• Journal of radiological science and technology
• /
• v.33 no.3
• /
• pp.179-184
• /
• 2010

A hard X-ray microscope system for obtaining images of nano-spatial resolution has been widely studied and requires monochromatic X-ray. A multilayer mirror of 84% reflectivity was designed to acquire tungsten characteristic X-ray of 8.4 keV from the white beam generated from an X-ray tube, and the C/W multilayer mirror of $50{\times}50\;mm$ size and 5.65 nm d-spacing was fabricated by the ion-beam sputtering system. The C/W multilayer had a uniformity of 99.5%, and the structure of the multilayer mirror was verified by a TEM image. The obtainable x-ray reflectivity for the C/W multilayer mirror at 8.4 keV was estimated from measuring the X-ray reflectivity using the copper characteristic X-ray of 8.05 keV. Monochromatic X-ray of 8.4 keV was generated by combining a X-ray tube, and the reflectivity and monochromaticity were 77.1% and 0.21 keV, respectively. Monochromatic X-ray generated from the combination of an X-ray tube and an C/W multilayer mirror has enough potential to use X-ray source for hard X-ray microscope system of laboratory size. If the C/W multilayer mirror of d-spacing of a few nanometers can be fabricated, monochromatic X-ray corresponded to 17.5 keV, molybdenum characteristic X-ray, can be obtained and applied to mammography in the medical application.

• Progress in Medical Physics
• /
• v.22 no.3
• /
• pp.117-123
• /
• 2011

Synchrotron radiation (SR) imaging enables us to observe internal structures of biologic samples without staining. In this study, we obtained X-ray microscopic images of human breast tissues with 11.1 KeV hard X-ray microscope of the Pohang light source and used zone plates and phase-contrast technique to get high resolution X-ray images. Hard X-ray microscopic images of fibrocystic change and breast cancer tissues with a spatial resolution of 60 nm were obtained and from these images, we could observe the micro-structures of human breast tissue. Also we analyzed and compared these images, which revealed distinct features of each condition. In conclusion, SR imaging with phase-contrast hard X-ray microscope for medical application, especially in breast disease can give some useful information for clinical research.

• The Journal of the Korea Contents Association
• /
• v.16 no.12
• /
• pp.70-77
• /
• 2016

In this study, we aim to obtain the fundamental data needed for the objective analysis and bio-mimetics of leeches, using x-ray imaging with radiation that allows 3D analysis of the detailed anatomic structures of leeches. It was confirmed that through using radiation, detailed images of leeches can be obtained, allowing 3D analysis of leeches' anatomical structures. Also, since the data obtained through the radiation allows you to observe the micro-structure, it can serve as a good resource for component analysis, as well as physiological and functional research. More, it is hoped to contribute to further research in the areas of bio-mimetics using leeches.

• Proceedings of the Optical Society of Korea Conference
• /
• 2006.07a
• /
• pp.323-324
• /
• 2006

• Optical Science and Technology
• /
• v.12 no.1
• /
• pp.29-36
• /
• 2008

• Journal of the Korean Society of Radiology
• /
• v.4 no.3
• /
• pp.27-31
• /
• 2010

Spatial resolution is determined by the performance of x-ray optics used in the x-ray imaging system. A zone plate was designed for obtaining a high spatial resolution image at x-ray energy of 8.5keV. A spatial resolution of 80 nm was estimated by the ray tracing when an x-ray tube of tungsten targe was used instead of synchrotron radiation. The designed zone plate of outermost zone width of 40nm was successfully fabricated by the electron-beam lithography.

• Journal of the Korean Society of Radiology
• /
• v.5 no.6
• /
• pp.391-400
• /
• 2011

