PURPOSE: To compare the performance of fluorine-18 fluorodeoxyglucose positron emission tomography and computed tomography (FDG PET/CT) with conventional imaging methods (CIM), including computed tomography (CT), magnetic resonance imaging (MRI), and mammography (MMG) in cancer of unknown primary (CUP).METHODS: A total of 36 patients with CUP, who referred to our clinic for a FDG PET/CTscan, were enrolled in this study. Thirty of the patients were also examined through either diagnostic CT/MRI and/or MMG. The diagnostic performance of both methods for the primary cancer location was analyzed. The results of FDG PET/CT and CIM were compared based on the standard reference of the histopathology and/or clinical and laboratory follow-up.RESULTS: The primary cancer locations were detected in 24 patients (66.6%, 24/36) by FDG PET/CT, whereas CIM identified the locations in 16 patients (53.3%, 16/30). Sensitivity, specificity, PPV, NPV, and accuracy rates of the detection of the primary tumor localizations were as follows: 83, 70, 89, 58, and 79% for FDG PET/CT; 70, 62, 84, 42, and 68% for CIM, respectively. There was no statistical significance between modalities regarding any of the categories in 30 patients.CONCLUSION: FDG PET/CT detected the primary tumors of the patients with CUP more than CIM did. However, the difference between them was not found to be statistically significant. It may be considered that FDG PET/CT scan can be performed as a first-line tool in the initial diagnosis of the patients with CUP and to add radiodiagnostic imaging in selective cases.We conclude that if the first-line examination of a CUP patient has been already performed by a CIM and the result was negative or inconclusive, FDG PET/CT can be considered to avoid unnecessary imaging procedures.
Diagnosis ; Follow-Up Studies ; Humans ; Magnetic Resonance Imaging ; Mammography ; Methods ; Positron-Emission Tomography ; Positron-Emission Tomography and Computed Tomography ; Sensitivity and Specificity

Occupational pneumoconiosis is one of the main occupational diseases in China. Progressive massive fibrosis in pneumoconiosis should be distinguished from lung cancer for their similar imaging features which is often identified by (18)F-FDG PET-CT in clinic. Here we reported two cases of pneumoconiosis. Both of them were suspected of carrying malignant tumors by preoperative PET-CT exam, however, nodules in these two patients were all proved to be benign by intraoperative pathology which suggested that there is false-positive possibility in the distinguishment of pneumoconiosis nodules by (18)F-FDG PET-CT.
Fibrosis ; Fluorodeoxyglucose F18 ; Humans ; Lung Neoplasms/pathology* ; Pneumoconiosis/pathology* ; Positron Emission Tomography Computed Tomography ; Positron-Emission Tomography/methods*

Prostate cancer is the most common malignant tumor in male urinary system, and the morbidity and mortality rate are increasing year by year. Traditional imaging examinations have some limitations in the diagnosis of prostate cancer, and the advent of molecular imaging probes and imaging technology have provided new ideas for the integration of diagnosis and treatment of prostate cancer. In recent years, prostate-specific membrane antigen (PSMA) has attracted much attention as a target for imaging and treatment of prostate cancer. PSMA ligand positron emission tomography (PET) has important reference value in the diagnosis, initial staging, detection of biochemical recurrence and metastasis, clinical decision-making guidance and efficacy evaluation of prostate cancer. This article briefly reviews the clinical research and application progress on PSMA ligand PET imaging in prostate cancer in recent years, so as to raise the efficiency of clinical applications.
Male ; Humans ; Prostate/pathology* ; Ligands ; Positron Emission Tomography Computed Tomography/methods* ; Prostatic Neoplasms/diagnostic imaging* ; Positron-Emission Tomography

This paper introduced the imaging principle, data acquisition method and image characteristics of PET/CT; Then reviewed several image reconstruction methods widely used in PET/CT at present in detail, such as FBP, ML-EM, 3DRP and so on. Finally, the advantages and disadvantages of these methods were summarized and compared.
Image Interpretation, Computer-Assisted ; methods ; Positron-Emission Tomography ; methods ; Tomography, X-Ray Computed ; methods

The applications of PET-CT have developed from qualitative analysis to quantitative analysis. Target volume is important for tumor biological volume defining, tumor isotope therapy, organ function evaluation, acceptor affinity calculation, and pharmaceutical metabolic kinetics. Many factors work on the target volume calculation, such as PET image acquisition mode, scatter correction, attenuation correction, reconstruction method, image display mode, positron pharmacy. The commonly-used methods of target volume calculation are background-threshold, max threshold, and background-max threshold. In this article we will discuss about the methods of target volume calculation.
Algorithms ; Positron-Emission Tomography ; methods ; Radiotherapy Planning, Computer-Assisted ; methods ; Tomography, X-Ray Computed ; methods

