• Journal of Korean Neurosurgical Society
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• 제30권1호
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• pp.47-53
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• 2001

Objective : This study was undertaken to evaluate operative results and prognosis according to preoperative clinical status and histopathological finding of spinal cord tumor. Methods : We analyzed of clinical feature, tumor location, histopathologic finding, operative results and prognosis in 55 patients with spinal cord tumor during last 10 years. Results : 1) The incidence of spinal cord tumors varies with the age of affected patients who are 2 to 75 years of age. Peak incidences were in the 5th & 7th decade of life, and the ratio of male to female was 1.2:1. 2) The most common histopathologic type was neurinoma(41.9%). 3) The tumors were located most frequently in the thoracic area(22 cases, 40.0%) and in the intradural extramedullary space(30 cases, 54.5%). 4) The most common initial clinical feature was pain in 20 cases(36.4%). For neurologic status on admission, 30 cases(54.5%) showed motor disturbance. 5) In radiologic studies, there were abnormal finding in 21 cases from plain X-rays among 37 cases. The entire 20 cases in when myelography was done showed subarachnoid blockade, either complete or incomplete. The magnetic resonance imaging, regard as the most accurate diagnostic method, revealed the exact location of the tumor and the relationship of the tumor with the adjacent anatomical structure. 6) The total removal was possible in 36 cases(65.5%), subtotal removal in 17 cases(30.9%) and biopsy in 2 cases (3.6%). Nineteen cases(90.5%) among 21 cases with preoperative radiculopathy group showed recovery or improvement, where as only 11 cases(36.7%) among 30 cases with preoperative motor weakness group showed recovery or improvement, with statistically significant difference(p<0.01). Pathologically, 26 cases(83.9%) among 31 cases of neurinoma and meningioma showed postoperative recovery or improved, but only 1 case(6.3%) among 16 cases of metastatic tumor, astrocytoma and ependymoma recovered. Postoperative complication noted in 5 cases(9.1%), and were noted postoperative hematoma, pneumonia, pulmonary edema and spinal cord infarction. Conclusion : Preoperative neurologic status and histopathologic finding are considered important factors of Postoperative outcome in patients with spinal cord tumor.

• Journal of Korean Neurosurgical Society
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• 제61권4호
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• pp.478-484
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• 2018

Objective : Cerebrovascular disease (CVD) was the third most common cause of death in South Korea in 2014. Evidence from abroad suggests that comprehensive stroke centers play an important role in improving the mortality rate of stroke. However, surgical treatment for CVD is currently slightly neglected by national policy, and there is still regional imbalance in this regard. For this reason, we conducted a survey on the necessity of, and the requirements for, establishing regional comprehensive cerebrovascular surgery centers (CCVSCs). Methods : This investigation was performed using the questionnaire survey method. The questionnaire was consisted with two sections. The first concerned the respondent's opinion regarding the current status of demand and the regional imbalance of cerebrovascular surgery in South Korea. The second section asked about the requirements for establishing regional CCVSCs. We sent the questionnaire to 100 board members of the Korean Society of Cerebrovascular Surgeons. Results : Most experts agreed that cerebrovascular surgery patients were concentrated in large hospitals in the capital area, and 83.6% of respondents agreed that it was necessary to alleviate the regional imbalance of cerebrovascular surgery. With regards to personnel, over 90% of respondents answered that at least two neuro-vascular surgeons and two neuro-interventionists are necessary to establish a CCVSC. Regarding facilities, almost all respondents stated that each CCVSC would require a neuro-intensive care unit and hybrid operating room. The survey asked the respondents about 13 specific neurovascular surgical procedures and whether they were necessary for a regional CCVSC. In the questions about the necessity of cerebrovascular surgical equipment, all seven pieces of equipment were considered essential by all respondents. A further five pieces of equipment were considered necessary on site: computed tomographic angiography, magnetic resonance angiography, conventional angiography, surgical microscope, and surgical navigation. Our results may provide a basis for future policy regarding treatment of cerebrovascular disease, including surgery. Conclusion : Raising the comprehensiveness of treatment at a regional level would lower the national disease burden. Policies should be drafted regarding comprehensive treatment including surgery for cerebrovascular disease, and related support plans should be implemented.

