• Korean Journal of Radiology
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• v.25 no.2
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• pp.189-198
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• 2024

Objective: To investigate the prognostic utility of radiomics features extracted from ¹⁸F-fluorodeoxyglucose (FDG) PET/CT combined with clinical factors and metabolic parameters in predicting progression-free survival (PFS) and overall survival (OS) in individuals diagnosed with extranodal nasal-type NK/T cell lymphoma (ENKTCL). Materials and Methods: A total of 126 adults with ENKTCL who underwent ¹⁸F-FDG PET/CT examination before treatment were retrospectively included and randomly divided into training (n = 88) and validation cohorts (n = 38) at a ratio of 7:3. Least absolute shrinkage and selection operation Cox regression analysis was used to select the best radiomics features and calculate each patient's radiomics scores (RadPFS and RadOS). Kaplan-Meier curve and Log-rank test were used to compare survival between patient groups risk-stratified by the radiomics scores. Various models to predict PFS and OS were constructed, including clinical, metabolic, clinical + metabolic, and clinical + metabolic + radiomics models. The discriminative ability of each model was evaluated using Harrell's C index. The performance of each model in predicting PFS and OS for 1-, 3-, and 5-years was evaluated using the time-dependent receiver operating characteristic (ROC) curve. Results: Kaplan-Meier curve analysis demonstrated that the radiomics scores effectively identified high- and low-risk patients (all P < 0.05). Multivariable Cox analysis showed that the Ann Arbor stage, maximum standardized uptake value (SUVmax), and RadPFS were independent risk factors associated with PFS. Further, β2-microglobulin, Eastern Cooperative Oncology Group performance status score, SUVmax, and RadOS were independent risk factors for OS. The clinical + metabolic + radiomics model exhibited the greatest discriminative ability for both PFS (Harrell's C-index: 0.805 in the validation cohort) and OS (Harrell's C-index: 0.833 in the validation cohort). The time-dependent ROC analysis indicated that the clinical + metabolic + radiomics model had the best predictive performance. Conclusion: The PET/CT-based clinical + metabolic + radiomics model can enhance prognostication among patients with ENKTCL and may be a non-invasive and efficient risk stratification tool for clinical practice.

• The Korean Journal of Nuclear Medicine
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• v.33 no.3
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• pp.327-336
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• 1999

Purpose: To assess the quantitative accuracy and the clinical utility of 3D volumetric PET imaging with FDG in brain studies, 24 patients with various neurological disorders were studied. Materials and Methods: Each patient was injected with 370 MBq of 2-[$^{18}F$]fluoro-2-deoxy-D-glucose. After a 30 min uptake period, the patients were imaged for 30 min in 2 dimensional acquisition (2D) and subsequently for 10 min in 3 dimensional acquisition imaging (3D) using a GE $Advance^{TM}$ PET system, The scatter corrected 3D (3D SC) and non scatter-corrected 3D images were compared with 2D images by applying ROIs on gray and white matter, lesion and contralateral normal areas. Measured and calculated attenuation correction methods for emission images were compared to get the maximum advantage of high sensitivity of 3D acquisition. Results: When normalized to the contrast of 2D images, the contrasts of gray to white matter were $0.75{\pm}0.13$ (3D) and $0.95{\pm}0.12$ (3D SC). The contrasts of normal area to lesion were $0.83{\pm}0.05$ (3D) and $0.96{\pm}0.05$ (3D SC). Three nuclear medicine physicians judged 3D SC images to be superior to the 2D with regards to resolution and noise. Regional counts of calculated attenuation correction was not significantly different to that of measured attenuation correction. Conclusion: 3D PET images with the scatter correction in FDG brain studies provide quantitatively and qualitatively similar images to 2D and can be utilized in a routine clinical setting to reduce scanning time and patient motion artifacts.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.5
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• pp.243-248
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• 2006

Purpose: Liver demonstrates heterogeneous FDG uptake and sometimes it shows abnormally increased uptake even though there is no malignant tissue. However, there was no previous study to correlate these various pattern of hepatic FDG uptake with benign liver disease. Therefore, we evaluated the significance of hepatic FDG uptake associated with various clinical factors including fatty liver, liver function tests and lipid profiles. Materials and Methods: We reviewed a total of 188 patients (male/female: 120/68, mean age: $50{\pm}9$) who underwent PET/CT for screening of malignancy. Patients with DM, impaired glucose tolerance, previous severe hepatic disease or long-term medication history were excluded. The FDG uptake in liver was analyzed semi-quantitatively using ROI on transaxial images (segment 8) and we compared mean standardized uptake value (SUV) between fatty liver and non-fatty liver group. We also evaluated the correlation between hepatic FDG uptake and various clinical factors including serum liver function test (ALT, AST), ${\gamma}-GT$, total cholesterol and triglyceride concentration. The effect of alcoholic history and body mass index on hepatic FDG uptake was analyzed within the fatty liver patients. Results: The hepatic FDG uptake of fatty liver group was significantly higher than that of non-fatty liver group. Serum total cholesterol and triglyceride concentration showed significant correlation with hepatic FDG uptake. However, there was no significant correlation between other factors (ALT, AST, and ${\gamma}-GT$) and FDG uptake. Also there was no difference of mean SUV between normal and abnormal groups on the basis of alcoholic history and body mass Index within fatty liver patients. Fatty liver and high serum triglyceride concentration were the independent factors affecting hepatic FDG uptake according to multivariate analysis. Conclusion: In conclusion, hepatic FDG uptake was strongly correlated with fatty liver and serum triglyceride concentration.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.5
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• pp.249-256
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• 2006

