• Korean Journal of Radiology
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• v.23 no.4
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• pp.466-478
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• 2022

Objective: ¹⁸F-fluorodeoxyglucose (FDG) PET/CT is often used for detecting malignancy in patients with newly diagnosed hemophagocytic lymphohistiocytosis (HLH), with acceptable sensitivity but relatively low specificity. The aim of this study was to improve the diagnostic ability of ¹⁸F-FDG PET/CT in identifying malignancy in patients with HLH by combining ¹⁸F-FDG PET/CT and clinical parameters. Materials and Methods: Ninety-seven patients (age ≥ 14 years) with secondary HLH were retrospectively reviewed and divided into the derivation (n = 71) and validation (n = 26) cohorts according to admission time. In the derivation cohort, 22 patients had malignancy-associated HLH (M-HLH) and 49 patients had non-malignancy-associated HLH (NM-HLH). Data on pretreatment ¹⁸F-FDG PET/CT and laboratory results were collected. The variables were analyzed using the Mann-Whitney U test or Pearson's chi-square test, and a nomogram for predicting M-HLH was constructed using multivariable binary logistic regression. The predictors were also ranked using decision-tree analysis. The nomogram and decision tree were validated in the validation cohort (10 patients with M-HLH and 16 patients with NM-HLH). Results: The ratio of the maximal standardized uptake value (SUVmax) of the lymph nodes to that of the mediastinum, the ratio of the SUVmax of bone lesions or bone marrow to that of the mediastinum, and age were selected for constructing the model. The nomogram showed good performance in predicting M-HLH in the validation cohort, with an area under the receiver operating characteristic curve of 0.875 (95% confidence interval, 0.686-0.971). At an appropriate cutoff value, the sensitivity and specificity for identifying M-HLH were 90% (9/10) and 68.8% (11/16), respectively. The decision tree integrating the same variables showed 70% (7/10) sensitivity and 93.8% (15/16) specificity for identifying M-HLH. In comparison, visual analysis of ¹⁸F-FDG PET/CT images demonstrated 100% (10/10) sensitivity and 12.5% (2/16) specificity. Conclusion: ¹⁸F-FDG PET/CT may be a practical technique for identifying M-HLH. The model constructed using ¹⁸F-FDG PET/CT features and age was able to detect malignancy with better accuracy than visual analysis of ¹⁸F-FDG PET/CT images.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3647-3652
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• 2013

Purpose: To evaluate the diagnostic value of $^{18}F$-FDG PET/CT for detection of bone metastasis in comparison with the efficacies of $^{18}F$-FDG PET/CT, CT, $^{18}F$-FDG PET and conventional planar bone scintigraphy in a series of cancer patients. Methods: Five hundred and thirty patients who underwent both $^{18}F$-FDG PET/CT and bone scintigraphy within 1 month were retrospectively analyzed. The skeletal system was classified into 10 anatomic segments and interpreted blindly and separately. For each modality, the sensitivity, specificity, accuracy, PPV and NPV were calculated and the results were statistically analyzed. Results: Bone metastases were confirmed in 117 patients with 459 positive segments. On patient-based analysis, the sensitivity, specificity, accuracy, PPV and NPV of $^{18}F$-FDG PET/CT were significantly higher than bone scintigraphy, CT and $^{18}F$-FDG PET (P<0.05). On segment-based analysis, the sensitivity of CT, bone scintigraphy, $^{18}F$-FDG PET and $^{18}F$-FDG PET/CT were 70.4%, 89.5%, 89.1% and 97.8%, respectively (P<0.05, compared with $^{18}F$-FDG PET/CT). The overall specificity and accuracy of the four modalities were 89.1%, 91.8%, 90.3%, 98.2% and 90.3%, 90.9%, 89.8%, 98.0%, respectively (P<0.05, compared with $^{18}F$-FDG PET/CT). The PPV and NPV were 89.8%, 87.6%, 85.6%, 97.2% and 85.6%, 93.2%, 92.8%, 98.6%, respectively. Three hundred and twelve lesions or segments were presented as lytic or sclerotic changes on CT images at the corresponding sites of increased $^{18}F$-FDG uptake. In lytic or mixed lesions, the sensitivity of $^{18}F$-FDG PET/CT and $^{18}F$-FDG PET were better than bone scintigraphy, while in osteoblastic lesions bone scintigraphy had a similar performance with $^{18}F$-FDG PET/CT but better than $^{18}F$-FDG PET alone. Conclusion: Our data allow the conclusion that $^{18}F$-FDG PET/CT is superior to planar bone scintigraphy, CT or $^{18}F$-FDG PET in detecting bone metastasis. $^{18}F$-FDG PET/CT may enhance our diagnosis of tumor bone metastasis and provide more information for cancer treatment.

