• Journal of the Korea Society of Computer and Information
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• v.26 no.7
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• pp.37-44
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• 2021

Automatic classification of brain MRI images play an important role in early diagnosis of brain tumors. In this work, we present a deep learning-based brain tumor classification model in MRI images using ensemble of deep features. In our proposed framework, three different deep features from brain MR image are extracted using three different pre-trained models. After that, the extracted deep features are fed to the classification module. In the classification module, the three different deep features are first fed into the fully-connected layers individually to reduce the dimension of the features. After that, the output features from the fully-connected layers are concatenated and fed into the fully-connected layer to predict the final output. To evaluate our proposed model, we use openly accessible brain MRI dataset from web. Experimental results show that our proposed model outperforms other machine learning-based models.

• Clinical and Experimental Pediatrics
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• v.49 no.6
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• pp.691-695
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• 2006

Hepatoblastoma is a hepatic tumor predominantly occurring in children. The usual site of metastasis is the lung. There are only several reports worldwide on the distant metastasis of hepatoblastoma to the central nervous system in children. Only one reported case showed survival of a patient after multiple resections of a recurrent brain lesion. Involvement of the cardiovascular system has been reported in the medical literature. Lesions almost always involve the right-side of the heart. We report a case of recurrent hepatoblastoma at multiple sites, including brain, left atrium of the heart and lung in a 6-year-old girl who was partially treated in the past at the age of 1.5 years; the patient had been event-free for four and a half years.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.239-246
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• 2021

Portal Dosimetry was verified using EPID to secure the clinical application and reliability of the existing research dose evaluation. The dose distribution of Geant4 was compared with the measured value by 360° rotational irradiation with a 2.5 cm cone for stereotactic brain surgery. To confirm the dose distribution of patients with brain metastasis, the dose distribution investigated by inserting a Gafchromic EBT film into the parietal phantom and the dose distribution obtained from the parietal phantom using VMAT are compared and applied to actual patients. As a result of the analysis, it was confirmed that the accuracy of the beam center and the center of the couch coincide accurately with an error within 1mm as a result of QA through a pin ball. In addition, it was confirmed that the EBT3 film has excellent linearity in the range of 0 to 10 Gy according to various dose irradiation. In the same setting as the two cervical phantoms, we confirm that the implementation and simulation results calculations of dose calculations based on Geant4 using photon beams match the experimental data within the treatment planning volume (PTV). Therefore, volume modulated arc treatment (VMAT) 360° rotational irradiation was performed, and the result of iso-dose distribution analysis by rotational irradiation confirmed that it is appropriate to include a virtual tumor.

• Radiation Oncology Journal
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• v.27 no.3
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• pp.140-144
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• 2009

Purpose: This study was performed to retrospectively analyze patient survival by weighting according to the primary tumor oncotype in 160 patients with brain metastasis and who underwent whole brain radiotherapy. Materials and Methods: A total of 160 metastatic brain cancer patients who were treated with whole brain radiotherapy of 30 Gy between 2002 and 2008 were retrospectively analyzed. The primary tumor oncotype of 20 patients was breast cancer, and that of 103 patients was lung cancer. Except for 18 patients with leptomeningeal seeding, a total of 142 patients were analyzed according to the prognostic factors and the Recursive Partitioning Analysis (RPA) class. Weighted Partitioning Analysis (WPA), with the weighting being done according to the primary tumor oncotype, was performed and the results were correlated with survival and then compared with the RPA Class. Results: The median survival of the patients in RPA Class I (8 patients) was 20.0 months, that for Class II (76 patients) was 10.0 months and that for Class III (58 patients) was 3.0 months (p<0.003). The median survival of patients in WPA Class I (3 patients) was 36 months, that for the patients in Class II (9 patients) was 23.7 months, that for the patients in Class III (70 patients) was 10.9 months and that for the patients in Class IV (60 patients) was 8.6 months (p<0.001). The WPA Class might have more accuracy in assessing survival, and it may be superior to the RPA Class for assessing survival. Conclusion: A new prognostic index, the WPA Class, has more prognostic value than the RPA Class for the treatment of patients with metastatic brain cancer. This WPA Class may be useful to guide the appropriate treatment of metastatic brain lesions.

• The Korean Journal of Nuclear Medicine
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• v.34 no.5
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• pp.371-380
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• 2000

Purpose: Thallim-201 ($^{201}Tl$) brain SPECT, which can represent cellular activity of brain lesions, may provide more useful information in differentiating between benign and malignant brain lesions more so than CT of MRI, that merely represents anatomic changes or breakdown of blood brain barrier. We used $^{201}Tl$ brain SPECT prospectively to evaluate the utility of $^{201}Tl$-indices as an indicator of benign or malig nant lesions. Materials and Methods: We studied 28 patients. There were 13 cases of benign lesions (3: nonspecific benign lesion, 3: meningioma, 2: low grade glioma, 1: tuberculoma, central neurocytoma, hemangioblastoma, radiation necrosis, and choroid plexus papilloma) and 15 cases of malignant lesions (6: glioblastoma multiforme, 5: anaplastic glioma, 2: medulloblastoma, 1: metastasis and lymphoma). In all patients, CT and/or MRI were obtained and then $^{201}Tl$ brain SPECT was obtained with measuring mean $^{201}Tl$ index and peak $^{201}Tl$ index. An unpaired t-test was performed to compare the $^{201}Tl$-indices and pathologic diagnoses to evaluate the utility of $^{201}Tl$-indices as all indicator of benign or malignant lesions. Results: There were no statistically significant difference in $^{201}Tl$-indices between benign and malignant brain lesion (p>0.05). Conclusion: These results demonstrated that we could not use $^{201}Tl$ indices on brain SPECT alone as an indicator of benign or malignant brain lesions.

