Zheng Fu

Diagnostic and Prognostic Value of 18F-FDG PET/CT for Patients with Suspected Recurrence from Squamous Cell Carcinoma of the Esophagus

Patients with esophageal squamous cell carcinoma (ESCC) are commonly at high risk of recurrence within 2 y after initial treatment. The aim of this study was to evaluate the role of 18F-FDG PET/CT in patients with possibly recurrent ESCC who underwent definitive treatment. Methods: Fifty-six patients with previously treated ESCC underwent PET/CT scans. The PET/CT findings were validated by histopathology or clinical follow-up of at least 6 mo. The sensitivity, specificity, and accuracy of PET/CT for detecting recurrence were calculated. Comparison of the standardized uptake value (SUV) was performed between patients grouped according to their status at the last follow-up (relapsed or relapse-free, alive or dead). The overall survival rates were estimated by the Kaplan–Meier method. The Cox proportional hazards model was used to evaluate independent prognostic variables for both univariate and multivariate survival analysis. Results: Forty-five (80.4%) patients had recurrence in 72 (66.1%) malignant sites. On PET/CT, there were 9 false-positive and 5 false-negative results. The overall sensitivity, specificity, and accuracy of PET/CT for detecting recurrence at all sites were 93.1% (67/72), 75.7% (28/37), and 87.2% (95/109), respectively. PET/CT was highly sensitive, specific, and accurate at regional and distant sites. At local sites, sensitivity was high, but specificity was lower (50%) because of a high incidence of false-positive findings. Patients who were confirmed with recurrence or who had died at the last follow-up had higher SUVs (P = 0.027 and <0.001, respectively). In multivariate survival analysis, therapeutic modality (hazard ratio = 0.437; P = 0.044), SUV (hazard ratio = 1.071; P = 0.029), and disease status on PET/CT (hazard ratio = 2.430; P = 0.045) were independent significant prognostic predictors for overall survival. The Kaplan–Meier survival curves indicated poor prognostic outcome in subgroup patients with higher SUVs or systemic disease on PET/CT. Conclusion: 18F-FDG PET/CT is highly effective for detecting recurrent ESCC. The relatively low specificity at local sites is associated primarily with a high rate of false-positive interpretations at anastomoses. PET/CT can also provide noninvasive and independent prognostic information using SUV and recurrent disease pattern on PET/CT images for previously treated ESCC.

PET-Based Biodistribution and Radiation Dosimetry of Epidermal Growth Factor Receptor–Selective Tracer 11C-PD153035 in Humans

The present study estimated the biodistribution and radiation-absorbed dose of epidermal growth factor receptor (EGFR) radioligand 11C-PD153035 in whole-body PET examinations of healthy volunteers. Methods: Two-dimensional whole-body PET was performed on 9 subjects after injection of 11C-PD153035 at 329.3 ± 77.8 MBq (mean ± SD). A total of 12 frames were acquired for approximately 90 min in 7 segments of the body. Regions of interest were drawn on PET images of source organs. Residence time was calculated as the area under the time–activity curve. Radiation dosimetry was calculated from organ residence time by use of MIRDOSE3 software. Results: The renal and hepatobiliary systems played important roles in 11C-PD153035 excretion from the body, accounting for the excretion of approximately 23% and 19% of the injected radioactivity, respectively. Blood-pool activity was only moderate and declined over time. Tracer accumulation in the lungs, bone marrow, and muscles was slight, resulting in low background activity in the chest. The organs with the highest radiation-absorbed doses were the urinary bladder and the gallbladder; the effective doses were 6.08E−02 ± 1.85E−02 and 2.40E−02 ± 8.01E−03 mGy/MBq, respectively. The effective dose equivalent was 7.43E−03 ± 1.10E−03 mSv/MBq, and the dose-limiting organ was the urinary bladder. Conclusion: On the basis of the estimated absorbed dose, 11C-PD153035 displayed a favorable radiation dose profile in humans and therefore could be used in multiple PET examinations of the same subject per year. 11C-PD153035 is a promising ligand for the investigation of EGFR in humans, especially in chest tumors such as non–small cell lung cancer.

Dual-time-point FDG PET for the evaluation of locoregional lymph nodes in thoracic esophageal squamous cell cancer.

