• Nuclear Medicine and Molecular Imaging
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• v.43 no.6
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• pp.543-556
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• 2009

Purpose: We studied the patterns of FDG uptake of primary papillary thyroid microcarcinoma (PTMCa) lesions and benign thyroid nodules in dual time point $^{18}F$-FDG PET/CT imaging. Materials and Methods: Consecutive 134 patients (154 lesions) with PTMCa and 49 patients (61 nodules) with benign thyroid nodules equal to or less than 1.0 cm who underwent dual time point $^{18}F$-FDG PET/CT study before surgery were enrolled. We calculated the maximum standardized uptake value of PTMCa and benign nodules in both time points, and percent change of SUVmax (${\Delta}%SUVmax$) and lesion to background ratio of SUVmax (${\Delta}L:B$% ratio) between both time points. The mean time interval between scans was $23.4{\pm}4.4$ minutes (thyroid to thyroid interval: $10.7{\pm}4.4$ minutes). Results: The mean of SUVmax of PTMCa was increased from $4.9{\pm}4.3$ to $5.3{\pm}4.7$ (p<0.001) and ${\Delta}%SUVmax$ was $12.3{\pm}23.6%$. But, the mean of SUVmax of benign nodules was no definite change ($2.1{\pm}1.0$ to $2.1{\pm}1.3$, p=0.686) and ${\Delta}%SUVmax$ was $-0.3{\pm}20.5%$. Of the 154 PTMCa, 100 nodules (64.9%) showed an increase in SUVmax over time, while 19 (31.1%) of the 61 benign thyroid nodules showed an increase (p<0.001). The dual time point $^{18}F$-FDG PET/CT found more PTMCa in visual assessment (62.3% vs. 76.6%, p=0.006), even in smaller than 0.5 cm (38.6% vs. 60.0%, p=0.011). Conclusion: Dual time time $^{18}F$-FDG PET/CT imaging was more useful than single time point $^{18}F$-FDG PET/CT imaging for distinction between PTMCa and benign nodule, especially when nodule showed equivocal or negative findings in single time point $^{18}F$-FDG PET/CT imaging or was smaller than 0.5 cm.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.52-59
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• 2008

In the management of colo-retal and anal cancer, accurate staging, treatment evaluation, early detection of recurrence are main clinical problems. F-18 FDG PET (PET/CT) has been reported as useful in the management of colo-rectal and anal cancer because that PET has high diagnostic performance comparing to conventional studies. In case of liver metastases, for confirmation of no extrahepatic metastases, in case of high risk of metastasis, for avoiding unnecessary operation, PET (PET/CT) is expected more useful. In anal cancer, PET is expected useful in lymph node staging. For the early prediction of chemotherapy or radiation therapy effect PET has been reported as useful, also. In early detection of recurrence by PET, cost-benefit advantages has been suggested, also. PET/CT is expected to have higher diagnostic performance than PET alone.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.126-129
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• 2008

Renal cell carcinoma is the most common histological type of renal malignancy, predominant in men and the primary treatment modality of this tumor is surgery. The role of diagnostic imaging in the management of this tumor is the evaluation of extent of disease as well as the detection and characterization of renal mass. US has long been a routine screening tool for kidney but tomographic imaging modalities such as CT and MRI begin to be also commonly used these days. On the other hand, the sensitivity of $^{18}F-FDG-PET$ in detection of renal mass is relatively low because of inherent limitation caused by FDG excretion pathway despite avid uptake of FDG to tumor cell per se. Many studies revealed FDG PET scan could play an important role in detection of metastatic lesions although the sensitivity for the detection of primary lesion is not so high. Furthermore, development of PET/CT scanner will make it possible to expand the indication of FDG PET scan in this malignancy.

• The Journal of the Korean bone and joint tumor society
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• v.14 no.2
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• pp.86-94
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• 2008

$^{18}F$-FDG PET/CT has led to advancement in diagnostic imaging, providing correlation of both physiology and anatomic information, and to new and innovative ways to utilize PET/CT imaging for the evaluation of musculoskeletal tumors. Recently, the most widely utilized musculoskeletal application of PET/CT imaging is for the detection and characterization of bone metastases, staging and restaging of primary malignant bone tumors and soft tissue sarcomas. And it is also useful in evaluating response to therapy for malignant musculoskeletal tumors and in detecting local recurrences or distant metastases during follow up. The future likely holds even more unique and potentially quite useful applications of PET/CT imaging for primary bone and soft tissue tumors. This article will review the useful applications of $^{18}F$-FDG PET/CT imaging for evaluating musculoskeletal tumors.