• Journal of radiological science and technology
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• v.32 no.3
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• pp.325-334
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• 2009

Purpose : This study was conducted to assess how effective the permeability ratio and relative cerebral blood volume ratio are to tumor through perfusion MRI by measuring and reflecting the grade assessment and differential diagnosis and the permeability and relative cerebral blood volume of contrast media plunged from blood vessel into organ due to breakdown of blood-brain barrier in cerebral. Subject and Method : Subject of study was 29 patients whose diagnosis were confirmed by biopsy after surgery and 550 (11 slice$\times$50 image) perfusion MRI were used to make image of relative cerebral blood volume with the program furnished on instrument. The other method was to transmit to private computer and the image analysis was made additionally by making image of relative cerebral blood volume-reformulated singular value decomposition, rCBV-rSVD and permeability using IDL.6.2. In addition, Kruskal-wallis test tonggyein non numerical average by a comparative analysis of brain tumors Results : The rCBV ratio (Functool PF; GE Medical Systems and IDL 6.2 program by analysis) and permeability ratio of tumors were as follows; high grade glioma(n=4), (14.75, 19.25) 13.13. low grade astrocytoma(n=5) (14.80, 15.90) 11.60, glioblastoma(n=5) (10.90, 18.60), 22.00, metastasis(n=6) (11.00, 15.08). 22.33. meningioma(n=6) (18.58, 7.67), 5.58. oliogodendroglioma(n=3) (23.33, 16.33, 15.67. Conclusion : It was not easy to classify the grade with the relative cerebral blood volume ratio measured by using the relative cerebral blood image by type of tumors, however, permeability ratio measured by permeability image revealed that the higher the grade of tumor, the higher the measured permeability ratio, showing the assessment of tumor grade is more effective to differential diagnosis.

• Journal of Korean Neurosurgical Society
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• v.29 no.9
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• pp.1267-1270
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• 2000

Krukenberg tumor has been traditionally defined as gastrointestinal malignancy metastatic to the ovary, and is known to account for 1 to 3% of ovarian neoplasms. The nature and behavior of this particularly virulent tumor still remains unclear. We have experienced a case of Krukenberg tumor with brain metastasis. A clinical description of our case is presented with a review of the literature.

• KSBB Journal
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• v.5 no.3
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• pp.201-205
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• 1990

The characteristics of steroid acyl transferase were studied in the rat brain with (4-14C)-dehydroepiandrosterone(DHEA). The results could be summarized as followings: The enzyme system responsible for the biosynthesis was localized at the microsome fraction. The optimum pH of this enzyme was 4.6 When DHEA was utilized as substrate, $\Delta$5-pregnenolone was proved to be a competitive inhibitor. However testosterone was a noncompetitive inhibitor. The acylation at 3${\beta}$-hydroxyl group was favored when the hydrophilicity at Cl7 position increased. However, this acylation at C3 was very low when A ring was aromatic. The acylation at Cl7 hydroxyl group reguired an absolute 17${\beta}$-conformation.

• Communications of Mathematical Education
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• v.11
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• pp.321-338
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• 2001

수학의 역사에 비하여 수학교육에 관한 연구는 비교적 짧다. 1960년대에 미국과 소련의 우주과학 경쟁이 시작되고 수학교육이 관심을 갖게 되었다. 이 후 전문 학회와 논문지가 출현하기 시작하면서 학문적으로 연구되고 발전하기 시작하였다. 한편 대학 수준의 수학교육에 관한 전문적인 연구는 뒤늦게 1990년대에 시작하였다. 한편 한국의 대학 수학교육은 현재 크게 변화하고 동요하고 있다. 대중화된 대학 교육, 수학 수강생 감소, 대학 수학교육의 개선, 7차 및 중등 교육과정 문제 대학으로 전이, 정보기술의 발전 및 활용 등으로 복잡하게 전개되고 있다. 수학교육 연구의 목적, 문제, 방법, 타당성 기준, 결과의 가치, 교육 개선 응용 등의 학문적 성격이 수학 연구와 크게 다르다. 대학 수학교육에서 새롭게 나타나고 부각되는 문제를 효과적으로 접근하기 위한 연구 방향을 제시한다. 그리고 뇌 과학과 인지 과학 연구에 바탕을 둔 실제 학습 모형에 응용할 수 있는 대학 수학 학습 이론을 소개한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.626-629
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• 2001

인간의 뇌에는 천 억개 이상의 신경세포들이 있다. 이들은 신경작용의 매우 복잡한 네트워크를 통해 서로서로 연결되어져 있다. 하나의 신경세포로부터 다른 신경세포로 신호가 전달되는 과정은 다른 화학 전달물질들에 의해 이루어지며 신호 전이는 시냅스라고 불리는 신경세포간의 특정 접촉부 위에서 일어난다. 뉴런의 신호전달 체계에 대한 연구는 20세기 초반에 본격적으로 이루어져 왔으며, 현재는 각 뉴런에 대한 정확한 신호전달 원리를 밝히는데 많은 연구가 이루어지고 있다. 최근에 연구가 활발하게 이루어지고 있는 신경전달 물질중 하나인 일산화 질소는 인간의 세포에 노출되었을 경우 세포막을 기준으로 농도 차가 발생하여 근육이 이완되는 현상을 유발한다. 이런 세포막을 기준으로 한 운동신경 변화, 심장박동의 변화, 근육의 이완철상 및 치명적인 이상을 초래하는 현상을 GENESIS를 이용하여 시뮬레이션 해 보았다.