• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.81-86
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• 2012

Purpose : Combined MR/PET scanners that use the MRI for PET AC face the challenge of absent surface coils in MR images and thus cannot directly account for attenuation in the coils. To make up for the weak point of MR attenuation correction, Three Modality System (PET/CT +MR) were used in Severance hospital. The goal of this work was to investigate the effects of MR Torso Coil on CT attenuation correction for PET. Materials and Methods : PET artifacts were evaluated when the MR Torso Coil was present of CTAC data with changing various kV and mA in uniformity water phantom and 1994 NEMA cylinderical phantom. They evaluated and compared the following two scenarios: (1) The uniform cylinder phantom and the MR Torso Coil scanned and reconstructed using CT-AC; (2) 1994 NEMA cylinderical phantom and the MR Torso Coil scanned and reconstructed using CT-AC. Results : Streak artifacts were present in CT images containing the MR Torso Coil due to metal components. These artifacts persisted after the CT images were converted for PET-AC. CT scans tended to over-estimate the linear attenuation coefficient when the kV and mA is increasing of the metal components when using conventional methods for converting from CT number. Conclusion : The presence of MR coils during PET/CT scanning can cause subtle artifacts and potentially important quantification errors. Alternative CT techniques that mitigate artifacts should be used to improve AC accuracy. When possible, removing segments of an MR coil prior to the PET/CT exam is recommended. Further, MR coils could be redesigned to reduce artifacts by rearranging placement of the most attenuating materials.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.1
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• pp.79-80
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• 2008

Including malignancy, various disease can show abnormal uptake in bone marrow. We report a case of non-specific inflammatory FDG uptake in bone marrow mimicking malignancy. A 35-year old woman with fever of unknown origin (FUO) underwent $^{18}F$-FDG PET/CT to find out fever $^{18}F$-FDG and unknown malignancy. $^{18}F$-FDG was injected and imaged 1hr after injection with Discovery ST (GE, USA), $^{18}F$-FDG PET/CT whole body image showed abnormal uptake in lower extremities (Fig. 1). MRI and biopsy was also done in the sites of abnormal uptake. PET and MRI suspect malignancy (Fig. 2, 3), but biopsy result was non-specific inflammatory process (Fig. 4). The patient was improved her clinical condition after antibiotics therapy.

• Korean Journal of Radiology
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• v.25 no.1
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• pp.86-102
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• 2024

Early diagnosis, accurate assessment, and localization of peritoneal metastasis (PM) are essential for the selection of appropriate treatments and surgical guidance. However, available imaging modalities (computed tomography [CT], conventional magnetic resonance imaging [MRI], and 18fluorodeoxyglucose positron emission tomography [PET]/CT) have limitations. The advent of new imaging techniques and novel molecular imaging agents have revealed molecular processes in the tumor microenvironment as an application for the early diagnosis and assessment of PM as well as real-time guided surgical resection, which has changed clinical management. In contrast to clinical imaging, which is purely qualitative and subjective for interpreting macroscopic structures, radiomics and artificial intelligence (AI) capitalize on high-dimensional numerical data from images that may reflect tumor pathophysiology. A predictive model can be used to predict the occurrence, recurrence, and prognosis of PM, thereby avoiding unnecessary exploratory surgeries. This review summarizes the role and status of different imaging techniques, especially new imaging strategies such as spectral photon-counting CT, fibroblast activation protein inhibitor (FAPI) PET/CT, near-infrared fluorescence imaging, and PET/MRI, for early diagnosis, assessment of surgical indications, and recurrence monitoring in patients with PM. The clinical applications, limitations, and solutions for fluorescence imaging, radiomics, and AI are also discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5508-5512
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• 2015

Objective.: Sparganosis locations in humans are usually presented with a subcutaneous tissue of abdominal wall, chest, abdominal vicera and brain, but are rarely found in the breast. Methods. A case of sparganosis was confirmed by surgical excision of two parasites in a 76-year-old female patient present to a palpable mass in the right breast (presumed to have been sparganosis approximately 3 years ago). She had no history to direct ingestion of snakes or frogs, but had the history of drinking contaminated water. Mammography, ultrasonography, MRI, and FDG PET/CT imaging findings for patient were characteristic of sparganosis due to suspicion of breast cancer. Conclusions: The first route of infection in humans is drinking contaminated water. The second route is the ingestion of raw or partially cooked snakes or frogs. The third route is infected wound snake, frog muscle that attach to the case. However, only a few cases of drinking contaminated water have been reported in the country. Ultrasonography, MRI is known to be helpful for diagnosis of breast sparganosis. However, Mammography, ultrasonography, MRI, and FDG PET/CT for breast sparganosis is not reported present in the country. Reported the case and reviewed the related literature briefly.

• 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.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.253-258
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• 2009

Bone scintigraphy using $^{99m}$Tc-labeled phosphate agents has long been the standard evaluation method for whole skeletal system. However, recent shortage of $^{99m}$Tc supply and advanced positron emission tomography (PET) technology evoked the attention to surrogate radiopharmaceuticals and imaging modalities for bone. Actually, fluorine-18 ($^{18}$F) was the first bone seeking radiotracer before the introduction of $^{99m}$Tc-labeled agents even though its clinical application failed to become pervasive anymore after the rapid spread of Anger type gamma camera systems in early 1970s. However, rapidly developed PET technology made us refocus on the usefulness of $^{18}$F as a PET tracer. Early study comparing $^{18}$F-Na PET scan and planar bone scintigraphy reported that PET has higher sensitivity and specificity in the diagnosis of metastatic bone lesions than planar bone scan. Subsequent reports comparing between PET and both planar and SPECT bone image also revealed better results of PET scan in similar study groups. Rapid clinical application of PET/CT also accumulated considerable amount of experiences in skeletal evaluation and this modality is known to have better diagnostic power than stand alone PET system as well as bone scan. Furthermore $^{18}$F-Na PET/CT revealed better or at least equal results in detection of primary and metastatic bone lesions compared with CT and MRI. Therefore, it is obvious that $^{18}$F-Na PET/CT has potential to become new imaging modality for practical skeletal evaluation so continuous and careful evaluation of this modality and radiopharmaceutical must be required.

