[en] The Steam Generator Tube Ruputure (SGTR) is an accident that U-tube inside the SG is defected so that the reactor coolant releases through broken U-tube and this is one of design basis accidents. Operating the Nuclear Power Plants (NPP), maintaing the integrity of core and preventing radiation release are most important things. Because of risks, many researchers have studied scenarios, impacts and the ways to mitigate SGTR accidents. The study to provide an experimental database of aerosol particle retention and to develop models to support accident management interventions during SGTR was performed. The scaled-down models of NPP were used for experiments, also, MELCOR and SCDAP/RELAP5 were used to simulate a design basis SGTR accident. This study had a major role to resolve uncertainties of various physical models for aerosol mechanical resuspension. The other study which analyzed SGTR accident for System-integrated Modular Advanced Reactor (SMART) was performed. In this analysis, the amount of break flow was focused and TASS/SMRS code was used. It assumed that maximum leak was generated, and found that high RCS pressure, low core inlet coolant temperature, and low break location of the SG cassette contributed to leakage. Although the leakage was large, there was no direct release to atmosphere because the pressure of secondary loop was maintained below the safety relief valve set point. In this analysis, comparison of mitigating procedure when SGTR occurs between shutdown condition and full power condition was performed. In shutdown condition, the core uncovery would not take place in 16 hours whether the cooling procedures are performed or not. Therefore, the integrated amount of break flow should be considered only. In this point of view, cooling through intact SG only, case 3, is the best way to minimize the amount of break flow. In full power condition, the core water level is changed due to high reactor power. The important thing to protect NPP is to keep core water level. Although the break flow rate is smaller when no HPSI is injected, the core water level decreases continuously so that HPSI injection is inevitable

[en] Pulmonary angiodysplasia indicates all forms of abnormal intrapulmonary arteriovenous communication, usually called pulmonary arteriovenous fistula. Most frequent form of pulmonary angiodysplasia is single or multiple discrete nodular lesion, and diffuse telangiectatic type consists another variety. More than 50% of pulmonary angiodysplasias are associated with hereditary hemorrhagic telangiectasia. And rarely chronic liver disease is complicated by pulmonary arteriovenous fistula which is called hepatogenic pulmonary angiodysplasia. We experienced 6 cases of pulmonary angiodysplasia confirmed by cardiac catheterization and angiography from 1977 to 1983. 5 cases were children below 11 years of age exhibiting cyanosis except one who has pulmonary angiodysplasia supplied by systemic arteries. 3 were hereditary hemorrhagic telangiectasia and one was hepatogenic pulmonary angiodysplasia. Discrete nodular pulmonary lesion was present in 3 cases while remaining 3 cases were diffuse telangiectatic type. The clinical and radiological findings of pulmonary angiodysplasia is described with a brief review of literature

[en] In this analysis, comparison of mitigating procedure when SGTR occurs between shutdown condition and full power condition was performed. In shutdown condition, the core uncovery would not take place in 16 hours whether the cooling procedures are performed or not. Therefore, the integrated amount of break flow should be considered only. In this point of view, cooling through intact SG only, case 3, is the best way to minimize the amount of break flow. In full power condition, the core water level is changed due to high reactor power. The important thing to protect NPP is to keep core water level. Although the break flow rate is smaller when no HPSI is injected, the core water level decreases continuously so that HPSI injection is inevitable. It is expected that SGTR EOP should be prepared for different mode of NPP, for instance, shutdown or full power.

[en] Radiation exposure does for patients during brain CT scan with General Electric C.T./T. 8800 was measured using CaF₂:Mn thermoluminescent dosimeter chips. The skin does in single slice scan was 1.26±0.10 rad, and that in 9 slice scan was 2.06±0.16 rad. So the ratio was 1.63. The surface dose in profile along axial distance in multiple slice scan was also measured, and was found to be low at the junction of 2 slices. The lend dose in multiple slice scan was 0.27±0.05 rad, too small to induce any pathologic condition. As noted from the above data, the radiation exposure dose during CT scanning is not high compared with other radiologic examinations

[en] We report on a 41-year-old woman with a chest wall desmoid tumour who was successfully treated with a computed tomography (CT)-guided steroid injection. She presented with a palpable mass in the right upper chest wall and was treated by surgical excision and postoperative radiation therapy due to recurrence of the mass at the surgical site. At 20 months after the second operation, a recurrent mass was again detected in the anterosuperior portion of the previous surgical site on CT. We performed a CT-guided steroid injection weekly for 4 weeks by applying a mixture of 3 mL of triamcinolone acetonide (40 mg/mL) and 3 mL of 1% Lidocaine, administering 4-6 mL of the mixture, to the lesion. Six months later, CT showed a marked decrease in the size of the mass.