• Journal of Korean Neurosurgical Society
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• 제63권3호
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• pp.397-405
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• 2020

Objective : We retrospectively evaluated the efficacy of Gamma Knife radiosurgery (GKS) for recurrent nasopharyngeal carcinoma (NPC) in patients who previously underwent radiotherapy, and analyzed the treatment outcomes over 14 years. Methods : Ten patients with recurrent NPC who had previously received radiotherapy underwent stereotactic radiosurgery using a Gamma Knife^® (Elekta Inc, Atlanta, GA, USA) between 2005 and 2018. The median target volume was 8.2 ㎤ (range, 1.7-17.8), and the median radiation dose to the target was 18 Gy (range, 12-30). The median follow-up period was 18 months (range, 6-76 months). Overall and local failure-free survival rates were determined using the Kaplan-Meier method. Results : The NPCs recurred at the primary cancer site in seven patients (70%), as distant brain metastasis in two (20%), and as an extension into brain in one (10%). The recurrent tumors in seven of the 10 patients (70%) were found on the routine follow-up imaging studies. Two patients presented with headache and one with facial pain. Local failure after GKS occurred in five patients (50%) : two of whom died eight and 6 months after GKS, respectively. No adverse radiation effects were noted after GKS. The 1- and 3-year overall survival rates after GKS were 90% and 77%, respectively. The local failure-free survival rates at 6 months, 1 year, and 3 years after GKS were 80%, 48%, and 32%, respectively. The median interval from GKS to local failure was 8 months (range, 6-12). Univariate analysis revealed that using co-registration with positron emission tomography-computed tomography (PET-CT) and magnetic resonance imaging (MRI) was associated with a lower local failure rate of recurrent NPC (p=0.027). Conclusion : GKS is an acceptable salvage treatment option for patients with recurrent NPC who previously received radiation therapy. PET-CT and MRI co-registration for dose planning can help achieve local control of recurrent NPC.

• 한국의학물리학회지:의학물리
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• 제11권1호
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• pp.39-47
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• 2000

신경 외과적 수술의 한분야인 정위적 방사선 수술은 두 개강 내의 병변의 위치 계산 후, 고선량의 방사선을 조사하여 병변을 치료하는 방법이기 때문에, 효과적인 수술을 위해서는 병변의 정확한 위치 정보가 무엇보다도 중요하다. 본 연구에서는 DSA(Digital Subtraction Angiography) 영상이 내재적으로 이미지 왜곡이라는 문제점을 가지고 있기 때문에, 이것의 보정을 통하여 더욱 정확한 target 위치를 계산하였다 이미지 왜곡을 보정하기 위하여 grid 팬텀을 제작하였고, localization 알고리즘의 정확도를 평가하기 위하여, target 팬텀을 제작하였다. Image Intensifier의 앞쪽에 grid 팬텀을 부착하고, target 팬텀을 Leksell Frame에 고정시킨 후, DSA 영상을 얻었다. 본 실험을 위하여 개발된 프로그램을 이용하여, Anterior and Posterior, Left and Right 영상에서 bilinear transform을 적용하여 왜곡을 보정한 후, target 위치를 계산하였다. 그리고, 이와 같은 방법을 통하여 계산된 target 위치 좌표와 target 팬텀의 절대 좌표의 비교를 통하여 localization 오차가 계산되었다. 이번 실험의 결과는 왜곡을 보정하지 않은 경우, localization 오차는 $\pm$0.41mm, 왜곡 보정을 한 경우는 $\pm$0.34mm이었다. 따라서 본 연구에서 개발된 알고리즘 정밀도가 인정되며, 환자의 치료에 적합한 것으로 사료된다.