• Korean Journal of Digital Imaging in Medicine
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• v.13 no.1
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• pp.33-38
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• 2011

Now a days, there's many change over for PACS among the most of hospital and it standard for DICOM 3.0. These kind of using of DICOM 3.0 improves increasing of medical imaging exchange and service for patient. However, there's some problems of compatibility caused during carry out CD and DVD from hospital. For this reason, this thesis analyzed patients image targeting those storages requested to hospitals in Seoul by using Validation Toolkit which is recommended from KFDA. The analyze type is like this. Make 100 data, total 500, each of MRI CT Plain x-ray Ultrasound PET-CT images and analyzed type of error occurred and loyalty of information. If express percentage of error occurred statistically, we can get a result as follows MRI 5%, Plain x-ray 11%, CT 18%, US 25%, PET-CT 30%. The reson why percentage of error occurred in PET-CT is because of imperfective support and we could notice that we weren't devoted to information. Even though, PET-CT showed highest percentage of error occurred, currently DICOM data improved a lot compare to past. Moreover, it should be devoted to rule of IHE TOOL or DICOM. In conclusion, we can help radiographer to analyze information of image by providing clues for solving primary problem and further more, each of PACS company or equipment company can enhance fidelity for following standard of image information through realizing the actual problem during transfer of image information.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.301-308
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• 2009

Purpose: The aim of this study was to evaluate the usefulness of FDG-PET/CT as follow up imaging tool in patients with endometrial cancer after therapy. Material and Methods: One hundred one patients with endometrial cancer who underwent FDG PET/CT after the treatment of this disease were included in this study population (25-79 yr old, Mean age 50.6 yr old) and all these patients also performed various laboratory and imaging studies such as serum tumor marker, CT or MRI. The lesions having increased focal FDG uptake were classified into benign, equivocal, and malignant one according to their pattern and activity. Tumor recurrence was confirmed by histopathological results and other clinical and imaging data. Results: Among the 19 patients with 30 malignant or equivocal hot uptakes, 11 of 14 patients supposed to be malignant finding in PET/CT were proved to be tumor recurrence, while one of 5 patients with equivocal lesions were recurred malignancy, Two false negative cases were turned out to be peritoneal carcinomatosis, Estimated sensitivity, specificity and accuracy of PET/CT for diagnosis of recurrence in endometrial carcinoma after treatment were 86 %, 92 % and 91 %, respectively. Positive and negative predictive values in the same issue were 63% and 98%, respectively. Conclusion: FDG-PET/CT is useful for regular work up of endometrial carcinoma after the treatment because of its high negative predictive value as well as high sensitivity and specificity.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.1
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• pp.44-48
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• 2008

Purpose: In FDG-PET/CT of breast cancer, a sensitivity was 80~96% and a specificity was 75~95% commonly. It was valuable to identify a cancer in early stage been difficult in Mammography. Most of the PET/CT scans have been examined on supine position, so, the image of breast has been acquired by reconstructed whole body scan image. However, using prone position with a compensator, a shape of breast was reassembly shown to be real by gravity. Therefore, the purpose of this study was to evaluate diagnostic value of prone position in FDG PET-CT of breast cancer. Materials and Methods: 30 female patients with doubtful or positive breast cancer were examined. The PET-CT whole body scan was acquired at 60 minutes after $^{18}F$-FDG injection on Supine position. Then, regional breast spot scan was progressed on prone position using a compensator. Each image was evaluated by physicians blinded to patient's data, and statistical analysis did through SUVs measured in PET-CT images. Results: In 27 of 30 patients, prone position was shown accurate discrimination and diagnostic value, but in another 3 patients had a lesion 1cm below, PET-CT couldn't detect it, unlike MRI. Consequently, prone position distinguished a lesion better than Supine position, because of low degree of metamorphosis by gravity. The SUVs analysis of each position was significant (p value=0.004). Conclusion: In PET-CT of breast cancer, prone position could detect micrometastasis as well as primary lesion, better than supine position. Therefore, this study proposes that any technical change considered morphological feature like prone position can offer adequate and useful diagnostic information, together with complementary quantitative analysis.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.01a
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• pp.239-240
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• 2017

본 연구는 의료영상내 특징정보를 추출 및 평가함으로서 정밀의료 실현 가능성을 확인하고자 하였다. 영상화는 PET/CT 및 MRI 스캐너를 이용하여 암환자의 기능적 정보와 해부학적 정보를 획득하고 관심영역을 설정하였으며 각각의 영상내 특징정보를 추출하였다. 영상내 특징정보는 GLCM을 이용하여 에너지, 대비, 엔트로피, 균질성을 획득하였고, 획득된 영상 데이터에 따른 관심영역 설정 차이를 확인하였다. 영상내 특징 정보는 MRI 영상의 해부학적 정보를 이용한 분석결과에서 엔트로피 및 균질성이 PET 보다 증가 하였고 대비는 감소함을 확인하였다. 추후연구는 다양한 영상내 특징 정보를 획득하고 정밀의료를 위한 기계학습에 활용할 예정이다.