• Radiation Oncology Journal
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• v.37 no.1
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• pp.51-59
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• 2019

Purpose: We evaluated failure pattern and treatment outcomes of observational approach on regional lymph node (LN) in cutaneous melanoma of extremities and sought to find clinico-pathologic factors related to LN metastases. Material and Methods: We retrospectively reviewed 73 patients with cutaneous melanoma of extremities between 2005 and 2016. If preoperative 18-F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) findings were non-specific for regional LNs, surgical resection of primary tumors with adequate margins was performed without sentinel lymph node biopsy (SLNB) and/or complete lymph node dissection (CLND), irrespective of tumor thickness or size. In patients with suspicious or positive findings on PET/CT or CT, SLNB followed by CLND or CLND was performed at the discretion of the surgeon. We defined LN dissection (LND) as SLNB and/or CLND. Results: With a median follow-up of 38 months (range, 6 to 138 months), the dominant pattern of failure was regional failure (17 of total 23 events, 74%) in the observation group (n = 56). Pathologic LN metastases were significant factor for poor regional failure-free survival (hazard ration [HR] = 3.21; 95% confidence interval [CI], 1.03-10.33; p = 0.044) and overall survival (HR = 3.62; 95% CI, 1.02-12.94; p = 0.047) in multivariate analysis. In subgroup analysis for cN0 patients according to the preoperative PET/CT findings, LND group showed the better trend of LRFFS (log rank test, p = 0.192) and RFFS (p = 0.310), although which is not statistically significant. Conclusion: Observational approach on regional LNs on the basis of the PET/CT in patients with cutaneous melanoma of extremities showed the dominant regional failure pattern compared to upfront LND approach. To reveal regional lymph node status, SLND for cN0 patients may of importance in managing cutaneous melanoma patients.

• The Journal of Korean Society for Radiation Therapy
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• v.25 no.1
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• pp.41-47
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• 2013

Purpose: To evaluate the usefulness of Integrated PET/CT and compare the gloss tumor volume (GTV) identified on CT, PET, PET/CT to that obtained from fluorodeoxyglucose (FDG). Materials and Methods: This experimental study was obtained using GE Discovery 690 (General Electric Healthcare, Milwaukee, MI, USA) PET/CT simulator with Gammex Laser System for five non-small cell lung cancer (NSCLC) patients. In order to increase the reproducibility of the patient setup, We have to fixed to patients using the Extended Wing Board. GTV delineation was painted using the EclipseTM ver.10 contouring program for CT, PET, PET/CT images. And then, We were to compare the changes in the GTV. Results: These results are drawn from 5 patients who have atelectasis or pneumonitis. Compared to CT defined GTV, PET was decreased by 10.5%, 11.8% and increased by 67.9%, 220%, 19.4%. PET/CT was decreased by 7.7%, 6.7%, 28% and increased by 232%, 24%. Conclusion: We were able to determine the usefulness of PET/CT simulator for NSCLC. PET/CT simulator in radiation therapy is useful to define the target volume and It is possible to delineate Objective and accurate target volume. It seems to be applicable to other areas in the near future.

• Korean Journal of Radiology
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• v.23 no.10
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• pp.986-997
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• 2022