Fluorodeoxyglucose F18 ; Humans ; Lymphoma ; diagnostic imaging ; Positron-Emission Tomography ; methods ; Tomography, X-Ray Computed ; methods

OBJECTIVE: Diffuse large B-cell lymphoma (DLBCL) is often associated with bone marrow infiltration, and 2-deoxy-2-(18F) fluorodeoxyglucose positron emission tomography/computed tomography ( ¹⁸F-FDG PET/CT) has potential diagnostic significance for bone marrow infiltration in DLBCL. METHODS: A total of 102 patients diagnosed with DLBCL between September 2019 and August 2022 were included. Bone marrow biopsy and ¹⁸F-FDG PET/CT examinations were performed at the time of initial diagnosis. Kappa tests were used to evaluate the agreement of ¹⁸F-FDG PET/CT with the gold standard, and the imaging features of DLBCL bone marrow infiltration on PET/CT were described. RESULTS: The total detection rate of bone marrow infiltration was not significantly different between PET/CT and primary bone marrow biopsy ( P = 0.302) or between the two bone marrow biopsies ( P = 0.826). The sensitivity, specificity, and Youden index of PET/CT for the diagnosis of DLBCL bone marrow infiltration were 0.923 (95% CI, 0.759-0.979), 0.934 (95% CI, 0.855-0.972), and 0.857, respectively. CONCLUSION ¹⁸F-FDG PET/CT has a comparable efficiency in the diagnosis of DLBCL bone marrow infiltration. PET/CT-guided bone marrow biopsy can reduce the misdiagnosis of DLBCL bone marrow infiltration.
Humans ; Positron Emission Tomography Computed Tomography/methods* ; Fluorodeoxyglucose F18 ; Bone Marrow/pathology* ; Retrospective Studies ; Positron-Emission Tomography/methods* ; Lymphoma, Large B-Cell, Diffuse/pathology*

OBJECTIVE: To explore the diagnostic value of ¹⁸F-FDG PET/CT in bone marrow infiltration (BMI) of newly diagnosed diffuse large B-cell lymphoma (DLBCL), compared with the results of bone marrow biopsy (BMB) and investigate whether the BMI diagnosed by ¹⁸F-FDG PET/CT and other factors have independent prognostic values. METHODS: Ninety-four newly diagnosed DLBCL patients who underwent PET/CT in Clinical Medical College of Shanghai General Hospital of Nanjing Medical University were included. BMB was performed within 2 weeks before or after PET/CT, and standardized treatment was performed after PET/CT. The manifestations of bone marrow (BM) FDG uptake were recorded. The diagnostic criteria of BMI were BMB positive or focal BM FDG uptake confirmed by imaging follow-up. The relationship between clinical features and BM FDG uptake and the values of PET/CT and BMB in the diagnosis of BMI was analyzed. The progression-free survival (PFS) was analyzed by Kaplan-Meier survival curves, log-rank test was used to compare PFS rate, and Cox regression model was used to analyze the independent risk factors affecting PFS. RESULTS: Among 94 DLBCL patients, 34 patients showed focal BM uptake (fPET), 7 patients showed super BM uptake (sBMU), 11 patients showed diffuse homogenous uptake higher than liver (dPET), and the other 42 patients had normal BM uptake (nPET) (lower than liver). BMB positive was found in all sBMU patients, in 20.6%(7/34) of fPET patients, and in 27.3% (3/11) of dPET patients. All nPET patients had negative BMB results. dPET patients were associated with lower hemoglobin level and leukocyte count compared with nPET group (P < 0.001, P =0.026). Compared with fPET patients, sBMU patients were more likely to have B symptoms and elevated lactate dehydrogenase (LDH). A total of 44 patients were diagnosed BMI, including 17 cases with BMB⁺. The sensitivity and specificity of BMB in the diagnosis of BMI was 38.6% (17/44) and 100% (50/50), respectively. Using fPET and sBMU as criteria of PET BMI, the diagnostic sensitivity and specificity of PET/CT was 93.2% (41/44) and 100% (50/50), respectively. Kaplan-Meier analysis showed that there was no significant difference in 2-year PFS rate between nPET and dPET patients (P >0.05), while sBMU patients had lower 2-year PFS rate compared with fPET patients (P < 0.001). Multivariate analysis showed that higher Ann Arbor stage (HR=9.010, P =0.04) and sBMU (HR=3.964, P =0.002) were independent risk factors affecting PFS. CONCLUSIONS Increased BM FDG uptake of DLBCL can be manifested as dPET, fPET and sBMU. fPET and sBMU can replace BMB to diagnose BMI. Although dPET cannot completely exclude the possibility of BMI, it does not affect the prognosis, so it can be diagnosed as PET BMI negative. sBMU is an independent prognostic risk factor.
Humans ; Positron Emission Tomography Computed Tomography/methods* ; Fluorodeoxyglucose F18 ; Prognosis ; Bone Marrow/pathology* ; Retrospective Studies ; China ; Positron-Emission Tomography/methods* ; Lymphoma, Large B-Cell, Diffuse/pathology* ; Biopsy

