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[en] AIM: To evaluate the pattern and site of involvement in neuro-Behcet's disease (NBD). MATERIALS AND METHODS: Twenty-one patients with NBD were evaluated. Using 1.5T magnetic resonance imaging (MRI), T1-weighted axial and sagittal images, gadolinium enhanced axial and coronal images and T2-weighted axial images were obtained. RESULTS: The brainstem, basal ganglia, cerebral white matter, internal capsule, thalamus and spinal cord were involved in eighteen, nine, nine, seven, six and two patients, respectively. In nine patients with cerebral white matter involvement, four had subcortical involvement and three had periventricular involvement, in addition to two patients with focal deep white matter lesions. Among the brainstem lesions, pons involvement was seen in fourteen patients, all had ventrally located lesions, and nine had tegmental involvement. Midbrain involvement was seen in fourteen patients; the cerebral peduncle was involved in 11 of these. Five patients had brainstem atrophy: two cases were demonstrated at initial MRI, the other three cases were seen on follow-up MRI. Pyramidal signs, the most common neurological signs, were demonstrated in fourteen patients. Follow-up MRI was obtained 10 days to 20 months after the initial MRI in eight cases; all showed changes in size, shape and site of involvement. After gadolinium enhancement, thirteen patients demonstrated mottled non-confluent enhancement in the brainstem (eight patients), posterior limb of the internal capsule (three patients), pachymeninges (two patients) and spinal cord (two patients). CONCLUSION: NBD manifests a reversible course, but chronic NBD may result in brainstem atrophy. Characteristic involvement along the corticospinal tract is well correlated with neurological signs. Lee, S. H. et al. (2001)
[en] We investigated the phenomenon of induced temporal coherence in optical parametric down conversion. We used a multimode blue-diode-laser pump and a single-mode laser for the injection signal beam. The temporal coherence of the idler beam is known to depend on the coherence function of the pump, the coherence function of the injection beam, the phase-matching condition, and the average photon number of the injection laser beam. Our experimental data show very good agreement with the multimode theory which predicts the changing the spectral shape as a function of the average photon number of the injection beam.
[en] A irradiation test of samples can be performed successfully in the OR5 test hole according to the user's requirements. The irradiation needs to meet the requirements if the chamber is placed at the position of the No. 3 capsule of the rig. To irradiate a small amount of samples such as SiC or Si at low temperature, a design of a small capsule and rig was reviewed. The conceptual design of a chamber and the capsule and rig, for irradiation was conducted, and the capsule and rig, for irradiation was conducted, and the most suitable places were reviewed in the test holes. The range of errors in the estimation of the nuclear characteristics and the temperature were reviewed according to the times of the operation cycle, and the vertical and horizontal positions of the samples
[en] TiO2 films were prepared on FTO glass using the sol-gel process for dye-sensitized solar cell applications. The TiO2 sol was prepared by using the hydrolysis/polycondensation. Titanium tetraispropoxide was used as a precursor, and nitric acid (HNO3) was used as a catalyst for the peptization. The crystallinity and the particle size were controlled by adjusting the catalyst concentration and the calcination temperature. The crystal structure and the morphology were measured by using scanning electron microscopy and X-ray diffraction. The TiO2 sol calcinated at low temperatures had an anatase phase, and the amount of the rutile phase with increasing calcination temperature. The properties of the TiO2 sol were adjusted by adjusting the concentration of the catalyst. The prepared TiO2 sol was coated on FTO glass by using a spin-coating method. The transmittance of the TiO2 films was investigated.
[en] Analyzing the current status and prospects for development of the southeast mega radiation facilities. - Current state of general nuclear facilities in the South-East Region - Status and characteristics of mega radiation facilities in the South-East Region - Status and prospects for development of the related industries. Investigating both domestic and international cases of utilizing mega radiation facilities as well as establishing innovative clusters. Measures for connecting and operating the southeast mega radiation facilities(Advanced reactors, Accelerators etc.) - Setting up tasks, the objective, future direction, subjects, a scope. Measures for expanding and improving the efficiency of radiation facilities. - Measures for activating the use of facilities(councils, promotions, international cooperation etc.) Activation plan for regional linkage. - Promotion plans for localized strategic industry of the medical radiation science (forming regional clusters etc.) - Measures for development of human resources (ties with major local universities, establishment of specialized graduate schools).