Purpose: Although computed tomography (CT) is widely used for diagnosing liver metastasis from colorectal cancer, diagnostic accuracy of CT is not satisfactory. Magnetic resonance (MR) imaging and F-18 FDG PET has been reported to be superior to CT. However, studies on direct comparison of PET and MR are scarce. We compared the diagnostic accuracy of FDG PET and MR in detecting liver metastasis from colorectal cancer. Materials and Methods: Among 363 colorectal cancer patients who underwent F-18 FDG PET (ECAT, Siemens-CTI, Knoxville; Gemini, Philips, Milpitas, U.S.), 26 patients (M:F=17:9, age=$62{\pm}11$) underwent MR to evaluate suspicious metastatic liver lesions. Finally, 35 liver lesions detected by CT from 26 patients were enrolled for analysis. PET and MR results were compared with pathologic reports, clinical findings or follow-up results. Results: Of the 35 lesions, 18 lesions (51.4%) were diagnosed as liver metastases, while remaining 17 (48.6%) as benign. The sensitivity and the specificity of PET were 94.4% and 94.1%, respectively, compared to 100% and 82.4% for MR. MR and PET was concordant in 30 lesions (85.7%: 17 metastatic (94.4%) and 13 benign (76.5%) lesions. ROC curve analysis revealed maximal SUV of 3.1 as the optimum standard in differentiating metastatic from benign liver lesions (AUC=0.897, p<0.001, sensitivity 83.3%, specificity 94.1%). For small lesions less than 1 cm ln diameter (n=20), diagnostic accuracy of PET was comparable to that of MR. Conclusion: F-18 FDG PET showed good diagnostic performance in detecting liver metastasis from colorectal cancer, which was comparable to MR.

• Radiation Oncology Journal
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• v.37 no.1
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• pp.30-36
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• 2019

Purpose: This study aimed to identify the feasibility of the maximum standardized uptake value (SUVmax) on baseline 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) as a predictive factor for prognosis in early stage primary lung cancer treated with stereotactic body radiotherapy (SBRT). Materials and Methods: Twenty-seven T1-3N0M0 primary lung cancer patients treated with curative SBRT between 2010 and 2018 were retrospectively evaluated. Four patients (14.8%) treated with SBRT to address residual tumor after wedge resection and one patient (3.7%) with local recurrence after resection were included. The SUVmax at baseline PET/CT was assessed to determine its relationship with prognosis after SBRT. Patients were divided into two groups based on maximum SUVmax on pre-treatment FDG PET/CT, estimated by receiver operating characteristic curve. Results: The median follow-up period was 17.7 months (range, 2.3 to 60.0 months). The actuarial 2-year local control, progression-free survival (PFS), and overall survival were 80.4%, 66.0%, and 78.2%, respectively. With regard to failure patterns, 5 patients exhibited local failure (in-field failure, 18.5%), 1 (3.7%) experienced regional nodal relapse, and other 2 (7.4%) developed distant failure. SUVmax was significantly correlated with progression (p = 0.08, optimal cut-off point SUVmax > 5.1). PFS was significantly influenced by pretreatment SUVmax (SUVmax > 5.1 vs. SUVmax ≤ 5.1; p = 0.012) and T stage (T1 vs. T2-3; p = 0.012). Conclusion: SUVmax at pre-treatment FDG PET/CT demonstrated a predictive value for PFS after SBRT for lung cancer.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.6
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• pp.488-490
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• 2008

A 75-year-old man with non-small cell lung cancer (NSCLC) underwent F-18 fluorodeoxyglucose (FDG) PET/CT for staging. PET/CT showed distant metastases to intra-abdominal lymph nodes (LNs) as well as bilateral mediastinal LNs (stage IV), He underwent PET/CT (restaging PET/CT) 1week after the completion of first-line chemotherapy (docetaxel+carboplatin). It showed markedly increased FDG uptake in primary tumor, whereas tumor size decreased significantly, compared to prior PET/CT. This lesion was aggravated on follow-up CT 3 months after the completion of chemotherapy. Although there are several reports that FDG PET has potential to evaluate early response to chemotherapy and prognosis, there are a few cases to show mismatch between FDG uptake and size on PET/CT. Thus we report a case of NSCLC showed increased FDG uptake of primary tumor while decreased tumor size on restaging PET/CT.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.23
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• pp.10171-10174
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• 2015

