• 대한방사선기술학회지:방사선기술과학
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• 제24권2호
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• pp.13-17
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• 2001

When most patients are diagnosed with the quiet progressed hepatoma which often would make the operation impossible, the Interventional Radiology hepatic artery embolization is an extremely useful method for such patients. An existence of the malfunction is evaluated by gaining a portal vein image as a delayed phase image after injecting a contrast media into the superior mesenteric artery. However, it is difficult to make a definite judgement due to the extended exposure time with the peristalsis and the intestine gas obstructing the sharpness of the image when the Patient exposure time increases and due to the increased usage of contrast media and its side effect. The portal vein can be evaluated by obtaining the MIP image after reconstructing a 3-dimensional personal computer setting using the 2-dimensional from an enhancement abdomen CT image that is almost a requisite in operation to a hepatoma patient. Such method nay prevent a decrease in the quality of image based upon the time delay and intestine gas; also, because the patient exposure dose and contrast media usage may be reduced, it is a new, valuable way to decide the operational matter of hepatic artery embolization on a pre-angiography.

• 대한방사선기술학회지:방사선기술과학
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• 제47권3호
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• pp.175-182
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• 2024

Advanced modeled iterative reconstruction (ADMIRE) represents a repetitive reconstruction method that can adjust strength and kernel, each of which are known to affect computed tomography (CT) image quality. The aim of this study was to quantitatively analyze the noise and spatial resolution of CT images according to ADMIRE control factors. Patient images were obtained by applying ADMIRE strength 2 and 3, and kernel B40 and B59. For quantitative evaluations, the noise level, spatial resolution, and overall image quality were measured using coefficient of variation (COV), edge rise distance (ERD), and natural image quality evaluation (NIQE). The superior values for the average COV, ERD, and NIQE results were obtained for the ADMIRE reconstruction conditions of ADMIRE 2 + B40, ADMIRE 3 + B59, and ADMIRE3 + B59. NIQE, which represents the overall image quality based on no-reference, was about 6.04 when using ADMIRE 3 + B59, showing the best result among the reconstructed image acquisition conditions. The results of this study indicate that the ADMIRE strength and kernel chosen for use in ADMIRE reconstruction have a significant impact on CT image quality. This highlights the importance of adjusting to the control factors in consideration of the clinical environment.

• 한국방사선학회논문지
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• 제10권6호
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• pp.451-456
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• 2016

방사선 검사로 환자의 병을 진단하기 위해서는 방사선 피폭이 따르게 된다. 최소한의 피폭으로 병변을 진단하는 일반촬영에 이중 엑스선 에너지 기법의 임상적용 가능성을 SNR 및 화질 점수화의 지표로 조사하였다. 이중 엑스선 에너지 기법은 검출기로 사용되는 두 개의 Image Plate 사이에 0.5 mm 두께의 Cu와 Al 필터를 추가함으로써 구현하였다. 한 번의 엑스선 조사로 획득된 두 IP 영상을 Subtraction 및 Enhance Contrast 기법을 적용하여 획득하였다. Enhance 영상은 첫 번째 IP에서 획득한 First 영상보다 SNR이 우수한 것으로 측정되었다. 이 일반촬영의 이중 엑스선 에너지 기법은 피폭선량을 줄이면서 영상의 품질을 높일 수 있는 방법으로 임상에서 매우 유용하게 적용될 수 있을 것이다.

• 대한방사선기술학회지:방사선기술과학
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• 제34권1호
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• pp.9-15
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• 2011

본 논문은 현재 임상에서 사용되고 있는 비정질 셀레늄을 이용한 평판형 X선 영상 검출기를 통해 획득된 영상의 변조전달함수(MTF)에 대한 정량적인 값을 도출하였다. 영상 질(quality)의 주요변수인 MTF의 측정은 먼저 test pattern 영상을 획득한 다음, contrast method를 이용하여 공간주파수(spatial frequency)에서의 line profile을 디지털 값으로 획득하여 MTF를 계산하였다. 측정 결과, test pattern 영상에서 3.0 lp/mm에서 36.1%의 MTF 값을 나타냈으며, 종래의 필름 영상보다 약 2배 높은 해상력을 가짐을 알 수 있었다. 측정된 값은 비정질 셀레늄을 이용한 직접방식의 디지털 방사선 검출기의 임상적 사용가치가 충분함을 뒷받침 할 수 있는 기초 자료로서 제공될 수 있을 것으로 판단된다.

• Nuclear Medicine and Molecular Imaging
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• 제42권2호
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• pp.172-180
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• 2008

PET/CT fused image with anatomical and functional information have improved medical diagnosis and interpretation. This fusion has resulted in more precise localization and characterization of sites of radio-tracer uptake. However, a motion during whole-body imaging has been recognized as a source of image quality degradation and reduced the quantitative accuracy of PET/CT study. The respiratory motion problem is more challenging in combined PET/CT imaging. In combined PET/CT, CT is used to localize tumors and to correct for attenuation in the PET images. An accurate spatial registration of PET and CT image sets is a prerequisite for accurate diagnosis and SUV measurement. Correcting for the spatial mismatch caused by motion represents a particular challenge for the requisite registration accuracy as a result of differences in PET/CT image. This paper provides a brief summary of the materials and methods involved in multiple investigations of the correction for respiratory motion in PET/CT imaging, with the goal of improving image quality and quantitative accuracy.

