• Journal of the Korean Society of Radiology
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• v.6 no.1
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• pp.53-61
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• 2012

This study was conducted to survey of the musculoskeletal disorders of radiological technologists and prevalence rate survey tool of musculoskeletal symptoms targeting the radiological technologists working currently in hospitals or clinics. For this study, survey was conducted from July 10th, 2011 to July 31st, 2011 for about 20 days with subject of radiological technologists in private clinics, hospitals, general hospitals and University hospitals. The main results of this study are as follows : First, frequency analysis on presence of musculoskeletal symptoms in each part of body showed that neck area was 22.5 %, shoulder area was 33.1 %, arm / elbow area was 8.3 %, hand / wrist / finger area was 15.5 %, waist area was 32.4 %, leg / foot area was 16.9% (p<0.05). Second, the results from summarizing the descriptive statistics of job stress, psychosocial stress and fatigue showed that the average of job stress was 2.48 out of Likert 4 points scale, the average of psychosocial stress was 2.27 out of Likert 4 points scale. Job stress was a little bit higher than the psychosocial stress. In case of fatigue, the average was 4.57 out of Likert 7 points scale and it was a slightly higher than 'normal' (p<0.05). In conclusion, we hope this study will be helpful to systematically and efficiently manage the resources as the basic material upon deploying the preventive measures about the musculoskeletal disorders of radiological technologists in the future.

• Journal of the Korean Society of Radiology
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• v.8 no.5
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• pp.225-230
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• 2014

Assessments of medical image was improved in accordance with development of medical imaging systems. One of them is edge method to determining MTF(Modulation Transfer Function) based on the Fujita method. Fujita was reduced sampling interval used slightly angulated slit to the direction of pixel array and composited finely sampled LSF to determine presampling MTF. In this study, we investigate the effect of sampling interval on the MTF under a digital imaging system by changing wire angle. The wire method was equivalent to the slit method except signal appearance. A Simens's MAMMOMAT Inspiration with $0.085{\times}0.085mm^2$ pixel size made by amorphous selenium was used and 96% accuracy on MTF in twice sampling interval compared with Fujita was obtained. However, three times of sampling interval showed 93% accuracy on 50% of MTF and 85% accuracy on 10% of MTF.

• Journal of the Korean Society of Radiology
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• v.10 no.3
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• pp.215-222
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• 2016

X-ray mammography is the most effective method for the diagnosis of calcified lesions of various breast diseases. To reduce patient dose and to obtain optimal image required for diagnosis, the performance of the mammography system should be maintained continuously. Because the target (anode) angle of the X-ray tube is measured from the central X-ray, the effective angle can be slightly different in view of the position on the detector, which can result in degrading spatial resolution of the imaging within the field of view. In this study, we measured the MTF to examine spatial resolution for positions on the detector in the digital mammography system. For a tungsten wire of $50{\mu}m$ diameter, the highest spatial frequency was obtained. It meant that a wire diameter for measuring MTF through LSF should be small compared to the pixel size of the detector used in the mammography system. The spatial resolution showed slightly different performance according to positions on the detector. The center position gave the best spatial resolution and positions away from the center showed the degraded performance although the difference of the spatial resolution was small. The effective focal spot size of the full width at half maximum also showed similar result. It concluded that the slightly increase of the effective focal spot size gave the degradation of the spatial resolution for positions on the detector.