Background: The purpose of this study was to determine the prognostic significance of the maximum standardized uptake value (SUVmax) on F-18-fluorodeoxyglucose (FDG)-positron emission tomography (PET) in patients undergoing surgical treatment for non-small cell lung cancer. Materials and Methods: Seventy-eight consecutive patients (58 with adenocarcinomas, 20 with squamous cell carcinomas) treated with potentially curative surgery were retrospectively reviewed. Results: The SUVmax was significantly higher in the patients with recurrent than with non-recurrent adenocarcinoma (p<0.01). However, among the patients with squamous cell carcinoma, there were no differences with or without recurrence (p=0.69). Multivariate analysis indicated that the SUVmax of adenocarcinoma lesions was a significant predictor of disease-free survival (p=0.04). In addition, an SUVmax of 6.19, the cut-off point based on ROC curve analysis of the patients with pathological IB or more advanced stage adenocarcinomas, was found to be a significant predictor of disease-free survival (p<0.01). Conclusions: SUVmax is a useful predictor of disease-free survival in patients with resected adenocarcinoma, but not squamous cell carcinoma. Patients with adenocarcinoma exhibiting an SUVmax above 6.19 are candidates for more intensive adjuvant therapy.

• Tuberculosis and Respiratory Diseases
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• v.74 no.4
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• pp.181-186
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• 2013

We report a rare synchronous presentation of primary lung cancer and adrenal pheochromocytoma. A 59-year-old woman was diagnosed with right upper lobe non-small cell lung carcinoma measuring 2.8 cm and a right adrenal gland mass measuring 3.5 cm, which displayed increased metabolic activity on $^{18}F$-fluorodeoxyglucose positron emission tomography-computed tomography. The adrenal lesion was revealed to be asymptomatic. The patient underwent right adrenalectomy and histological examination revealed a pheochromocytoma. Ten days later, right upper lobectomy was performed for lung cancer. This case indicates that incidental adrenal lesions found in cases of resectable primary lung cancer should be investigated.

• Journal of Yeungnam Medical Science
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• v.25 no.2
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• pp.128-133
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• 2008

Acinar cell carcinoma is a rare tumor that represents 1~2% of all pancreatic cancers. Clinical and radiologic findings are inconclusive in this disease. Acinar cell carcinoma is characterized by rapid progression and early metastasis, which lead to its poor prognosis. A 41-year-old man was admitted to our hospital for abdominal pain. Abdominal computed tomography (CT) and positron emission tomography-computed tomography (PET-CT) showed a splenic mass, which was being invaded by a pancreatic tail mass and which had increased $^{18}F$-fluorodeoxyglucose (FDG) uptake. Primary radical distal pancreatectomy and splenectomy were performed. Pathologic findings revealed an acinar cell carcinoma of the pancreas. The patient underwent a total gastrectomy three months later because of gastric recurrence. Four months later, multiple hepatic metastases were discovered, and the patient underwent a left hepatectomy. During treatment with capecitabine, there was no evidence of tumor progression for 14 months. We report a case of metastatic pancreatic acinar cell carcinoma, which did not progress for an extended period while the patient was being treated with capecitabine.

• Radiation Oncology Journal
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• v.36 no.2
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• pp.95-102
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• 2018

Purpose: To evaluate the prognostic value of $^{18}F$-fluorodeoxyglucose positron-emission tomography (FDG PET) with computed tomography (CT) before and during radiotherapy (RT) in patients with head and neck cancer. Methods: Twenty patients with primary head and neck squamous cell carcinoma were enrolled in this study, of whom 6 had oropharyngeal cancer, 10 had hypopharyngeal cancer, and 4 had laryngeal cancer. Fifteen patients received concurrent cisplatin and 2 received concurrent cetuximab chemotherapy. FDG PET/CT was performed before RT and in the 4th week of RT. The parameters of maximum standardized uptake value, metabolic tumor volume, and total lesion glycolysis (TLG) of the primary tumor were measured, and the prognostic significance of each was analyzed with the Cox proportional hazards model. Results: Higher TLG (>19.0) on FDG PET/CT during RT was a poor prognostic factor for overall survival (OS) (p = 0.001) and progression-free survival (PFS) (p = 0.007). In the multivariate analysis, TLG during RT as a continuous variable was significantly associated with OS and PFS rate (p = 0.023 and p = 0.016, respectively). Tumor response worse than partial remission at 1 month after RT was another independent prognostic factor for PFS (p = 0.024). Conclusions: Higher TLG of the primary tumor on FDG PET/CT during RT was a poor prognostic factor for OS and PFS in patients with head and neck cancer.