Earticle

Among various physical or subjective assessments of the quality of X-ray images, physical assessments can be quantitative but they are eventually judged by the view of observers thus subjective assessments including the aspect of observers are required. The changes in the ability to detect lesions caused by changes in the thickness of acrylic plates were tested with the ROC interpretation method that has taken into consideration, all the features of physical assessments as well as observers’ ability to observe and mental stages and even surrounding environments using an Alvim phantom and the result indicated that as the thickness of acrylic plates increased, the amount of noises occurred increased compared to signals and thus the ability to detect signals as well as the sensitivity that is an ability to signals accurately and the ability to distinguish noises from signals thus it is considered that more efforts of radiologic technologists will be required to detect small lesions of fat patients with diagnostic X-ray generating apparatus.

As online reviews increasingly combine text and user-generated images, prior research has paid limited attention to whether visual quality contributes to review helpfulness beyond image presence. Using 80,145 reviews from MercadoLibre Chile, this study examines how aesthetic image quality (MUSIQ), technical image quality (BRISQUE), and textual characteristics shape review helpfulness for search and experience goods. Predictive models show that visual quality provides modest but clearer performance gains for experience goods than for search goods. Fuzzy-set Qualitative Comparative Analysis (fsQCA) further shows that visual quality is not a core condition in high-helpfulness pathways. Instead, sufficient configurations are more consistently linked to authentic writing and balanced evaluative tone. The findings suggest that prediction model performance and configurational analysis provide different forms of evidence. This study contributes by offering a product-type-sensitive view of visual quality and by showing that visual quality can support helpfulness without defining its main configurational pathways.

Background: The conventional cerium-doped Gd2Al2Ga3O12 (GAGG(Ce)) scintillator-based gamma-ray imager has a bulky detector, which can lead to incorrect positioning of the gammaray source if the shielding against background radiation is not appropriately designed. In addition, portability is important in complex environments such as inside nuclear power plants, yet existing gamma-ray imager based on a tungsten mask tends to be weighty and therefore difficult to handle. Motivated by the need to develop a system that is not sensitive to background radiation and is portable, we changed the material of the scintillator and the coded aperture. Materials and Methods: The existing GAGG(Ce) was replaced with Bi4Ge3O12 (BGO), a scintillator with high gamma-ray detection efficiency but low energy resolution, and replaced the tungsten (W) used in the existing coded aperture with lead (Pb). Each BGO scintillator is pixelated with 144 elements (12 × 12), and each pixel has an area of 4 mm × 4 mm and the scintillator thickness ranges from 5 to 20 mm (5, 10, and 20 mm). A coded aperture consisting of Pb with a thickness of 20 mm was applied to the BGO scintillators of all thicknesses. Results and Discussion: Spectroscopic characterization, imaging performance, and image quality evaluation revealed the 10 mm-thick BGO scintillators enabled the portable gamma-ray imager to deliver optimal performance. Although its performance is slightly inferior to that of existing GAGG(Ce)-based gamma-ray imager, the results confirmed that the manufacturing cost and the system’s overall weight can be reduced. Conclusion: Despite the spectral characteristics, imaging system performance, and image quality is slightly lower than that of GAGG(Ce), the results show that BGO scintillators are preferable for gamma-ray imaging systems in terms of cost and ease of deployment, and the proposed design is well worth applying to systems intended for use in areas that do not require high precision.

