• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.50-54
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• 2010

Purpose: The uptake of $^{18}F$-FDG is often observed in normal cell of colon to patients who have non-insulin-dependent diabetes mellitus and had taken anti-diabetic drugs including Metformin in PET/CT scan. In this study, the region of colon was compared between the patients who took anti-diabetic drugs including Metfomin and other patients who took the other anti-diabetic drugs through SUV measurements. Materials and Methods: A hundred eighty patients were studied. 120 patients who have non-insulin-dependent diabetes mellitus (Including Metformin: 60, Excluding Metformin: 60) and 60 patients as a control group were composed. The patient fasted at least 6 hours before receiving an intravenous injection of 370-592 MBq (10-16 mCi) of $^{18}F$-FDG. Scanning from the base of the skull though the mid thigh was performed using the Discovery STe PET/CT Equipment (GE Healthcare, Milwaukee, WI, USA). The highest uptake region was measured SUV among ascending, transverse and descending colon. Results: The values of patients who took the anti-diabetic drugs including Metformin were $6.16{\pm}3.64$ g/mL, $4.41{\pm}2.94$ g/mL, and $5.46{\pm}2.44$ g/mL. The patients who took the anti-diabetic drugs which does not have Metformin were $3.05{\pm}1.39$ g/mL, $2.08{\pm}0.97$ g/mL and $3.15{\pm}1.85$ g/mL. The control group were $2.02{\pm}0.88$ g/mL, $1.68{\pm}0.87$ g/mL and $2.19{\pm}1.88$ g/mL. Conclusion: The effect of the intake of Metformin was observed from the SUV on region of large bowel in this study. Thus, it could be helpful for the results by identifying the ingredient of anti-diabetic drug before the examination and the possibility of interpretation of false positive will be reduced.

• Korean Journal of Head & Neck Oncology
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• v.27 no.2
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• pp.218-221
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• 2011

The anterior approach to the cervical spine surgery is associated with possible complications such as dysphagia, hoarseness and granuloma formation etc. Because of orthopedic metallic plates, the increasing or focal uptake pattern may be demonstrated in $^{18}F$-FDG PET/CT scan. A 67-year-old-man came to our department, complained of dysphagia during the 4 months. He underwent cervical spine surgery three years ago. The CT and MRI findings mimicked typical posterior pharyngeal wall cancer with cervical metastasis. Furthermore, the SUV in $^{18}F$-FDG PET/CT was 10.3. But he was finally diagnosed as a granuloma resulting from the metallic cervical implants. The clinical correlation and medical history should be taken into account to avoid false-positive findings in PET/CT and to avoid many erroneous diagnostic pathways.

• 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.

• Journal of the Korea Society of Computer and Information
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• v.12 no.2 s.46
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• pp.123-130
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• 2007

The aim of this study was to propose a fusion and registration method with heterogeneous small animal acquisition system in small animal in-vivo study. After an intravenous injection of $^{18}F$-FDG through tail vain and 60 min delay for uptake, mouse was placed on an acryl plate with fiducial markers that were made for fusion between small animal PET (microPET R4, Concorde Microsystems, Knoxville TN) and Discovery LS CT images. The acquired emission list-mode data was sorted to temporally framed sinograms and reconstructed using FORE rebining and 2D-OSEM algorithms without correction of attenuation and scatter. After PET imaging, CT images were acquired by mean of a clinical PET/CT with high-resolution mode. The microPET and CT images were fusion and co-registered using the fiducial markers and segmented lung region in both data sets to perform a point-based rigid co-registration. This method improves the quantitative accuracy and interpretation of the tracer.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.2
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• pp.37-43
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• 2013

