• Journal of the Korean Society of Radiology
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• v.7 no.3
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• pp.227-232
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• 2013

The pixels used in a digital X-ray detector have different sensitivities and offset values. A non-uniform image is consequently obtained. Flat-field correction was introduced to resolve this problem and carried out image preprocessing in a digital imaging system. Nevertheless, the non-uniform images caused by several reasons have been being occasionally acquired. In this study, the non-uniform images acquired in digital imaging systems were applied to flat-field correction, and NPSs were calculated and analyzed with those images before and after correction. It was confirmed that low frequency noise were effectively eliminated.

• Journal of the Korean Society of Radiology
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• v.85 no.4
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• pp.693-704
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• 2024

Artificial intelligence (AI) technology is actively being applied for the interpretation of medical imaging, such as chest X-rays. AI-based software medical devices, which automatically detect various types of abnormal findings in chest X-ray images to assist physicians in their interpretation, are actively being commercialized and clinically implemented in Korea. Several important issues need to be considered for AI-based detection assistant tools to be applied in clinical practice: the evaluation of performance and efficacy prior to implementation; the determination of the target application, range, and method of delivering results; and monitoring after implementation and legal liability issues. Appropriate decision making regarding these devices based on the situation in each institution is necessary. Radiologists must be engaged as medical assessment experts using the software for these devices as well as in medical image interpretation to ensure the safe and efficient implementation and operation of AI-based detection assistant tools.

• Korean Journal of Digital Imaging in Medicine
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• v.17 no.1
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• pp.43-48
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• 2015

Intracrnial 3D TOF MR angiography was performed in 30 normal volunteers with both 1.5 and 3.0 T MRI system with high resolutions. Used Voxel sizes were $0.39{\times}0.39{\times}0.2$(1.5 T) and $0.19{\times}0.19{\times}0.35$(3.0 T), respectively. High image quality and depiction of small vessel branches were equality demonstrated with 1.5 T and 3.0 T HR TOF MRA(p<0.05). Intracranial high resolution TOF MRA with 1.5 T and 3.0 T provides high diagnostic information with having merits and demerits in depiction of vascular branches.

• Proceedings of the Korea Contents Association Conference
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• 2016.05a
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• pp.141-142
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• 2016

의료 기관에서 정확한 진단하기 위해 아날로그 시스템인 Film System보다 Digital System을 선호하고, 장비의 설치 또한 Digital System으로 많이 보급이 되고 있다. 장비가 많이 보급이 되었지만 현재 장비에 대한 안전관리나 품질관리는 미흡하다고 할 수 있다.이에 본 연구는 Digital System의 품질관리의 중요성을 알리고, 품질관리의 항목을 설정하여, 기준 값을 제시하고자 3개월 동안 SNR, MTF, DQE를 측정한 결과 다음과 같이 나타났다. 1달은 SNR 4.02, MTF 50% 4.6lp/mm, DQE는1.4로 측정이 되었다. 3주후 SNR은 3.55, MTF 50% 3.0lp/mm, DQE는 0.7로 나타났다. 3개월 뒤 SNR은 3.45, MTF 50% 2.1lp/mm, DQE는 0.5로 나타났다. 시간이 지나갈수록 영상의 디지털영상의 물리적 평가들이 저하되는 것으로 나타났다. 시간이 지나감에 따라 의료영상이 저하됨에 따라 안전관리 뿐만 아니라 영상의 품질관리도 같이 이루어져야 할 것이다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.792-795
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• 2013

본 연구에서는 조영증강 의료 초음파 영상에서 조영제의 도달시간(arrival time)과 전이시간(transit time)에 관한 정보를 영상화하는 과정에서 정보의 왜곡을 개선하는 방법론을 제시한다. 간 질환 진단을 위한 파라미터 영상에서 병변 형태의 왜곡은 호흡에 의한 흔들림 현상과 노이즈의 영향에 기인한다. 본 논문에서는 이를 개선하는 방법으로서 MRF(Markov Random Field) 모델을 적용한 최적화 기법을 제안한다. 이를 위하여 Gibbs 샘플러를 적용하기 위한 에너지 함수를 정의하고 이를 기반으로 하는 영상개선 알고리즘을 구현하였다. 제안된 이론은 실제 의료진단 데이터에 적용함으로써 그 유용성을 평가하였다.

