• Journal of the Korean Society of Radiology
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• v.6 no.1
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• pp.47-51
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• 2012

PET/CT is taken 1 hour after $^{18}F$-FDG(F-18-fluoro-2-deoxy-D-glucose) injection. However, these would be often delayed for more than 2 or 3 hours due to equipment fault or unexpected situation. In the study, SUV(standardized uptake value) were measured from got image over time according to the parts of the body. As a result, there were great and small decrease in liver(middle of the right hepatic lobe), fat(Lt pelvis), lung (Rt upper lobe), aorta(ascending aorta level) of the body in delayed image, and ${\Delta}$SUVmax was increase of 37% in bone only(L5 vertebral body) of the body. ${\Delta}$SUVmax was increase of 37.6% in lesion, and the contrast degree was greater because of uptake increase in lesion and uptake decrease in the normal body.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.110-112
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• 2008

Endometrial carcinoma is one of the most common gynecologic malignancies and which is predominant in postmenopausal women. Clinically many patients are hospitalized in early stage due to clinical sign and symptom such as vaginal bleeding and in this case, patient's prognosis is known to be good. However, considerable number of patients with advanced and relapsed disease reveal poor prognosis. Therefore, exact staging work up is essential for proper treatment as is primary lesion detection. $^{18}F-FDG-PET$ has been widely used for the evaluation of gynecologic malignancies such as cervical carcinoma and ovarian cancer. In contrast, FDG PET application to endometrial carcinoma is limited until now and there is no sufficient data to validate the usefulness of FDG PET for this disease yet. However, several studies showed promising results that FDG PET is sensitive and specific in detection of recurrent or metastatic lesions. Therefore further active investigation in this field can facilitate the use of FDG PET for endometrial carcinoma.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.116-120
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• 2008

Prostate cancer is the second leading cause of cancer death of men in western countries and the death related to this disease in Korea is also getting increased. Although anatomic imaging tools such as transrectal US or MRI have been playing a great role in detection of primary prostate lesion, the evaluation of regional lymph node or distant organ metastasis using these modalities is not successful. $^{18}F-FDG-PET$ scan is emerging diagnostic tool for various malignancies. Considering the usual characteristics of prostate cancer such as slow growing and osteoblastic metastasis, the application of FDG PET scan to this disease might be limited. However, in advanced prostate cancer refractory to chemotherapy, FDG PET scan show strong FDG uptake and SUV changes in serial PET scan can be a good indicator of treatment response. Although FDG PET can be useful only in limited cases of prostate cancer, its indication can be widened in future owing to rapid technical improvement and accumulated experiences in this field.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3465-3468
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• 2016

Background: Fluorodeoxyglucose ($^{18}FDG$) PET/CT imaging has become an important component of the management paradigm in oncology. However, the significant imparted radiation exposure is a matter of growing concern especially in younger populations who have better odds of survival. The aim of this study was to estimate the effective dose received by patients having whole body $^{18}F$-FDG PET/CT scanning as per recent dose reducing guidelines at a tertiary care hospital. Materials and Methods: This prospective study covered 63 patients with different cancers who were referred for PET/CT study for various indications. Patients were prepared as per departmental protocol and 18FDG was injected at 3 MBq/Kg and a low dose, non-enhanced CT protocol (LD-NECT) was used. Diagnostic CT studies of specific regions were subsequently performed if required. Effective dose imparted by 18FDG (internal exposure) was calculated by using multiplying injected dose in MBq with coefficient $1.9{\times}10^{-2}mSv/MBq$ according to ICRP publication 106. Effective dose imparted by CT was calculated by multiplying DLP (mGy.cm) with ICRP conversion coefficient "k" 0.015 [mSv / (mG. cm)]. Results: Mean age of patients was $49{\pm}18$ years with a male to female ratio of 35:28 (56%:44%). Median dose of 18FDG given was 194 MBq (range: 139-293). Median CTDIvol was 3.25 (2.4-6.2) and median DLP was 334.95 (246.70 - 576.70). Estimated median effective dose imparted by $^{18}FDG$ was 3.69 mSv (range: 2.85-5.57). Similarly the estimated median effective dose by low dose (non-diagnostic) CT examination was 4.93 mSv (range: 2.14 -10.49). Median total effective dose by whole body 18FDG PET plus low dose non-diagnostic CT study was 8.85 mSv (range: 5.56-13.00). Conclusions: We conclude that the median effective dose from a whole body 18FDG PET/CT in our patients was significantly low. We suggest adhering to recently published dose reducing strategies, use of ToF scanner with CT dose reducing option to achieve the lower if not the lowest effective dose. This would certainly reduce the risk of second primary malignancy in younger patients with higher odds of cure from first primary cancer.