• 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.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.5
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• pp.275-278
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• 2006

We report the case of a 73-year-old man who had prostate cancer with bone metastases. Tc-99m HDP Whole body bone scan revealed multiple areas of increased bony uptake consistent with widespread bone metastases. F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) demonstrated mild F-18 FDG uptake in the lymph nodes of neck, abdomen, and pelvis. However, abnormal F-18 FDG uptake was not seen in the skeletal system. Biopsy and immunohistochemical stains of left supraclavicular mass showed metastatic prostate adenocarcinoma. Currently, there are a few reported cases of F-18 FDG PET/CT evaluation of bone metastases in prostate cancer. We discuss the discrepancy between F-18 FDG PET/CT and bone scan in the detection of osseous metastases of prostate cancer.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.5
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• pp.369-374
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• 2008

Purpose: F-18 FDG PET/CT has excellent sensitivity and specificity for staging non-Hodgkin lymphomas, but to the author's knowledge few studies to date have evaluated FDG PET/CT in peripheral T cell lymphoma. We evaluated the usefulness of F-18 FDG PET/CT in staging of patients with peripheral T cell lymphoma, especially indolent cutaneous T cell lymphomas. Materials and Methods: Twenty five patients (M:F=17:8, age $53.7{\pm}14.8$ yrs) with biopsy-proven indolent cutaneous T cell (CL) or noncutaneous T cell lymphomas (NCL) underwent PET/CT scans for staging at baseline. Peak standardized uptake values (p-SUV) of all abnormal foci were measured and compared between cutaneous and noncutaneous lesions. F-18 FDG PET/CT was performed on 6 patients with indolent CL and on 19 patients with NCL. Results: All 6 patients with indolent CL had no significant FDG avidity in the skin despite histologically positive cutaneous lesions. However, FDG avidity appeared in extracutaneous lesions (lymph nodes) in two patients with CL where CT imaging suggested lymphoma involvement (mean p-SUV $4.26{\pm}0.37$ in noncutaneous lesions in CL). In NCL, FDG avidity was demonstrated in all lesions where CT imaging suggested lymphoma involvement (mean p-SUV, $8.52{\pm}5.00$ in noncutaneous lesions in NCL). Conclusion: F-18 FDG PET/CT has the limitation of usefulness for the evaluation of the skin in indolent CL. In contrast, F-18 FDG PET/CT is sensitive in staging evaluation of extracutaneous lesions regardless of CL or NCL.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.5
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• pp.271-274
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• 2006

We report the case of a 64-year-old man with superior vena cava (SVC) syndrome due to tumor thrombus from recurrent hepatocellular carcinoma (HCC). He presented with new onset of facial swelling for 10 days. HCC was detected ten years ago. He has undergone repeated transcatheter arterial embolization (TAE) and chemotherapy. Chest computed tomography (CT) demonstrated tumor thrombus in the SVC extending to right atrium. He underwent whole body F-18 fluorodeoxyglucose(FDG) positron emission tomography/computed tomography (PET/CT) scanning for assessing the effect of TAE in HCC. F-18 FDG PET/CT showed increased uptake in the residual liver mass indicating viable tumor. There was another intense F-18 FDG accumulation in SUV extending to right atrium to suggest tumor thrombus. This case illustrates that F-18 FDG PET/CT is useful to identification of distant metastases as well as assessment of response to therapy in long-term survival HCC patients.

• 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.5
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• pp.410-413
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• 2008

A 56 years old woman referred to our hospital with dysphagia and epigastric soreness. Gastroendoscopy revealed huge submucosal tumor with ulceration extending from distal esophagus to lesser curvature of stomach. Subsequent computed tomography(CT) demonstrated soft tissue mass encircling distal esophagus, and 18F-FDG PET/CT demonstrated intense $^{18}F-FDG$ accumulation in it. Finally this case was diagnosed as esophageal leiomyoma based on pathologic evaluation of the surgical specimen.