• 대한방사선기술학회지:방사선기술과학
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• 제42권4호
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• pp.279-284
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• 2019

The purpose of this study was to find the best protocol for balance of image quality and dose in brain CT scan. Images were acquired using dual-source CT and AAPM water phantom, noise and dose were measured, and effective dose was calculated using computer simulation program ALARA(S/W). In order to determine the ratio of image quality and dose by each protocol, FOM (figure of merits) equation with normalized DLP was presented and the result was calculated. judged that the ratio of image quality and dose was excellent when the FOM maximized. Experimental results showed that protocol No. 21(120 kVp, 10 mm, 1.5 pitch) was the best, the organ with the highest effective dose was the brain(33.61 mGy). Among organs with high radiosensitivity, the thyroid gland was 0.78 mGy and breast 0.05 mGy. In conclusion, the optimal parameters and the organ dose in the protocol were also presented from the experiment, It may be helpful to clinicians who want to know the protocol about the optimum state of image quality and dose.

• 대한디지털의료영상학회논문지
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• 제12권2호
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• pp.81-87
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• 2010

The setting parameters of ultrasound scanner give influences to change of image. Sonographers have used a Matlab program to make Low Contrast Sensitivity(LCS) value and compared original images in order to evaluate the use of the supersonic diagnosis machinery. We confirmed the change of image in Grayscale values using Photoshop program. Experiment equipment of our research used A Medison Accuvix V10, A Multi-Tissue Ultrasound Phantom(040 GSE) of CHRIS Company, A Adobe Photoshop CS4 Program, A Convex Probe, A USB memory stick, A Probe Fixation Equipment. The method used Gain, Dynamic Range(DR) of the setting parameters of ultrasound scanner and researched Gain and DR was set to 10 dB. We changed the different settings to see the changes of images using Grayscale values of a Photoshop program about tissue images of a phantom. This study evaluated DR and Gain whether it is an image controller to get the optimum contrast to produce an image to see the how effect on the images. We did not use Gateway in supersonic diagnosis machinery. We can easily open to open the files through Photoshop program before we get Digital Imaging and Communications in Medicine(DICOM) files use USB memory stick in supersonic diagnosis machinery. When we diagnosed the lesion of the patient with ultrasound, the contrast and the Gray scale value of image are very important. In this research, we determined the optimum setting parameters that provided useful information to diagnose disease and evaluated the change of improved images.

• Journal of Magnetics
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• 제22권1호
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• pp.55-59
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• 2017

The purpose of this study was to quantitatively evaluate image quality using intensity profile, coefficient of variation (COV), and peak signal to noise ratio (PSNR) with respect to noise reduction techniques in the ultrasound images. For that purpose, we compared with the median filter, Rudin-Osher-Fatemi (ROF), Anscombe and proposed patch group prior based denoising (PGPD) techniques. To evaluate image quality, the Shepp-Logan phantom and the ultrasound image were acquired using simulation and experiment, respectively. According to the results, the difference of intensity profile using PGPD technique is lowest compared with original Shepp-Logan phantom. In simulation, the measured COV was 0.249, 0.198, 0.198, 0.177, and 0.080 using noisy, median, ROF, Anscombe and PGPD technique, respectively. Also, in experimental image, the measured COV was 0.245, 0.230, 0.231, 0.242 and 0.187 using noisy, median, ROF, Anscombe and PGPD technique, respectively. Especially, when we used PGPD technique, the PSNR has highest value in both simulation and experiment. In this study, we performed simulation and experiment study to compare various denoising techniques in the ultrasound image. We can expect the PGPD technique to improve in medical diagnosis with excellent noise reduction.

• 한국방사선학회논문지
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• 제16권6호
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• pp.727-733
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• 2022

본 연구는 방사선과 대학생을 대상으로 개인병원에 근무하는 방사선사의 이미지에 대한 유형을 파악하고, 범주화된 유형에 따라 개인병원 방사선사의 이미지 향상을 위한 전략을 제시하고자 수행되었다. 본 연구목적을 달성하기 위해 인간의 주관성 연구에 적합한 Q방법론을 적용하였다. 방사선과 대학생 31명을 P 표본으로 하여, 이들의 20개의 Q표본을 강제분포하도록 하였다. 연구결과 방사선과 대학생이 생각하는 개인병원에 근무하는 방사선사의 이미지는 3가지 유형으로 발견되었으며, '미래 불안정형', '업무 분위기 긍정형', '조직체계 불만족형'으로 확인되었다. 본 연구는 각 유형별 특징을 파악하여 개인병원에 근무하는 방사선사의 이미지를 향상시키기 위한 기초자료로 활용할 수 있다고 생각한다.

• 대한방사선기술학회지:방사선기술과학
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• 제43권2호
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• pp.65-70
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• 2020

PA(postero-anterior) and AP(antero-posterior) chest projections are the most sought-after types of all kinds of projections. But if a radiological technologist puts wrong information about the position in the computer, the orientation of left and right side of an image would be reversed. In order to solve this problem, we utilized CNN(convolutional neural network) which has recently utilized a lot for studies of medical imaging technology and rule-based system. 70% of 111,622 chest images were used for training, 20% of them were used for testing and 10% of them were used for validation set in the CNN experiment. The same amount of images which were used for testing in the CNN experiment were used in rule-based system. Python 3.7 version and Tensorflow r1.14 were utilized for data environment. As a result, rule-based system had 66% accuracy on evaluating whether the orientation reversal on chest x-ray image. But the CNN had 97.9% accuracy on that. Being overcome limitations by CNN which had been shown on rule-based system and shown the high accuracy can be considered as a meaningful result. If some problems which can occur for tasks of the radiological technologist can be separated by utilizing CNN, It can contribute a lot to optimize workflow.