• Journal of radiological science and technology
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• v.41 no.3
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• pp.223-229
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• 2018

The purpose of this study is to present the reference values for cardiac size and cardiothoracic ratio change, normal range and diagnosis of cardiovascular disease in pregnancy and non pregnancy of normal Korean women using chest X-ray. The subjects of this study were 58 women, who were read as normal by chest radiologist, had chest radiography taken on both last month of pregnancy, pre-pregnancy and within 2 years following delivery. In this study, we defined the last month of pregnancy as pregnancy and before or post pregnancy as non-pregnancy. CS and CTR were measured by two radiological technologist who had clinical experience more ten years with Danzer's method. Statistical methods were paired t-test and one-way ANOVA. Significance level ${\alpha}$ was 0.05 and p-value 0.05 or less was statistically significant. For pregnancy, the mean of left and right cardiac size was $40.11{\pm}8.73mm$ and $89.51{\pm}11.9mm$, CS was $128.60{\pm}13.15mm$, CTR was $44.51{\pm}4.21%$. In non pregnancy, $36.50{\pm}8.18mm$ and $77.68{\pm}13.1mm$. CS and CTR were $114.18{\pm}14.28mm$ and $42.03{\pm}4.04%$. Both pregnancy and non pregnancy, the difference of the mean value in left and right cardiac size, CS and CTR were statistically significant (p<0.01). but comparing mean on age, height and weight, the difference of the mean value between groups was not (p>0.05). In the result of this study, the mean size of CS increased by 12.6% in pregnancy($128.60{\pm}13.15mm$) compared to the non pregnancy($114.18{\pm}14.28mm$), and increased by 9.8% in the right side of the heart and 15.2% in the left side. The mean size of CTR increased about 5.9% in pregnancy ($44.5{\pm}4.21%$) compared to non pregnancy($42.03{\pm}4.04%$).

• Journal of radiological science and technology
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• v.34 no.2
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• pp.97-103
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• 2011

The Full-length examination of the femur sometimes does not show all of the femur because of the limited width in collimator and size of detectors although it is located in the diagonal direction. Aim of this study is to identify usefulness of the method of combining images which obtained from two radiographic images containing the femoral head and condyle respectively. Our group interviewed 30 radiological technologists who used both palliative DR method and SM method in their examinations of the femur of patients who were carried to the emergency rooms in Gwang-ju city from August 2007 to November 2009. We evaluated twenty images according to the contraction of femoral neck, turning of knee joints and inclusion of the femur. The examination were performed by two radiologists and six radiological technologists who have more than ten years of career. The results are as follows: SM method was graded with higher score for examination time, number of examiners, emaciation, retake and patients' discomfort (p< 0.001) while the. SM method was scored higher than the palliative DR method in the palliative DR method for examination of long bone.

• Journal of the Korean Society of Radiology
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• v.7 no.2
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• pp.131-136
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• 2013

Panorama of dental radiation generators can observe the wide anatomical structures of oral and maxillofacial areas but there can be distortion of lengths, angles, or shapes. CBCT can diagnose 3D images and get the ones whose errors by superposition and interference are remarkably smaller between anatomical structures. But the quality of the images by movement of subjects can be lowered as it takes long to diagnose them. And if there are impermeable radiation objects like metal in mouths, impermeable radiation lines can radially appear with the objects as center. This study tries to analyze accuracy of panorama and CBCT and get useful anatomical information in dental treatment by comparing the length of wisdom teeth which were measured by Panorama and CBCT with the teeth which were actually extracted and analyzing distortion of the teeth. The test result could be found that Panorama is expanded by average 7.3% as the errors of Panorama and Digital Vernier Caliper range from 110.7% to 103.9%. The length of wisdom teeth which were measured in CBCT and Digital Vernier Caliper could be found that the error range is 1.3%. And the length of wisdom teeth which were measured in Panorama and Digital Vernier Caliper has found that the error range shows 7.3%. So it could be found that the images of CBCT is about 6% more exact than those of Panorama. It could be found that CBCT shows the more exact images than those of Panorama. But because the examination expenses of CBCT are higher than those of Panorama and exposure dose of CBCT is much more than that of Panorama, it is thought to find proper ways in examination.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.297-304
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• 2018