PURPOSEnCompare dual-time-point and single-time 18F-FDG PET in the evaluation of locoregional lymph node metastases in patients with esophageal squamous cell cancer. Then assess the efficacy of dual-time-point PET in the diagnosis of such nodules.nnnMETHODSn34 patients with thoracic esophageal squamous cell cancer underwent dual-time-point PET before surgery. Semi-quantitative analysis was performed using the standardized uptake value (SUV), obtained from early and delayed images (SUVearly and SUVdelayed, respectively). The retention index (RI) calculated according to the equation: (SUVdelayed-SUVearly) x 100/SUVearly was assessed. Results were compared prospectively in relation to pathologic findings.nnnRESULTSn71 of 354 resected nodal groups from 28 patients were confirmed positive by pathology. SUVearly of 2.5 and RI of 10 were chosen as arbitrary cutoffs for differentiating malignancy from benign, the sensitivity, specificity, accuracy, negative and positive predictive value of dual-time-point PET were 88.73% (63/71 nodal groups), 91.87% (260/283), 91.24% (323/354), 97.01% (260/268) and 73.25% (63/86) respectively, those of single-time were 76.06% (54/71), 85.16% (241/283), 83.33% (295/354), 93.41% (241/258) and 56.25% (54/96) respectively. P values were 0.047, 0.012, 0.002, 0.052 and 0.017 respectively, indicating remarkable differences in sensitivity, specificity, accuracy, and positive predictive value between dual-time-point and single-time PET.nnnCONCLUSIONnDual-time-point 18F-FDG PET has the potential for improving the sensitivity, specificity, accuracy and positive predictive value in the evaluation of locoregional lymph nodes in thoracic esophageal squamous cell cancer.

Bone metastasis in patients with non-small cell lung cancer: The diagnostic role of F-18 FDG PET/CT

PURPOSEnTo evaluate the performance of F-18 FDG PET/CT in the detection of bone metastasis in non-small cell lung cancer (NSCLC) patients.nnnMATERIALS AND METHODSnThree hundred and sixty-two consecutive NSCLC patients who underwent F-18 FDG PET/CT scanning were retrospectively analyzed. Each image of PET/CT, combined CT, and PET was performed at 10 separate areas and interpreted blindly and separately. The sensitivity, specificity and accuracy of F-18 FDG PET/CT, combined CT and F-18 FDG PET were calculated and the results were statistically analyzed.nnnRESULTSnBone metastasis was confirmed in 82 patients with 331 positive segments based on the image findings and clinical follow-up. On patient-based analysis, the sensitivity of F-18 FDG PET/CT (93.9%) was significantly higher than those of combined CT (74.4%) and F-18 FDG PET (84.1%), respectively (p<0.05). The overall specificity and accuracy of combined CT, F-18 FDG PET, and F-18 FDG PET/CT were 90.7%, 93.2%, 98.9% and 87.0%, 91.2%, and 97.8%, respectively (compared with PET/CT, p<0.05). On segment-based analysis, the sensitivity of the three modalities were 79.5%, 94.3%, and 98.8%, respectively (compared with PET/CT, p<0.05). The overall specificity and accuracy of the three modalities were 87.9%, 89.2%, 98.6% and 84.5%, 91.2%, 98.7%, respectively (compared with PET/CT, p<0.05).nnnCONCLUSIONnF-18 FDG PET/CT is superior to F-18 FDG PET or combined CT in detecting bone metastasis of NSCLC patients because of the complementation of CT and PET. It is worth noting that the added value of F-18 FDG PET/CT may beneficially impact the clinical management of NSCLC.

18F-deoxyglucose positron emission tomography/computed tomography to predict local failure in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) patients are at risk for local failure (LF) following treatment. Predicting tumor regions at high risk for local failure before radiotherapy may increase treatment efficacy by permitting an escalated radiation dose specifically to those regions critical for tumor control. Forty-one patients with non-resectable locally advanced ESCC underwent 18F-deoxyglucose positron emission tomography/computed tomography (FDG PET/CT) imaging before concurrent chemoradiotherapy (CCRT). After CCRT, a second (failure) FDG PET/CT was performed in cases of relapse. Failure FDG PET/CT scans were fused to pre-treatment scans to identify tumor regions at high risk for LF. Within a median follow-up time of 26 months, 20 patients (48.8%) had LF. In 19 patients, the failure occurred within a pre-treatment high FDG uptake region; the failure occurred outside these regions in only one patient. Pre-treatment metabolic tumor volume (MTV) was independently associated with LF (P<0.001, HR 1.128, 95% CI: 1.061–1.198). LF was more likely in patients with MTVs ≥27 cm3. In initial PET/CT images, when 50% maximum standardized uptake value (SUVmax) was used as the threshold, delineated subvolumes overlapped LF regions. These results confirm that LF occurs most commonly within pre-treatment high FDG uptake regions.