The aim of this study was to set up the optimal exposure condition according to detector type considering image quality (IQ) with radiation dose in chest digital radiography. We used three detector type such as flat-panel detector (FP) and computed radiography (CR), and charge-coupled device (CCD). Entrance surface dose (ESD) was measured at each exposure condition combined tube voltage with tube current using dosimeter, after attaching on human phantom, it was repeated 3 times. Phantom images were evaluated independently by three chest radiologists after blinding image informations. Standard exposure condition using each institution was 117 kVp-AEC at FP and 117 kVp-8 mAs at CR, and 117 kVp-8 mAs at CCD. Statistical analysis was performed by One way ANOVA (Dunnett T3 test) using SPSS ver. 19.0. In FP, IQ scores were not significant difference between 102 kVp-4 mAs and 117 kVp-AEC (28.4 vs. 31.1, p=1.000), even though ESD was decreased up to 50% (62.3 μGy vs. 125.1 μGy). In CR, ESD was greatly decreased from 117 kVp-8 mAs to 90 kVp-8 mAs without significant difference of IQ score (p=1.000, 24.6 vs. 19.5). In CCD, IQ score of 117 kVp-8 mAs was similar with 109 kVp-8 mAs (29.6 vs. 29.0), with decreasing from 320.8 μGy to 284.7 μGy (about 11%). We conclude that optimal x-ray exposure condition for chest digital radiography is 102 kVp-4 mAs in FP and 90 kVp-8 mAs in CR, and 109 kVp-8 mAs in CCD.

The rapid development in digital acquisition technology in radiography has not been accompanied by information regarding optimum radiolographic technique for use witli an amorphus silicon flat panel detector. The purpose of our study was to compared imaging characteristics and image quality of an amorphus silicon flat panel detectors for digital chest radiography. All examinations were performed by using an amorphus silicon flat panel detector. Chest radiographs of an chest phantom were obtained with peak kilovoltage values of 60 〜 150 kVp. Published data on the effect of x-ray beam energy on imaging characteristics and image quality when using an amorphus silicon flat panel detector. It is important that radiographers are aware of optimum kVp selection for an amorphus silicon flat panel detector system, particularly for the commonly performed chest examination.

Purpose: The purpose of this study was to examine the correlations of body image, sexual quality of life (SQOL), depression, and quality of life, and to identify the influencing factors on quality of life of middleaged adults in the community. Methods: The participants of this study were 367 middle-aged adults. Data were collected through personal interviews using a questionnaire. Data were analyzed using descriptive statistics, t tests, oneway analysis of variance, Pearson's correlation coefficients, and stepwise multiple regression. Results: Body image, SQOL, depression, and quality of life according to the general characteristics and health-related characteristics commonly showed significant differences in age, level of education, duration of marriage, living arrangement, occupation, monthly income, presence of disease, exercise, stressor, frequency of sexual intercourse with spouse, and degree of deep sleep. Quality of life showed significant positive correlations with body image and SQOL, but a significantly negative correlation with depression. Body image, depression, education level, SQOL, and stressor, which accounted for 42.0% of the variance, were significant predictors influencing quality of life in middle-aged adults in the community. Conclusions: To improve quality of life in middle-aged adults ahead of old age, an assessment of their body image, depression, SQOL should be made and a variety of nursing interventions should be followed to improve their positive body image, depression, and SQOL.

Purpose: This study aimed to examine body image, self-esteem, and quality of life (QOL) in children and adolescents with Inflammatory bowel disease (IBD) and to analyze factors influencing QOL. Methods: This descriptive study involved 87 participants at a tertiary hospital aged 10 to 18 years who were diagnosed with IBD. Body image, self-esteem, and QOL were measured. Descriptive analysis, the independent t-test, the Mann-Whitney U test, analysis of variance, Pearson correlation analysis, and stepwise multiple regression were used for data analysis. Results: The average score was 16.95±3.55 for body image, 31.32±5.25 for self-esteem, and 78.64±15.98 for QOL. Height, weight, hospitalization experience, current symptoms, and consumption of oral steroids showed statistically significant effects on QOL. The most significant predictors of QOL were self-esteem (β=.31, p=.002), body image (β=.28, p=.005), number of symptoms (β=-.25, p=.004), and number of hospitalizations in the last year (β=-.24, p=.004). Conclusion: To improve the QOL of children and adolescents with IBD, it is necessary to evaluate self-esteem, body image, and physical problems. In addition, various intervention strategies to improve self-esteem and body image and to reduce physical discomfort should be developed.

