OBJECTIVES: To evaluate the value of ⁶⁸Ga-DOTATATE and ¹⁸F-FDG PET/CT imaging in staging and treatment decision for gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN). METHODS: This retrospective analysis was conducted in 49 patients with GEP-NEN undergoing ¹⁸F-FDG and ⁶⁸Ga-DOTATATE PET/CT imaging at our hospital from August, 2020 to March, 2023, including 34 newly diagnosed patients and 15 patients with recurrence or metastasis after treatment. GEP-NEN were classified into G1, G2, and G3 neuroendocrine tumors (NET) and neuroendocrine carcinomas (NEC) based on pathological typing. The detection efficiency were classified into 4 patterns based on the number of positive tumor lesions detected by the two tracers: ⁶⁸Ga-DOTATATE>¹⁸F-FDG (A); ⁶⁸Ga-DOTATATE=¹⁸F-FDG (B); ⁶⁸Ga-DOTATATE<¹⁸F-FDG (C); and complementation (D). The value of dual-modality imaging in staging and treatment decision were evaluated by visual analysis. RESULTS: In the 49 patients with GEP-NEN, ⁶⁸Ga-DOTATATE PET/CT was superior to ¹⁸F-FDG PET/CT for detecting systemic tumor lesions (P<0.001) and more sensitive for detecting primary/recurrent lesions, lymph node metastasis, liver metastasis, and bone metastasis (P<0.05), while ¹⁸F-FDG PET/CT had higher detection rates for lung metastasis and peritoneal metastasis (P<0.05). In terms of the detection efficiency, Pattern A was found in 46.9% (23/49) patients, Pattern B in 38.8% (19/49), Pattern C in 12.2% (6/49), and Pattern D in 2.0% (1/49). The complementary value of ¹⁸F-FDG PET/CT to ⁶⁸Ga-DOTATATE PET/CT was 0% in G1 NET patients (0/13), 8.3% in G2 NET patients (2/24), 50% in G3 NET patients (3/6), and 33.3% in NEC patients (2/6). 12.2% (6/49) of the patients had their staging confirmed or changed due to additional lesions detected by ¹⁸F-FDG PET/CT imaging, resulting subsequently in establishment or adjustment of their treatment plans. CONCLUSIONS ⁶⁸Ga-DOTATATE PET/CT imaging should be the primary choice for GEP-NEN patients. Additional ¹⁸F-FDG PET/CT imaging can potentially improve precision of staging and treatment decision-making for G2, G3 and NEC patients but provides virtually no clinical benefits for G1 NET patients.
Humans ; Positron Emission Tomography Computed Tomography/methods* ; Neuroendocrine Tumors/therapy* ; Pancreatic Neoplasms/therapy* ; Retrospective Studies ; Organometallic Compounds ; Stomach Neoplasms/therapy* ; Neoplasm Staging ; Fluorodeoxyglucose F18 ; Intestinal Neoplasms/therapy* ; Female ; Male ; Middle Aged ; Aged ; Adult

