• Journal of radiological science and technology
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• v.28 no.2
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• pp.123-128
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• 2005

It is necessary to obtain images of high diagnosis worth based on ability and skill of radiological technologist in case of acquisition of medical radiologaphy information. In addition, we need the various kinds of education considering individual radiological technologist variation and the organization of clinical education according to the large amount of learning and more expensive knowledge of radiology. In this paper, we implement CAI system for cervical vertebrae fracture radiograph with multimedia authoring tools on web environments. The CAI system can train a new radiological technologist and study a lot of radiological technologist on the cervical vertebrae fracture radiography acquisition based on more objective and systematical data in radiography room. The proposed CAI system is also expected as a useful program which can help to cure patients based on accurate diagnosis as well as obtain radiography more quickly using a technology of radiography acquisition for cervical vertebrae fracture.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.01a
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• pp.31-32
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• 2021

신종 코로나바이러스 감염증(Coronavirus disease 2019; COVID-19)이 빠르게 확산됨에 따라 세계적인 전염병 대유행인 팬데믹(Pandemic)으로 선언되었다. 감염자들은 꾸준히 증가하고 있고 최근에는, 무증상 감염자들이 나타나고 있어 의심 환자를 조기에 판단하고 선별할 수 있는 기술이 필요하다. 본 논문에서는 흉부 방사선 검사(chest Radiography; CXR) 영상을 딥러닝(Deep Learning)하여 정상인, 폐렴 환자, 코로나바이러스 감염자를 분류할 수 있도록 한다.

• Journal of radiological science and technology
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• v.36 no.4
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• pp.273-280
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• 2013

This study was proven for the T-spine breathing technique in lateral projection, using computer radiography (CR), charge coupled device (CCD), indirect digital radiography (IDR) and direct digital radiography (DDR). All images were evaluated and compared with CNR and SNR measured with the mean pixels and the standard deviation as setting ROI of spinous process, pedicle, vertebral body, intervertebral foramen and intervertebral disk using Image J. In experiment results of 4 type detectors, T-spine breathing technique was indicated as excellent in ROI of spinous process, pedicle, vertebral body, intervertebral foramen and intervertebral disk. As T-spine breathing technique indicated excellent images compared to the existing T-spine lateral radiography, this method would be useful for elderly patients who have difficulty in deep exhalation. This study was indicated the application possibility of T-spine breathing technique by presenting contrast to noise ratio (CNR) and signal to noise ratio (SNR) with quantitative value in 4 type detectors.

• Journal of radiological science and technology
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• v.27 no.3
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• pp.25-29
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• 2004

Among the digital radiography systems, the computed radiography Image Plate Detector System is most frequently being used for the general radiography and also this system commonly diffracts the x-ray images since it is the system that is influenced by the light diffusion from the fluorescent substances. In this study, by using the X-ray Generator, a comparative analysis has been made between 2 different models of computer radiography image plate investigate each model's resolution and sharpness through the modulation transfer function(MTF) measurement. For the analysis, two image plates for general radiography one Fuji ST-VN model(more than 3years old) and one Fuji ST-VL model(less than 2years old) that are currently being used in "Hospital A" were sampled for the MTF measurement here. As the experimental method for this study, the resolution chart method has been carried out by using X-ray generator. Also all the experimental data were printed out by laser printer and measured by microdensitometer. As the results of the experiment carried out in this study, some differences have been found between the two different IP models and Fuji ST-VL has shown its excellence in both of the resolution and the sharpness fields.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.185-193
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• 2011

There is no exact standard of detecting pulmonary tuberculosis(TB) in digital image of simple chest radiography. In this study, I experimented on the principal components analysis(PCA) algorithm in the past and suggested six other parameters as identification of TB lesions. The purpose of this study was to develop and test computer aided diagnosis(detection) method for the detection and measurement of pulmonary abnormalities on digital chest radiography. It showed comparatively low recognition diagnosis rate using PCA method, however, six kinds of texture features parameters algorithm showed similar or higher diagnosis rates of pulmonary disease than that of the clinical radiologists. Proposed algorithms using computer-aided of texture analysis can distinguish between areas of abnormality in the chest digital images, differentiate lesions having pulmonary disease. The method could be useful tool for classifying and measuring chest lesions, it would play a major role in radiologist's diagnosis of disease so as to help in pre-reading diagnosis and prevention of pulmonary tuberculosis.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.94-95
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• 1998

We developed a digital x-ray medical imaging system using commercially available amorphous silicon image sensor plate. The image readout could be accomplished within 3.5 sec after radiation exposure and be displayed on a monitor through computer interface. This system needs not the conventional x-ray films and film processors, and also provides digital radiographic images. This system is the fastest digital radiography system developed so far, and expected to replace many of the conventional x-ray film systems or digital radiography systems.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.01a
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• pp.235-238
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• 2017

