• Journal of radiological science and technology
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• v.38 no.3
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• pp.245-252
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• 2015

To obtain the best SNR (signal to noise ratio) due to changes in CTDI (computed tomography dose index) made for the purpose of setting the optimum image obtained by reducing the dose in abdominal CT. Abdominal CT scans of 59 patients a $400-499cm^2$ (n = 12), $500-599cm^2$ (n = 21), $600-699cm^2$ (n = 17), $700-799cm^2$ (n = 9) were separated by four groups and the effective dose was used in the Excel to get the area of the patient using the ImageJ program. Patients of CTDI, DLP, SNR, the effective dose were analyzed. Abdominal CT area was increased to 13 mGy in CTDI is 7.3 mGy, DLP to 732 in $394.4mGy{\cdot}cm$, also effective dose was 5.9 mSv increase in 11mSv. SNR is 15 dB was maintained at 12.7. CTDI according to the average of the abdominal area of 8.9 mGy, the average of the DLP was $481.54mGy{\cdot}cm$, the effective dose is calculated to be 7.2 mSV. Effective dose was calculated by multiplying the load factor of DLP in the abdomen showed no statistically significant difference of (p < .05), there was a significant difference in SNR (p > . 05). To improve image quality of abdominal CT scan image in consideration of the CTDI according to the volume of the patient it should be able to reduce the radiation exposure of the patients.

• Journal of the Korean Society of Radiology
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• v.16 no.5
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• pp.661-672
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• 2022

After the outbreak of the SARS-CoV2 virus that causes COVID-19, it spreads around the world with the number of infections and deaths rising rapidly caused a shortage of medical resources. As a way to solve this problem, chest X-ray diagnosis using Artificial Intelligence(AI) received attention as a primary diagnostic method. The purpose of this study is to comprehensively analyze the detection of COVID-19 via AI. To achieve this purpose, 292 studies were collected through a series of Classification methods. Based on these data, performance measurement information including Accuracy, Precision, Area Under Cover(AUC), Sensitivity, Specificity, F1-score, Recall, K-fold, Architecture and Class were analyzed. As a result, the average Accuracy, Precision, AUC, Sensitivity and Specificity were achieved as 95.2%, 94.81%, 94.01%, 93.5%, and 93.92%, respectively. Although the performance measurement information on a year-on-year basis gradually increased, furthermore, we conducted a study on the rate of change according to the number of Class and image data, the ratio of use of Architecture and about the K-fold. Currently, diagnosis of COVID-19 using AI has several problems to be used independently, however, it is expected that it will be sufficient to be used as a doctor's assistant.

• Journal of radiological science and technology
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• v.46 no.6
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• pp.519-526
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• 2023

This study was intended to evaluate the shielding rate of radiation shields manufactured using 3D printers that have recently been used in various fields by comparing them with existing shields made of lead, and to find out their applicability through experiments. A 3D printer shield made of tungsten filament 1 mm, 2 mm, 4 mm shield, RNS-TX (nanotungsten) 1.1 mm, lead 0.2 mmPb, and 1mmPb were exposed to ^99mTc, ¹⁸F, and ²⁰¹TI for 15, 30, 45 minutes, and 60 minutes after measuring cumulative dose three times. Based on this, the shielding rate of each shield was calculated based on the dose in the absence of the shield. In addition, ^99mTc, ¹⁸F, and ²⁰¹TI were located 100 cm away from the phantom in which the OSLD nano Dot device was inserted, and if there was no shield for 60 minutes, the dose of thyroid was measured using 1.0 mm of lead shield, 1.1 mm of RNS-TX shield, and 2 mm of tungsten shield made by 3D printer. The use of shields during radiation shielding emitted from open radiation sources all resulted in a reduction in dose. The radiation dose emitted from the radionuclides under the experiment was all reduced when the shield was used. This study has been confirmed that tungsten is a material that can replace lead due to its excellent performance and efficiency as shield, and that it even shows the possibility of manufacturing a customized shield using 3D printer.

• The Journal of Korean Society for Radiation Therapy
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• v.21 no.2
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• pp.57-65
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• 2009

Purpose: The purpose of this paper is to provide basic data in order to systemize the management of demand and supply of radiologic technicians, to pursue a fair regional distribution of educational institutions, and furthermore to keep reasonable medical treatment and fee. This research was carried out through the investigation of radiologic equipments and technicians according to the distribution of the population. Materials and Methods: We compared and analyzed the correlation between regional population, the number of clinics and hospitals, the number of medical imaging devices, and the number of radiologists and radiologic technicians in 5 cities without "Gu" administrative units in 2008. Results: 27,317 radiologic technicians have been produced since the administration of the national qualifying exam for radiologic technicians. About 18,000 radiologic technicians are currently working. There are 39 colleges or universities with Departments of Radiology and the admission quota is 2,120 students excluding one college. The ratio of radiologic equipments to radiologic technicians is 2.6 to 1. Conclusion: There is a dilemma in which some radiologic technicians fail to find appropriate jobs while some clinics or hospitals are in need of radiologic technicians. This dilemma is due to unreasonable regional discrepancies in pay system and welfare situation, and excessive profit-oriented recruiting system of clinics and hospitals. The increase of students of Radiologic Departments and approval of additional departments will end up with producing superfluous high academic degree holders, which is on the contrary to the government policy to produce more job opportunities. So the policy of increasing Radiologic Departments should be reconsidered.