• Journal of Radiation Industry
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• v.17 no.3
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• pp.233-238
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• 2023

This study was conducted to confirm the safety of the operator's radiation exposure in the micro PET-CT image acquisition experiment using the ¹⁸F-FDG. The usage of ¹⁸F-FDG and the exposure dose of handlers were measured at University B in Metropolitan City A, which uses ¹⁸F-FDG for micro PET-CT image acquisition. As a result of the measurement, the exposure dose is far below the effective dose limit of radiation workers, 50 mSv per year, and the equivalent dose limit of 500 mSv per year for hands, feet, and skin. has been measured Since these exposure doses can be further increased according to the number of times of use of ¹⁸F-FDG, it is judged that the exposure dose compared to the handling amount of ¹⁸F-FDG shown in this study can be used as reference data. In addition, as changed environments such as the use of materials other than unopened RI are occurring in education and research environments, such as the use of ¹⁸F-FDG at University B, radiation exposure with more interest in safety management by checking the factors of radiation exposure of the handler concerned We will always do our best to reduce it.

• Korean Journal of Radiology
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• v.21 no.7
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• pp.829-837
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• 2020

Objective: The aim of this study was to investigate the prognostic value of the maximum standardized uptake value (SUV_max) measured while restaging with F-18 fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) to predict the 3-year post-recurrence survival (PRS) in patients with recurrent gastric cancer after curative surgical resection. Materials and Methods: In total, 47 patients with recurrent gastric cancer after curative resection who underwent restaging with ¹⁸F-FDG PET/CT were included. For the semiquantitative analysis, SUV_max was measured over the visually discernable ¹⁸F-FDG-avid recurrent lesions. Cox proportional-hazards regression models were used to predict the 3-year PRS. Differences in 3-year PRS were assessed with the Kaplan-Meier analysis. Results: Thirty-nine of the 47 patients (83%) expired within 3 years after recurrence in the median follow-up period of 30.3 months. In the multivariate analysis, SUV_max (p = 0.012), weight loss (p = 0.025), and neutrophil count (p = 0.006) were significant prognostic factors for 3-year PRS. The Kaplan-Meier curves demonstrated significantly poor 3-year PRS in patients with SUV_max > 5.1 than in those with SUV_max ≤ 5.1 (3-year PRS rate, 3.5% vs. 38.9%, p < 0.001). Conclusion: High SUV_max on restaging with ¹⁸F-FDG PET/CT is a poor prognostic factor for 3-year PRS. It may strengthen the role of ¹⁸F-FDG PET/CT in further stratifying the prognosis of recurrent gastric cancer.

• Journal of the Korean Society of Radiology
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• v.82 no.4
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• pp.903-913
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• 2021

Purpose To identify the imaging features indicative of sarcoid-like reactions in patients with intrathoracic lymphadenopathy after complete remission of malignancies. Materials and Methods This study enrolled five patients with histopathologically confirmed sarcoid-like reactions that developed after cancer remission. The clinical features and findings of CT and ¹⁸F-fluorodeoxyglucose (FDG) PET/CT were assessed. Results The underlying malignancies included breast, nasopharyngeal, colon, and endometrial cancer and lymphoma. The time intervals between complete remission of malignancy and the diagnosis of sarcoid-like reaction ranged from 6 to 78 months. CT findings of sarcoid-like reaction included bilateral hilar and mediastinal lymphadenopathies (n = 5), pulmonary nodules (1-15 mm) with peribronchovascular, fissural, or subpleural distribution, and interlobular interstitial thickening in the lungs (n = 4). ¹⁸F-FDG PET/CT revealed hypermetabolic uptake in the mediastinal and hilar lymph nodes and both lungs in the absence of extrathoracic uptake (n = 3). The sarcoid-like reactions resolved in all patients after corticosteroid treatment. Conclusion In patients with complete remission of malignancies, newly developed bilateral hilar and mediastinal lymphadenopathies with or without pulmonary nodules of perilymphatic distribution, in the absence of recurrence at the primary tumor site and extrathoracic metastasis, may suggest a sarcoid-like reaction. Such cases warrant histologic evaluation of the lymph nodes to prevent unnecessary systemic chemotherapy.

