• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.411-420
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• 2009

Purpose: The aim of this study was to investigate the usefulness of $^{18}F$-FDG PET/CT with neck ultrasonography (neck US) in patients with recurrent, papillary thyroid cancer. Material and methods: This retrospective study (December 2006 to April 2008) enrolled sixty-one patients (ninety-one lesions) who underwent high-dose $^{131}I$-ablation therapy after total thyroidectomy, and evaluated recurred papillary thyroid cancer. All lesions were confirmed by histopathology and compared histopathologic findings to PET, PET/CT, and neck US findings. Results: In sixty-one patients (57 women, 4 men; age range, 24-81 years, mean 49 years; 61 papillary carcinomas), the sensitivity, specificity, accuracy of $^{18}F$-FDG PET/CT was 87.2%, 64.0%, 78.1% on a patient basis and 92.3%, 66.7%, 80.9% on a lesion basis, respectively. The sensitivity, specificity, accuracy of $^{18}F$-FDG PET was 71.8% (p=0.03), 59.0% (p=1.00), 67.2% (p=0.03) on a patient basis and 78.8% (p<0.01), 64.1% (p=1.00), 72.5% (p=0.02) on a lesion basis, respectively. The sensitivity, specificity, accuracy of neck US was 71.1% (p=0.07), 52.2% (p=0.75), 63.9% (p=0.05) on a patient basis and 71.2% (p<0.01), 61.5% (p=1.00), 67.0% (p=0.06) on a lesion basis, respectively. Combined $^{18}F$-FDG PET/CT with neck US improved the sensitivity, specificity, accuracy to 94.7% (p=0.50), 82.6% (p=0.13), 90.2% (p=0.03) on a patient basis and 96.2% (p=0.50), 89.7% (p<0.01), 93.4% (p<0.01) on a lesion basis, respectively. Conclusion: $^{18}F$-FDG PET/CT demonstrated significantly higher sensitivity than neck US for the detection of recurred papillary thyroid cancer lesions. Furthermore, combined $^{18}F$-FDG PET/CT with neck US showed more improved sensitivity, specificity, accuracy for diagnosis of recurrent papillary thyroid cancer.

• The Journal of the Korean bone and joint tumor society
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• v.14 no.1
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• pp.44-50
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• 2008

Purpose: To evaluate usefulness in diagnosing primary malignant lesion of metastatic bone tumor using $^{18}F$ FDG PET/CT. Material & Methods: Retrospective analysis was executed on 5,452 patients who were taken with $^{18}F$ FDG PET/CT between December 2003 and December 2007. 180 patients who had not any history of malignancy and complained musculoskeletal pain and had ill-defined osteolytic lesion in plain X-ray, were included. 96 male and 84 female were enrolled and mean age was 59.1 year old (22~90). We analyzed diagnostic accuracy, age and sex distribution of primary malignant lesion, location of metastatic lesion. Results: We could confirmed primary malignant lesion in 152 cases (84.4%). Most common malignant primary lesion was lung (28.3%), breast (18.9%) and gastrointestinal system (16.7%) and spine was the most common metastatic location of primary malignant lesion. Conclusion: $^{18}F$ FDG PET/CT is a effective molecular imaging detecting primary malignant lesion in patients having metastatic bone lesion without history of malignancy.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.6
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• pp.456-463
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• 2008

Purpose: We evaluated the incidence and malignant risk of focal breast lesions incidentally detected by $^{18}F-FDG$ PET/CT. Various PET/CT findings of the breast lesions were also analyzed to improve the differentiation between benign from malignant focal breast lesions. Materials & Methods: The subjects were 3,768 consecutive $^{18}F-FDG$ PET/CT exams performed in adult females without a history of breast cancer. A focal breast lesion was defined as a focal $^{18}F-FDG$ uptake or a focal nodular lesion on CT image irrespective of $^{18}F-FDG$ uptake in the breasts. The maximum SUV and CT pattern of focal breast lesions were evaluated, and were compared with final diagnosis. Results: The incidence of focal breast lesions on PET/CT in adult female subjects was 1.4% (58 lesions in 53 subjects). In finally confirmed 53 lesions of 48 subjects, 11 lesions of 8 subjects (20.8%) were proven to be malignant. When the PET/CT patterns suggesting benignancy (maximum attenuation value>75 HU or <30HU; standard deviation of mean attenuation > 20) were added as diagnostic criteria of PET/CT to differentiate benign from malignant breast lesions along with maximum SUV, the area under ROC curve of PET/CT was significantly increased compared with maximum SUV alone ($0.680{\pm}0.093$ vs. $0.786{\pm}0.076$, p<0.05). Conclusion: The malignant risk of focal breast lesions incidentally found on $^{18}F-FDG$ PET/CT is not low, deserving further diagnostic confirmation. Image interpretation considering both $^{18}F-FDG$ uptake and PET/CT pattern may be helpful to improve the differentiation from malignant and benign focal breast lesion.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.499-504
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• 2009