Pneumonia is an infection of the lungs and respiratory system and can be classified by a variety of factors such as infectious agents, etiology, infection area, and other criteria. From a 46-year-old male, who was suspected of being infected with atypical pathogen pneumonia and underwent such tests as serological testing, examination of sputum, urine examination, parasite examination, bronchoscopy, needle biopsy and so on, no significant abnormality was found. This patient also showed no specific symptoms like auscultatory abnormalities, high fever, nonproductive cough, muscle stiffness, sputum production, dyspnea. Prescription of broad-spectrum oral antibiotics and ant-parasitic didn't seem to be effective against bacterial and atypical pathogen. The patient's condition alternately repeated between natural cure and recurrence. The average healing process during which scarring, nodule recurrence and disappearance on the lungs happened was about 20 days. Chest radiography and chest high resolution computerized tomographic scans(HRCT scan) was performed to depict parenchymal aberrations and demarcate the extent and distribution of atypical pathogen pneumonia. As a result, chest radiography did not show the specific symptoms, whereas areas of opacity (seen as white) which represent consolidation were revealed in chest HRCT scan. This indicates that only chest radiography is not that useful for early diagnosis of atypical pathogen pneumonia in patients, since it can't show exactly what the symptom is because of the barriers such as diaphragm, liver, and spine. Therefore, it is desirable that chest HRCT should be used in the diagnosis to compare with the results of chest radiography. Here, report with literature investigations the case of recurrent atypical pathogen pneumonia.

• The Korean Journal of Mycology
• /
• v.44 no.4
• /
• pp.318-322
• /
• 2016

The prototypes, Rto-x+$Ca(NO_3)_2$, K-Ca, and Rto-$x{\beta}$, which were extracted from spent mushroom substrate of Hericium erinaceus, strongly inhibited the growth of Ralstonia solanacearum. The control efficacies of tomato bacterial wilt by treatment with Rto-x+$Ca(NO_3)_2$, K-Ca, and Rto-$x{\beta}$ were 87.4~92.4%, 46.0~100%, and 65.0~91.9%, respectively. These results indicate that Rto-x+$Ca(NO_3)_2$, K-Ca, and Rto-$x{\beta}$ have a potential as eco-friendly antibacterial materials for the control of tomato bacterial wilt caused by R. solanacearum.

• Journal of the Korean Society of Radiology
• /
• v.9 no.6
• /
• pp.403-408
• /
• 2015

Hard X-ray has been widely used in medical and industrial fields because it can be applied to observe the inside of a sample. Computed tomography provides sectional images of the sample through the reconstruction of the projection images. The quality of sectional images strongly depends on that of projection images. Ring artifact appeared on the seconal image can be made by the abnormal pixels of the detector used. In this study, we examine the ring artifact ratio in the circle phantom as a function of detection error of the detector used in computed tomography. The ring artifact increased with the increment of detection error under parallel and fan beam geometries and strongly increased near the center of rotation. The corrections, dead pixel and flat field corrections, for the images taken with the detector are required before the image reconstruction process to reduce the ring artifact in the computed tomography.

• Radiation Oncology Journal
• /
• v.27 no.4
• /
• pp.218-227
• /
• 2009

Purpose: To investigate the radiobiologic effects of neutron and X-ray irradiation on DU-145 prostate carcinoma cells by identifying the differences of HIF-$1\alpha$ expression and apoptosis. Materials and Methods: Nude mice were injected with the human prostate cancer cell line, DU-145, and then irradiated with 2 Gy and 10 Gy X-rays, or 0.6 Gy and 3.3 Gy neutrons, respectively. The mice were sacrificed at 24 hours and 120 hours after irradiation. The expression levels of HIF-$1\alpha$, Bcl-2 and Bax were compared with immunohistochemical staining and western blotting. The apoptotic indexes were compared with the Terminal deoxynucleotidyl biotin-dUTP nick and labeling (TUNEL) assay. Results: At day 1, HIF-$1\alpha$ and Bcl-2 expression decreased, while Bax expression and the number of TUNEL positive cells increased in neutron irradiated groups for the control and X-ray irradiated groups. The Bcl-2/Bax ratio was significantly lower in the neutron irradiated groups regardless of dose (p=0.001). The same pattern of the differences in the expressions of the HIF-$1\alpha$, Bcl-2, Bax, Bcl-2/Bax ratio, and apoptotic indexes were indentified at day 5. HIF-$1\alpha$ expression was related with Bcl-2 (p=0.031), Bax (p=0.037) expressions and the apoptotic indexes (p=0.016) at day 5. Conclusion: Neutron irradiation showed a decrease in HIF-$1\alpha$, Bcl-2 expression, and Bcl-2/Bax ratio, but increased Bax expression regardless of dose. This study suggests that the differences radiobiological responses between photon and neutron irradiation may be related to different HIF-$1\alpha$ expression and subsequent apoptotic protein expressions.