• The Korean journal of internal medicine
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• v.39 no.2
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• pp.327-337
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• 2024

Background/Aims: The prognostic significance of ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography-computed tomography (PET/CT) in peripheral T-cell lymphomas (PTCLs) are controversial. We explored the prognostic impact of sequential ¹⁸F-FDG PET/CT during frontline chemotherapy of patients with PTCLs. Methods: In total, 143 patients with newly diagnosed PTCLs were included. Sequential ¹⁸F-FDG PET/CTs were performed at the time of diagnosis, during chemotherapy, and at the end of chemotherapy. The baseline total metabolic tumor volume (TMTV) was calculated using the the standard uptake value with a threshold method of 2.5. Results: A baseline TMTV of 457.0 cm³ was used to categorize patients into high and low TMTV groups. Patients with a high TMTV had shorter progression-free survival (PFS) and overall survival (OS) than those with a low TMTV (PFS, 9.8 vs. 26.5 mo, p = 0.043; OS, 18.9 vs. 71.2 mo, p = 0.004). The interim ¹⁸F-FDG PET/CT response score was recorded as 1, 2-3, and 4-5 according to the Deauville criteria. The PFS and OS showed significant differences according to the interim ¹⁸F-FDG PET/CT response score (PFS, 120.7 vs. 34.1 vs. 5.1 mo, p < 0.001; OS, not reached vs. 61.1 mo vs. 12.1 mo, p < 0.001). Conclusions: The interim PET/CT response based on visual assessment predicts disease progression and survival outcome in PTCLs. A high baseline TMTV is associated with a poor response to anthracycline-based chemotherapy in PTCLs. However, TMTV was not an independent predictor for PFS in the multivariate analysis.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.2
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• pp.68-72
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• 2014

Purpose The nuclear medicine examination, there is a difficulty to carry out the inspection of both on the day of residual isotope due to the half-life. In this study, by studying the mutual influence and $^{18}F$-FDG of $^{99m}TcO_4{^-}$, I would like to explain the matters to be considered in the case of performing the same day. Materials and Methods With the NEMA-1994 Phantom, and experiments were performed 3 times. Create a 1: 4 Background ratio HOT and the $^{99m}TcO_4{^-}$ The first experiment: After underwent SPECT in INFINIA (GE Healthcare, MI, USA), and were injected with $^{18}F$-FDG 37 MBq in the Background area, 13 once for 60 minutes under the same conditions was time Scan. Create a 1: 4 Background ratio HOT and the $^{18}F$-FDG second is: The Scan in PET/CT Discovery 600 (GE Healthcare, MI, USA), and 148 MBq after injection $^{99m}TcO_4{^-}$ the Background area, once for 60 minutes, 6 under the same conditions was time Scan. Create a 1: 4 Background ratio HOT and the $^{18}F$-FDG experiments las, increments of 296 MBq and 148 MBq the 1 Bed Scan after $^{99m}TcO_4{^-}$, was 1 Bed Scan under the same conditions. Non BKG area and HOT, I was measured comparing the Total Counts and SNR or CNR. Results Showed a significant difference in the ratio CNR of enforcement during SPECT $^{18}F$-FDG is, (p>0.05). The $^{99m}TcO_4{^-}$ was no significant difference between the SNR ratio of PET / CT at the time of the effective date (p<0.05). I got the results $^{99m}TcO_4{^-}$ that reduce the Total Counts of PET / CT scan. Conclusion If you make a PET / CT scan, may affect the test using the $^{99m}TcO_4{^-}$ up to 12 hours, when it is performed before the $^{99m}TcO_4{^-}$, does not affect the SNR and SUV, PET / CT scan I reduced the detection efficiency. The inspection of day, we'd like to recommend a way to complement the detection efficiency to increase the inspection time of PET / CT in move forward the inspection using the $^{99m}TcO_4{^-}$.

