• Korean Journal of Radiology
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• v.24 no.1
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• pp.51-61
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• 2023

Objective: To develop and test a machine learning model for classifying human papillomavirus (HPV) status of patients with oropharyngeal squamous cell carcinoma (OPSCC) using ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET-derived parameters in derived parameters and an appropriate combination of machine learning methods in patients with OPSCC. Materials and Methods: This retrospective study enrolled 126 patients (118 male; mean age, 60 years) with newly diagnosed, pathologically confirmed OPSCC, that underwent ¹⁸F-FDG PET-computed tomography (CT) between January 2012 and February 2020. Patients were randomly assigned to training and internal validation sets in a 7:3 ratio. An external test set of 19 patients (16 male; mean age, 65.3 years) was recruited sequentially from two other tertiary hospitals. Model 1 used only PET parameters, Model 2 used only clinical features, and Model 3 used both PET and clinical parameters. Multiple feature transforms, feature selection, oversampling, and training models are all investigated. The external test set was used to test the three models that performed best in the internal validation set. The values for area under the receiver operating characteristic curve (AUC) were compared between models. Results: In the external test set, ExtraTrees-based Model 3, which uses two PET-derived parameters and three clinical features, with a combination of MinMaxScaler, mutual information selection, and adaptive synthetic sampling approach, showed the best performance (AUC = 0.78; 95% confidence interval, 0.46-1). Model 3 outperformed Model 1 using PET parameters alone (AUC = 0.48, p = 0.047) and Model 2 using clinical parameters alone (AUC = 0.52, p = 0.142) in predicting HPV status. Conclusion: Using oversampling and mutual information selection, an ExtraTree-based HPV status classifier was developed by combining metabolic parameters derived from ¹⁸F-FDG PET/CT and clinical parameters in OPSCC, which exhibited higher performance than the models using either PET or clinical parameters alone.

• 대한핵의학회:학술대회논문집
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• 1999.11a
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• pp.21.2-21.2
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• 1999

• 대한핵의학회:학술대회논문집
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• 2004.11a
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• pp.399.1-399.1
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• 2004

• Korean Journal of Radiology
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• v.25 no.8
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• pp.742-748
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• 2024

Objective: ¹⁸F-N-(2-(Diethylamino)ethyl)-5-(2-(2-(2-fluoroethoxy)ethoxy)ethoxy) picolinamide (¹⁸F-PFPN) is a novel positron emission tomography (PET) probe designed to specifically targets melanin. This study aimed to evaluate the diagnostic feasibility of ¹⁸F-PFPN in patients with ocular or orbital melanoma. Materials and Methods: Three patients with pathologically confirmed ocular or orbital melanoma (one male, two females; age 41-59 years) were retrospectively reviewed. Each patient underwent comprehensive ¹⁸F-PFPN and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET scans. The maximum standardized uptake value (SUV_max) of the lesion and the interference caused by background tissue were compared between ¹⁸F-PFPN and ¹⁸F-FDG PET imaging. In addition, the effect of intrinsic pigments in the uvea and retina on the interpretation of the results was examined. The contralateral non-tumorous eye of each patient served as a control. Results: All primary tumors (3/3) were detected using ¹⁸F-PFPN PET, while only two primary tumors were detected using ¹⁸F-FDG PET. Within each lesion, the SUV_max of ¹⁸F-PFPN was 2.6 to 8.3 times higher than that of ¹⁸F-FDG. Regarding the quality of PET imaging, the physiological uptake of ¹⁸F-FDG PET in the brain and periocular tissues limited the imaging of tumors. However, ¹⁸F-PFPN PET minimized this interference. Notably, intrinsic pigments in the uvea and retina did not cause abnormal concentrations of ¹⁸F-PFPN, as no anomalous uptake of ¹⁸F-PFPN was detected in the healthy contralateral eyes. Conclusion: Compared to ¹⁸F-FDG, ¹⁸F-PFPN demonstrated higher detection rates for ocular and orbital melanomas with minimal interference from surrounding tissues. This suggests that ¹⁸F-PFPN could be a promising clinical diagnostic tool for distinguishing malignant melanoma from benign pigmentation in ocular and orbital melanomas.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.6
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• pp.444-450
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• 2008

Purpose: The aim of this study was to evaluate the usefulness of whole body positron emission tomography (PET) using $^{18}F-fluorodeoxyglucose$ ($^{18}F-FDG$) for cancer screening in asymptomatic subjects. Materials and Methods: The subjects were 1,762 men and 259 women who voluntarily underwent $^{18}F-FDG$ PET for cancer screening as a part of a routine health examination. Final diagnosis was decided by other diagnostic studies, pathological results or clinical follow-up for 1 year. Results: Of 2,021 subjects, 40 (2.0%) were finally proved to have cancer. Abnormal focal $^{18}F-FDG$ uptake suggesting malignancy was found in 102 subjects (5.0%). Among them, 21 subjects (1.0%) were proved to have cancer. Other tests in the routine health examination could not find 9 of 21 cancers (42.9%) detected by PET. The sensitivity, specificity, positive predictive value, and negative predictive value of PET for cancer screening were 52.5%, 95.9%, 20.6%, and 99.0%, respectively. Pathologies of cancers missed on PET were adenocarcinoma (n = 9; 3 colon cancers, 3 prostate cancers, 2 stomach cancers, and 1 rectal cancer), differentiated thyroid carcinoma (n = 6), bronchioalveolar cell carcinoma (n = 2), urinary bladder cancer (n = 1), and melanoma (n = 1). More than half of cancers which were not detected by PET were smaller than 1 cm in diameter. Conclusion: $^{18}F-FDG$ PET might be useful for cancer screening in asymptomatic subjects due to its high specificity and negative predictive value and playa supplementary role to the conventional health check-up, but it could not replace due to limited sensitivity for urological cancers, small-sized tumors and some hypometaboic cancers.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.247-251
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• 2007