Objective: Whether metabolic redistribution occurs in patients with white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) is unknown. This study aimed 1) to propose a measure of the brain metabolic network for an individual patient and preliminarily apply it to identify impaired metabolic networks in patients with WMHs, and 2) to explore the clinical and imaging features of metabolic redistribution in patients with WMHs. Materials and Methods: This study included 50 patients with WMHs and 70 healthy controls (HCs) who underwent ¹⁸F-fluorodeoxyglucose-positron emission tomography/MRI. Various global property parameters according to graph theory and an individual parameter of brain metabolic network called "individual contribution index" were obtained. Parameter values were compared between the WMH and HC groups. The performance of the parameters in discriminating between the two groups was assessed using the area under the receiver operating characteristic curve (AUC). The correlation between the individual contribution index and Fazekas score was assessed, and the interaction between age and individual contribution index was determined. A generalized linear model was fitted with the individual contribution index as the dependent variable and the mean standardized uptake value (SUV_mean) of nodes in the whole-brain network or seven classic functional networks as independent variables to determine their association. Results: The means ± standard deviations of the individual contribution index were (0.697 ± 10.9) × 10^-3 and (0.0967 ± 0.0545) × 10^-3 in the WMH and HC groups, respectively (p < 0.001). The AUC of the individual contribution index was 0.864 (95% confidence interval, 0.785-0.943). A positive correlation was identified between the individual contribution index and the Fazekas scores in patients with WMHs (r = 0.57, p < 0.001). Age and individual contribution index demonstrated a significant interaction effect on the Fazekas score. A significant direct association was observed between the individual contribution index and the SUV_mean of the limbic network (p < 0.001). Conclusion: The individual contribution index may demonstrate the redistribution of the brain metabolic network in patients with WMHs.

• The Korean Journal of Nuclear Medicine
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• v.32 no.4
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• pp.332-343
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• 1998

Purpose: The purpose of this study was to assess the diagnostic accuracy of various quantitation methods using F-18-fluorodeoxyglucose (FDG) in patients with malignant or benign lung lesion. Materials and Methods: 22 patients (13 malignant including 5 bronchoalverolar cell cancer; 9 benign lesions including 1 hamartoma and 8 active inflammation) were studied after overnight fasting. We performed dynamic PET imaging for 56 min after injection of 370 MBq (10 mCi) of FDG. Standardized uptake values normalized to patient's body weight and plasma glucose concentration (SUVglu) were calculated. The uptake rate constant of FDG and glucose metabolic rate were quantified using Patlak graphical analysis (Kpat and MRpat), three compartment-five parameter model (K5p, MR5p), and six parameter model taking into account heterogeneity of tumor tissue (K6p, MR6p). Areas under receiver operating characteristic curves (ROC) were calculated for each method. Results: There was no significant difference of rate constant or glucose metabolic rate measured by various quantitation methods between malignant and benign lesions. The area under ROC curve were 0.73 for SUVglu, 0.66 for Kpat, 0.77 for MRpat, 0.71 for K5p, 0.73 for MR5p, 0.70 for K6p, and 0.78 for MR6p. No significant difference of area under the ROC curve between these methods was observed except the area between Kpat vs. MRpat (p<0.05). Conclusion: Quantitative methods did not improve diagnostic accuracy in comparison with nonkinetic methods. However, the clinical utility of these methods needs to be evaluated further in patients with low pretest likelihood of active inflammation or bronchoalveolar cell carcinoma.

• Korean Journal of Radiology
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• v.23 no.4
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• pp.446-454
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• 2022

Objective: To evaluate whether hyperoxia-induced ΔR₁ (hyperO₂ΔR₁) can accurately identify histological infarction in an acute cerebral stroke model. Materials and Methods: In 18 rats, MRI parameters, including hyperO₂ΔR₁, apparent diffusion coefficient (ADC), cerebral blood flow and volume, and ¹⁸F-fluorodeoxyglucose uptake on PET were measured 2.5, 4.5, and 6.5 hours after a 60-minutes occlusion of the right middle cerebral artery. Histological examination of the brain was performed immediately following the imaging studies. MRI and PET images were co-registered with digitized histological images. The ipsilateral hemisphere was divided into histological infarct (histological cell death), non-infarct ischemic (no cell death but ADC decrease), and nonischemic (no cell death or ADC decrease) areas for comparisons of imaging parameters. The levels of hyperO₂ΔR₁ and ADC were measured voxel-wise from the infarct core to the non-ischemic region. The correlation between areas of hyperO₂ΔR₁-derived infarction and histological cell death was evaluated. Results: HyperO₂ΔR₁ increased only in the infarct area (p ≤ 0.046) compared to the other areas. ADC decreased stepwise from non-ischemic to infarct areas (p = 0.002 at all time points). The other parameters did not show consistent differences among the three areas across the three time points. HyperO₂ΔR₁ sharply declined from the core to the border of the infarct areas, whereas there was no change within the non-infarct areas. A hyperO₂ΔR₁ value of 0.04 s^-1 was considered the criterion to identify histological infarction. ADC increased gradually from the infarct core to the periphery, without a pronounced difference at the border between the infarct and non-infarct areas. Areas of hyperO₂ΔR₁ higher than 0.04 s^-1 on MRI were strongly positively correlated with histological cell death (r = 0.862; p < 0.001). Conclusion: HyperO₂ΔR₁ may be used as an accurate and early (2.5 hours after onset) indicator of histological infarction in acute stroke.