• IEMEK Journal of Embedded Systems and Applications
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• v.18 no.6
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• pp.267-275
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• 2023

This paper presents the development of specialized software for annotating volume-of-interest on ¹⁸F-FDG PET/CT images with the goal of facilitating the studies and diagnosis of head and neck cancer (HNC). To achieve an efficient annotation process, we employed the SE-Norm-Residual Layer-based U-Net model. This model exhibited outstanding proficiency to segment cancerous regions within ¹⁸F-FDG PET/CT scans of HNC cases. Manual annotation function was also integrated, allowing researchers and clinicians to validate and refine annotations based on dataset characteristics. Workspace has a display with fusion of both PET and CT images, providing enhance user convenience through simultaneous visualization. The performance of deeplearning model was validated using a Hecktor 2021 dataset, and subsequently developed semi-automatic annotation functionalities. We began by performing image preprocessing including resampling, normalization, and co-registration, followed by an evaluation of the deep learning model performance. This model was integrated into the software, serving as an initial automatic segmentation step. Users can manually refine pre-segmented regions to correct false positives and false negatives. Annotation images are subsequently saved along with their corresponding ¹⁸F-FDG PET/CT fusion images, enabling their application across various domains. In this study, we developed a semi-automatic annotation software designed for efficiently generating annotated lesion images, with applications in HNC research and diagnosis. The findings indicated that this software surpasses conventional tools, particularly in the context of HNC-specific annotation with ¹⁸F-FDG PET/CT data. Consequently, developed software offers a robust solution for producing annotated datasets, driving advances in the studies and diagnosis of HNC.

• Korean Journal of Radiology
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• v.20 no.8
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• pp.1293-1299
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• 2019

Objective: The purpose of this study was to evaluate the diagnostic performance of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for chronic empyema-associated malignancy (CEAM). Materials and Methods: We retrospectively reviewed the ¹⁸F-FDG PET/CT images of 33 patients with chronic empyema, and analyzed the following findings: 1) shape of the empyema cavity, 2) presence of fistula, 3) maximum standardized uptake value (SUV) of the empyema cavity, 4) uptake pattern of the empyema cavity, 5) presence of a protruding soft tissue mass within the empyema cavity, and 6) involvement of adjacent structures. Final diagnosis was determined based on histopathology or clinical follow-up for at least 6 months. The abovementioned findings were compared between the ¹⁸F-FDG PET/CT images of CEAM and chronic empyema. A receiver operating characteristic (ROC) analysis was also performed. Results: Six lesions were histopathologically proven as malignant; there were three cases of diffuse large B-cell lymphoma, two of squamous cell carcinoma, and one of poorly differentiated carcinoma. Maximum SUV within the empyema cavity (p < 0.001) presence of a protruding soft tissue mass (p = 0.002), and involvement of the adjacent structures (p < 0.001) were significantly different between the CEAM and chronic empyema images. The maximum SUV exhibited the highest diagnostic performance, with the highest specificity (96.3%, 26/27), positive predictive value (85.7%, 6/7), and accuracy (97.0%, 32/33) among all criteria. On ROC analysis, the area under the curve of maximum SUV was 0.994. Conclusion: ¹⁸F-FDG PET/CT can be useful for diagnosing CEAM in patients with chronic empyema. The maximum SUV within the empyema cavity is the most accurate ¹⁸F-FDG PET/CT diagnostic criterion for CEAM.

• Journal of the Korean Society of Radiology
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• v.81 no.6
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• pp.1424-1435
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• 2020

Purpose The purpose of this study was to evaluate the usefulness of multiphasic CT and ¹⁸F-fluorodeoxyglucose (FDG) PET/CT for the differentiation of combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CCA) from hepatocellular carcinoma (HCC). Materials and Methods From January 2007 to April 2016, 93 patients with pathologically confirmed HCC (n = 84) or cHCC-CCA (n = 9) underwent CT and PET/CT imaging. Contrast enhancement patterns were divided into three types based on the attenuation of the surrounding liver parenchyma: type I (early arterial enhancement with delayed washout), type II (early arterial enhancement without delayed washout), and type III (early hypovascular, infiltrative appearance, or peripheral rim enhancement). Results cHCC-CCAs (89%) had a higher PET/CT positive rate than did HCCs (61%), but the PET/CT positive rate did not differ significantly (p = 0.095). Among the 19 cases of the type II enhancement pattern, 3 (21%) of 14 HCCs and 4 (80%) of 5 cHCC-CCAs were PET/CT positive. cHCC-CCAs had a significantly higher PET/CT positive rate (p = 0.020) in the type II enhancement pattern. Conclusion The PET/CT positive rate of cHCC-CCA was significantly higher than that of HCC in lesions with a type II enhancement pattern. The ¹⁸F-FDG PET/CT can be useful for the differentiation of cHCC-CCA from HCC in lesions with a type II enhancement pattern on multiphasic CT.