U.S. nuclear power plant decommissioning guidelines(MARSSIM and MARLAP) are recommends to use DQOs when planning and conducting site surveys. The DQOs which is constructed in the site survey planning stage provide a way to make the best use of data. It helps we can get the important information and data to make decisions as well. From fifth to seventh steps of DQOs are the process of designing a site survey by using the collected data and information in the previous step to make reasonable and reliable decisions. The gray region that is set up during this process is defined as the range of concentrations where the consequences of type II decision errors are relatively small. The gray region can be set using DCGL and the average concentration of radionuclide in the sample collected at the survey unit. By setting up the gray region, site survey plan can be made most resource-efficient and the consequences on decision errors can be minimized. In this study, we set up the gray region by using the DCGL of Kori-1 which was derived from the previous research. In addition, we proposed a method to assess the concentration of radionuclide in samples for making decisions correctly.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.335-341
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• 2018

With the improvement of medical state, patients' expectations for the most advanced medical equipment are increasing. Particularly, Magnetic Resonance Image (MRI) is used as one of the core image diagnosis methods in all clinical area. However, it has been reported that many of patients who go through the examination suffer from anxiety to the severe noise level during the examination. In this study, both the noise reduction evaluation of headsets with sound-blocking materials added to existing sound-absorbing materials and the existence of sound blocking materials as artifacts on the examination image are tested. An MRI test noise is recorded as a speaker by cross-ordination the sound material (sponge) and the sound material (acrylic plate, copper plate, and 3D copper plate) inside the headset made from 3D pring. A quantitative assessment of headsets showed that the average headset value was 81.8 dB. The average dB value of the most soundproof material combination(Copper, acrylic plate, sponge, sponge) headsets on headsets with added charactering material was measured at 70.4 dB, and MRI showed that the copper was diamagnetic substance and excluded. The second most soundproof headset(Sponge, acrylic plate, 3D copper plate, sponge) was measured at 70.6 dB and MRI showed no artifacts. The same simulation of the material printed with a 3D copper PLA containing approximately 40 % copper powder resulted in no artifacts, therefore, the material output as a 3D printing was better suited for use. For MRI related research, the mutual development of 3D printing is highly anticipated.

• Journal of the Korean Society of Radiology
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• v.12 no.4
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• pp.497-503
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• 2018

The purpose of this study was to investigate the degree of image degradation and the improvement of image quality caused by the density difference between the orthodontic filling material and the surrounding anatomical structure during the examination of the facial CT by quantitative and qualitative analysis. The teeth were scanned using 64-MDCT (Discovery 750 HD, GE HEALTH CARE, Milwaukee, USA). The teeth were scanned and compared according to tube voltage, silicone application, and MAR application. As a result, 10.36% CT value decreased at 140 kVp and 5.81% decrease at the application of silicon material. As a result of the qualitative evaluation, it was evaluated that 7 of the 10 observers and 3 of the acceptors were applied to the MAR algorithm. Therefore, it is possible to reduce the unnecessary burden on the radiation exposure dose as well as to reduce the loss of image data by reducing the high density artifacts, as well as the inspection parameters used in the current clinical application and various algorithms that can reduce the high density artifacts. It can be expected to provide a lot of image information.

