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Objectives: The aim of the study was to evaluate the predictive value of fluorine-18 fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) pretreatment on local control (LC) and survival after radical radiotherapy or chemoradiotherapy in patients with locally advanced esophageal squamous cell carcinoma (SCC) and to discuss its potential value for establishing optimal radiation treatment plans., Methods: Fifty-eight patients with pathologically proven esophageal SCC who underwent ¹⁸F-FDG PET/CT pretreatment in our center were retrospectively reviewed. We examined the correlation between the PET parameters of primary tumors and LC and overall survival. The coefficient of variation was used to estimate the ¹⁸F-FDG uptake in heterogeneity., Results: The mean duration of follow-up for surviving patients was 38 months, and 36 patients died because of tumor recurrence or other diseases. The rates of 3-year overall survival and LC were 40.4 and 50.4%, respectively. Multivariate analysis of LC revealed that metabolic tumor volume (MTV) greater than 16.08 ml was the only predictor of outcome, with a lower 3-year LC (P=0.017, hazard ratio: 1.608, 95% confidence interval: 1.090-2.371). The coefficient of variations of their primary lesion were higher compared with those of patients who had smaller MTVs., Conclusion: In this study, MTV assessed by PET/CT might be an adverse factor for predicting LC in esophageal SCC. For those with higher MTVs, higher intratumor heterogeneity suggests that irradiation may need to be boosted in stable high-uptake regions to improve LC. These results need to be prospectively validated in larger cohorts.

Purpose: Tumour burden is one of the most important prognosticators for pancreatic ductal adenocarcinoma (PDAC). The aim of this study was to investigate the predictive significance of metabolic tumour burden measured by (18)F-FDG PET/CT in patients with resectable PDAC., Methods: Included in the study were 122 PDAC patients who received preoperative (18)F-FDG PET/CT examination and radical pancreatectomy. Metabolic tumour burden in terms of metabolic tumour volume (MTV) and total lesion glycolysis (TLG), pathological tumour burden (tumour size), serum tumour burden (baseline serum CA19-9 level), and metabolic activity (maximum standard uptake value, SUVmax) were determined, and compared for their performance in predicting overall survival (OS) and recurrence-free survival (RFS)., Results: MTV and TLG were significantly associated with baseline serum CA19-9 level (P = 0.001 for MTV, P < 0.001 for TLG) and tumour size (P < 0.001 for MTV, P = 0.001 for TLG). Multivariate analysis showed that MTV, TLG and baseline serum CA19-9 level as either categorical or continuous variables, but not tumour size or SUVmax, were independent risk predictors for both OS and RFS. Time-dependent receiving operating characteristics analysis further indicated that better predictive performances for OS and RFS were achieved by MTV and TLG compared to baseline serum CA19-9 level, SUVmax and tumour size (P < 0.001 for all)., Conclusion: MTV and TLG showed strong consistency with baseline serum CA19-9 level in better predicting OS and RFS, and might serve as surrogate markers for prediction of outcome in patients with resectable PDAC.

Objectives: Maximum standardized uptake value (SUV(max)) is a marker of tumor glucose metabolism detected by [(18)F]-fluorodeoxyglucose ((18)F-FDG) PET/computed tomography (PET/CT) and reflects tumor aggressiveness. The aim of the study was to evaluate the value of SUV(max) in differentiating benign from malignant solitary pancreatic lesions and explore the correlation between SUV(max) and tumor proliferative activity., Materials and Methods: F-FDG PET/CT scans were performed in 80 patients with solitary pancreatic lesions who were scheduled for resective surgery. The relationships between SUV(max) and postoperative pathologic diagnosis, histologic grade, and Ki-67 proliferation index (PI) were analyzed., Results: Of these 80 patients, 54 had malignant lesions. The SUV(max) of malignant tumors (6.3 ± 2.4) was significantly greater than that of benign lesions (2.9 ± 2.0) (P<0.001). Receiver-operating characteristic curve analysis showed that the SUV(max) cutoff value of 3.5 had a high sensitivity (92.6%) and specificity (76.9%) for the diagnosis of malignancies. Among pancreatic cancers with low (Ki-67<5%), moderate (5% ≤ Ki-67<50%), and high (Ki-67 ≥ 50%) PI, SUV(max) increased significantly from 4.2 ± 1.2, through 6.0 ± 1.7, to 8.6 ± 2.5 (P<0.001). The SUV(max) had a positive correlation with Ki-67 PI (P<0.001, r=0.60)., Conclusion: The SUV(max) of F-FDG PET/CT can be used in the differential diagnosis of solitary pancreatic lesions and can also aid in the prediction of proliferative activity of pancreatic cancer.

There is an increasing need to develop non-invasive molecular imaging strategies for visualizing and quantifying apoptosis status of diseases (especially for cancer) for diagnosis and monitoring treatment response. Since externalization of phosphatidylserine (PS) is one of the early molecular events during apoptosis, Annexin B1 (AnxB1), a member of Annexins family with high affinity toward the head group of PS, could be a potential positron emission tomography (PET) imaging probe for imaging cell death process after labeled by positron-emitting nuclides, such as (18)F. In the present study, we investigated a novel PET probe, (18)F-labeled Annexin B1 ((18)F-AnxB1), for apoptosis imaging. (18)F-AnxB1 was prepared reliably by conjugating AnxB1 with a (18)F-tag, N-succinimidyl 4-[(18)F]fluorobenzoate ([(18)F]SFB), in a radiolabeling yield of about 20 % within 40 min. The in vitro binding of (18)F-AnxB1 with apoptotic cells induced by anti-Fas antibody showed twofold increase compared to those without treatment, confirmed by flow cytometric analysis with AnxV-FITC/PI staining. Stability tests demonstrated (18)F-AnxB1 was rather stable in vitro and in vivo without degradation. The serial (18)F-AnxB1 PET/CT scans in healthy rats outlined its biodistribution and pharmacokinetics, indicating a rapid renal clearance and predominant accumulation into kidney and bladder at 2 h p.i. (18)F-AnxB1 PET/CT imaging was successfully applied to visualize in vivo apoptosis sites in tumor induced by chemotherapy and in kidney simulated by ischemia-reperfusion injury. The high-contrast images were obtained at 2 h p.i. to delineate apoptotic tumor. Apoptotic region could be still identified by (18)F-AnxB1 PET 4 h p.i., despite the high probe retention in kidneys. In summary, we have developed (18)F-AnxB1 as a PS-specific PET probe for the apoptosis detection and quantification which could have broad applications from disease diagnosis to treatment monitoring, especially in the cases of cancer.

Two cases of postoperative female patients with ovarian serous papillary carcinoma were referred for F-18 Fluorodeoxyglucose (F-18 FDG) PET/CT to evaluate suspicious recurrence and/or metastasis. One patient presented with multiple extensive calcified lesions with increased FDG uptake in the abdominopelvic cavity and the series of PET/CT scans showed progression of disease after chemotherapy. The other patient presented with three calcified masses with intensive uptake of FDG located in the left pelvis, the right subphrenic region, and the right supradiaphragmatic area, respectively. These suggest that F-18 FDG PET/CT can be useful in identifying malignant calcification and assessing therapeutic response of calcified malignancy.