OBJECTIVES: The purpose of this study was to compare lymph node (LN) staging using ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) with contrast-enhancement (CE) PET/CT and contrast-enhanced neck CT (neck CT) in patients with thyroid cancer with level-by-level comparison with various factors. METHODS: This was a retrospective multicenter study. A total of 85 patients were enrolled. Patients who underwent a preoperative evaluation by CE PET/CT and neck CT for thyroid cancer were enrolled. The gold standard for LN was the combination of surgical pathology and clinical follow-up. We compared CE PET/CT with neck CT using a level-by-level method. Factors, including age, sex, camera, arm position, tumor size, extra-thyroidal extension, tumor location, number of primary tumors, primary tumor maximum standardized uptake value, and the interval from scan to operation were also analyzed. RESULTS: Overall accuracy was 81.2% for CE PET/CT and 68.2% for neck CT. CE PET/CT was more sensitive than neck CT (65.8% vs. 44.7%). Also, CE PET/CT showed higher negative predictive value (77.2% vs. 66.1%). CE PET/CT showed good agreement with the gold standard (weighted kappa [κ], 0.7) for differentiating N0, N1a, and N1b, whereas neck CT showed moderate agreement (weighted κ, 0.5). CE PET/CT showed better agreement for the number of levels involved with the gold standard (weighted κ, 0.7) than that of neck CT with the gold standard (weighted κ, 0.5). The accuracies for differentiating N0, N1a, and N1b were 81.2% for CE PET/CT and 68.2% for neck CT. Level-by-level analysis showed that CE PET/CT was more sensitive and has higher negative predictive value for detecting ipsilateral level IV and level VI LNs than neck CT. Other analyzed factors were not related to accuracies of both modalities. CONCLUSION: CE PET/CT was more sensitive and reliable than neck CT for preoperative LN staging in patients with thyroid cancer.
Arm ; Electrons ; Fluorodeoxyglucose F18 ; Follow-Up Studies ; Humans ; Lymph Nodes* ; Methods ; Neck* ; Pathology, Surgical ; Positron-Emission Tomography ; Positron-Emission Tomography and Computed Tomography* ; Retrospective Studies ; Thyroid Gland* ; Thyroid Neoplasms*

BACKGROUND/AIMS: ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) has been suggested as a reliable imaging technique for monitoring of disease activity in patients with adult-onset Still’s disease (AOSD). Therefore, we investigated the clinical significance of ¹⁸F-FDG PET/CT in Korean AOSD patients. METHODS: Thirteen AOSD patients were included in the study. The PET/CT images were evaluated with visual and semiquantitative method using standardized uptake values (SUVs). RESULTS: The presence of increased ¹⁸F-FDG uptake was noted in 90% of clinically active AOSD patients. ¹⁸F-FDG uptake was located in the lymph node, spleen, and bone marrow. Visual grade and SUV intensity of lymph node was significantly correlated with the systemic score of AOSD. Visual grade of spleen was significantly correlated with the systemic score, erythrocyte sedimentation rate (ESR), and ferritin. Additionally, visual grade and SUV intensity of bone marrow was significantly correlated with the systemic score, ESR, leukocyte, and neutrophil. CONCLUSIONS: Visual grade and SUV intensity of lymph node, spleen, and bone marrow on ¹⁸F-FDG PET/CT scan showed significant correlations with known disease activity markers. The data suggest that ¹⁸F-FDG PET/CT scan may be a useful imaging technique for evaluation of disease activity in AOSD patients.
Blood Sedimentation ; Bone Marrow ; Electrons* ; Ferritins ; Humans ; Leukocytes ; Lymph Nodes ; Methods ; Neutrophils ; Positron-Emission Tomography and Computed Tomography ; Positron-Emission Tomography* ; Spleen