DR has had an important fact not only in the department of radiology but also in productivity or work efficiency of a whole hospital. The environment of DR has more various parameter than CR, so it is able to supply high quality of medical services. The current environment of radiology department in each hospital has been changed from Film-Screen system to DR through Full-PACS. This hospital which uses Full-PACS became to study the proper condition of CR and DDR and how the image quality of them is expressed among general photographing systems in the DR environment. From this experiment, the image quality of DDR is better than CR under the same exposure condition. And in the DDR system, the score of image which uses AEC is a little higher than the score which doesn’t use it. Especially it can be known that the function of AEC of DDR is useful to improve the image quality in the part of skull and chest. (The function of AEC : It is the tool that detects the ionized current of x-ray which goes through objects with using the ion chamber which is in the detector. Also it controls the examination of X-ray when the proper density is reached.) B洙ause the proper degree of density can be represented by this system, the photographing can be taken much 期sily without consideration of the exposure condition with the thickness of various objects. From the result of this experiment, it can be known that the selection of proper exposure condition plays an important rule to gain good Image Quality. More researches will be necessary about DDR system which has potential ability in the future.

The CT urography is a non-invasive, essential examination for patients who have a urinary system disease. Maximizing the opacification and distention of the bladder is important because it facilitates the detection of tumors and provides morphological information on the bladder. This study evaluates the difference in the quality of the bladder filling image and the total dose of radiation exposed to patients when the repositioned patient, after having rolled over, is not rescanned in the scout phase before proceeding to be scanned in the excretory phase. The CT urography protocols are divided into two groups, In Group A, the patient is scanned twice in the scout phase, first in the supine position and then again in the prone position after being repositioned on the CT table. In Group B, the patient is scanned only once in the scout phase in the prone position before being repositioned. In the quantitative evaluation of the two groups, Group B had lower average standard deviation of the CT number in the bladder than Group A (p<0.05). In the qualitative and total dose evaluation of the two groups, Group B had higher value than Group A (p<0.05). This study demonstrates that it is possible to get a homogeneous image of the bladder by not rescanning the patient after being repositioned.

Computed Tomography (CT) 영상에서 Gaussian noise는 영상이 획득되는 과정에서 불가피하게 발생되며, 이는 segmentation의 성능 및 진단의 정확도를 저하시키는 요인으로 작용한다. 따라서, 본 연구에서는 denoising filter의 종류에 따른 영역확장 (region growing, RG) 기반 segmentation 알고리즘의 성능을 정량적으로 비교 평가하였다. 실험을 위해 Shepp-Logan phantom 영상으로부터 0.05의 표준편차 값을 갖는 Gaussian noise를 부가하고 각각 mean, median, Wiener filter를 적용하였다. 이후, RG 기반 segmentation 알고리즘을 적용하였으며, 이에 대한 정량적 평가를 위해 F1-score와 IoU를 측정하였다. 결과적으로, F1-score 및 IoU 인자 모두 noisy, mean filter, median filter 그리고 Wiener filter 순으로 우수한 값을 보였다. 특히, Wiener filter를 적용하였을 때 noisy 영상과 비교하여 F1-score 및 IoU 인자는 각각 약 1.42배 및 1.75배 향상됨을 확인하였다. 결론적으로, CT 영상의 segementation 정확도를 향상시키기 위해 적합한 denoising filter를 적용해야 함을 증명하였다.

Segmentation is very important in accurate surgical planning such as liver transplantation and resection and identification of lung nodules. In a computed tomography image, Gaussian noise inevitably occurs in the process of acquiring the image. Gaussian noise can interfere with segmentation and interfere with accurate diagnosis, resulting in fatal consequences for patients. Therefore, this study attempted to compare and evaluate which filter is most effective for denoising in performing segmentation. For the study, Gaussian noise was added to Shepp-Logan phantom and mean, median, and Wiener filter were applied, respectively. Thereafter, segmentation was performed using the thresholding technique to evaluate using F1-score and IoU to find the most suitable filter for denoising. As a results, the F1-score was 0.62 for noise-added image, 0.697 for mean filter, 0.858 for median filter, and 0.88 for Wiener filter. The IoU was 0.449 for noise-added image, 0.535 for mean filter, 0.752 for median filter, and 0.785 for Wiener filter. Therefore, the Wiener filter was confirmed to be the most effective for denoising, and it was confirmed that the F1-score improved 1.42 times and the IoU 1.75 times compared to the noise-added image. In conclusion, various denoising filter methods were analyzed to improve the accuracy of segmentation, and Wiener filter is expected to be used in an efficient way.

