• Journal of the Korean Society of Radiology
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• v.85 no.1
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• pp.138-146
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• 2024

Purpose To evaluate whether the image quality of chest radiographs obtained using a camera-type portable X-ray device is appropriate for clinical practice by comparing them with traditional mobile digital X-ray devices. Materials and Methods Eighty-six patients who visited our emergency department and underwent endotracheal intubation, central venous catheterization, or nasogastric tube insertion were included in the study. Two radiologists scored images captured with traditional mobile devices before insertion and those captured with camera-type devices after insertion. Identification of the inserted instruments was evaluated on a 5-point scale, and the overall image quality was evaluated on a total of 20 points scale. Results The identification score of the instruments was 4.67 ± 0.71. The overall image quality score was 19.70 ± 0.72 and 15.02 ± 3.31 (p < 0.001) for the mobile and camera-type devices, respectively. The scores of the camera-type device were significantly lower than those of the mobile device in terms of the detailed items of respiratory motion artifacts, trachea and bronchus, pulmonary vessels, posterior cardiac blood vessels, thoracic intervertebral disc space, subdiaphragmatic vessels, and diaphragm (p = 0.013 for the item of diaphragm, p < 0.001 for the other detailed items). Conclusion Although caution is required for general diagnostic purposes as image quality degrades, a camera-type device can be used to evaluate the inserted instruments in chest radiographs.

• Progress in Medical Physics
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• v.13 no.3
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• pp.169-175
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• 2002

The purpose of this study is to verify the usefulness of X-ray simulator which uses a visible light source for further study. We developed a small experimental equipment which is composed of three main components - source, localizer and detector. Cartesian coordinate was set in 3D space, and the position of target was assumed the origin of the coordinate. The light from the source passes directly through the target, and projection image is formed on the screen, which can be taken with the digital camera. Since projection images were acquired behind the screen, they were flipped over right and left. By examining the characters of visual light source and equipments, it could be concluded that developed system was useful for experimental purpose.

• Progress in Medical Physics
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• v.18 no.3
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• pp.144-148
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• 2007

Current digital radiography systems are rapidly glowing in clinical applications. The purpose of this study was to evaluate the characteristics of a mobile digital radiographic system. The performance of the mobile DR system was evaluated by measuring the modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE). Measurements were made on a LISTEM Mobix-1000 generator and a Teleoptic PRA Alpha-R4000 detector. Imaging characteristics were measured for these two systems using the IEC-61267 defined RQA5 (kVp: 74, additional filtration: 21 mmAl) radiographic condition. The MTF at 10% was measured as 2.4 cycles/mm and the DQE(0) values for radiation exposure 0.19, 0.5, and 1.3 mR were measured as 54%, 55%, and 76%, respectively. The NPS curves gradually decreased at high spatial frequencies. This high DQE at low frequencies, may be useful for low frequency information. The results suggested that mobile DR system could be integrated with emergency ambulance system in teleradiologic imaging applications.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.535-540
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• 2015

Collimator has important functions with control primary X-ray that decrease radiation exposure dose for patients and reduce scatter ray and make better quality of image. But there are no regulations for X-ray mammography device of collimator, so widely used device adopt rectangularly controlled collimator. Though digital X-ray mammography device expand supply recently, rectangularly controlled collimator of film/screen mode still used. After searching for real condition of beam field with digital mammography, we made a multi-leaf collimator which is able to adjust the beam field in accordance with size and shape of breast, and we measuring up the transitions of image quality, average glandular dose(AGD) and, Dose area product(DAP). There are no significant differences between rectangularly controlled collimator and multi-leaf collimator, and DAP value decreased by 50.72%. As conclusion, there needs to expand the use of multi-leaf collimator for optimum adoption of beam field in digital mammography, and also need to develop an automatic regulation of beam field for reduce of exposure dose to patients.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.555-561
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• 2014

For five diagnostic X-ray generators (DR), four units turned out to be appropriate in tests on the reproducibility of radiation output suggested in the IEC 60601-2-54 standard, but in one unit of the X-ray equipment, an item measured in a combination of 50% of the highest tube voltage of the diagnostic X-ray equipment, the test setting of Group C with authorized output doses between $1{\mu}Gy$ and $5{\mu}Gy$ of mAs turned out to be inappropriate. As a result, the radiation dose to the IEC 60601-2-54 standard for quantification standards proposed by the radiation output from diagnostic X-ray imaging device reproducibility of performance management should be aware that an important evaluation factor.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.533-542
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• 2017

In diagnostic radiology, the imaging system has been changed from film/screen to digital system. However, the method for removing scatter radiation such as anti-scatter grid has not kept pace with this change. Therefore, authors have devised the indirect flat panel detector (FPD) system with net-like lead in substrate layer which can remove the scattered radiation. In clinical context, there are many radiographic examinations with angulated incident X-ray. However, our proposed FPD has net-like lead foil so the vertical lead foil to the angulate incident X-ray would have bad effect on its performance. In this study, we identified the effect of vertical/horizontal lead foil component on the novel system's performance and improved the structure of novel system for clinical usage with angulated incident X-ray. Grid exposure factor and image contrast were calculated to investigate various structure of novel system using Monte Carlo simulation software when the incident X-ray was tilted ($0^{\circ}$, $15^{\circ}$, and $30^{\circ}$ from the detector plane). More photons were needed to obtain same image quality in the novel system with vertical lead foil only then the system with horizontal lead foil only. An optimal structure of novel system having different heights of its vertical and horizontal lead foil component showed improved performance compared with the novel system in a previous study. Therefore, the novel system will be useful in a clinical context with the angulated incident X-ray if the height and direction of lead foil in the substrate layer are optimized as the condition of conventional radiography.