Purpose: PET/CT scan using the SUV (Standardized Uptake Value) of radiopharmaceutical uptake in organs and tissues as an objective indicator makes it possible to analyze physiological and chemical reactions of human organs. This study analyzes the change of the SUV uptake in accordance with the way how PET/CT patients take a rest after the injection of $^{18}F-FDG$ (Fluororo-deoxyglucose). And also subjective satisfaction is assessed listening to music while taking a rest. Materials and Methods: From April 2011 until February 2013, Among the Primary cancer patients who admitted to the Catholic Medical Center (Seoul & Bucheon St. Mary's Hospital) and scanned $^{18}F-FDG$ PET/CT and also received care through the tracking test (mean age $55.61{\pm}12.41$ years, 108 people, 48 men and 60 women) were selected. The patients were divided into two groups. The first group (A: basal study) is requested to take a rest in bed quietly after the injection. However the second one (B: follow up study) is requested to listen to the music while taking a rest. And then SUV analysis was performed respectively. At the end of the scan, ROI (Region Of Interest) were set from the center of the liver (right lobe) and 3 spots of the brain (frontal, temporal, and occipital lobes). And the SUV was calculated. To identify the correlation among those ROIs, paired t-test was performed using SPSS software (Version 12.0K for windows, P>0.05). Also, after the PET/CT scan the satisfaction study was conducted of all the patients. 1:1 questionnaire survey was performed, and that questionnaire was made using the Likert 5-point scale. By utilizing those questionnaires, the analysis about simple frequency, percentage, average, and standard deviation was performed. Results: The SUV change of the 4 designated ROIs in accordance with listening to music was not statistically significant. (Frontal lobe P-value=0.611, Occipital lobe P-value=0.499, Temporal lobe P-value=0.717, Liver P-value=0.334: P-value>0.05) And the satisfaction study indicated that group B was appear to be 0.42 points (5 basis points) higher than group A. It showed that patients are more satisfied in group B than group A. Conclusion: when performing PET/CT scan using $^{18}F-FDG$, listening to music after the injection of the radiopharmaceuticals does not affect the SUV but given the state of the psychological comfort that may increase the patient's satisfaction.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9879-9884
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• 2014

Aim: The purpose of the current study was to conduct a systematic review of the published literature to evaluate the diagnostic accuracy of FDG-PET, PTE/CT, MRI and scintigraphy for multiple myeloma related bone disease. Methods: Through a search of PubMed, EMBASE, and the Cochrane Library, two reviewers independently assessed the methodological quality of each study. We estimated pooled sensitivity, specificity, positive and negative likelihood ratios (PLR and NLR), and two sample Z-tests were conducted to evaluate for differences in sensitivity, specificity, area under the curve (AUC), and the $Q^*$ index between any two diagnostic modalities. Results: A total of 17 studies were reviewed. The MRI had a pooled sensitivity of 0.88, specificity of 0.68, AUC of 0.897, and $Q^*$ index of 0.828, whereas for MIBI, the corresponding values were 0.98, 0.90, 0.991, and 0.962, respectively, and for bone scan, they were 066, 0.83, 0.805, and 0.740, respectively. The corresponding values of MIBI were 0.98, 0.90, 0.991, and 0.962, respectively. For PET and PET/CT, the values were 0.91, 0.69, 0.927 and 0.861, respectively. Statistically significant differences were not found in the sensitivity, specificity, AUC, and $Q^*$ index between MRI, scintigraphy, FDG-PET and PET/CT. Conclusions: On the condition that X ray is taken as a reference in our study, we suggested that FDG-PET, PTE/CT, MRI and scintigraphy are all associated with high detection rate of bone disease in patients with MM. Thus, in clinical practice, it is recommended that we could choose these tests according to the condition of the patient.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.258-259
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• 2007

Benign metastasizing leiomyoma(BML) is a rare condition affecting women with a history of having undergone hysterectomy or myomectomy for a benign uterine fibroid, that is found to have metastasized to extrauterine sites, usually many years after hysterectomy. 1,2) Patient with BML almost always asymptomatic, although if the lesions are large enough, they can cause compressive symptoms. Among several hypothesis of pathogenesis, most plausible theory is that these tumors represent a true metastatic lesion but are very low-grade sarcoma. 3) Because the tumor is responsive to estrogen, menopause and pregnancy have slowed the growth of these lesion 4) and it seems reasonable to perform hysterectomy in patients with a uterine mass and, at the same time, perform oophorectomy for hormonal control. BML is an unusual cause of diffuse pulmonary nodules which should be considered in females with unexplained nodules and a history of surgery for uterine leiomyoma.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.101-109
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• 2008