A 38-year-old man who was diagnosed with malignant paraganglioma underwent computed tomography (CT) and I-131 metaiodobenzylguanidine (MIBG) san. CT showed extensive lymph node enlargement in right iliac area and retroperitoneum with severe hydronephrosis and mass on posterior bladder wall. However, I-131 MIBG scan didn't showed abnormal uptake. He also underwent F-18 fluorodeoxyglucose (FDG) positron emisson tomography/CT for localizing accurate tumor site. F-18 FDG PET/CT showed multiple metastases of left supraclavicular, hilar, mediastinal para-aortic, inguinal, right iliac lymph nodes, lung, vertebrae, and pelvis. There are a few reports showing that the F-18 FDG PET/CT is helpful for staging and localizing tumor site of patients who are diagnosed with negative on the MIBG scans. Thus, we report a case with paraganglioma which showed negative I-131 MIBG scan, but revealed multiple intense hypermetabolic foci in F-18 FDG PET/CT.

• The Korean Journal of Nuclear Medicine
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• v.35 no.6
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• pp.398-400
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• 2001

The authors report a case of unsuspected myocardial ischemia detected during CoDe FDG PET (coincidence detection fluorodeoxyglucose positron emission tomogram) which was performed for the evaluation of a solitary pulmonary nodule. Camera-based FDG PET without attenuation correction often reveals false defect in the inferior wall of the left ventricle in normals due to excessive attenuation. However, this asymptomatic patient had increased uptake in the inferior wall suggesting ischemic myocardium. The scan finding was confirmed by Tl-201 myocardial SPECT and coronary angiogram. The patient then underwent successful PTCA of mild RCA and right ventricular branch followed by right upper lobectomy for small cell lung cancer.

• The Korean Journal of Nuclear Medicine
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• v.33 no.6
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• pp.502-511
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• 1999

Purpose: F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been proven to be useful in the differential diagnosis of breast mass and staging of breast cancer. This study assessed the diagnostic accuracy of F-18-FDG PET in the differentiation of breast mass and staging of breast cancer. Materials and Methods: Total 42 patients who had breast mass underwent F-18-FDG PET (all female, 40: 10 year old). We compared F-18 FDG PET results with pathologic findings in 24 patients Results: In the differentiation of breast mass, sensitivity and specificity were 95% (19/20) and 77% (7/9) respectively. Three false positive cases were due to inflammation and one false negative patient had small tumor less than 1 cm. In the assessment of axillary lymph node status, sensitivity and specificity were 73% (8/11) and 100% (7/7) respectively. We found distant metastasis that were not suspected before F-18-FDG PET in 2 patients. Conclusion: F-18-FDG PET shows good diagnostic performance in differentiation of breast mass and staging of breast cancer.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.5
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• pp.414-418
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• 2008

The role of positron emission tomography (PET) with F-18 fluorodeoxyglucose (F-18 FDG) in the diagnosis of hepatocellulcar carcinoma (HCC) has been limited because of a variable FDG uptake in HCC. However, the usefulness of PET/CT for detecting extrahepatic metastasis and monitoring of the treatment response in HCC has been reported. A 55-year-old man with a hepatitis B surface antigen-positive, was admitted to our hospital due to dyspnea, general weakness and body weight loss for one month. Chest X-ray showed multiple reticulo-nodular densities on both lower lung fields, which implies metastatic lesions. F-18 FDG PET/CT revealed consecutively intense hypermetabolic mass in right hepatic lobe, inferior vena cava and right atrium. We report a case of HCC with IVC and right atrium invasion identified by F-18 FDG PET/CT.

• Tuberculosis and Respiratory Diseases
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• v.64 no.2
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• pp.133-137
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• 2008

Pulmonary paragonimiasis continues to be a diagnostically challenging parasitic disease, despite a drastically decreased prevalence in South Korea during the past decade. Pulmonary paragonimiasis is characterized by fever, chest pain, and chronic cough with hemoptysis. Numerous radiographic and computed tomographic findings including the presence of pneumothorax, pleural effusion, and parenchymal lesions such as nodular or infiltrative opacities have been reported. The clinical and radiological manifestations of paragonimiasis can resemble those of lung cancer, tuberculosis or a metastatic malignancy. Furthermore, this disease can mimic lung cancer as seen on $^{18}F$-fluorodeoxyglucose positron emission tomography (FDG-PET). We report a case of pulmonary paragonimiasis in a 48-year old man that presented with a solitary pulmonary nodule and was suspected as a lung cancer based on FDG-PET imaging.