• Journal of radiological science and technology
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• v.35 no.4
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• pp.309-314
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• 2012

Nowadays, digital Radiography (DR) systems are widely used in clinical sites and substitute the analog-film x-ray imaging systems. The resolution of DR images depends on several factors such as characteristic contrast and motion of the object, the focal spot size and the quality of x-ray beam, x-ray scattering, the performance of the DR detector (x-ray conversion efficiency, the intrinsic resolution). The DR detector is composed of an x-ray capturing element, a coupling element and a collecting element, which systematically affect the system resolution. Generally speaking, the resolution of a medical imaging system is the discrimination ability of anatomical structures. Modulation transfer function (MTF) is widely used for the quantification of the resolution performance for an imaging system. MTF is defined as the frequency response of the imaging system to the input of a point spread function and can be obtained by doing Fourier transform of a line spread function, which is extracted from a test image. In clinic, radiologic technologists, who are in charge of system maintenance and quality control, have to evaluate or make routine check on their imaging system. However, it is not an easy task for the radiologic technologists to measure MTF accurately due to lack of their engineering and mathematical backgrounds. The objective of this study is to develop and provide for radiologic technologists a medical system imaging evaluation tool, so that they can measure and quantify system performance easily.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.691-696
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• 2021

In order to prevent and treat a patient's disease, the anatomical structure of the lesion through medical imaging is one of the important processes. However, there is a limit to the image displayed on the screen, so many studies are underway to overcome this by using 3D printing technology. To this end, this study implemented a three-dimensional cardiovascular model using actual patient image data, printed it out using a 3D printer, and conducted a usefulness test on current medical professionals. As a result of the usefulness evaluation, when the questionnaire conducted by a total of 5 people was converted to the Likert scale, the average value of all items showed a high result of 4.83 points, and the result of the cross-analysis was (P) = 10.000 (0.265), which was equally positive among all the questionnaires survey results were presented. Based on the results, it is expected that 3D printing technology will help advance medical technology.

• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1165-1170
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• 2023

In this study, we aimed to develop a cost-effective neuro-modulation device for use in neuroscientific and clinical medical imaging applications. To achieve this, we designed and fabricated a brain neuro-modulation device with a material cost of less than $500, and subsequently evaluated its performance. The measured performance was found to be comparable to existing medical devices (TENS), with the developed device being compact in size, measuring less than 3 cm by 3 cm. The outcomes of this study are expected to be applicable in accelerating research and development in related fields, as well as in the rapid commercialization of neuro-modulation technology. Furthermore, it is anticipated that this work will contribute to advancements in functional radiological medical imaging technology and enhance accessibility to brain science and brain stimulation technology.

• Journal of radiological science and technology
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• v.28 no.2
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• pp.111-115
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• 2005

The quality of image from the system that creates medical images by using X-ray depends on the various different reasons such as the X-ray generator, the subject and the image transmission medium. In other words, thereare various factors existing that can influence on the quality of image from the moment when the X-ray is generated and until the final image is created. Therefore, the operator who creates images at the clinical site should make continuous evaluation and observation from the final image. There are various methods of evaluating the medical images, but it is assumed that the MTF measurement method can be suitable for measuring actual or effective resolution. So in this study, the MTF measurement method by using X-ray film has been avoided and the MTF features according to the deterioration of the X-ray system have been measured by using the software (the program used Borland C++ builder software and LEAD tools software) that can measure the MTF of the digital medical images. As the result of this measurement, it has been found out through the MTF graph that the resolution and sharpness from the old x-ray generator with a many years of using and many numbers of times of using were deteriorated for the quality of image comparing to those from the new system. Also a simple and easy measurement method for the MTF from the digital medical images can be obtained in this study.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.232-235
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• 2013

간 질환 진단을 위한 의료 초음파 동영상에서 호흡으로 인한 영상의 흔들림 현상은 전이시간(transit time) 요소와 같은 진단 파라미터의 신뢰도를 저하시킬 뿐만 아니라, 정확한 병변 형태의 추출을 어렵게 한다. 본 연구에서는 호흡 주기를 자동으로 감지하고 이를 기반으로 ROI 를 추적하는 방법과 프레임 샘플링을 통하여 TIC(Time-Intensity Curve) 형태의 왜곡을 보정하는 방법을 고찰한다. 세부적으로 동적 가중치와 모멘텀 요소를 고려한 추적 기법을 제시하고 유용성을 평가한다. 또한 호흡주기와 프레임간 유사도(similarity)를 기반으로 한 영상 샘플링 기법을 제안하고 이로부터 신호의 왜곡을 보정할 수 있음을 보인다.