• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.4
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• pp.391-397
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• 2011

Conventional film radiographic test has been generally and widely used in the inspection on the weldment for quality assurance. On the other hand, since the analog RT is well known for typical time and cost consuming method with complex process of inspection, the industry has researched various ways how to improve radiographic test technology. In this study, we verified the fact that digital RT provides a lot more benefit in effectively detecting defects, ever film details, through digital processing of image enhancement, compared to film RT. As a result, we reached conclusion that digital RT is positively able to replace the film RT in industry in part or in whole.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.731-739
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• 2021

This work compared the bright calibration of digital radiation with signal-to-noise ratio and basic spatial resolution according to multi frame to enable effective inspection of welding parts of structures at industrial sites. A total of 130 images were obtained by using a ⁷⁵Se radiation source for flat weld test pieces and segmenting bright calibration and multi frame prior to shooting. The study confirms that the signal-to-noise ratio improves as the number of bright calibrations and the number of multi frame increases. The basic spatial resolution satisfied the baseline for both radiographic images. It was confirmed that the number of signal-to-noise ratio was similar by comparing images taken after installing lead shielding for scattering radiation. Although signal-to-noise ratio increases as multi frame increases, it is believed that good quality digital radiographs can be obtained if appropriate radiographic techniques are devised because exposure time of radiation affects workers' exposure and work efficiency.

• Journal of the Korean Society of Radiology
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• v.16 no.4
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• pp.395-403
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• 2022

Flat-panel detector (FPD) used in digital radiographic imaging systems was used to perform a quantitative power spectrum evaluation as a result of the thickness change of polymethyl methacrylate (PMMA), a tissue equivalent. As the PMMA thickness increases with the resolution-chart phantom image, the effect of the scattering line increases, indicating that the modulation characteristics decrease, and the image is bright. The results show that the noise of the image increases, and noise-power spectral images are obtained by Fourier transform to confirm by spatial frequency. Thus, it can be verified that the PMMA thickness and noise are proportional through the result of evaluating the change of resolution characteristics and representing the 2D noise-power spectrum as one-dimensional values by evaluating the change of scattering line with MTF as the PMMA thickness increases in the image.

• Korean Journal of Digital Imaging in Medicine
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• v.7 no.1
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• pp.23-31
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• 2005

원격진료 홈네트워크 아파트 진료용 키오스크 모바일주치의 등으로 대표되는 U-헬스케어에 있어서 기초가 되는 것은 의료정보를 디지털화해서 전자적 자료의 형태로 저장 보관하고 이를 송 수신할 수 있는 기술이라고 할 수 있다. 우리나라의 경우, U-Korea 전략의 하나로 보건복지부가 주축이 되어 2005년 10월 현재 국가보건의료정보화계획(ISP)을 수립하기 위한 작업을 추진중에 있다. 여기서, 예컨대 임상병리검사소견이나 방사선촬영소견 등의 의료정보가 전자적 장치에 의해 디지털화 할 경우 디지털 의료정보가 되는 것이며, 이 가운데 특히 방사선촬영소견 등 방사선분야의 모든 촬영기록이 PACS시스템을 통해 기재되거나 저장 전송될 경우 이를 디지털 의료영상정보라고 할 수 있다. 그런데 오늘날 정보통신기술의 발달로 말미암아 디지털 의료영상정보를 포함한 디지털의료정보는 대량적으로 수집 저장되고 유통 내지 공동활용이 보편화되어 감에 따라 그 의료정보의 보호에 관한 문제가 중요한 이슈로 대두되고 있다. 결론적으로 말하자면, 이러한 디지털 의료영상정보가 전자의무기록(EMR) 형태로 저장 보관되는 경우 이는 전자의무기록에 관한 법률규정이 적용되어 법률적 보호를 받게 되며, 그 보호의 강도는 종래 오프라인 상의 의료정보 보호보다 한층 강화된 규정을 두고 있다. 이와 같은 흐름에 있어서 최근 정부가 국가보건의료정보화계획 수립과 함께 제정작업을 추진하고 있는 가칭 의료정보화촉진 및 개인정보보호에 관한 법률(안)은 시사점이 크다고 보기 때문에 소개하고자 한다.

• Journal of radiological science and technology
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• v.40 no.1
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• pp.71-78
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• 2017

Scattered radiation is inherent phenomenon of x-ray, which occurs to the subject (or patient). Therefore it cannot be avoidable but also interacts as serious noise factor because the only meaningful information on x-ray radiography is primary x-ray photons. The purpose of this study was to quantify scattered radiation for various shooting parameters and to verify the effect of anti-scatter grid. We employed beam stopper method to characterize scatter to primary ratio. To evaluate effect on the projection images calculated contrast to noise ratio of given shooting parameters. From the experiments, we identified the scattered radiation increases in thicker patient and smaller air gap. Moreover, scattered radiation degraded contrast to noise ratio of the projection images. We find out that the anti-scatter grid rejected scattered radiation effectively, however there were not fewer than 100% of scatter to primary ratio in some shooting parameters. The results demonstrate that the scattered radiation was serious problem of medical x-ray system, we confirmed that the scattered radiation was not considerable factor of dig ital radiog raphy.