This study was to develop a portable digital radiography (PDR) system with a function measuring the X-ray source-with-detector angle (SDA) and to evaluate the imaging performance for the diagnosis of chest imaging. The SDA device consisted of an Arduino, an accelerometer and gyro sensor, and a Bluetooth module. According to different angle degrees, five anatomical landmarks on chest images were assessed using a 5-point scale. Mean signal-to-noise ratio and contrast-to-noise ratio were 182.47 and 141.43. Spatial resolution (10% MTF) and entrance surface dose were 3.17 lp/mm ($157{\mu}m$) and 0.266mGy. The angle values of SDA device were not significant difference as compared to those of the digital angle meter. In chest imaging, SNR and CNR values were not significantly different according to different angle degrees (repeated-measures ANOVA, p>0.05). The visibility scores of the border of heart, 5th rib and scapula showed significant differences according to different angles (rmANOVA, p<0.05), whereas the scores of the clavicle and 1st rib were not significant. It is noticeable that the increase in SDA degree was consistent with the increase of visibility score. Our PDR with SDA device would be useful to be applicable to clinical radiography setting according to the standard radiography guideline at various fields.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.2
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• pp.417-422
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• 1999

Purpose : The aim of this study was to assess the validity of standard deviation of gray scale histogram in digital subtraction radiography as a test parameter for superimposition error. Materials and Methods : Twenty periapical radiographs were used as baseline images and they were copied to exclude the influence of exposure geomety and contrast differences. These subsequent images were linearly displaced by 0.1-0.5 mm in the x-. y- and xy-directions, rotated by 0.5-3° and distorted by angular contraction of 1-5° in x- and y-axis before subtraction. The standard deviations of gray levels in the subtraction images were obtained and paired t-tests were performed. Pearson correlation coefficients(r) were calculated between the standard deviations and the superimposition errors. Results : Linear displacement showed high correlation coefficients of 0.997, 0.997 and 0.995 in x-. y- and xy-axis respectively. Statistically significant different standard deviation existed among all linearly displaced groups(p<0.05). Distortion showed relatively low correlation coefficients of 0.982 and 0.959 in x- and y-axis. The standard deviations between the two distortion groups were statistically significant different(p<0.05). Conclusion : Standard deviation of gray level distribution in digital subtraction images is satisfactory but not perfect similarity measure to assess the superimposition errors.

• Applied Science and Convergence Technology
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• v.24 no.5
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• pp.125-131
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• 2015

We investigated the thermal characteristics of rotating anode X-ray tube to develop it for digital radiography by using computer simulation. The target which is the area of the anode struck by electrons is the most important component to get a long life of X-ray tube. So we analyze the thermal characteristics of the target and rotor assembly according to their emissivity by using ANSYS transient thermal simulation and then compare with the measured data of the target temperature operating in aging process of X-ray tube. Especially, keeping the lead coated layer as the role of metal lubricant on ball bearing enables to prevent the noise in rotating anode. The simulation result showed that its temperature was under the melting point of the lead in X-ray tube for digital radiography with 1.2 mm large focal spot 0.6 mm small focal spot and 150 kV tube voltage. We also investigated the relationship between the diameter of the anode shaft and the temperature of the anode and rotor assembly. It has been confirmed that the smaller anode shaft could be good for the rotor thermal characteristics.

• Journal of Periodontal and Implant Science
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• v.28 no.4
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• pp.797-809
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• 1998

The purposes of this study were to develop the computer program for the contrast and geometric correction in digital subtration radiography with the IDL (Interactive Data Language) and compare the results with this program for the correction of the non-standardized radiographs to those of standardized radiographs and those with "Emago" software, the commercial program for the correction. The procedures were written for the contrast correction and subtraction with the geometric correction, using IDL. 32 pairs of periapical radiographs of premolar and molar portion of two dry human mandibles were taken at two different occasions with XCP film holder(nonstandardized films) and another 32 pairs with customized XCP film holder(standardized films). Subtraction of standardized film pairs was performed. Subtraction after the contrast and geometric correction of non-standardized films was performed using the newly developed program and Emago software. Standard deviations of grey levels of the subtracted images by the newly developed program were compared with those of the standardized group and Emago-corrected group. Standard deviations of grey levels of new program-corrected group were much smaller than those of the Emago-corrected group (p<0.001) and slightly larger than those of standardized group (p<0.05). However, the difference was very minute. This study indicates that the newly developed program written with IDL may substitute the mechanical standardization for digital subtraction radiography.