본 연구에서는 CT에 사용되는 MAR, monoenergetic 알고리즘 적용 시 영상 화질변화에 대해 비교하고자 한다. Dual layer CT와 ACR 팬톰을 이용하여 동일 조건으로 촬영 후, 원시 데이터에 MAR, monoenergetic, MAR+monoenergetic 알고리즘을 각각 적용하여 알고리즘 별 10장의 영상을 획득하였다. 획득한 영상 화질 비교를 위해 MSE, RMSE, PSNR, SSIM 지표를 통해 화질을 비교하였으며, 측정된 데이터를 이용하여 통계분석을 진행하였다. CT 영상 알고리즘 적용에 따른 각 지표 결과 origin 영상 MSE, RMSE, PSNR, SSIM은 각각 310.02 ± 11.3, 17.60 ± 0.32, 23.22 ± 0.16, 0.35 ± 0.005 였으며, MAR만 적용한 영상 결과는 각각 305.94 ± 16.61, 17.48 ± 0.48, 23.28 ± 0.24, 0.36 ± 0.009 였으며, MonoE만 적용한 영상 결과는 각각 224.46 ± 8.37, 14.98 ± 0.28, 24.62 ± 0.16, 0.38 ± 0.007 이었으며, MAR와 MonoE를 적용한 영상 결과는 각각 224.49 ± 8.37, 14.98 ± 0.28, 24.62 ± 0.16, 0.38 ± 0.008이었다. 통계분석 결과 origin 영상을 기준으로 알고리즘이 적용된 모든 영상 간 유의한 차이가 있었으며(p < 0.05), 사후분석 결과 MSE, RMSE, PSNR에서는 origin영상과 MAR 적용 영상 간, MonoE 영상 과 MAR+MonoE 적용 영상 간 유의한 차이가 없었으며, SSIM 사후분석에서는 MonoE 영상과 MAR+MonoE 적용 영상에서만 유의한 차이가 없었다(p > 0.05). 알고리즘이 적용되지 않은 origin 영상과 MAR 적용 영상 간 화질차이는 없었지만, MonoE가 적용되는 경우 영상 화질이 개선되는 것을 확인할 수 있었다. 따라서 본 연구를 통해 진단목적에 맞는 알고리즘을 선택하여 사용한다면 양질의 CT 영상을 획득할 수 있을 것으로 사료된다.

In this study, we compare the change in image quality when applying the MAR, monoenergetic algorithm used in CT. After imaging under the same conditions using dual layer CT and ACR phantom, 10 images for each algorithm were acquired by applying MAR, monoenergetic, and MAR+monoenergetic algorithms to the raw data, respectively. To compare the acquired image quality, the image quality was compared through MSE, RMSE, PSNR, and SSIM indicators, and statistical analysis was performed using the measured data. Origin image MSE, RMSE, PSNR, and SSIM as a result of each index according to the application of the CT image algorithm were 310.02 ± 11.3, 17.60 ± 0.32, 23.22 ± 0.16, and 0.35 ± 0.005, respectively, and the image results using only MAR were 305.94 ± 16.61, 17.48 ± 0.005, respectively. 0.48, 23.28 ± 0.24, 0.36 ± 0.009, and the image results using only MonoE were 224.46 ± 8.37, 14.98 ± 0.28, 24.62 ± 0.16, and 0.38 ± 0.007, respectively, and the image results using MAR and MonoE were 224.49 ± 8.3, respectively. 7, 14.98 ± 0.28, 24.62 ± 0.16, and 0.38 ± 0.008. As a result of statistical analysis, there was a significant difference between all images to which the algorithm was applied based on the origin image (p < 0.05). As a result of post-hoc analysis, MSE, RMSE, and PSNR showed a significant difference between origin images and MAR-applied images, and between MonoE images and MAR+MonoE-applied images. In SSIM post-analysis, there was no significant difference between MonoE image and MAR+MonoE applied image (p > 0.05). There was no difference in image quality between the original image without the algorithm applied and the image applied with MAR, but it was confirmed that the image quality improved when MonoE was applied. Therefore, it is considered that high-quality CT images can be obtained if an algorithm suitable for the purpose of diagnosis is selected and used through this study.

