• 대한방사선방어학회:학술대회논문집
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• 2009.11a
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• pp.44-45
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• 2009

• 대한방사선방어학회:학술대회논문집
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• 2009.04a
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• pp.220-221
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• 2009

• Radiation Oncology Journal
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• v.29 no.3
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• pp.214-217
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• 2011

To avoid improper tumor volume contouring in radiation therapy (RT) and other invasive procedures, we report a case of uterine adenomyosis showing increased $^{18}F$-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET)/computed tomography (CT) mimicking malignant tumor in a 44-year-old woman during concurrent chemoradiation therapy (CCRT) for uterine cervical cancer. The adenomyosis was not associated with her menstrual cycle or with normal endometrium uptake, and it resolved one month after completion of RT. This case indicates that uterine adenomyosis in a premenopausal woman may show false positive uptake of $^{18}FDG$-PET/CT associated with CCRT.

• 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.

• Korean Journal of Radiology
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• v.24 no.1
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• pp.51-61
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• 2023

Objective: To develop and test a machine learning model for classifying human papillomavirus (HPV) status of patients with oropharyngeal squamous cell carcinoma (OPSCC) using ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET-derived parameters in derived parameters and an appropriate combination of machine learning methods in patients with OPSCC. Materials and Methods: This retrospective study enrolled 126 patients (118 male; mean age, 60 years) with newly diagnosed, pathologically confirmed OPSCC, that underwent ¹⁸F-FDG PET-computed tomography (CT) between January 2012 and February 2020. Patients were randomly assigned to training and internal validation sets in a 7:3 ratio. An external test set of 19 patients (16 male; mean age, 65.3 years) was recruited sequentially from two other tertiary hospitals. Model 1 used only PET parameters, Model 2 used only clinical features, and Model 3 used both PET and clinical parameters. Multiple feature transforms, feature selection, oversampling, and training models are all investigated. The external test set was used to test the three models that performed best in the internal validation set. The values for area under the receiver operating characteristic curve (AUC) were compared between models. Results: In the external test set, ExtraTrees-based Model 3, which uses two PET-derived parameters and three clinical features, with a combination of MinMaxScaler, mutual information selection, and adaptive synthetic sampling approach, showed the best performance (AUC = 0.78; 95% confidence interval, 0.46-1). Model 3 outperformed Model 1 using PET parameters alone (AUC = 0.48, p = 0.047) and Model 2 using clinical parameters alone (AUC = 0.52, p = 0.142) in predicting HPV status. Conclusion: Using oversampling and mutual information selection, an ExtraTree-based HPV status classifier was developed by combining metabolic parameters derived from ¹⁸F-FDG PET/CT and clinical parameters in OPSCC, which exhibited higher performance than the models using either PET or clinical parameters alone.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.317-322
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• 2009

Purpose: $^{18}$F-flurodeoxyglucose (FDG) uptake on positron emission tomography (PET) scan has been found to reflect tumor aggressiveness and prognosis in various types of cancer. However, pattern of FDG uptake in biliary malignancies and its clinical significance have not been studied well. The purpose of this study was to assess the additional value of $^{18}$F-FDG PET in differential diagnosis and prognosis of cholangiocarcinoma (CC) according to the tumor location and tumor morphology. Materials and Methods: From April 2005 to May 2008, eighty two patients (M:F = 55:27, age 66.2$\pm$9.6 yrs) with CC underwent $^{18}$F-FDG PET. For semiquantitative analysis, the maximum standardized uptake value (SUV$_{max}$) was obtained from the primary tumor. The difference of SUV$_{max}$ according to the tumor location and tumor growth pattern, such as scirrhous type, nodular type, polypoid type were compared. Results: Overall sensitivity of PET scan was 81.7% in CC. SUV$_{max}$ on PET scan in intrahepatic CC was significantly higher compared to extrahepatic CC. In extrahepatic CC, polypoid type showed significantly higher SUV$_{max}$ compared to scirrhous type. Conclusion: $^{18}$F-FDG PET may have a significant impact on clinical decision-making and on the management of intrahepatic cholangiocarcinoma. And it is related to the shape of the tumor and the sensitivity of detection is higher in the mass-forming type than in the scirrhous type.