• Journal of radiological science and technology
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• v.41 no.5
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• pp.479-485
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• 2018

Radiologic technologists working at the second and third medical institutions are classified as radiation-related workers and radiation workers according to their working departments, and are subject to double regulation by the Ministry of Health and Welfare and the Nuclear Safety Commission. We will try to understand the system of dualization and to understand the investigation of recognition. The dualized system of radiation-related workers and radiation workers includes the difference in name and terminology, the effective dose limit, the maintenance education and training of radiologic technologists, the period of medical examination, the radiation zone, dose of the woman whose pregnancy is confirmed in radiologic technologists, the qualification criteria of the safety officer, and the period of the regular inspection of the radiological equipment. In the questionnaire survey on the dualization system, there were various items showing significant differences between the radiation-related workers and radiation workers Overall, the radiation workers were more aware of the radiation workers' education and related terms than the radiation-related workers.

• Journal of radiological science and technology
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• v.36 no.2
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• pp.157-163
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• 2013

Multileaf collimators whose Pb leaves are moving in two-dimensional directions have been used. We propose a different concept three-dimensional (3D) collimator with 3D shape that is automatically changeable to modulate the radiation dose even for complex tumors in real time. A voxel collimator, including a hinged Pb plane and a 3D assembly of many voxel collimators, was used. In each frame rotation axis, a motor, which was controlled by a circuit with field-programmable gate array (FPGA) board connected with computer, was operated according to a predetermined plan. Simulations of that, which are generally used for planning, were performed and compared with experimental results.

• Journal of radiological science and technology
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• v.11 no.1
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• pp.43-62
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• 1988

The purpose of this study is to analyze the problems of the Current Curriculum of Radiologic Technology Department in Junior College, try to find a future solution of the education of Radiologic Technology and a reform measure, and suggest a new substantial model. So this study refered to sundary records, posed a question by papers, made a reform measure of curriculum on the basis of the results, examined it throughly by discussion with the related professors and the industrials figures, and decided a new model. The characteristics of the reform measure reflected in the new model are as follows; 1. It increased the numbers of credits like 94 or 95 ones, to positively accept a developing medical technique and modern science. 2. It set up various general studies and offered a free selection. 3. It closely related majors and their credits to the national examination of lisence and the task of industrial job site. 4. It kept the balance between the periods of lecture, practice, training and their credits. 5, It reinforced the subjects of fundamental medical science such as Introduction to Medicine, Pathology, Biochemistry, Patient Care, etc. 6. It newly established Clinical Trainings as a regular education course. 7. It newly established Introduction to Computer Science, Ultrasonography and Magenetic Resonance Imaging, to cope with the development of the future medical technique. 8. It newly established Humanism in Medicine as a regular education course. 9. It changed the names of subjects resonably.

• Journal of radiological science and technology
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• v.35 no.4
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• pp.353-360
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• 2012

Diverse designs of collimator have been applied to Single Photon Emission Computed Tomography (SPECT) according to the purpose of acquisition; thus, it is necessary to reflect geometric characteristic of each collimator for successive image reconstruction. This study carry out reconstruction algorithm for imaging system in nuclear medicine with pinhole collimator. Especially, we study to solve sampling problem which caused in the system model of pinhole collimator. System model for a maximum likelihood expectation maximization (MLEM) was developed based on the geometry of the collimator. The projector and back-projector were separately implemented based on the ray-driven and voxel-driven methods, respectively, to overcome sparse sampling problem. We perform phantom study for pinhole collimator by using geant4 application for tomographic emission(GATE) simulation tool. The reconstructed images show promising results. Designed iterative reconstruction algorithm with unmatched system model effective to remove sampling problem artefact. Proposed algorithm can be used not only for pinhole collimator but also for various collimator system of imaging system in nuclear medicine.

• Journal of radiological science and technology
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• v.37 no.4
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• pp.253-259
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• 2014

Large volume of $6{\times}6{\times}12mm^3$ CdZnTe ${\gamma}$-ray detector was fabricated with CdZnTe single crystals grown by Traveling Heater Method (THM) to evaluate the energy resolution of 662 keV in $^{137}Cs$. Hole tailing effect which originated from the large mobility difference in electron and hole degrade energy resolution of radiation detector and its effects become more severe for a large volume detectors. Generally, single carrier collection technique is very useful method to remove/minimize hole tailing effect and thereby improvement in energy resolution. Virtual Frisch-grid technique is also one of single charge collection method through weighting potential engineering and it is very simple and easily applicable one. In this paper, we characterized CZT detector grown by THM and evaluated the effectiveness of virtual Frisch-grid technique for a high energy gamma-ray detector. The proper position and width of virtual Frisch-grid was determined from electric field simulation using ANSYS Maxwell ver. 14.0. Energy resolution of 2.2% was achieved for the 662 keV ${\gamma}$-peak of $^{137}Cs$ with virtual Frisch-grid CdZnTe detector.

• Journal of Veterinary Clinics
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• v.39 no.4
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• pp.197-197
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• 2022