디지털 X-선 영상에서는 불완전한 영상시스템에 의해 왜곡된 정보가 반영되어 나타나며 이는 영상 진단에 있어 위양 성을 발생시키는 원인이 된다. 특히 유한한 X-선 튜브의 초점크기와 디지털 디텍터의 유한한 픽셀크기 등으로 인해 발생되는 시스템 열화함수 (point-spread function, PSF)는 영상을 블러링 시키는 주된 원인이 된다. 본 연구에서는 이러한 PSF를 영상 시스템에서 측정하여 제한된 역필터링 기법을 통해 블러링을 제거함으로써 영상 복원을 수행하였다. 본 연구에서의 결과는 노이즈와 같은 방해요소가 있는 영상에서도 제안하는 제한된 역필터링 기법이 효과적임을 확인할 수 있다.

In this study, we proposed a new image restoration method using the limited inverse direct filtering method in digital radiography for improving image quality. The obtained image from the imaging system is imperfect due to infinite focal spot size and detector pixel size mainly. It is influenced to the diagnosis toward the false. We implemented the image restoration focused on the inverse filtering using the point spread-function (PSF) using the proposed method. The results of this study show that the limited inverse direct filtering interferences such as noise is effective.

본 연구에서는 혈관조영장비로 투시영상 및 비감산조영영상에서의 각 영상별 확대율에 따른 화질변화를 측정하고자 하였다. 이를 위해 MATLAB 프로그램을 통해 각 영상별 동일 크기의 관심영역을 설정하여 noise level을 측정하였으며, 평가인자로는 coefficient of variation(COV), contrast to noise ratio(CNR), 그리고 signal to noise ratio(SNR) 이 사용되었다. 결과적으로 투시영상에 비해 비감산조영영상에서 평균 COV는 약 4~7배 낮게 측정되었고, 평균 CNR은 약 2~3배 높게 측정되었으며, 평균 SNR은 약 3~7배 높게 측정되어 상대적으로 화질이 좋음을 확인하였다. 또한 두 영상 모두에서 영상을 최대로 확대시켰을 때, 투시영상의 경우 평균 COV는 약 4.9배 감소하였으며, 평균 CNR은 약 2.9배, 그리고 평균 SNR은 약 5.0배 증가하였고, 비감산조영영상의 경우 평균 COV는 약 3.9배 감소하였으며, 평균 CNR은 약 3.4배, 그리고 평균 SNR은 약 3.9배 증가하였다. 결론적으로 투시영상에 비해 비감산조영영상에서, 그리고 확대율이 높을수록 화질이 향상됨을 확인하였다.

In this study, an angiography equipment is used to measure changes in image quality in fluoroscopy and non-subtraction angiography images depending on the magnification of each image. For this purpose, the noise level is measured by setting a region of interest (ROI) of the same size for each image through the MATLAB program, and the evaluation factors are coefficient of variation (COV), contrast to noise ratio (CNR), and signal to noise ratio (SNR) was used. As a result, the mean COV was measured about 4 to 7 times lower, the mean CNR was measured about 2 to 3 times higher, and the mean SNR was measured about 3 to 7 times higher in the non-subtraction contrast image than in the fluoroscopy image. Also, for both images, when the intensifier size is set to the smallest (at maximum magnification), the mean COV is decreased by about 4.9 times, the mean CNR is increased by about 2.9 times, and the mean SNR is increased by about 5.0 times in fluoroscopy images. And in the case of non-subtraction angiography images, the mean COV decreased by about 3.9 times, the mean CNR increased by about 3.4 times, and the mean SNR increased by about 3.9 times. In conclusion, it was confirmed that the noise of the non-subtraction angiography image is less than that of the fluoroscopy image, and that the higher the magnification of both images, the better the image quality.