• Radiation Oncology Journal
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• v.33 no.3
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• pp.179-187
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• 2015

Purpose: The purpose of this study was to investigate the predictable value of pretreatment $^{18}F$-fluorodeoxyglucose positron emission tomography-computed tomography ($^{18}F$-FDG PET-CT) in radiotherapy (RT) for patients with hepatocellular carcinoma (HCC) or portal vein tumor thrombosis (PVTT). Materials and Methods: We conducted a retrospective analysis of 36 stage I-IV HCC patients treated with RT. $^{18}F$-FDG PET-CT was performed before RT. Treatment target was determined HCC or PVTT lesions by treatment aim. They were irradiated at a median prescription dose of 50 Gy. The response was evaluated within 3 months after completion of RT using the Response Evaluation Criteria in Solid Tumors (RECIST). Response rate, overall survival (OS), and the pattern of failure (POF) were analyzed. Results: The response rate was 61.1%. The statistically significant prognostic factor affecting response in RT field was maximal standardized uptake value (maxSUV) only. The high SUV group (maxSUV ${\geq}5.1$) showed the better radiologic response than the low SUV group (maxSUV < 5.1). The median OS were 996.0 days in definitive group and 144.0 days in palliative group. Factors affecting OS were the %reduction of alpha-fetoprotein (AFP) level in the definitive group and Child-Pugh class in the palliative group. To predict the POF, maxSUV based on the cutoff value of 5.1 was the only significant factor in distant metastasis group. Conclusion: The results of this study suggest that the maxSUV of $^{18}F$-FDG PET-CT may be a prognostic factor for treatment outcome and the POF after RT. A %reduction of AFP level and Child-Pugh class could be used to predict OS in HCC.

• Journal of radiological science and technology
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• v.29 no.4
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• pp.257-260
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• 2006

In order to evaluate the exposure to the radiologic technologists from patients who had been administrated with radiopharmaceuticals, we measured the spatial dose rates at $5{\sim}300\;cm$ from skin surface of patients using an proportional digital surveymeter, 1.5(PET scan) and 4hr(bone scan) after injection. In results, the exposure to the technologists in each procedure was small, compared with the dose limits of the medical workers. However, the dose-response relationships in cancer and hereditary effects, referred to as the stochastic effects, have been assumed linear and no threshold models ; therefore, the exposure should be minimized. For this purpose, the measurements of spatial dose rate distributions were thought to be useful.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.8
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• pp.4143-4147
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• 2016

Purpose: We evaluated all PET/CTs acquired for patients without a primary diagnosis of colorectal cancer, and compared results for those who had subsequent colonoscopy within 6 months, to assess the accuracy of FDG PET/CT for detection of incidental pre-malignant polyps and malignant colon cancers. Materials and Methods: Medical records of 9,545 patients who underwent F-18 FDG PET/CT studies over 3.5 years were retrospectively reviewed. Due to pre-existing diagnosis of colorectal cancer, 818 patients were excluded. Of the remainder, 157 patients had colonoscopy within 6 months (79 males; mean age 61). We divided the colon into 4 regions and compared PET/CT results for each region with colonoscopy and histopathologic findings. True positive lesions included colorectal cancer, villous adenoma, tubulovillous adenoma, tubular adenoma and serrated hyperplastic polyp/hyperplastic polyposis. Results: Of 157 patients, 44 had incidental colonic uptake on PET/CT (28%). Of those, 25 had true positive (TP) uptake, yielding a 48% positive predictive value (PPV); 9% (4/44) were adenocarcinoma. There were 23 false positive (FP) lesions of which 4 were hyperplastic polyp, one was juvenile polyp and 7 were explained by diverticulitis. Fifty eight patients had false negative PET scans but colonoscopy revealed true pre-malignant and malignant pathology, yielding 23% sensitivity. The specificity, negiative predictive value (NPV) and accuracy were 96%, 90% and 87%, respectively. The average SUVmax values of TP, FP and FN lesions were 7.25, 6.11 and 2.76, respectively. There were no significant difference between SUVmax of TP lesions and FP lesions (p>0.95) but significantly higher than in FN lesions (p<0.001). The average size (by histopathology and colonoscopy) of TP lesions was 18.1 mm, statistically different from that of FN lesions which was 5.9 mm (p<0.001). Fifty-one percent of FN lesions were smaller than 5 mm (29/57) and 88% smaller than 10 mm (50/57). Conclusions: The high positive predictive value of incidental focal colonic FDG uptake of 48% for colonic neoplasia suggests that colonoscopy follow-up is warranted with this finding. We observed a low sensitivity of standardly acquired FDG-PET/CT for detecting small polyps, especially those less than 5 mm. Clinician and radiologists should be aware of the high PPV of focal colonic uptake reflecting pre-malignant and malignant lesions, and the need for appropriate follow up.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.33-37
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• 2010