• Journal of the Korean Society of Radiology
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• v.10 no.5
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• pp.291-298
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• 2016

Recently, the interest in the orthodontic treatment for children is increased by a rise in national income level. The number of cephalometric radiography that could diagnose a malocclusion and malposition between teeth and jawbone increased. It required attention to radiation exposure, because the subject of dental examination is children which are more sensitive to radiation and the head and neck, the object of that include radiation sensitive organ such as the thyroid, bone marrow, eyes, salivary gland, and so on. In this study, we measured two-dimensional dose distribution in cephalometric radiography system (VATEC Pax-400C) using Agfa CP-G Plus film and MagicMax Dosimeter, and calculated radiation organ dose of head and neck through MCNPX simulation. And then we designed a radiation protective device to decrease radiation dose. The dose distribution of the cephalometric radiography system irradiated the head and neck overall as well as the oral and maxillofacial parts. The radiation organ dose calculated that thyroid, oesophagus and eyes are irradiated high, and the radiation organ dose decreased about 70 ~ 80% by the application of the radiation protective device. The results of this study will be used construction of database for dental radiation exposure and research of reducing radiation dose.

• Journal of the Korean Society of Radiology
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• v.9 no.5
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• pp.295-300
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• 2015

There are various type of particle accelerators such as Kyoungju 100-MeV proton beam accelerator in Korea. And Korea plans to build large particle accelerator such as heavy ion accelerator and 4th generation light source facility. The accelerated high energy particles of these facility produce 2nd neutron after nuclear reaction with target materials. And then these 2nd neutron activate structural materials and surrounding environment. Accordingly, it is important to consider the activation and shielding calculation on design of facility for safety operation. In this study, we tried to calculate and compare the neutron flux from the interaction $^{la}150$ beam with target material(Cu) according to thickness of iron and concrete shielding material by MCNPX 2.7 with nuclear library JENDL/HE 07and la150. To verify the properties of nuclear library, we compared computational results with experimental value. These results can be used for dose evaluation technology in planning of the shielding of large particle accelerator.

• Journal of the Korean Society of Radiology
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• v.8 no.7
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• pp.449-454
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• 2014

The purpose of this study is(was) to investigate the shielding ratio of 1 mmPb and the off axis ratio outside the field edge at depth of 1 cm from a phantom surface for 6 MV photon beam. A dose of 180 cGy was delivered to a depth of 10 cm for a $10{\times}10cm^2$ and $15{\times}15cm^2$ field in the SAD technique. The off axis ratio was calculated by measuring the dose of optically stimulated luminescent nanoDot dosimeters(OSLnDs) positioned at 2, 4 and 6 cm from the field edge, and the center axis of field. And the shielding ratio of 1 mmPb was calculated by measuring the dose of OSLnDs positioned at 2, 4 and 6 cm from the field edge.. As a result, for a $10{\times}10cm^2$ and $15{\times}15cm^2$ field, the off axis ratios were acquired 0.008-0.023 and 0.011-0.028, respectively. Also the shielding ratios of 1 mmPb were acquired 0.868-0.888 and 0.807-0.842, respectively. These results provide data to protect organs at risk outside the radiation treatment field.

• Journal of the Korean Society of Radiology
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• v.11 no.4
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• pp.247-252
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• 2017

Radiologists who experience extravasation of the contrast medium even once suffer mentally during testing due to the fear of its reoccurrence. Establishing a plan for preventing it beforehand is necessary above all because patients experience severe physical and mental pain and become distrusting of medical staff and treatment. Therefore, the present study attempts to prevent extravasation, which is the result of damage from pressure applied to the patient's blood vessels, by lowering PSI, and conducted a comparative analysis of PSI changes during contrast medium injection depending on the diameter of the Y-shape connecting tube which connects the automatic injector and the intravenous injection of the patient. In the case of product A in which the diameter of the Y-shape connecting tube is about 2mm, the average PSI for all ages was 98.5 and standard deviation was 9.72. In the case of product B in which the diameter of the Y-shape connecting tube is about 3mm, the average PSI for all ages was 62.0 and standard deviation was 8.59. Product B with its wider diameter decreased in average pressure by 37.05% when compared to product A, and when product B is used with the p-value at 0.00, pressure decreased even more, achieving statistically significant results.