• Journal of radiological science and technology
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• v.30 no.4
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• pp.373-379
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• 2007

Purpose : There is difference between PET and PET/CT method on their transmission image for attenuation correction. The CT image is used for attenuation correction on PET/CT and the parameters of CT may be affected on PET image. We performed the phantom study to evaluate whether the change of CT parameters(kilovolts peak and milliampere) affect standardized uptake value(SUV) on PET image. Material and Method: The data spectrum lung phantom containing diluted [18F]fluorodeoxyglucose ([18F]FDG) solution(1.909 mCi for phantom 1, $913\;{\mu}Ci$ for phantom 2) was used. The CT images of phantom were acquired with varying parameters (80, 100, 120, 140 for kVp, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 for mA). The PET images were reconstructed with the each CT images and SUVs were compared. Result : The SUVs of phantom 1 reconstructed with each 80, 100, 120 and 140 kVp showed $12.26{\pm}0.009$, $12.27{\pm}0.005$, $12.27{\pm}0.006$ and $12.27{\pm}0.009$, respectively. The SUVs of phantom 2 revealed $4.52{\pm}0.043$, $4.53{\pm}0.004$, $4.52{\pm}0.007$ and $4.52{\pm}0.005$ with elevation of voltage. There was no statistically significant difference of SUVs between groups based on various kVp. Also SUVs of phantom 1 and 2 showed no significant change with elevation of milliampere in CT parameter. Conclusion : The parameters of CT did not significantly affect SUV on PET image in our study. Therefore we can apply various parameters of CT appropriated for clinical conditions without significant change of SUV on PET CT image.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.2
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• pp.137-142
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• 2009

Purpose: This study was performed to find the current problems of positron emission tomography/computed tomography(PET/CT) data on CD for inter-hospital transfer. Materials and Methods: The subjects were 746 consecutive $^{18}F$-fluorodeoxyglucose PET/CT data CDs from 56 hospitals referred to our department for image interpretation. The formats and contents of PET/CT data CDs were reviewed and the email questionnaire survey about this was performed. Results: PET/CT data CDs from 21 of 56 hospitals(37.5%) included all transaxial CT and PET images with DICOM standard format which were required for authentic interpretation. PET/CT data from the others included only secondary capture images or fusion PET/CT images. According to this survey, the main reason of limited PET/CT data on CD for inter-hospital transfer was that the data volume of PET/CT was too large to upload to the Picture Archiving and Communication System. Conclusion: The majority of hospitals provided limited PET/CT data on CD for inter-hospital transfer, which could be inadequate for accurate interpretation and clinical decision making. It is necessary to standardize the format of PET/CT data on CD for inter-hospital transfer including all transaxial CT and PET images with DICOM standard format.

• Radiation Oncology Journal
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• v.23 no.1
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• pp.9-16
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• 2005