Purpose: In the early stage of using PET/CT, it was used to damper revision but recently shows that CT with MDCT is commonly used and works well for an anatomical diagnosis. This hospital makes the accuracy and convenience more higher in the diagnosis and evaluate of coronary heart disease through concurrently running myocardial perfusion SPECT examination, myocardial PET examination with FDG, and CT coronary artery CT angiography(coronary CTA) used PET/CT with 64-slice. This report shows protocol and image based on results from about 400 coronary heart disease examinations since having 64 channels PET/CT in July 2007. Materials and Methods: An Equipment for this examination is 64-slice CT and Discovery VCT (DVCT) that is consisted of PET with BGO ($Bi_4Ge_3O_{12}$) scintillation crystal by GE health care. First myocardial perfusion SPECT with pharmacologic stress test to reduce waiting time of a patient and get a quick diagnosis and evaluation, and right after it, myocardial FDG PET examination and coronary CTA run without a break. One-stop evaluation protocol of ischemic heart disease is as follows. 1)Myocardial perfusion SPECT with pharmacologic stress: A patient is injected with $^{99m}Tc$-MIBI 10 mCi and does not have any fatty food for myocardial PET examination and drink natural water with ursodeoxcholic acid 100 mg and we get SPECT image in an hour. 2)Myocardial FDG PET: To reduce blood fatty content and to increase uptake of FDG, we used creative oral glucose load using insulin and Acipimox to according to blood acid content. A patient is injected with $^{18}F$-FDG 5 mCi for reduction of his radiation exposure and we get a gated image an hour later and get delay image when we need. 3) Coronary CTA: The most important point is to control heart rate and to get cooperation of patient's breath. In order to reduce a heart rate of him or her below 65 beats, let him or her take beta blocker 50 mg ~ 200 mg after a consultation with a doctor about it and have breath-practices then have the examination. Right before the examination, we spray isosorbide dinitrate 3 to 5 times to lower tension of bessel wall and to extension a blood wall of a patient. It makes to get better the shape of an anatomy. At filming, a patient is injected CT contrast with high pressure and have enough practices before the examination in order to have no problem. For reduction of his radiation exposure, we have to do ECG-triggered X-ray tube modulation exposure. Results: We evaluate coronary artery stenosis through coronary CTA and study correlation (culprit vessel check) of a decline between stenosis and perfusion from the myocardial perfusion SPECT with pharmacologic stress, coronary CTA, and can check viability of infarction or hibernating myocardium by FDG PET. Conclusion: The examination makes us to set up a direction of remedy (drug treatment, PCI, CABG) because we can estimate of effect from remedy, lesion site and severity. In addition, we have an advantage that it takes just 3 hours and one-stop in that all of process of examinations run in succession and at the same time. Therefore it shows that the method is useful in one stop evaluation of ischemic heart disease.