[en] To assess the ability of FDG PET for the detection of bone marrow infiltration compared to iliac crest biopsy in patients with lymphoma. Seventy-three patients (30 females and 43 males, mean age 47 years old) with malignant lymphoma (4 Hodgkin's disease, HD and 69 non-Hodgkin's lymphoma, NHL) were included. FDG PET was performed for staging in 53 patients and to assess treatment response after the completion of chemotherapy in 20 patients. Final conclusions were based on biopsy, other imaging studies, or clinical follow-up. There were 54 (74%) of the 73 patients in whom FDG PET and iliac crest biopsy were concordant. Forty-seven of the 54 patients showed concordant negative results while the remaining 7 patients had concordant positive results. Of 19 patients with discordant results, FDG PET accurately detected bone marrow infiltration in 6 patients with negative iliac crest biopsy. On the contrary, iliac biopsy identified bone marrow infiltration in 6 patients with negative iliac crest biopsy was true negative but FDG PET was falsely positive. FDG PET seems to be an adjunct in detecting marrow infiltration that may not be revealed by iliac crest biopsy at staging. For the assessment of treatment response, it may be less helpful than biopsy in detecting microscopic residual disease in the bone marrow
[en] To classify the cerebral cavernous malformations and to investigate the natural history of cavernous malformations according to the classification, 41 patients with 61 cavernous malformations (40 cavernous malformations from 22 patients treated with gamma knife surgery) were regularly followed up using MR imaging for a mean period of 25.5 months in treated cavernous malformations and 20.7 months in untreated cavernous malformations, respectively. Cavernous malformations were classified into four types. Follow-up MR images were analyzed to evaluate changes in size, signal intensity, rebleeding, and perilesional adverse reaction of irradiation. A total of 61 cavernous malformations including 17 in type I, 23 in type II, 10 in type III, and 11 in type IV showed usual degradation of blood product in 22 cavernous malformations, no change in shape and signal intensity in 31 cavernous malformations, and eight cavernous malformations with rebleedings in the serial MR images. In these eight cavernous malformations with rebleedings, six occurred in type II and two in type III, but none in type I or IV. Rebleedings were more frequent in type II than in other types. Adverse reaction of irradiation was observed in five of 22 patients treated with gamma knife surgery. Although most cerebral cavernous malformations showed evolution of hemorrhage or no change in size or shape on follow-up MR images, cerebral cavernous malformations represented as mixture of subacute and chronic hemorrhage with hemosiderin rim (type II) have a higher frequency to rebleed than other types of cerebral cavernous malformations. Cerebral cavernous malformations represented as hemosiderin deposition without central core (type IV) have a lower tendency to rebleed than other types and do not need any treatment. Most of the adverse reaction of irradiation after gamma knife surgery around cavernous malformations are transient findings and are considered to be perilesional edema. (K.H)
[en] The irradiation tests of the materials in HANARO have usually been performed at temperatures below 300 .deg. C, at which the RPV (Reactor Pressure Vessel) materials of commercial reactors such as a light water reactor and CANDU are operated. As future nuclear systems will be operated under conditions of high temperature and a high neutron flux, the requirements for the irradiation of the materials at very high temperatures have recently been gradually increasing. To overcome the restriction in the use of the existing Al thermal media at high temperature, a new capsule with double thermal media composed of two kinds of materials such as Al-Ti and Al-graphite was designed and fabricated, enabling it to be tested at higher temperature than a single thermal media capsule. Graphite and Ti materials combined with Al are used as thermal media instead of Al in this capsule because Al might melt at high temperature. At the irradiation test of the capsule until now, the temperature of the specimens successfully reached 700.deg. C and the integrity of Al, Ti and graphite materials was maintained. The expected operating temperature of VHTR is 1,000 .deg. C, which is much higher than the irradiation temperatures of the material capsules tested at HANARO up to recently. For this, the soundness of the Al material and the instruments such as a thermocouple and heater will be reviewed. In the near future, an irradiation capsule operating well at such a high temperature will be designed and fabricated
[en] Herein we report about the adenosine stress perfusion MR imaging findings of a 50-year-old man who exhibited two different perfusion defects resulting from two different mechanisms after a coronary artery bypass surgery. An invasive coronary angiography confirmed that one perfusion defect at the mid-anterior wall resulted from an ischemia due to graft stenosis. However, no stenosis was detected on the graft responsible for the mid-inferior wall showing the other perfusion defect. It was assumed that the perfusion defect at the mid-inferior wall resulted from delayed perfusion owing to the long pathway of the bypass graft. The semiquantitative analysis of corrected signal-time curves supported our speculation, demonstrating that the rest-to-stress ratio index of the maximal slope of the myocardial territory in question was similar to those of normal myocardium, whereas that of myocardium with the stenotic graft showed a typical ischemic pattern. A delayed perfusion during long graft pathway in a post-bypass graft patient can mimick a true perfusion defect on myocardial stress MR imaging. Radiologists should be aware of this knowledge to avoid misinterpretation of graft and myocardial status in post bypass surgery patients.
[en] As the result of study on decommissioning, discussion has made and data have been collected about experiences, plannings, and techniques for decommissioning through visit to GA and JAERI. GA supplied our Research Reactor No. 1 and No. 2, and JAERI made a memorial museum after dicommissioning of JRR-1 and is dismentling JPDR now. Also many kinds of documents are collected and arranged such as documents related to TRIGA reactor dicommissioning, 30 kinds of documents including decommissioning plan, technical criteria and related regulatory, and 1,200 kinds of facility description data. (Author)