• The Korean Journal of Nuclear Medicine
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• v.39 no.3
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• pp.163-173
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• 2005

Purpose: Abutted scatter energy windows used for a triple energy window (TEW) method may provide wrong estimation of scatter. This study is to propose an extended TEW (ETEW) method, which doesn't require abutted scatter energy windows and overcomes the shortcomings of TEW method. Materials & Methods: The ETEW is a modification of the TEW which corrects for scatter by using abutted scatter rejection windows, which can overestimate or underestimate scatter. The ETEW is compared to the TEW using Monte Carlo simulated data for point sources as well as hot and cold spheres in a cylindrical water phantom. Various main energy window widths (10 %, 15 % and 20 %) were simulated. Both TEW and ETEW improved image contrast, % recovery coefficients and normalized standard deviation. Results: Both of TEW and ETEW improved image contrast and % recovery coefficients. Estimated scatter components by the TEW were not proportional to the true scatter components over the main energy windows when ones of 10 %, 15 %, and 20 % were simulated. The ETEW linearly estimated scatter components over the width of the main energy windows. Conclusion: We extended the TEW method into the method which could linearly estimate scatter components over the main energy windows.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.739-747
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• 2019

As the research for analyzing the awareness and the performance level for infection control of radiological technologists working at the clinic located in Gyoungsangnam province, this study was conducted to provide the basic education data of infection control for radiological technologist who works in the clinic. During July 14, 2014 to March 31, 2015, after we sent out a total of 150 questionnaires for the survey to radiological technologists working at the clinic located in Gyoungsangnam province, 131 questionnaires suitable for research were analysis by using SPSS 18.0 statistical analysis software. As the infection control factors, a total of 60 items about the awareness and the performance level for infection control (12 items for infection control characteristics included) were analyzed. Descriptive statistics, t-test, ANOVA, correlation, and regression analysis were performed based on the general characteristics of the study subjects. Regarding the awareness factor for infection control, the total awareness level was high as $4.15{\pm}.05$ and the total performance level was also high as $4.05{\pm}.05$. Through these results, although the performance level was slightly lower than awareness level, the level of infection control of the radiological technologists working at the clinics located in Gyeongnam was analyzed to be relatively high. The infection control of the clinic's radiological technologist should be carried out through the continuous infection education and prevention activities of the hospital staff, and radiological technologist working in clinics should also be positioned as specialists in infection control.

• Journal of the Korean Society of Radiology
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• v.15 no.7
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• pp.1041-1047
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• 2021

In this study, the effective dose for frequently general radiography among the diagnostic reference level (DRL) for examinations provided by the government in Korea was evaluated using the Monte Carlo N-Particle eXtended (MCNPX) simulation tool. We were selected to evaluate for a total of 5 examination sites which included head anterior-posterior, chest (posterior-anterior, lateral), abdomen anterior-posterior and pelvis anterior-posterior. Physical conditions such as tube voltage and tube current used in MCNPX simulation were used in domestic conditions of the Korea Disease Control and Prevention Agency (KDCA). To evaluate domestic medical radiation exposure, we used the HDRK-Man computerized human phantom manufactured based on the international standard ICRP 103 that was applied to the MCNPX simulation. The phantom could represent the standard body shape of Koreans. As a results, the effective dose corresponding to the DRL based on adult males of head anterior-posterior position was 0.086 mSv, chest posterior-anterior position was 0.05 mSv, chest lateral was 0.354 mSv, abdomen anterior-posterior position was 0.548 mSv, and pelvis anterior-posterior position was 0.451 mSv.

• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.771-779
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• 2021

It is necessary to overlap several peaks to form spread out Bragg peak (SOBP) in order to cover the tumor volume because a mono-energetic proton beam forms a narrow Bragg peak. The tumor density has been considered as a brain tissue and then the absorbed dose of the tumor is calculated using Monte Carlo simulations. However, densities of tumors were not a constant. In this study, the SOBP of proton beams was calculated according to changing density of tumors by using Geant4. Tumors were selected as 10 mm and 20 mm width which were the treatment range in the brain phantom. The energies and relative weights of the proton beams were calculated using mathematical formula to form the SOBP suitable for the location and size of the tumor. As the density of the tumor was increased, the 95% modulation range and the practical range were decreased, and average absorbed dose in the 95% modulation range was increased. The change of the tumor density affects the dose distribution of the proton beams, which results in short SOBP within the tumor volume. The consideration of the tumor density affects the determination of the range, so that the margin of the treatment volume can be minimized, and the advantages of proton therapy can be maximized.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.749-754
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• 2021