• The KIPS Transactions:PartB
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• v.11B no.3
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• pp.275-280
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• 2004

In this paper, we propose automatic subtraction radiography algorithms to overcome conventional subtraction radiography's defects by applying image processing technique. In order to reach these goals, this paper suggests the image alignment method that is necessary for getting subtraction image and ROI(Region Of Interest) focused on a selection method using the structure characteristics in target images. Therefore, we use these methods because they give accurary, consistency and objective information or data to results. According to the results, easily and visually we can identify fine difference int the affected parts wether they have problems or not.

• 대한방사선방어학회:학술대회논문집
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• 2011.04a
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• pp.132-133
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• 2011

• Journal of Veterinary Clinics
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• v.29 no.1
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• pp.18-22
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• 2012

This study was performed to evaluate the sensitivity of conventional film-screen radiography (CFSR) and direct digital radiography (DDR) for detection of various amounts of free peritoneal fluid. Ten adult male healthy beagles were used in this study. Radiographic examinations were performed in the right lateral and ventrodorsal positions. Fluid was injected in increments of 2.0 ml/kg of body weight up to 20.0 ml/kg of body weight. The images of CFSR and DDR were evaluated by two veterinary radiologists for evidence of abdominal fluid without knowledge of injected fluid volume. Data were evaluated by using the receiver operation curve (ROC) analysis and the area under the curve (AUC). There was no significant difference in detection of peritoneal fluid between DDR and CFSR in the ROC analysis. The accuracy of CFSR (0.805) was relatively higher than that of DDR (0.733), based on the ROC analysis and AUC. AUC of CFSR was higher in most injection doses. These results suggest that CFSR is more accurate than DDR for the detecting peritoneal fluid. Therefore, for situation in which digital radiographs are equivocal or small amount of fluid is suspected, other imaging modalities, such as ultrasonography would be helpful for determining the presence of fluids.

• Journal of the Korean Society of Radiology
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• v.16 no.5
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• pp.585-594
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• 2022

The detector for digital radiography testing, which is currently mainly used, consists of a detector with a flat structure, making it impossible to fully adhere to the digital radiography testing of the test object with curvature. In this study, a curved panel detector capable of adhering to curvature was fabricated to improve the quality of the digital image during the digital radiography testing of piping welds at industrial sites, and digital radiography images using flat and curved panel detectors were obtained for 6in pipes with different nominal thickness. As a result of the experiment, it was confirmed that the flat panel detector does not fully adhere to the pipe, resulting in a gap between the outer part of the pipe and the detector, resulting in a difference in the unsharpness and diffusion of the digital image. On the other hand, it was confirmed that the curved panel detector minimizes the gap between the pipe outer part and the detector, so that digital image diffusion is less than that of the flat panel detector. The higher the confidence of the image, the lower the quality and error in reading, so it is believed that higher quality images can be obtained than conventional flat panel detectors when using detectors that can be closely attached to the inspection object.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.329-335
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• 2010

Digital imaging detectors can use a variety of detection materials to convert X-ray radiation either to light or directly to electron charge. Many detectors such as amorphous silicon flat panels, CCDs, and CMOS photodiode arrays incorporate a scintillator screen to convert x-ray to light. The digital radiography systems based on semiconductor detectors, commonly referred to as flat panel detectors, are gaining popularity in the clinical & hospital. The X-ray detectors are described between a-Silicon based indirect type and a-Selenium based direct type. The DRS of detectors is used to convert the x-ray to electron hole pairs. Image processing is described by specific image features: Latitude compression, Contrast enhancement, Edge enhancement, Look up table, Noise suppression. The image features are tuned independently. The final enhancement result is a combination of all image features. The parameters are altered by using specific image features in the different several hospitals. The image in a radiological report consists of two image evaluation processes: Clinical image parameters and MTF is a descriptor of the spatial resolution of a digital imaging system. We used the edge test phantom and exposure procedure described in the IEC 61267 to obtain an edge spread function from which the MTF is calculated. We can compare image in the processing parameters to change between original and processed image data. The angle of the edge with respect to the axes of detector was varied in order to determine the MTF as a function of direction. Each MTF is integrated within the spatial resolution interval of 1.35-11.70 cycles/mm at the 50% MTF point. Each image enhancement parameters consists of edge, frequency, contrast, LUT, noise, sensitometry curve, threshold level, windows. The digital device is also shown to have good uniformity of MTF and image parameters across its modality. The measurements reported here represent a comprehensive evaluation of digital radiography system designed for use in the DRS. The results indicate that the parameter enables very good image quality in the digital radiography. Of course, the quality of image from a parameter is determined by other digital devices in addition to the proper clinical image.