[en] A breast cholesterol granuloma is an uncommon nodular breast lesion. We incidentally detected a persistently enhancing breast mass on the dynamic abdominal computed tomography (CT) of a 78-year-old woman. The mass decreased in diameter over 50 days following a core needle biopsy. This report is the first to describe the dynamic-enhanced CT features of a breast cholesterol granuloma

[en] To evaluate the usefulness of three dimensional sonohysterography (3D SHG) in the evaluation of uterine endometrial and submucosal lesions in comparison with conventional two-dimensional sonohysterography (2D SHG). Our series consisted of 26 patients (mean aged 41 years) who complained of uterine bleeding, menorrhagia, or dysmenorrhea. 2D SHG was performed, and then 3D SHG was done after the volume mode was switched on. Simultaneous display of three perpendicular two-dimensional planes and surface rendering of findings on particular section were obtained. We analyzed whether the endometrium was thickened or not, and the location, size, shape, echogenicity, posterior shadowing, and echogenic rim of the focal lesion. The results were compared with the pathologic findings or MRI. There were submucosal myomas (n=12), intramural myomas (n=2), endometrial polyps (n=7), placental polyp (n=1), and normal endometrial cavities (n=4) on SHG. Nineteen cases were confirmed by pathologic findings or MRI. The results were correlated in 89% (17/19) of the cases. We misdiagnosed 2 cases: focal endometrial hyperplasia and choriocarcinoma were misdiagnosed as endometrial polyp and placental polyp, respectively. Imaging diagnoses were same in the techniques. Comparing with 2D SHG, 3D SHG provided a subjective display of pathologic findings and an additional information about spatial relationship between focal lesion and surroundings.

[en] Thyroid imaging is indicated to evaluate congenital hypothyroidism during newborn screening or in cases of a palpable thyroid mass in children and adolescents. This pictorial essay reviews the ultrasonography (US) of thyroid diseases in children and adolescents, including normal thyroid gland development, imaging features of congenital thyroid disorders (dysgenesis, [aplasia, ectopy, hypoplasia], dyshormonogenesis, transient hypothyroidism, thyroglossal duct cyst), diffuse thyroid disease (Grave's disease, Hashimoto's thyroiditis, and suppurative thyroiditis), and thyroid nodules. The primary imaging modalities for evaluating thyroid diseases are US and radionuclide scintigraphy. Additionally, US can be used to guide aspiration of detected nodules.

[en] Adoption of Filtered Containment Venting System (FCVS) installation in Pressurized Water Reactor (PWR) causes safety issues even though it has many beneficial features. Also, the effect of FCVS differs depending on operation strategies, type of Nuclear Power Plants (NPP) and accident scenarios, etc.. Therefore, many researchers studied about FCVS. Bracht et al. proposed an idea of hydrogen issue using Shapiro diagram in German nuclear power plants depending on the opening time of FCVS. Late venting could not avoid entering detonation region while early venting could avoid it. Y. S. Na et al. analyzed the thermal-hydraulic issue of FCVS using MELCOR computer code. He focused on the evaporation time of FCVS pool depending on diameter of venting/exhausting pipes. When the diameter of exhausting pipe is smaller, the pool exists for a long time so that the performance of FCVS can be kept. The performance and safety issue of FCVS were studied in this paper. The amount of fission products released to the environment decreases due to pool and filter in FCVS. However, when the valve which is connected with containment and FCVS is opened, the concentration of hydrogen in the FCVS increases rapidly compared with steam and air concentration. It takes about 12 minutes to avoid the detonation and flammability region. FCVS can prevent over-pressurization of containment and reduce the amount of radioactive material release to the environment. However, the risk of hydrogen explosion at instant time when FCVS is actuated may exist so that the further work related with safety issue of FCVS should be performed.

[en] To evaluate the significance of fetal choroid plexus cysts (CPCs) in the second trimester of pregnancy. Eighty-nine cases of isolated CPCs were prospectively followed up and 5 consecutive pregnancies of trisomy 18 were analyzed. Isolated CPCs were defined as follows: 1)there were no other abnormalities except CPCs on the detailed ultrasound. 2) the mother did not have any risk factors requiring amniocentesis. We compared maternal age, gestational age at time of detection, and the characteristics of CPCs in the groups of isolated CPCs and trisomy 18. We evaluated the autopsy findings or sonographic abnormalities in the group of trisomy 18. Material and gestational age were not different in both groups (29 ± 2.1 vs 31 ± 3.9 years old; 19 ± 1.8 vs 19 ± 1.3 week; p>0.05). The size of isolated CPCs was smaller than that of trisomy 18 (6.5 ± 2.5 vs 12.6 ± 4.6 mm; p<0.01). All of isolated CPCs had disappeared and there was no trisomy 18. In the group of trisomy 18, all of them had CPCs and at least one other associated abnormalities. The risk of trisomy 18 in cases of isolated CPCs was very low. In this setting, the detailed ultrasound examination rather than the routine karyotyping is mandatory.