F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET/CT) plays an important role in diagnosis of malignant tumors and adds to conventional imaging in the staging of pertoneal carcinomatosis. However, false positive cases resulting from benign disease such as tuberculosis may occur. We report two cases of peritoneal tuberculosis on F-18 FDG PET/CT which showed multiple hypermetabolic foci in the mesentery and peritoneum with increased serum cancer antigen 125 (CA 125). Subsequent F-18 FDG PET/CT showed a disappearance of pathologic uptake following treatment with anti-tuberculosis drugs.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.137-139
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• 2008

Wilms Tumor is a great therapeutic success story within pediatric oncology. Therefore, accurate initial staging is needed to assess tumor spread and to assign patients appropriately to the different risk branches. However, it is recognized that FDG-PET can provide useful information about tumor and has better accuracy than CT and MRI for staging, but its role in Wilms tumor is unclear. According to clinical research data, FDG PET may be useful for the management of selected patients with Wilms tumors.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.71-75
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• 2008

The prevalence of pancreas cancer is increasing. Due to difficulty in detecting early stage disease, the prognosis of pancreas cancer is known to be poor. Clinical use of FDG PET in pancreas has been reported. FDG PET showed good performance in diagnosing pancreas cancer, and is expected to be useful in staging and detecting recurrence.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.309-316
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• 2009

Purpose: F-18 FDG can be accumulated in the liver, bowel, kidney, urinary tract, and muscles physiologically. The aim of this study was to evaluate the clinical value of dual time point 18F-FDG PET /8 imaging for the differentiation of the colonic focal uptake lesions. Materials and Methods: One hundred thirty two patients (M:F = 77:55, Age 62.8$\pm$11.6 years) underwent $^{18}$F-FDG PET/CT at two time points, prospectively: early image at 50-60 min and delayed image at 4-4.5 hours after the intravenous injection of $^{18}$F-FDG. Focally increased uptake lesions on early images but disappeared or shifted on delayed images defined a physiological uptake. For the differential evaluation of persistent focal uptake lesions on delayed images, colonoscopy and histopathologic examination were performed. SUVmax changes between early and delayed images were also compared. Results: Among the 132 patients, 153 lesions of focal colonic uptake were detected on early images of $^{18}$F-FDG PET/CT. Of these, 72 (47.1%) lesions were able to judge with physiological uptake because the focal increased uptake disappeared from delayed image. Among 81 lesions which was showed persistent increased uptake in delayed image, 61 (75.3%) lesions were confirmed as the malignant tumor and 14 (17.3%) lesions were confirmed as the benign lesions including adenoma and inflammatory disease. Remaining 6 (7.4%) lesions were confirmed as the physiological uptake because there was no particular lesion in the colonoscopy. In the malignant lesions, the calculated dual time point change for SUVmax ($\Delta$%SUVmax) was 20.8$\pm$18.7%, indicating a significant increase in SUVmax between the two point (p<0.01). In contrast, the change in SUVmax for the non-malignant lesions including benign lesions and physiological uptake was -13.7%$\pm$24.2%. For the differentiation of the malignant and non-malignant focal colonic uptake lesions, $\Delta$%SUVmax was the most effective parameter, and the cut-off value using -5% provided the best sensitivity, specificity, and accuracy. Conclusion: The dual time point $^{18}$F-FDG PET/CT imaging with SUVmax change evaluation could be an important noninvasive method for the differentiation of malignant and benign focal colonic uptake lesions including physiologic uptake.