Objective:To compare the diagnostic efficacy of 18F-fibroblast activation protein inhibitor (FAPI)-42 PET/CT and 18F-FDG PET/CT for bone metastasis in patients with malignant tumors. Methods:From January 2022 to October 2023, the data of 238 patients (160 males, 78 females; age: 58(50, 66) years) with various malignant tumors who underwent both 18F-FAPI-42 and 18F-FDG PET/CT imaging at Nanfang Hospital, Southern Medical University were retrospectively reviewed. An abnormal focal radioactive uptake in bones on the PET images was considered as positive lesion for bone metastasis. The efficacy of 2imaging methods and the supplementary role of CT in the diagnosis of bone metastasis were evaluated by McNemar test. Results:Of 238 patients, 95 were with bone metastases and 143 were without bone metastases, including 436 lesions with bone metastases and 358 lesions without bone metastases. Based on the visual analysis, 18F-FAPI-42 PET showed a higher diagnostic sensitivity than 18F-FDG PET (98.4%(429/436) vs 86.5%(377/436); χ2=41.95, P<0.001), while 18F-FDG PET had a higher diagnostic specificity than 18F-FAPI-42 PET (83.2%(298/358) vs 70.4%(252/358); χ2=22.50, P<0.001), and the accuracies of both methods were similar (85.8%(681/794) vs 85.0%(675/794); χ2=0.16, P=0.685). However, when the positive lesions seen in PET were analyzed combined with the image features on CT by the same scanner, the diagnostic specificity of 18F-FAPI-42 PET/CT was significantly improved compared to that of 18F-FAPI-42 PET alone (91.3%(327/358) vs 70.4%(252/358); χ2=73.01, P<0.001), and was similar to 18F-FDG PET/CT (93.0%(333/358); χ2=0.78, P=0.377). Meanwhile, this combined analysis brought a higher sensitivity and accuracy of 18F-FAPI-42 PET/CT than 18F-FDG PET/CT in diagnosing bone metastases (sensitivity: 98.4%(429/436) vs 86.5%(377/436); χ2=41.95, P<0.001; accuracy: 95.2%(756/794) vs 89.4%(710/794); χ2=21.54, P<0.001). Conclusions:The diagnostic sensitivity of 18F-FAPI-42 PET for bone metastasis is superior to 18F-FDG PET, but the specificity is lower. However, when CT features is combined for analysis, the diagnostic specificity of 18F-FAPI-42 PET/CT is significantly improved, which thus can be used to diagnose bone metastasis accurately and is superior to 18F-FDG PET/CT.

Objective To evaluate the value of 68Ga-DOTATATE and 18F-FDG PET/CT imaging in staging and treatment decision for gastroenteropancreatic neuroendocrine neoplasms(GEP-NEN).Methods This retrospective analysis was conducted in 49 patients with GEP-NEN undergoing 18F-FDG and 68Ga-DOTATATE PET/CT imaging at our hospital from August,2020 to March,2023,including 34 newly diagnosed patients and 15 patients with recurrence or metastasis after treatment.GEP-NEN were classified into G1,G2,and G3 neuroendocrine tumors(NET)and neuroendocrine carcinomas(NEC)based on pathological typing.The detection efficiency were classified into 4 patterns based on the number of positive tumor lesions detected by the two tracers:68Ga-DOTATATE>18F-FDG(A);68Ga-DOTATATE=18F-FDG(B);68Ga-DOTATATE<18F-FDG(C);and complementation(D).The value of dual-modality imaging in staging and treatment decision were evaluated by visual analysis.Results In the 49 patients with GEP-NEN,68Ga-DOTATATE PET/CT was superior to 18F-FDG PET/CT for detecting systemic tumor lesions(P<0.001)and more sensitive for detecting primary/recurrent lesions,lymph node metastasis,liver metastasis,and bone metastasis(P<0.05),while 18F-FDG PET/CT had higher detection rates for lung metastasis and peritoneal metastasis(P<0.05).In terms of the detection efficiency,Pattern A was found in 46.9%(23/49)patients,Pattern B in 38.8%(19/49),Pattern C in 12.2%(6/49),and Pattern D in 2.0%(1/49).The complementary value of 18F-FDG PET/CT to 68Ga-DOTATATE PET/CT was 0%in G1 NET patients(0/13),8.3%in G2 NET patients(2/24),50%in G3 NET patients(3/6),and 33.3%in NEC patients(2/6).12.2%(6/49)of the patients had their staging confirmed or changed due to additional lesions detected by 18F-FDG PET/CT imaging,resulting subsequently in establishment or adjustment of their treatment plans.Conclusion 68Ga-DOTATATE PET/CT imaging should be the primary choice for GEP-NEN patients.Additional 18F-FDG PET/CT imaging can potentially improve precision of staging and treatment decision-making for G2,G3 and NEC patients but provides virtually no clinical benefits for G1 NET patients.