• 한국방사선학회논문지
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• 제3권4호
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• pp.13-21
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• 2009

MRI System은 각종 여러 가지 Parameter들로 구성되어 있다. 그중 MRI 영상의 화질을 빼놓고 MRI를 논한다는 것은 어려운 일이다. 각종 Parameter들이 개발되고 발전되어오면서 MRI영상에서도 예전 System에서 보여지는 영상과는 비교 할 수 없을 정도의 고화질을 출력하고 있다. 그리고 방사선 영상 System이 고식적인 Film방식에서 digital방식으로 전환되어가고 있고 그에 따른 병원의 모든 시스템이 전산화가 되어가고 있다. 방사선 영상의 관리에 있어서 저장 이라는 부분이 아주 중요한 ��을 차지하고 있다. 그 방대한 자료를 Server에 저장하는 방법으로는 압축을 이용 하여 저장하는 방법을 사용하게 된다. 이 때 발생한 문제점은 원본 영상에 비해 압축시 영상의 화질 저하가 발생한다는 것이다. 의료 영상에서는 조그마한 화질저하도 오진의 우려가 있으므로 각별히 주의해야할 사항이다. 본 논문에서는 병원에서 진료중인 영상을 대상으로 각각의 파일 변환과 원본과의 비교, 원본 영상과 진료에 사용되어지는 모니터에서의 MRI 영상의 화질을 PSNR을 이용한 평가와 영상 평가방법에 의한 평가를 하였다. 실험결과 원본과 각종 영상 압축방법을 이용하여 압축한 영상을 비교 분석 하였는데 화질저하가 거의 나타나지 않았다. 하지만 원본영상을 display하는 모니터의 화질 에서 상당한 문제점이 드러났다. 판독용 모니터 와 의료용 모니터에서는 손색없는 고해상도의 영상을 출력해 냈는가 반면 일반 CRT, LCD 모니터에서는 각종 노이즈, 영상왜곡등 많은 문제점들이 나타났다.

• 감성과학
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• 제12권4호
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• pp.425-432
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• 2009

본 연구에서는 공간 및 언어 과제를 수행하게 하면서 뇌 기능 영상을 획득하여, 각 인지 과제 수행에 따른 소뇌 활성화 영역을 알아보고, 소뇌 편측화의 차이를 규명하고자 한다. 8명의 오른손잡이 남자 대학생(평균 $21.5{\pm}2.3$세)과 8명의 오른손잡이 남자 대학생(평균 $23.3{\pm}0.5$세)이 각각 공간 및 언어 과제 실험에 참여하였다. 3T MRI 에서 single-shot EPI 기법을 이용하여 뇌 기능 영상을 획득하였다. 뇌 기능 영상 데이터는 SPM-99 S/W 를 사용하여 분석하였다. 실험은 네 개의 블록으로 구성되며, 각 블록은 통제과제(1분), 인지 과제(1분)을 포함하며, 한 실험당 소요시간은 블록당 2분씩, 총 8분이었다. 감산법을 이용하여 공간 및 언어 과제에 대한 소뇌 활성화 영역을 알아보았고, 소뇌의 활성화 voxel 수를 이용하여 소뇌의 편측화 지수를 계산하였다. 두 인지 과제 수행 시 활성화된 소뇌 영역은 선행 연구와 비교하여 유사한 영역이었다. 두 인지 과제 모두 좌, 우소뇌 반구의 활성화 voxel 수가 비슷하여 소뇌 기능의 편측화가 나타나지 않았다.

