• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.357-360
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• 2009

Malignant mesothelioma of the peritoneum is a rare neoplasm with a rapidly fatal course. The tumour arises from the mesothelial cells lining the pleura and peritoneum or, rarely, in the pericardium or tunica vaginalis. This neoplasm is characterized by being difficult to diagnose, having a rapid evolution and a poor response to therapy. Mesothelioma is very glucose avid, and malignant pleural mesothelioma has been reported concerning the utility of F-18 FDG PET or PET/CT. But little has been known about the imaging finding of malignant peritoneal mesothelioma on F-18 FDG PET/CT. We report a case of malignant peritoneal mesothelioma mimicking peritoneal carcinomatosis of F-18 FDG PET/CT.

• 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.

• The Korean Journal of Nuclear Medicine
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• v.39 no.4
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• pp.231-238
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• 2005

Purpose: We investigated prospectively whether the interpretation considering the patterns of FDG uptake and the findings of unenhanced CT for attenuation correction can improve the diagnostic accuracy for assessing malignant lymph node (LN) and N stage in non-small cell lung cancor (NSCLC) using CT-corrected FDG-PET (PET/CT). Materials & Methods: Subjects were 91 NSCLC patients (M/F 62/29, age: $60{\pm}9$ yr) who underwent PET/CT before in dissection. We evaluated the maximum SUV (maxSUV), patterns of FDG uptake, short axis diameter, and calcification of LN showing abnormally increased FDG uptake. Then we investigated criteria improving the diagnostic accuracy and correlated results with postoperative pathology. In step 1, in was classified as benign or malignant based on maxSUV only. In step 2, LN was regarded as benign if it had lower maxSUV than the cut-off value of step 1 or it had calcification irrespective of its maxSUV. In step 3, LN regarded as malignant in step 2 was classified as benign if they had indiscrete margin of FDG uptake. Results: Among 432 LN groups surgically resected (28 malignant, 404 benign), 71 showed abnormally increased FDG uptake. We determined the cut-off as maxSUV=3.5 using ROC curve analysis. The sensitivity, specificity, and accuracy for assessing malignant LN were 64.3%, 86.9%, 85.4% in step 1, 64.3%, 95.0%, 93.1% in step 2, and 57.1%, 98.0%, 95.4% in step3, respectively. The accuracy for assessing N stage was 64.8% in step 1, 80.2% in step 2, and 85.7% in step 3. Conclusion: interpreting PET/CT, consideration of calcification and shape of the FDG uptake margin along with maxSUV can improve the diagnostic accuracy for assessing malignant involvement and N stage of hilar and mediastinal LNs in NSCLC.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.2
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• pp.120-128
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• 2009

Purpose: Early detection of recurrence is an important factor for long term survival of patients with colorectal cancer. Measurement of serum levels of CEA, CA 19-9, CT and PET/CT has been commonly used in the postoperative surveillance of colorectal cancer. The purpose of this study was to compare the diagnostic ability of PET/CT, tumor marker and CT for recurrence in colorectal cancer patients after treatment. Materials and Methods: F-18 FDG PET/CT imaging was performed in 189 colorectal cancer patients who underwent curative surgical resection and/or chemotherapy. Measurement of serum levels of CEA, CA 19-9 and CT imaging were performed within 2 months of PET/CT examination. Final diagnosis of recurrence was made by biopsy, radiologic studies or clinical follow-up for 6 months after each study. Results: Overall sensitivity, specificity of PET/CT was 94.7%, 91.1%, while those of serum CEA were 44.7% and 97.3%, respectively. Sensitivity and specificity were 94.2%, 90.4% for PET/CT and better than those of combined CEA and CA 19-9 measurement(52.1%, 88.5%) in 174 patients measured available both CEA and CA 19-9 data. In 115 patients with both tumor markers and CT images available, PET/CT showed similar sensitivity but higher specificity(92.9%, 91.3%) compared to combination of tumor markers and CT images(92.9%, 74.1%). Conclusion: PET/CT was superior for detection of recurred colorectal cancer patients compared with both CEA, CA 19-9, and even with combination of both tumor markers and CT. Therefore PET/CT could be used as a routine surveillance examination to detect recurrence or metastasis of colorectal cancer.

• The Korean Journal of Nuclear Medicine
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• v.39 no.4
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• pp.239-245
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• 2005

Purpose: Hypereosinophilic syndrome (HES) is an infiltrative disease of eosinophils affecting multiple organs including the iung. F-18 2-fluoro-2-deoxyglucose (F-18 FDG) may accumulate at sites of inflammation or injection, making interpretation of whole body PET scan difficult in patients with cancer. This study was to evaluate the PET findings of HES with lung involvement and to find out differential PET features between lung malignancy and HES with lung involvement. Material and Methods: F-18 FDG PET and low dose chest CT scan was performed for screening of lung cancer. light patients who showed ground-glass attenuation (GGA) and consolidation on chest CT scan with peripheral blood eosinophilia werr included in this study. The patients with history of parasite infection, allergy and collagen vascular disease were excluded. CT features and FDG PET findings were meticulously evaluated for the distribution of GGA and consolidation and nodules on CT scan and mean and maximal SUV of abnormalities depicted on F-18 FDG PET scan. In eight patients, follow-up chest CT scan and FDG PET scan were done one or two weeks after initial study. Results: F-18 FDG PET scan identified metabolically active lesions in seven out of eight patients. Maximal SUV was ranged from 2.8 to 10.6 and mean SUV was ranged from 2.2 to 7.2. Remaining one patient had maximal SUV of 1.3. On follow-up FDG PET scan taken on from one to four weeks later showed decreased degree of initially noted FDG uptakes or migration of previously noted abnormal FDG uptakes. Conclusions: Lung involvement in the HES might be identified as abnormal uptake foci on FDG PET scan mimicking lung cancer. Follow-up FDG PET and CT scan for the identification of migration or resolution of abnormalities and decrement of SUV would be of help for the differentiation between lung cancer and HES with lung involvement.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.5
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• pp.414-418
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• 2008