Cervix cancer is one of common gynecological cancers in the world, and staged with FIGO or TNM system. However, these clinical staging systems lack information about lymph node or distant metastases, thus imaging modalities are considered to make an appropriate therapeutic plan and enhance overall survival rate. In this context, FDG PET is recommended to pre-treatment stating and prognosis prediction, for it could noninvasively evaluate the status of lymph nodes, especially abdominal paraaortic nodes which are closely related with prognosis. Moreover, the degree of FDG uptake is correlated with prognosis. Although there is no consistent method for surveillance of cervix cancer, FDG PET seems a very important tool in detecting tumor recurrence because it is much more advantageous than conventional imaging modalities such as MRI for discerning recurrent tumor from fibrosis caused by radiation or surgery. Furthermore, FDG PET could be used to evaluate treatment response. On the other hand, recently introduced PET/CT is expected to play an ancillary role to FIGO staging by adding anatomical information, and enhance diagnostic performance of PET by decreasing false positive findings.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.5
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• pp.359-363
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• 2007

Purpose: Incidental parotid lesions on F-18 FDG-PET can mimic distant metastasis of underlying malignancy. The prevalence and the clinico-pathologic findings of PET positive parotid lesions have not been known. We investigated how often incidental parotid lesions are found on clinical FDG-PET studies and what the clinico-pathologic characteristics of those parotid lesions are in the present study. Materials and Methods: We retrospectively reviewed 3,344 cases of FDG-PET which had been obtained in our hospital from May 2003 to Dec 2006. The indications of FDG-PET were: evaluation of known/suspected cancer (n= 3,212) or screening of cancer in healthy subjects (n=132). Incidental parotid lesion on FDG-PET was defined as an un-expected FDG uptake in one of parotid glands which was not primary target lesion of current FDG-PET. FDG uptake was represented by maximum standardized uptake value (maxSUV). Final diagnosis was made by pathologic analysis or clinical follow-up assessment. Results: Fifteen (0.45% = 15/3,344) incidental parotid lesions were found and they were all benign lesions. The maxSUV ranged from 1.7 to 8.6 (mean${\pm}$s.d. = $3.7{\pm}1.9$). Final diagnoses of the incidental parotid lesions were; Warthin's tumor (n=2), pleomorphic adenoma (n=1), other un-specified benign lesion (n=1), and benign lesions under bases of imaging studies (n=3) and of clinical follow-up (n=8). Conclusion: All of incidentally found parotid lesions in clinical FDG-PET studies were confirmed as benign lesions with prevalence of 0.45%. Close follow up using PET or CT might be a reasonable approach for determining the nature of incidentally found parotid lesions.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.2
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• pp.17-21
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• 2014

Purpose With the recent rise of social issue regarding radiation exposure, attention to medical radiation use has been placed under a great spotlight. During PET-CT examination, generally about 40% more of $^{18}F$-FDG is used than EANM recommendation. While maintaining the diagnostic test result, we hope to find optimal injection dose to minimize the $^{18}F$-FDG in patients by utilizing the latest PET-CT scanner which is equiped with the newest technology. Materials and Methods During this experiment, the Biograph Truepoint 40 (siemens, USA) installed in 2007 and mCT 64 (siemens, USA) installed in 2011 were used and evaluated NECR (noise-equivalent counting rate) by using a scatter phantom. For the image quality evaluation of each scanner, we injected 3.7, 4.44 and 5.18 MBq/kg of $^{18}F$-FDG in NEMA IEC Body Phantom and also evaluated SNR between two scanners by using the data acquired at 60, 70, 80, 90, 100, 110 and 120 sec per bed. For the clinical evaluation, actual data of patients who were injected $^{18}F$-FDG 3.7, 4.44, 5.18 MBq/kg were used to compare SNR and draw a final result. Results As a result, mCT 64 peak NECR value was 1.65e+005, which is 10% higher than Turepoint 40. SNR values using the IEC body phantom was 17.9%, 17.4% and 17.1% higher in $^{18}F$-FDG 3.7 MBq/kg, 4.44 MBq/kg and 5.18 MBq/kg. In clinical patients, SNR values of the image mCT 64 was 16.5, which is 25% higher than Turepoint 40 scanner. Conclusion To draw a conclusion from the test result of this experiment, the same quality of SNR could be attained even with 10% reduced injection dose, if when the duration is extended by 10 sec/bed. This optimal result was possible due to enhanced equipment. The NECR (one of the equipment's performance assessment criteria for the scanner) increased by 10% and the SNR (one of the image quality assessment criteria) also increased by 17.5%. Therefore, we can expect to reduce the injection dose without deterioration of image quality. In consequence, it will also help to decrease the patient's anxiety of the radiation exposure.