Objective:To compare the diagnostic efficacy of 18F-fibroblast activation protein inhibitor (FAPI)-42 PET/CT and 18F-FDG PET/CT for bone metastasis in patients with malignant tumors. Methods:From January 2022 to October 2023, the data of 238 patients (160 males, 78 females; age: 58(50, 66) years) with various malignant tumors who underwent both 18F-FAPI-42 and 18F-FDG PET/CT imaging at Nanfang Hospital, Southern Medical University were retrospectively reviewed. An abnormal focal radioactive uptake in bones on the PET images was considered as positive lesion for bone metastasis. The efficacy of 2imaging methods and the supplementary role of CT in the diagnosis of bone metastasis were evaluated by McNemar test. Results:Of 238 patients, 95 were with bone metastases and 143 were without bone metastases, including 436 lesions with bone metastases and 358 lesions without bone metastases. Based on the visual analysis, 18F-FAPI-42 PET showed a higher diagnostic sensitivity than 18F-FDG PET (98.4%(429/436) vs 86.5%(377/436); χ2=41.95, P<0.001), while 18F-FDG PET had a higher diagnostic specificity than 18F-FAPI-42 PET (83.2%(298/358) vs 70.4%(252/358); χ2=22.50, P<0.001), and the accuracies of both methods were similar (85.8%(681/794) vs 85.0%(675/794); χ2=0.16, P=0.685). However, when the positive lesions seen in PET were analyzed combined with the image features on CT by the same scanner, the diagnostic specificity of 18F-FAPI-42 PET/CT was significantly improved compared to that of 18F-FAPI-42 PET alone (91.3%(327/358) vs 70.4%(252/358); χ2=73.01, P<0.001), and was similar to 18F-FDG PET/CT (93.0%(333/358); χ2=0.78, P=0.377). Meanwhile, this combined analysis brought a higher sensitivity and accuracy of 18F-FAPI-42 PET/CT than 18F-FDG PET/CT in diagnosing bone metastases (sensitivity: 98.4%(429/436) vs 86.5%(377/436); χ2=41.95, P<0.001; accuracy: 95.2%(756/794) vs 89.4%(710/794); χ2=21.54, P<0.001). Conclusions:The diagnostic sensitivity of 18F-FAPI-42 PET for bone metastasis is superior to 18F-FDG PET, but the specificity is lower. However, when CT features is combined for analysis, the diagnostic specificity of 18F-FAPI-42 PET/CT is significantly improved, which thus can be used to diagnose bone metastasis accurately and is superior to 18F-FDG PET/CT.

68Ga-DOTATATE/18F-FDG two-day low-dose total-body PET/CT imaging is increasingly employed to facilitate the diagnosis,prognosis,and heterogeneity assessment of neuroendocrine neoplasms.We present a consensus on operational guideline for a two-day combined imaging from experts in low-dose/ultra-low-dose total-body PET/CT from several domestic medical institutions.

Objective:To explore the relationship between 18F-fibroblast activation protein inhibitor (FAPI)-42 SUV max of primary gastric cancer and clinicopathological factors of patients. Methods:Fifty-one patients (31males, 20 females, age: 51(47, 65) years) with gastric cancer who underwent 18F-FAPI-42 PET/CT before surgical resection in Nanfang Hospital, Southern Medical University from February 2022 to January 2023 were analyzed retrospectively. The clinicopathological factors that might affect tumor SUV max (including gender, age, tumor location, pathological type, histological grade, Lauren classification, vascular and(or) neural invasion, programmed cell death-ligand 1 (PD-L1) expression, pathologic(p)T stage, pN stage and pTNM stage) were evaluated by the univariate analysis (Mann-Whitney U test or Kruskal-Wallis rank sum test) and multivariate analysis (multiple linear regression analysis). Results:The sensitivity of 18F-FAPI-42 PET/CT in the diagnosis of patients with primary gastric cancer was 82.35% (42/51). The diagnostic sensitivities for early gastric cancer (T1) and locally advanced gastric cancer (T2-T4) were 59.09%(13/22) and 100%(29/29), respectively. The SUV max of primary lesion was 4.90(1.71, 12.51). The univariate analysis showed that SUV max of primary gastric cancer was related to tumor location ( z=-2.00, P=0.046), pT stage ( H=36.94, P<0.001), pN stage ( z=-3.89, P<0.001), pTNM stage ( H=31.49, P<0.001) and vascular and(or) nerve invasion ( z=-5.22, P<0.001), but not related to pathological type, histological grade, Lauren typing, and PD-L1 expression ( z values: from -1.78 to -0.09, all P>0.05). pT stage was found to be a significant independent factor for SUV max in primary gastric lesion by multivariate analysis ( t=2.52, P=0.015). Conclusions:The 18F-FAPI-42 SUV max of primary tumor was related to tumor location, pT stage, pN stage, pTNM stage, and vascular and(or) nerve invasion; pT stage is an independent factor affecting tumor SUV max. The ability of 18F-FAPI-42 PET/CT to detect gastric cancer is mainly affected by pT stage.