• 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.

• Korean Journal of Radiology
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• v.24 no.11
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• pp.1142-1150
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• 2023

Objective: To evaluate ^99mtechnetium-three polyethylene glycol spacers-arginine-glycine-aspartic acid (^99mTc-3PRGD₂) single-photon emission computed tomography (SPECT)/computed tomography (CT) imaging for diagnosing lymph node metastasis of primary malignant lung neoplasms. Materials and Methods: We prospectively enrolled 26 patients with primary malignant lung tumors who underwent ^99mTc-3PRGD₂ SPECT/CT and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/CT imaging. Both imaging methods were analyzed in qualitative (visual dichotomous and 5-point grades for lymph nodes and lung tumors, respectively) and semiquantitative (maximum tissue-to-background radioactive count) manners for the lymph nodes and lung tumors. The performance of the differentiation of lymph nodes with and without metastasis was determined at the per-lymph node station and per-patient levels using histopathological results as the reference standard. Results: Total 42 stations had metastatic lymph nodes and 136 stations had benign lymph nodes. The differences between metastatic and benign lymph nodes in the visual qualitative and semiquantitative analyses of ^99mTc-3PRGD₂ SPECT/CT and ¹⁸F-FDG PET/CT were statistically significant (all P < 0.001). The area under the receiver operating characteristic curve (AUC) in the semi-quantitative analysis of ^99mTc-3PRGD₂ SPECT/CT was 0.908 (95% confidence interval [CI], 0.851-0.966), and the sensitivity, specificity, positive predictive value, and negative predictive value were 0.86 (36/42), 0.88 (120/136), 0.69 (36/52), and 0.95 (120/126), respectively. Among the 26 patients (including two patients each with two lung tumors), 15 had pathologically confirmed lymph node metastasis. The difference between primary lung lesions in patients with and without lymph node metastasis was statistically significant only in the semi-quantitative analysis of ^99mTc-3PRGD₂ SPECT/CT (P = 0.007), with an AUC of 0.807 (95% CI, 0.641-0.974). Conclusion: ^99mTc-3PRGD₂ SPECT/CT imaging may notably perform in the direct diagnosis of lymph node metastasis of primary malignant lung tumors and indirectly predict the presence of lymph node metastasis through uptake in the primary lesions.

• Journal of the Korean Society of Radiology
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• v.81 no.6
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• pp.1486-1491
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• 2020

Kikuchi disease is a type of benign, self-limiting necrotizing lymphadenitis that occurs most commonly in young women and usually manifests as palpable cervical lymph nodes and fever. Patients with an unusual location of lymph node involvement can be misdiagnosed with malignant disease. Here, we report a case of Kikuchi disease in a 15-year-old girl presenting with persistent fever for 2 weeks. Imaging studies, including ultrasonography, CT, and ¹⁸F-fluorodeoxyglucose PET/CT, revealed splenomegaly and enlarged lymph nodes in the neck, axilla, abdomen, retroperitoneum, and inguinal region. Laparoscopic excision of the celiac lymph nodes confirmed histiocytic necrotizing lymphadenitis, also known as Kikuchi disease. Conservative treatment with corticosteroids improved the patient's condition.

• Korean Journal of Radiology
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• v.23 no.9
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• pp.921-930
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• 2022

Objective: To identify epidermal growth factor receptor (EGFR) mutations in lung adenocarcinoma based on ¹⁸F-fluorodeoxyglucose (FDG) PET/CT radiomics and clinical features and to distinguish EGFR exon 19 deletion (19 del) and exon 21 L858R missense (21 L858R) mutations using FDG PET/CT radiomics. Materials and Methods: We retrospectively analyzed 179 patients with lung adenocarcinoma. They were randomly assigned to training (n = 125) and testing (n = 54) cohorts in a 7:3 ratio. A total of 2632 radiomics features were extracted from the tumor region of interest from the PET (1316) and CT (1316) images. Six PET/CT radiomics features that remained after the feature selection step were used to calculate the radiomics model score (rad-score). Subsequently, a combined clinical and radiomics model was constructed based on sex, smoking history, tumor diameter, and rad-score. The performance of the combined model in identifying EGFR mutations was assessed using a receiver operating characteristic (ROC) curve. Furthermore, in a subsample of 99 patients, a PET/CT radiomics model for distinguishing 19 del and 21 L858R EGFR mutational subtypes was established, and its performance was evaluated. Results: The area under the ROC curve (AUROC) and accuracy of the combined clinical and PET/CT radiomics models were 0.882 and 81.6%, respectively, in the training cohort and 0.837 and 74.1%, respectively, in the testing cohort. The AUROC and accuracy of the radiomics model for distinguishing between 19 del and 21 L858R EGFR mutational subtypes were 0.708 and 66.7%, respectively, in the training cohort and 0.652 and 56.7%, respectively, in the testing cohort. Conclusion: The combined clinical and PET/CT radiomics model could identify the EGFR mutational status in lung adenocarcinoma with moderate accuracy. However, distinguishing between EGFR 19 del and 21 L858R mutational subtypes was more challenging using PET/CT radiomics.

