = 10) or [68Ga]Ga-DOTA-NOC-positive/[18F]DOPA-negative (n = 8). In subgroup analyses, [68Ga]Ga-DOTA-NOC PET/CT detected significantly more metastases of sPGL (91.1%, 236/259) and SDHx-related PPGL (89.6%, 86/96) than [18F]DOPA PET/CT (48.6%[126/259] and 50.0%[48/96], respectively; both p < 0.001). However, [18F]DOPA showed significantly higher detection rates of PCC in both primary/recurrent and metastatic lesions (94.3%[50/53] vs. 62.3%[33/53] and 87.9%[174/198] vs. 69.2%[137/198], respectively; both p < 0.001). Regarding metastases in different organs, [68Ga]Ga-DOTA-NOC PET/CT detected more lesions than [18F]DOPA PET/CT in bone (96.2%[176/183] vs. 66.1%[121/183]; p < 0.001) and lymph nodes (82.0%[73/89] vs. 53.9%[48/89]; p < 0.001) but less lesions in peritoneum (20%[4/20] vs. 100%[20/20]; p < 0.001). Conclusion: [68Ga]Ga-DOTA-NOC and [18F]DOPA are complementary in diagnosing PPGL under the appropriate clinical setting. [68Ga]Ga-DOTA-NOC should be considered as the ideal first-line tracer for detecting metastases of sPGL and SDHx-related tumours, whereas [18F]DOPA may be the optimal tracer for evaluating non-SDHx-related PCC, especially in detecting primary lesions and monitoring recurrence. [ABSTRACT FROM AUTHOR]

Objectives: This prospective study compared the detection efficacy of analog 18F-fluoro-2-deoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) (aF PET/CT), digital [18F]FDG PET/CT (dF PET/CT), and digital 13N-ammonia (13N-NH3) PET/CT (dN PET/CT) for patients with lung adenocarcinoma featuring ground glass nodules (GGNs). Methods: Eighty-seven patients with lung adenocarcinoma featuring GGNs who underwent dF and dN PET/CT were enrolled. Based on the GGN component, diameter, and solid-part size, 87 corresponding patients examined using aF PET/CT were included, with age, sex, and lesion characteristics closely matched. Images were visually evaluated, and the tumor to background ratio (TBR) was used for semi-quantitative analysis. Results: Ultimately, 40 and 47 patients with pure GGNs (pGGNs) and mixed GGNs (mGGNs), respectively, were included. dF PET/CT revealed more positive lesions and higher tracer uptake in GGNs than did aF PET/CT (53/87 vs. 26/87, p < 0.05; TBR: 3.08 ± 4.85 vs. 1.42 ± 0.93, p < 0.05), especially in mGGNs (44/47 vs. 26/47, p < 0.05; TBR: 4.48 ± 6.17 vs. 1.78 ± 1.16, p < 0.05). However, dN PET/CT detected more positive lesions than did dF PET/CT (71/87 vs. 53/87, p < 0.05), especially in pGGNs (24/40 vs. 9/40, p < 0.05). Conclusions: dF PET/CT provides superior detection efficacy over aF PET/CT for patients with lung adenocarcinoma featuring GGNs, particularly mGGNs. dN PET/CT revealed superior detection efficacy over dF PET/CT, particularly in pGGNs. aF, dF, and dN PET/CT are valuable non-invasive examinations for lung cancer featuring GGNs, with dN PET/CT offering the best detection performance. Key Points: • Digital PET/CT provides superior detection efficacy over analog PET/CT in patients with lung adenocarcinoma featuring GGNs. • dN PET/CT can offer more help in the early detection of malignant GGN. [ABSTRACT FROM AUTHOR]

Purpose: This prospective study was aimed to investigate the potential utility of [18F]fibroblast activation protein inhibitor (FAPI) PET/CT for evaluating focal liver lesions (FLLs) with [18F]FDG non-avidity. Methods: From January 2021 to March 2022, this prospective study included 80 FLLs that were not avid on [18F]FDG PET/CT from 37 patients, then underwent [18F]FAPI PET/CT. All patients with FLL(s) with biopsy-proof or follow-up confirmation were categorized into four subgroups (20 hepatocellular carcinomas [HCCs]/5 non-HCC malignancies/4 inflammatory FLLs/8 benign noninflammatory FLLs). The diagnostic value of [18F]FAPI for detecting liver malignancy was determined by visual evaluation. Differences in the maximum standardized uptake value (SUVmax) and lesion-to-background ratio (LBR) obtained from [18F]FAPI PET/CT among the four subgroups were analyzed by semiquantitative analysis. Results: Among the thirty-seven enrolled participants (34 males; median age 57 years, range 48–67 years), on visual evaluation, the sensitivity, specificity, and accuracy of [18F]FAPI PET for detecting liver malignancy in the patient-based analysis were 96.0% (24/25), 58.3% (7/12), and 83.8% (31/37), respectively. On semiquantitative analysis, the SUVmax and LBR of [18F]FAPI PET in liver malignancy (33 HCC lesions; 19 non-HCC malignant lesions) were significantly higher than those in 11 benign noninflammatory FLLs [HCC: SUVmax: 6.4 vs. 4.5, P = 0.017; LBR: 5.1 vs. 1.5, P = 0.003; non-HCC: SUVmax: 5.5 vs. 4.5, P = 0.008; LBR: 4.4 vs. 1.5, P = 0.042]. Notably, there was no significant difference in the SUVmax of [18F]FAPI PET between 33 HCC lesions and 17 inflammatory FLLs (6.4 vs. 8.2, P = 0.37), but the LBR of [18F]FAPI PET in HCC were significantly lower than that in inflammatory FLLs (5.1 vs. 9.1, P = 0.003). Conclusions: [18F]FAPI PET/CT shows high sensitivity in detecting HCC and non-HCC malignancy with [18F]FDG non-avidity. [18F]FAPI might be a promising radiopharmaceutical for the differential diagnosis of benign noninflammatory FLLs and liver malignancy with [18F]FDG non-avidity. [ABSTRACT FROM AUTHOR]

Background: This study aimed to assess the clinical usefulness of 13N-ammonia and 11C- Methionine (MET) positron emission tomography (PET)/ computed tomography (CT) in the differentiation of residual/recurrent pituitary adenoma (RPA) from the pituitary gland remnant (PGR) after trans-sphenoidal adenomectomy.Methods: Between June 2012 and December 2019, a total of 19 patients with a history of trans-sphenoidal adenomectomy before PET/CT scans and histological confirmation of RPA after additional surgery in our hospital were enrolled in this study. Images were interpreted by visual evaluation and semi-quantitative analysis. In semi-quantitative analysis, the maximum standard uptake value (SUVmax) of the target and gray matter was measured and the target uptake/gray matter uptake (T/G) ratio was calculated.Results: The T/G ratios of 13N-ammonia were significantly higher in PGR than RPA (1.58 ± 0.69 vs 0.63 ± 1.37, P < 0.001), whereas the T/G ratios of 11C-MET were obviously lower in PGR than RPA (0.78 ± 0.35 vs 2.17 ± 0.54, P < 0.001). Using the canonical discriminant analysis, we calculated the predicted accuracy of RPA (100%), PGR (92.9%), and the overall predicted accuracy (96.43%).Conclusions: The combination of 13N-ammonia and 11C-MET PET/CT is valuable in the differentiation of RPA from PGR after trans-sphenoidal adenomectomy. [ABSTRACT FROM AUTHOR]