본 연구의 목적은, 전세계적으로 디지털 의료영상이미지를 국제표준규약에 따른 DICOM (digital imaging and communications in medicine)의 형식으로 저장하고 있다. DICOM 형식의 의료영상을 이용하여 원하는 장기의 관심 영역을 설정함으로써 다양한 정량적인 분석값을 획득하여 영상의 질을 평가하고 있다. 또한, DICOM 형식 외에도 현재 다양한 영상 저장 형식이 개발 및 사용되고 있으며, 본 연구의 목적으로 핵의학 및 CT (computed tomogrphy) 영상을 활용하여 DICOM 형식과 다양한 영상 저장 형식에 따른 영상의 질을 평가해보고자 한다. 의료영상 획득을 위하여 SPECT/CT (Discovery NM670, GE)를 사용하였다. 핵의학 영상은 NEMA IEC body 팬텀을 이용하였고, 99mTc을 주입하여 영상을 획득하였고, CT 영상은 Hoffman 3D 팬텀을 활용해 획득했다. 획득영상을 기반으로 TIFF (tagged image file format), JPEG (joint photographic experts group), AVI (audio video interleave), PNG(portable network graphics)로 각각 변환하고, 관심영역을 각각 영상에 설정하여 평균값과 표준편차를 구하여 영상의 질을 비교분석하였다. NEMA IEC body 팬텀의 핵의학 영상은 DICOM, TIFF, JPEG, AVI, PNG 의 영상 순서로 평균값은 100455.39, 100455.39, 203.55, 203.89, 203,71이고, 표준편차값은 21906.07, 21906.07, 44.13.00, 44.43, 43.45로 나타났다. 또한, Hoffman 3D 팬텀의 평균값은 11.16, 11.16, 70.02, 33803.16, 70.10이고, 표준편차값은 18.13, 18.13, 2.97, 18.13, 2.95의 결과값를 나타냈다. 본 연구결과를 바탕으로 디지털의료영상이미지의 대표적으로 사용되는 DICOM 형식과 평균값과 표준편차 인자로 비교했을 때 TIFF 영상 형식이 가장 유사한 결과값을 나타내었다.

The purpose of this study was to compare digital medical imaging between DICOM (digital imaging and communications in medicine) form and TIFF (tagged image file), JPEG (joint photographic experts group), AVI (audio video interleave), and PNG (portable network graphics) format. The SPECT/CT was used for acquisition nuclear medicine with NEMA IEC body phantom and computed tomography imaging with Hoffman 3D phantom, repectively. The mean count and standard deviation were used for quantitative analysis. According to results, the mean counts of nuclear medicine imaging for DICOM, TIFF, JPEG, AVI, and PNG were 100455.39, 100455.39, 203.55, 203.89, and 203,71, stnadard deviation was 21906.07, 21906.07, 44.13.00, 44.43, and 43.45. In addition, the mean counts of CT imaging were 11.16, 11.16, 70.02, 33803.16, and 70.10, standard deviation was 18.13, 18.13, 2.97, 18.13, and 2.95. In conclusion, the medical imaging of DICOM format is the most similar TIFF format.