In recent years, fibroblast activation protein (FAP) has emerged as an attractive target for the diagnosis and radiotherapy of cancers using FAP-specific radioligands. Herein, we aimed to design a novel ¹⁸F-labeled FAP tracer ([¹⁸F]AlF-P-FAPI) for FAP imaging and evaluated its potential for clinical application. The [¹⁸F]AlF-P-FAPI novel tracer was prepared in an automated manner within 42 min with a non-decay corrected radiochemical yield of 32 ± 6% (n = 8). Among A549-FAP cells, [¹⁸F]AlF-P-FAPI demonstrated specific uptake, rapid internalization, and low cellular efflux. Compared to the patent tracer [¹⁸F]FAPI-42, [¹⁸F]AlF-P-FAPI exhibited lower levels of cellular efflux in the A549-FAP cells and higher stability in vivo. Micro-PET imaging in the A549-FAP tumor model indicated higher specific tumor uptake of [¹⁸F]AlF-P-FAPI (7.0 ± 1.0% ID/g) compared to patent tracers [¹⁸F]FAPI-42 (3.2 ± 0.6% ID/g) and [⁶⁸Ga]Ga-FAPI-04 (2.7 ± 0.5% ID/g). Furthermore, in an initial diagnostic application in a patient with nasopharyngeal cancer, [¹⁸F]AlF-P-FAPI and [¹⁸F]FDG PET/CT showed comparable results for both primary tumors and lymph node metastases. These results suggest that [¹⁸F]AlF-P-FAPI can be conveniently prepared, with promising characteristics in the preclinical evaluation. The feasibility of FAP imaging was demonstrated using PET studies.

Objective:To explore and compare the value of radiomic features based on 18F-fluorodeoxyglucose (FDG) PET and CT in distinguishing epidermal growth factor receptor (EGFR) mutation status in patients with lung adenocarcinoma. Methods:Pretreatment 18F-FDG PET/CT images and EGFR gene status of 114 patients (64 males and 50 females, aged range: 35-84 (average age: 61) years) with primary lung adenocarcinoma between January 2017 and December 2017 were retrospectively collected. The volume of interest was drawn manually slice by slice, then the features were extracted by the LIFEx software. The parameters were screened by least absolute shrinkage and selection operator (LASSO) method for 200 times, and ten-fold cross-validation was used to select the best tuning parameter λ. Three models, namely M PET, M CT, M PET+ CT, were constructed by binary logistic stepwise regression. The receiver operating characteristic (ROC) curve was generated and the corresponding area under the curve (AUC), sensitivity, specificity and accuracy were calculated. The AUCs of three models were compared by Delong test. Results:Totally, 53.51%(61/114) patients were with wild type EGFR and 46.49%(53/114) patients had EGFR mutation. There were 3, 3, 7 parameters selected to form M PET, M CT, M PET+ CT, respectively. The AUCs for M PET, M CT, M PET+ CT were 0.730, 0.752 and 0.866 respectively. When the cut-off values were 0.427, 0.522, 0.378 for M PET, M CT and M PET+ CT, the Youden index were up to the maximum as 0.420, 0.405, 0.630, with sensitivities of 83.0%(44/53), 58.5%(31/53), 92.5%(49/53), specificities of 59.0%(36/61), 82.0%(50/61), 70.5%(43/61) and accuracies of 70.2%(80/114), 71.1%(81/114), 80.7%(92/114), respectively. There was no significant difference between AUC of M PET and M CT ( z=-0.320, P>0.05). The differences of AUCs between M PET+ CT and M PET, M PET+ CT and M CT were statistically significant ( z values: 2.963, 2.523, both P<0.05). Conclusions:PET, CT and PET+ CT radiomic features are all associated with EGFR gene expression in lung adenocarcinoma. M PET+ CT has the highest predictive efficiency.