• Progress in Medical Physics
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• v.18 no.3
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• pp.118-125
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• 2007

In this study we estimated a geometric correlation among digitally reconstructed radiographic image (DRRI), kV x-ray image (kVXI) from the On-Board Imager (OBI) and electric portal image (EPI). To verify geometric correspondence of DRRI, kVXI and EPI, specially designed phantom with indexed 6 ball bearings (BBs) were employed. After accurate setup of the phantom on a treatment couch using orthogonal EPIs, we acquired set of orthogonal kVXIs and EPIs then compared the absolute positions of the center of the BBs calculated at each phantom plane for kVXI and EPI respectively. We also checked matching result for obliquely incident beam (gantry angle of $315^{\circ}$) after 2D-2D matching provided by OBI application. A reference EPI obtained after initial setup of the phantom was compared with 10 series of EPIs acquired after each 2D-2D matching. Imaginary setup errors were generated from -5 mm to 5 mm at each couch motion direction. Calculated positions of all center positions of the BBs at three different images were agreed with the actual points within a millimeter and each other. Calculated center positions of the BBs from the reference and obtained EPIs after 2D-2D matching agreed within a millimeter. We could tentatively conclude that the OBI system was mechanically quite reliable for image guided radiation therapy (IGRT) purpose.

• Journal of the Korean Society of Radiology
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• v.10 no.1
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• pp.1-6
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• 2016

Recently, the various digital X-ray imaging devices using CCD and TFT LCD-based flat panel digital X-ray sensor are being used. In particular, a number of studies on photon counting sensor technique have been reported. In this study, the incident X-rays fluence on the photon counting sensor material was measured to estimate photon detection efficiency which is the quantitative performance evaluation factor of photon counting sensor. The result of measuring the photon fluence by using RQA-M2 Radiation beam quality of IEC 61223-1-2 recommendations, the incident photon fluence could be defined as about $4 photons/(0.01mm)^2{\cdot}{\mu}Gy$ within $10{\mu}m$ pin-hole area, and about $50photons/(0.03mm)^2{\cdot}{\mu}Gy$ within $30{\mu}m$ pin-hole area, and about $698photons/(0.1mm)^2{\cdot}{\mu}Gy$ within $100{\mu}m$ pin-hole area. Consequently, with the previously setup of the incident fluence, the measuring of actual photon counting efficiency by observing the output waveform of the photon counting sensor material was considered possible.

• Korean Journal of Digital Imaging in Medicine
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• v.12 no.1
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• pp.5-8
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• 2010

Opened a court in February 10, 2006, a rule of safety management of the diagnosis radiation system was promulgated for safety of the radiation worker, patients and patients' family members. The purpose of this rule is to minimize the risk of being exposed to radiation during the process of handling X-ray. For this reason, we manufactured shielding device of mobile X-ray unit collimator for diminution of skin dose. Shielding device is made to a thickness of Pb 0.375mm. For portable chest radiography, we measured skin dose 50cm from center ray to 200cm at intervals of 20cm by Unfors Xi detector. As a result, a rule of safety management of the diagnosis radiation system has been strengthened. But there are exceptions, such as ER, OR, ICU to this rule. So shielding device could contribute to protect unnecessary radiation exposure and improve nation's health.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.1
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• pp.31-35
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• 1994

전남대학교 치과진료처에 내원한 환자의 구내방사선사진중 1단계 (Cl: 30개 병소)또는 2단계(C2: 213.8병소)의 인접면 치아우식을 가진 방사선사진 168장을 연구대상으로 하였다. 이들 방사선사진은 코닥사의 Ektaspeed(E group) 필름을 사용하여 평행촬영법으로 촬영하였다. 168장의 방사선사진에 대하여 1단계 및 2단계 치아우식증을 4명의 구강악안면방사선학을 전공한 치과의사들이 같이 판독하여 그 결과를 기록하였다. 또한 168장의 방사선사진을 필름-비디오 변환장치를 이용하여 디지털 영상으로 전환하였다. 이때 486 DX PC에 PCVision과 frame grabber를 이용하였다. 각각의 구내방사선사 진영상은 17"크기의 1280×768픽셀의 해상도를 갖는 모니터상에서 256단계 흑화도를 갖는 700×480픽셀로 제시되었다. 모니터상에서의 치아우식 판독 결과를 구내방사선사진 판독 결과와 비교하였다. 그 결과 sensitivity는 0.98이었다. 1단계 치아우식은 0.87, 2단계 치아우식 은 1.00의 sensitivity를 나타내었다.