본 연구의 목적은, 테이블과 디텍터간의 거리에 따른 SPECT 영상의 질을 평가하고자 한다. 영상의 질 평가를 위해 SPECT/CT (GE, USA) 와 NEMA IEC 몸통 팬텀을 이용하였다. 방사성동위원소는 99mTc를 팬텀에 삽입하였고, hot sphere 와 background 방사능량 비율을 8:1 로 유지하였고, 테이블과 디텍터 간의 거리를 22.4 cm 와 35.7 cm 유지하며 10분동안 영상을 획득하였다. 정량적인 평가인자로는 signal to noise ratio (SNR), coefficient of variation (COV), contrast to noise ratio (CNR)을 적용하였다. SNR, COV, CNR 의 결과값을 바탕으로, 테이블과 디텍터간의 거리가 가까울수록 영상의 질이 우수함을 확인하였다.

This study aimed to compare the image quality according to distant from table to detector (22.4 and 35.7 cm) when acquiring single photon emission tomography (SPECT) images. The discovery SPECT/computed tomography (GE, USA) and NEMA IEC body phantom were used, and image was aquired by using 99mTc which is maintained as 8:1 between hot sphere and background activity ratio during 10 minutes. In addition, quantitative analysis was performed by drawing the region of interests (ROIs) using singal to noise ratio (SNR), coefficient of variation (COV), and contrast to noise ratio (CNR). Based on the results, SNR result occurred diffenrece approximatley 16.1 % accoriding to distance from table to detector. In addition, COV result was also approximately 6.2 % and CNR result show approximately 11.6 %. In conclusion, the distant from table to detector is crucial in nuclear medicine image because it is effective for image quality. We confirmed that image quality is improved in SPECT images when locating to object closely.

본 연구의 목적은 뇌혈관조영검사에서 4차원 디지털 감산 혈관조영술 (4D DSA)을 이용하여 Dose Per Frame (DPF)에 따른 영상의 화질과 선량을 평가하고 2D 및 3D DSA와 비교하여 선량을 최적화하기 위한 적절한 프로토콜을 정립하는 것이다. 4D DSA는 조영제의 동적 흐름을 시간에 따라 관찰하면서 미세혈관 및 해부학적 구조를 나타내는 3차원 혈관조영술을 얻을 수 있다. 영상 획득을 위해 기존 프로토콜을 이용하여 2D 및 3D DSA를 수행하였고, DPF를 변경해가며 (0.36, 0.24, 0.17, 0.12, 0.08 μGy/frame) 4D DSA 영상을 획득하였다. 2D 및 3D DSA의 총 선량을 4D DSA의 선량과 비교하였으며, 각 프로토콜의 1초와 3초 영상을 선택하고 Signal to Noise Ratio (SNR)에 따라 정량적으로 비교, 분석하였다. 그 결과, 0.24 μGy/frame의 프로토콜은 2D 및 3D DSA의 총 선량과 유사하였으며, 기존 프로토콜 (0.36 μGy/frame)과 비교하여 SNR에 큰 차이가 없었다. 결론적으로 4D DSA에서 0.24 μGy/frame의 프로토콜을 적용함으로써 영상의 화질은 유지하면서 환자에 대한 피폭선량을 최적화할 수 있다는 것을 확인하였다.

The purpose of this study was to evaluate an image quality and dose according to Dose Per Frame(DPF) using Four-Dimensional Digital Subtraction Angiography (4D DSA) and establish an appropriate protocol to be optimized dose by comparing 2D and 3D DSA in cerebral angiography. 4D DSA can obtain three-dimensional angiography to represent microvascular and anatomical structures with a dynamic flow of contrast medium by time. For the image acquisition, 2D and 3D DSA were performed with existing protocols, and 4D DSA was acquired with various DPF settings (0.36, 0.24, 0.17, 0.12, 0.08 μ Gy/frame). A total dose of both 2D and 3D DSA was compared with the one from 4D DSA. Images at 1 and 3 seconds were selected and quantitatively analyzed based on Signal to Noise Ratio (SNR). As a result, the protocol with 0.24 μGy/frame was similar with the total dose from both 2D and 3D DSA. There were no significant differences compared with the default protocol (with 0.36 μGy/frame). In conclusion, it was demonstrated that the image quality can be maintained and the exposed radiation dose towards patients can be optimized by applying the protocol with 0.24 μGy/frame in 4D DSA.