Objective To investigate the clinical value of radiomics nomogram,which is established by 18F-fluorodeoxyglucose (FDG) PET/CT radiomics signature combined with clinical-pathologic risk factors,in predicting the prognosis of patients with postoperative gastric carcinoma.Methods 18F-FDG PET/CT data of 207 patients (143 males,64 females,age range:20-85 years) with postoperative gastric carcinoma from January 2008 to August 2015 was reviewed retrospectively.Patients were divided into training group (n=104) and validation group (n =103),and the clinicopathologic information and disease-free survival (DFS) data were acquired.Significant textural features were selected from PET/CT images,and radiomics score (RS) for individual patient was calculated based on the radiomics signatures.The relationship between RS and DFS was analyzed.Cox regression analysis was performed to determine the risk factors ofDFS.The radiomics nomo-gram,obtained from combination of RS with clinicopathologic risk factors,was established and further evaluated in predictive value for recurrence or metastasis of postoperative gastric carcinoma,and the concordance index (C-index) was calculated.Results Cox regression analysis demonstrated that RS,tumor location,depth of invasion,lymph node metastasis,and distant metastasis were the significant risk factors for DFS (hazard ratios:2.148-2.828,all P＜0.05).The radiomics nomogram combined with RS and 4 clinicopathologic risk factors had a better prediction for the estimated DFS,comparing to RS alone.C-index of radiomics nomogram and RS were 0.830 and 0.700 in training group,and 0.776 and 0.681 in validation group,respectively.Conclusion Radiomics nomogram which is established by radiomics signatures and clinicopathologic risk factors may be better for predicting DFS of patients with postoperative gastric carcinoma.

Objective To explore the differences in the prognosis of patients with different immunophenotypes gastrointestinal diffuse large B-cell lymphoma (GI-DLBCL) who received different treatment strategies.Methods From March 2006 to January 2016,at Nanfang Hospital,Southern Medical University in Guangzhou,the clinical data of 99 patients with pathologically confirmed GI-DLBCL were retrospectively analyzed.According to treatment strategies,patients were divided into chemotherapy alone group and combination of surgery and chemotherapy group.According to immunophenotypes,patients were divided into germinal center B-cell-like (GCB) type and non-GCB type.The two-year progression-free survival (PFS) rate and overall survival (OS) rate were evaluated.Kaplan-Meier analysis,log-rank test and Cox regression were performed for statistical analysis.Results Among the 99 patients with GI-DLBCL,51 patients were treated with chemotherapy alone,and 48 patients were treated with combination of surgery and chemotherapy.Forty-one cases were GCB phenotype and 40 cases were non-GCB phenotype.The median follow-up time was 25 months.The two-year PFS and OS rates were 70.9％ and 89.5％,respectively.The two-year PFS and OS rates of chemotherapy alone group were 63.6％ and 85.0％,respectively;both were lower than those of combination of surgery and chemotherapy group (79.4％ and 94.7％),and the differences were statistically significant (x2 =4.232,P =0.040 and x2 =4.260,P =0.039).The two-year PFS and OS rates of GCB group were 68.8％ and 93.9％,respectively.And the two-year PFS and OS rates of non-GCB group were 73.2％ and 85.6％,respectively.There were no statistically significant differences between these two groups (both P ＞ 0.05).Among 41 patients with GCB type,25 were treated with combination of surgery and chemotherapy and 16 were treated with chemotherapy alone.The two-year PFS rate of patients treated with combination of surgery and chemotherapy (83.1％) was higher than that of patients treated with chemotherapy alone (49.2％),and the difference was statistically significant (x2 =5.627,P =0.018).The results of multivariate analysis indicated that treatment strategy was not an independent prognostic factor for all the enrolled patients and in patients with GCB type (all P ＞ 0.05).Conclusions Immunophenotypes may lack evaluation value of prognosis in patients with GI-DLBCL.Although among all the enrolled patients and patients with GCB type,the prognosis of patients treated with combination of surgery and chemotherapy is better than that of patients treated with chemotherapy alone,treatment strategy is not an independent prognostic factor.Multi-factors should be evaluated before selection of treatment strategy.