The role of positron emission tomography (PET) with F-18 fluorodeoxyglucose (F-18 FDG) in the diagnosis of hepatocellulcar carcinoma (HCC) has been limited because of a variable FDG uptake in HCC. However, the usefulness of PET/CT for detecting extrahepatic metastasis and monitoring of the treatment response in HCC has been reported. A 55-year-old man with a hepatitis B surface antigen-positive, was admitted to our hospital due to dyspnea, general weakness and body weight loss for one month. Chest X-ray showed multiple reticulo-nodular densities on both lower lung fields, which implies metastatic lesions. F-18 FDG PET/CT revealed consecutively intense hypermetabolic mass in right hepatic lobe, inferior vena cava and right atrium. We report a case of HCC with IVC and right atrium invasion identified by F-18 FDG PET/CT.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.91-100
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• 2008

Ovarian cancer is often fatal since it is difficult to diagnose early and recurrence is quite frequent despite successful implementation of cytoreductive surgery and chemotherapy, thus exact diagnosis and early detection of recurrence are crucial to patient management. For pre-treatment staging, FDG PET could be helpful in a limited patient group possessing high risks of ovarian cancer. Besides, FDG PET could be recommended to patients with a high suspicion of recurrence i.e. rise of CA-125, especially in cases of conventional diagnostic imaging modalities presenting no evidence of disease because FDG PET provides critical information for treatment planning such as recurrence site or pattern. In order to expand the use of FDG PET to general population at staging or routine surveillance of ovarian cancer, more investigation is needed. The usefulness of FDG PET in evaluating treatment response and prognosis of ovarian cancer has not yet been determined, but it has been reported that FDG PET could evaluate treatment response early and show a close relationship with overall survival. PET/CT has been actively adopted in management of ovarian cancer. Not only in detecting tumor recurrence and evaluating treatment response but also in pre-treatment staging, FDG PET/CT is expected to playa role due to available anatomical information.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.395-401
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• 2009

Purpose: We evaluated $^{18}F$-FDG PET/CT findings in initially diagnosed adenoid cystic carcinoma (ACC) of the head and neck in association with pathological subtype, staging, uptake comparison with squamous cell carcinoma (SqCC) and prognosis. Materials and Methods: The subjects were 16 patients with initially diagnosed ACC of head and neck who underwent pretreatment $^{18}F$-FDG PET/CT. Histological subtype (solid pattern vs. tubular/cribriform pattern), $SUV_{max}$ of size-matched SqCC of the head and neck as control group, disease-free survival (DFS) were compared with the $SUV_{max}$ of ACC of the head and neck. Results: Of total 16 patients, 6 had solid pattern and the remaining 10 had tubular/cribriform pattern. The $SUV_{max}$ were significantly higher in solid pattern group than in tubular/cribriform pattern group ($6.7{\pm}3.2$ vs. $4.2{\pm}0.9$, p=0.03). PET/CT found unexpected distant metastasis in 18.7% of patients (3/16) and changed the therapeutic plan in those patients. The $SUV_{max}$ of ACC was significantly lower than that of size-matched SqCC ($5.1{\pm}2.4$ vs. $13.6{\pm}6.0$, p<0.001). DFS was not significantly different according to the histological subtype. In contrast, patients with high $^{18}F$-FDG uptake ($SUV_{max}$ ${\geq}$6.0) had significantly shorter DFS than those with low $^{18}F$-FDG uptake ($SUV_{max}$ <6.0). Conclusion: $^{18}F$-FDG uptake of ACC of the head and neck is significantly associated with histological subtype and DFS. $^{18}F$-FDG PET/CT may be useful for detecting unexpected metastasis. Since $^{18}F$-FDG uptake of tubular/cribriform ACC compared with SqCC is relatively low, it is necessary to interpret PET images carefully in patients without alleged ACC.

• 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.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.4
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• pp.233-236
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• 2006

A 67-year-old man with a history of chronic obstructive pulmonary disease (COPD) underwent F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for staging of gastric cancer. The projection images of F-18 FDG PET/CT showed intensely increased F-18 FDG uptake in the anterior neck, chest wall, and upper abdomen. We suspected distant metastases of cervical lymph nodes, ribs, and peritoneum in gastric canter. However, the transaxial images of F-18 FDG PET/CT showed abnormal F-18 FDG uptake in scalene muscles of anterior neck, intercostal muscles of chest wall, and diaphragm of upper abdomen. Patients with COPD use respiratory muscles extensively on the resting condition. These excessive physiologic use of respiratory muscles causes increased F-18 FDG uptake as a result of increased glucose metabolism. The F-18 FDG uptake in respiratory muscles of gastric cancer patient with COPD mimicked distant metastases in cervical lymph nodes, ribs, and peritoneum.