• 대한약리학회지
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• 제29권2호
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• pp.283-295
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• 1993

일부 malignant tumor에 Pt-complex의 임상 응용 과정에서 신장독성등의 심한 부작용이 문제점으로 지적되고 있다. 이 연구에서는 기존의 cisplatin보다 항암효과는 우수하면서, 부작용을 감소시킨 새로운 Pt-complex의 개발에 역점을 두었다. 본 연구에서는 합성한 Pt (II) complex는 carrier ligand로서 1, 2-diaminocyclohexane (dach)을 사용하였고, leaving group으로는 diphosphine류인 1, 3-bis (diphenylphosphine)의 propane (DPPP) 및 ethane (DPPE)을 도입하였으며, 물에 대한 용해도를 높이기 위해 dinitrate로 만들었다. 새로이 합성한 [Pt (II)-(trans-1-dach)(DPPP)] $(NO_3)_2$ 과 [Pt (II)(trans-1-dach)(DPPE)] $(NO_3)_2$ 는 원소 분석, IR 및 $^{13}C-NMR$ 분석 data에 의하여 위의 물질임이 확인되었다. KHPC-001과 KHPC-002는 MTT assay method에 의한 항암활성 연구를 통하여 P-388, L-1210 lymphocytic leukemia cell에서 항암효과가 인정되었으며, 이 항암효과는 대조 약물로 사용된 cisplatin에 비하여 우수하였다. KHPC-001과 KHPC-002는 토끼의 신세뇨관 세포와 인체의 신피질 세포를 이용한 cytotoxity 및 thymidine 섭취율과 인체 신피질 조직 배양을 이용한 glucose consumption 실험을 통하여 모두 cisplatin보다 신장독성이 현저히 감소되었다. 이상의 결과로 보아 Pt (II) complex는 carrier ligand와 leaving group의 선택에 따라 항암활성의 증가와 신독성의 감소를 일으키는 요인으로 보여지며, 이 연구에서 만들어진 두 Pt (II) complex는 앞으로 다각적인 검토를 거쳐 새로운 anticancer chemotherapeutic agent로 개발될 가능성이 있을 것으로 생각된다.

• 한국통신학회논문지
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• 제22권11호
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• pp.2573-2584
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• 1997

본 연구에서는 Ca와 Sn이 치환된 YIG(Yttrium Iron Garnet)계 세라믹 자성체에서 Fe자리의 일부를 Al 치환한 자성체를 제조하고 스트립라인 서큘레이터를 설계한 후, 마이크로파대 서큘레이터를 구현하고 특성을 평가하였다. Al의 치환량에 따른 Ca와 Sn이 치환된 YIG 세라믹 자성체의 전기적, 자기적 및 마이크로파 특성을 측정한 결과, 마이크로파대에서 유전율($\varepsilon$')과 투자율($\mu$')은 각각 15.623, 0.972이었다. $Y_{2.4}Ca_{0.3}Sn_{0.3}Fe_{5-x}Al_xO_{12}$의 조성을 가진 자성체를 $1450^{\circ}C$에서 소결 제조한 결과, 페리자성 공명선폭($\Delta{H}$)이 42 Oe이고 포화자화가 487 G인 세라믹 자성체를 제조할 수 있었다. 3차원 유한요소법을 이용한 소프트웨어로 스트립라인 서큘레이터를 시뮬레이션하였으며, 중심주파수 1.9GHz 에서 삽입손실 0.8 dB, 반사손실 25 dB, 격리도 35 dB인 서률레이터를 설계하였다. 제조된 세라믹 자성체를 이용하여 중심주파수 1.9 GHz에서 삽입손실 0.869 dB, 반사손실 26.955 dB, 격리도 44.409 dB인 마이크로파용 서큘레이터를 제작할 수 있었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제26권5호
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• pp.462-469
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• 2000