• The Korean Journal of Nuclear Medicine
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• v.33 no.2
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• pp.111-119
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• 1999

Purpose: As mesial temporal lobe epilepsy (TLE) shows hypometabolism of medial and lateral temporal lobe, we investigated whether symmetric uptake of F-18-FDG in medial temporal lobes can differentiate mesial from lateral TLE. Materials and Methods: In 113 patients (83 mesial TLE, 30 lateral TLE) who underwent anterior temporal lobectomy and/or corticectomy with good surgical outcome, we performed F-18-FDG PET and compared F-18-FDG uptake of medial and lateral temporal lobes. All the patients with mesial TLE had hippocampal sclerosis except one congenital abnormal hippocampus. Patients with lateral TLE revealed cerebromalacia, microdysgenesis, arteriovenous malformation, old contusion, and cortical dysplasia. Results: Sensitivity of F-18-FDG PET and MR for mesial TLE was 84% (70/83) and 73% (61/83), respectively. Sensitivity of F-18-FDG PET and MR for lateral TLE was 90% (27/30) and 66% (20/30), respectively. Twelve patients were normal on F-18-FDG PET. 101 patients had hypometabotism of lateral temporal lobe. Among 88 patients who showed hypometabolism of medial temporal lobe as well as lateral temporal lobe, 70 were mesial TLE patients and 18 were lateral TLE on pathologic examination. Positive predictive value of medial temporal hypometabolism for mesial TLE was 80%. Among 13 patients who showed hypometabolism of only lateral temporal lobe, 4 were mesial TLE and 9 were lateral TLE. Positive predictive value of hypometabolism of lateral temporal lobe for the diagnosis of lateral TLE was 69% (9/13). Normal MR findings stood against medial TLE, whose negative predictive value was 66%. Conclusion: Lateral temporal lobe epilepsy should be suspected when there is decreased F-18-FDG uptake in lateral temporal lobe with normal uptake in medial temporal lobe.

• Korean Journal of Clinical Laboratory Science
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• v.39 no.3
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• pp.249-255
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• 2007

While respiratory burst enhances neutrophil glucose utilization, many neutrophil functions are critically influenced by extracellular matrix interaction and phosphoinositide-3-OH kinase (PI3K) signaling. We thus evaluated the role of RGD integrin occupancy and PI3K inhibition on respiratory burst and [18F]FDG uptake of stimulated neutrophils. Human neutrophils were stimulated by 100 ng/mL phorbol-myristate-acetate (PMA), and respiratory burst was measured by cumulative luminescence with lucigenin. [18F]FDG uptake and total hexokinase activity was measured 20 min after PMA stimulation in the presence or absence of soluble RGD peptides (200 g/mL) and/or the PI3K inhibitor wortmannin (200 nM). PMA induced a 71.70.9 fold increase in neutrophil oxygen intermediate generation. [18F]FDG uptake was increased to $194.6{\pm} 3.7%$ and hexokinase activity to $145.0{\pm}2.0%$ of basal levels (both p<0.0005). RGD peptides attenuated respiratory burst activation to $35.6{\pm}0.2%$ (p<0.005), but did not inhibit stimulated [18F]FDG uptake or hexokinase activity. In contrast, without affecting respiratory burst activation, wortmannin inhibited PMA stimulated [18F]FDG uptake to $66.9{\pm}1.6%$ and hexokinase activity to $81.0{\pm}4.2%$ (both P<0.0005), demonstrating its dependence on PI3K activity. Neither RGD nor wortmannin reversed the other's inhibitory effect on stimulated [18F]FDG uptake and hexokinase activity or respiratory burst, which suggests the involvement of distinct signaling pathways. Neutrophil [18F]FDG uptake is enhanced by PMA through a mechanism that requires PI3K activity but is independent of integrin receptor occupancy or respiratory burst activation.

• Journal of radiological science and technology
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• v.40 no.2
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• pp.275-280
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• 2017

In addition to tumors, normal tissues, such as the brain and myocardium can intake $^{18}F$-FDG, and the amount of $^{18}F$-FDG intake by normal tissues can be altered by the surrounding environment. Therefore, a process is necessary during which the contrasts of the tumor and normal tissues can be enhanced. Thus, this study examines the effects of glucose levels on FDG PET images of brain tissues, which features high glucose activity at all times, in small animals. Micro PET scan was performed on fourteen mice after injecting $^{18}F$-FDG. The images were compared in relation to fasting. The findings showed that the mean SUV value w as 0.84 higher in fasted mice than in non-fasted mice. During observation, the images from non-fasted mice showed high accumulation in organs other than the brain with increased surrounding noise. In addition, compared to the non-fasted mice, the fasted mice showed higher early intake and curve increase. The findings of this study suggest that fasting is important in assessing brain functions in brain PET using $^{18}F$-FDG. Additional studies to investigate whether caffeine levels and other preprocessing items have an impact on the acquired images would contribute to reducing radiation exposure in patients.