In order to maximize the matching ratio between the scintillation pixel and the photosensor of the PET detector using a small number of photosensor, various arrays of scintillation pixels and four photosensors were used. The array of scintillation pixels consisted of six cases from 6 × 6 to 11 × 11. The distance between the photosensors was applied equally to all scintillation pixels, and the arrangement was expanded by reducing the size of scintillation pixel. DETECT2000 capable of light simulation was used to acquire flood images of the designed PET detectors. At the center of each scintillation pixel array, light generated through the interaction between extinction radiation and scintillation pixels was generated, and the light was detected through for four photosensors, and then a flood image was reconstructed. Through the reconstructed flood image, we found the largest arrangement in which all the scintillation pixels can be distinguished. As a result, it was possible to distinguish all the scintillation pixels in the flood image of 8 × 8 scintillation pixel array, and from the 9 × 9 scintillation pixel flood image, the two edge scintillation pixels overlapped and appeared in the image. At this time, the matching ratio between the scintillation pixel and the photosensor was 16:1. When a PET system is constructed using this detector, the number of photosensors used is reduced and the cost of the oveall system is expected to be reduced through the simplification of the signal processing circuit.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.603-612
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• 2021

The effect of Advanced Modeled Iterative Reconstruction (ADMIRE) on the coronary artery calcium (CAC) score of computed tomography was evaluated. Coronary artery calcium images (348 calcium, 6 groups, total of 2088 calcium) were acquired by 128-slice dual-source CT of 89 patients.Volume score and Agatston score were measured from images reconstructed with filtered back projection (FBP) and ADMIRE (1-5). The difference between FBP and ADMIRE Strength (1-5) was confirmed through the Kruskal-Wallis test, and the post-hoc analysis was performed using the Mann-Whitney U test based on FBP. Both volume score and Agatston score showed statistically significant differences between FBP and ADMIRE (1-5) (P=0.015, P=0.0.38). As a result of post hoc analysis, the volume score decreased to 9.5% in ADMIRE 4 (Z=-2.359, P=0.018) and 13.2% in ADMIRE 5 (Z=-3.113, P=0.002) based on FBP. Agatston score decreased to 10.4% in ADMIRE 4 (Z=-2.051, P=0.040) and 14.0% in ADMIRE 5 (Z=-2.718, P=0.007) based on FBP. High ADMIRE strength affected the volume score and Agatston score due to the decrease in calcium area. In addition, the change in the Density factor due to the decrease in Maximum HU may affect the calculation of the Agatston score.

• Journal of the Korean Society of Radiology
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• v.15 no.7
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• pp.1031-1040
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• 2021

In this study, the actual condition of ultrasound examination was conducted for radiological technologist working across the country. The measuring tool of the study was a questionnaire, and it was targeted to radiological technologist engaged in ultrasound examination at medical institutions located across the country from February 01 to July 31, 2021. In consideration of the COVID-19 situation, 431 questionnaires suitable for research were analyzed using the SPSS/PC Ver 18.0 program using email and SNS in a non-face-to-face manner. The general characteristics of study subjects, ultrasound examination job characteristics, and job satisfaction factors were analyzed using descriptive statistics. As a result of analyzing the job characteristics of radiological technologist who perform ultrasound examination as overall job satisfaction, the overall job satisfaction was 3.30 ± 0.56. The job satisfaction level of radiological technologist performing ultrasound examinations was higher than the average of 3.0 points, indicating a higher job satisfaction level than the average. Since insurance coverage for ultrasound examinations started, many radiological technologists have been very interested in ultrasound examination work. Therefore, the Korean radiological technologists of Association and radiological technolgists engaged in ultrasound examination more attention and effort should be put into strengthening professionalism.