Positron Emission Tomography(PET) is a new diagnostic method that can create functional images of the distribution of positron emitting radionuclides, which when administered intravenously in the body, makes possible anatomical and functional analysis by quantity of biochemical and physiological process. After genetic and biochemical changes in initial stage, malignant tumor undergoes functional changes before undergoing anatomical changes. So, early diagnosis of malignant tumors by functional analysis with PET can be achieved, replacing traditional anatomical analysis, such as computed tomography(CT) and magnetic resonance image(MRI), etc. Similarly, PET can identify malignant tumor without confusion with scar and fibrosis in follow up check. In the Korea Cancer Center Hospital(KCCH) from October 1997 to September 1999, clinical study was performed in 79 cases that underwent 89 times PET evaluation with [18F]-Fluorodeoxyglucose for diagnosis of oral and maxillofacial tumors, and the data was analysed by Bayesian $2{\times}2$ Classification Table. The results were as follows : Evaluation for initial diagnosis with FDG-PET (P<0.005) 1. Agreement rate or accuracy rate is 88.9%. 2. Sensitivity is 95.2%, and specificity 66.7%. 3. Positive predictive rate is 90.9%, and negative predictive rate 80.0%. 4. In consideration of tumor stage, diagnostic rate in less than stage II was 90% and in greater than stage III 100%. 5. In consideration of tumor size, diagnostic rate in less than T2 was 92.3% and in greater than T3 100%. After primary treatment, evaluation for follow up check with FDG-PET (P < 0.001) 1. Agreement rate or accuracy rate is 85.4%. 2. Sensitivity is 87.5%, and specificity 82.4%. 3. Positive predictive rate is 87.5%, and negative predictive rate 82.4%. 4. In 24 recurred cases, 6 had distant metastasis, and 5 of them were diagnosed with FDG-PET, resulting in diagnostic rate of FDG-PET of 83.3%. From the above results, Positron Emission Tomography with [18F]- Fluorodeoxyglucose appears to be more sensitive and accurate for detecting the presence of oral and maxillofacial tumors, and has various clinical applications such as early diagnosis of tumor in initial and follow up check and detection of distant metastasis.

• Journal of Magnetics
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• 제11권4호
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• pp.195-207
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• 2006

The recently published and new results on design and fabrication of magnetophotonic crystals of different dimensionality are surveyed. Coupling of polarized light to 3D photonic crystals based on synthetic opals was studied in the case of low dielectric contrast. Transmissivity of opals was demonstrated to strongly depend on the propagation direction of light and its polarization. It was shown that in a vicinity of the frequency of a single Bragg resonance in a 3D photonic crystal the incident linearly polarized light excites inside the crystal the TE- and TM-eigen modes which passing through the crystal is influenced by Brags diffraction of electromagnetic field from different (hkl) sets of crystallographic planes. We also measured the faraday effect of opals immersed in a magneto-optically active liquid. It was shown that the behavior of the faraday rotation spectrum of the system of the opal sample and magneto-optically active liquid directly interrelates with transmittance anisotropy of the opal sample. The photonic band structure, transmittance and Faraday rotation of the light in three-dimensional magnetophotonic crystals of simple cubic and face centered cubic lattices formed from magneto-optically active spheres where studied by the layer Korringa-Kohn-Rostoker method. We found that a photonic band structure is most significantly altered by the magneto-optical activity of spheres for the high-symmetry directions where the degeneracies between TE and TM polarized modes for the corresponding non-magnetic photonic crystals exist. The significant enhancement of the Faraday rotation appears for these directions in the proximity of the band edges, because of the slowing down of the light. New approaches for one-dimensional magnetophotonic crystals fabrication optimized for the magneto-optical Faraday effect enhancement are proposed and realized. One-dimensional magnetophotonic crystals utilizing the second and the third photonic band gaps optimized for the Faraday effect enhancement have been successfully fabricated. Additionally, magnetophotonic crystals consist of a stack of ferrimagnetic Bi-substituted yttrium-iron garnet layers alternated with dielectric silicon oxide layers of the same optical thickness. High refractive index difference provides the strong spatial localization of the electromagnetic field with the wavelength corresponding to the long-wavelength edge of the photonic band gap.