Purpose : To prospectively evaluate the use of positron emission tomography with the glucose analog fluoro-deoxyglucose (FDG-PET) to deoxyglucose (FDG-PET) to predict disease-free survival (DFS) after concurrent chemo-radiotherapy (CCRT) in patients with non-disseminated nasopharyngeal carcinoma (NPC). Materials and Methods : We studied 41 patients with non-disseminated NPC scheduled to undergo platinum-based CCRT were eligible for this study. Patients were studied by FDG-PET prior to the CCRT. FDG uptake of tumors were measured with the maximal standardized uptake value (SUV). Results : Complete response rate was $100\%$. In ten patients who presented with any component of treatment failure, the median $SUV_{max}$ was 8.55 (range: $2.49\~14.81$) in any component of failure and the median $SUV_{max}$ was 5.48 (range: $2.31\~26.07$) In the remaining patients without any such failure. Patients having tumors with high FDG uptake had a significantly lower 3-year DFS ($51\%\;{\nu}91\%$, p=0.0070) compared with patients having low uptake tumors. Conclusion : FDG uptake, as measured by the SUV, has potential value in predicting DFS in NPC treated by CCRT, High FDG uptake may be a useful parameter for Identifying patients requiring more aggressive treatment approaches.

• Tuberculosis and Respiratory Diseases
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• v.71 no.6
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• pp.417-424
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• 2011

Background: Recent evidences have revealed metabolic functions of p53 in cancer cells; adaptation or survival to metabolic stress and metabolic shift toward oxidative phosphorylation. However, further studies in clinical setting are needed. We investigated whether p53 protein expression, as a surrogate marker for loss of p53 function, is associated with metabolic features of stage I non-small cell lung cancer (NSCLC), focusing on tumor necrosis and maximal standardized uptake value (SUVmax) on $^{18}F$-fluorodeoxyglucose positron emission tomography. Methods: Clinical information was obtained from retrospective review of medical records. p53 expression was assessed by immunohistochemical staining. Results: p53 protein expression was detected in 112 (46%) of 241 NSCLC cases included in this study. p53 expression was independently associated with the presence of necrosis (odds ratio [OR], 2.316; 95% confidence interval [CI], 1.215~4.416; p=0.011). Non-adenocarcinoma histology (OR, 8.049; 95% CI, 4.072~15.911; p<0.001) and poorly differentiation (OR, 6.474; 95% CI, 2.998~13.979; p<0.001) were also independently associated with the presence of necrosis. However, p53 expression was not a significant factor for SUVmax. Conclusion: p53 protein expression is independently associated with the presence of necrosis, but not SUVmax.

• Radiation Oncology Journal
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• v.33 no.2
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• pp.126-133
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• 2015

Purpose: To evaluate the outcomes of adjuvant radiotherapy (RT) and to analyze prognostic factors of survival in the International Federation of Gynecology and Obstetrics (FIGO) IB-IIA uterine cervical cancer. Materials and Methods: We retrospectively reviewed the medical records of 148 patients with FIGO IB-IIA uterine cervical cancer who underwent surgery followed by adjuvant RT at the Yonsei Cancer Center between June 1997 and December 2011. Adjuvant radiotherapy was delivered to the whole pelvis or an extended field with or without brachytherapy. Among all patients, 57 (38.5%) received adjuvant chemotherapy either concurrently or sequentially. To analyze prognostic factors, we assessed clinicopathologic variables and metabolic parameters measured on preoperative 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). To evaluate the predictive performance of metabolic parameters, receiver operating characteristic curve analysis was used. Overall survival (OS) and disease-free survival (DFS) were analyzed by the Kaplan-Meier method. Results: The median follow-up period was 63.2 months (range, 2.7 to 206.8 months). Locoregional recurrence alone occurred in 6 patients, while distant metastasis was present in 16 patients, including 2 patients with simultaneous regional failure. The 5-year and 10-year OSs were 87.0% and 85.4%, respectively. The 5-year and 10-year DFSs were 83.8% and 82.5%, respectively. In multivariate analysis, pathologic type and tumor size were shown to be significant prognostic factors associated with both DFS and OS. In subset analysis of 40 patients who underwent preoperative PET/CT, total lesion glycolysis was shown to be the most significant prognostic factor among the clinicopathologic variables and metabolic parameters for DFS. Conclusion: Our results demonstrated that adjuvant RT following hysterectomy effectively improves local control. From the subset analysis of preoperative PET/CT, we can consider that metabolic parameters may hold prognostic significance in early uterine cervical cancer patients. More effective systemic treatments might be needed to reduce distant metastasis in these patients.