• Journal of the Korea Convergence Society
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• v.9 no.1
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• pp.433-440
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• 2018

Recently, MTV(metabolic tumor volume) has been used as indices of the whole tumor FDG uptake on FDG PET image but it is influenced by image reconstruction. The purpose of this study was to evaluate the correlation between actual volume and metabolic tumor volume applying different SUVmax threshold for different reconstruction algorithm on phantom study. Measurement were performed on a Siemens Biograph mCT40 using a NEMA IEC body phantom containing different size six spheres filled with F18-FDG applying four SBRs (4:1, 8:1, 10:1, 20:1). Images reconstructed four algorithms (OSEM3D, OSEM3D+PSF, OSEM3D +TOF, OSEM3D+TOF+PSF) and MTV were measured with different SUVmax threshold. Overall, the use of increasing thresholds result in decreasing MTV. and increasing the signal to background ratio decreased MTV by applying same SUVmax threshold. The 40% SUVmax threshold gave the best concordance between measured and actual volume in PSF and PSF+TOF reconstruction image. and the 45% threshold had the best correlation between the volume measured and actual volume in OSEM3D and TOF reconstruction image. we believe that this study will be used when the measurement of MTV applying various reconstruction image.

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.1
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• pp.69-74
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• 2019

Purpose $^{18}F$-FDOPA using amino acid is particularly attractive for imaging of brain tumors because of the high uptake in tumor tissue and the low uptake in normal brain tissue. But, on the other hand, $^{18}F$-FDG is highly uptake in both tumor tissue and normal brain tissue. The purpose of study is to evaluate comparison of contrasts in $^{18}F$-FDOPA Brain PET/CT and $^{18}F$-FDG Brain PET/CT and to find out optimal scan time by analysis of variation in SUV with the passage of uptake time. Materials and Methods A region of interest of approximately $350mm^2$ at the center of the tumor and cerebellum in 12 patients ($51.4{\pm}12.8yrs$) who $^{18}F$-FDG Brain PET/CT and $^{18}F$-FDOPA Brain PET/CT were examined more than once each. The $SUV_{max}$ was measured, and the $SUV_{max}$ ratio (T/C ratio) of the tumor cerebellum was calculated. In the analysis of SUV, T/C ratio was calculated for each frame after dividing into 15 frames of 2 minutes each using List mode data in 25 patients ($49.{\pm}10.3yrs$). SPSS 21 was used to compare T/C ratio of $^{18}F$-FDOPA and T/C ratio of $^{18}F$-FDG. Results The T/C ratio of $^{18}F$-FDOPA Brain PET/CT was higher than the T/C ratio of $^{18}F$-FDG Brain, and show a significant difference according to a paired t-test(t=-5.214, p=0.000). As a result of analyzing changes in $SUV_{max}$ and T/C ratio, the peak point of $SUV_{max}$ was $5.6{\pm}2.9$ and appeared in the fourth frame (6 to 8 minutes), and the peak of T/C ratio also appeared in the fourth frame (6 to 8 minutes). Taking this into consideration and comparing the existing 10 to 30 minutes image and 6 to 26 minutes image, the $SUV_{max}$ and T/C ratio increased by 0.2 and 0.1 each, compared to the 10 to 30 minutes image for 6 to 26 minutes image. Conclusion From this study, $^{18}F$-FDOPA Brain PET/CT is effective when reading the image, because the T/C ratio of $^{18}F$-FDOPA Brain PET/CT was higher than T/C ratio of $^{18}F$-FDG Brain PET/CT. In addition, in the case of $^{18}F$-FDOPA Brain PET/CT, there was no difference between the existing 10 to 30 minutes image and 6 to 26 minutes image. Through continuous research, we can find possibility of shortening examination time in $^{18}F$-FDOPA Brain PET/CT. Also, we can help physician to accurate reading using additional scan data.