• Journal of radiological science and technology
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• v.45 no.1
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• pp.1-9
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• 2022

In this study, we proposed an image quality control for an automatic exposure control (AEC) of digital radiographic imaging system and tried to analyze the performance of the AEC by various manufacturer. The subjects of the experiment were analyzed for the AEC image quality evaluation using digital radiation generators from four manufacturer such as PHILIPS, GE Healthcare, SAMSUNG Healthcare, DK Medical Solution. We used as materials for the implementation of the image quality evaluation by coins (500 won, KOMSCO, Korea). This study evaluated the performance evaluation of the AEC as image quality and exposure dose (Milliampere-seconds; mAs). The image quality evaluation was tried visual assessment by two radiologic technologists and contrast to noise (CNR) by ImageJ. The exposure dose investigated mAs on digital radiation generators. The radiographic coin images acquired 360 images based on change in the control factors of the AEC, which were kVp, the consistency of field configuration and dominant zone, sensitivity and density. As a result, there was a significant difference in the AEC performance between manufacturer. The CNR by the AEC for each manufacturer showed a difference of up to about 1.9 times. The exposed tube current by the AEC for each manufacturer showed a difference of up to about 5.8 times. It is expected that our proposed evaluation method using coins could be applied as the AEC performance evaluation method in the future.

• Journal of radiological science and technology
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• v.46 no.2
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• pp.151-157
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• 2023

The purpose of this study was to develop an assist device that could correct and support patient position during biopsy on computed tomography (CT) using 3D printing technology. The development method was conducted in the order of 3D design, 3D output, intermediate evaluation for product, final assist device evaluation. The 3D design method was conducted in the order of prior research data survey, measurement, primary modeling, 3D printing, output evaluation, and supplementary modeling. The 3D output was the 3D printer (3DWOX 2X, Sindoh, Korea) with additive manufacturing technology and the polylactic acid (PLA) materials. At this time, the optimal strength was evaluated to infill degree of product as the 3D printing factors into 20%, 40%, 60%, and 80%. The intermediate evaluation and supplementation was measured noise in the region of interest (ROI) around the beam hardening artifact on the CT images. We used 128-channel MDCT (Discovery 75 HD, GE, USA) to scan with a slice thickness of 100 kVp, 150 mA, and 2.5 mm on the 3D printing product. We compared the surrounding noise of the final 3D printing product with the beginning of it. and then the strength of it according to the degree of infill was evaluated. As a result, the surrounding noise of the final and the early devices were measured at an average of 3.3 ± 0.5 HU and 7.1 ± 0.1 HU, respectively, which significantly reduced the noise of the final 3D printing product (p<0.001). We found that the percentage of infill according to the optimal strength was found to be 60%. Finally, development of assist devices for CT biopsy will be able to minimize artifacts and provide convenience to medical staff and patients.

• Journal of the Korean Society of Radiology
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• v.5 no.2
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• pp.59-66
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• 2011

There is a difficulty because of classifying the anatomical structure in the neck CT scan by the beam hardening artifact no more than disease and it including the 6, 7 number cervical spine and intervertebral disk. In case of enforcing the neck CT scan cause of the inner diameter of beam artifact tried to be inquired by the image evaluation according to the change of the image evaluation according to the direction of the shoulder joint applying the variation method of a posture and location and Kernel value and it was most appropriate, the lion tax and Kernel value try to be searched for through an experiment. Somatom Sensation 16 (Siemens, Enlarge, Germany) equipment was used in a patient 30 people coming to the hospital for the neck CT scan. A workstation used the AW 4.4 version (GE, USA). According to a direction and location of the shoulder joint, the patient posture gave a change to the direction of the shoulder joint as the group S it gave a change as three postures and placed the both arms comfortably and helps a group N and augmented unipolar left in the wealthy merchant and group P it memorized the both hands and ordered the eversion and drops below to the utmost and enforced a scan. By using a reconstructing method as the second opinion, it gave and reconstructed the Kernel value a change based on scan data with B 10 (very smooth), B 20 (smooth), B 30 (medium smooth), B 40 (medium), B 50 (medium sharp), B 60 (sharp), and B 70 (very sharp). By using image data which gave the change of the examination posture and change of the Kernel value and are obtained, we analyzed through the noise value measurement and image evaluation of. The outside wire eversion orders the both hands and the examination posture is cost in the neck CT scan with the group P it drops below to the utmost. And in case of when reconstructing with B 40 (medium) or B 50 (medium sharp) being most analyzed into the inappropriate posture and Kernel value and applying the Kernel value to a clinical, it is considered to be very useful.

• Journal of radiological science and technology
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• v.35 no.1
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• pp.51-57
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• 2012

In this experiment, we investigated 82 patients who suffered adverse reactions due to contrast medium. We selected the subjects out of 21,178 people who had an intravenous injection of contrast medium to undergo MDCT examination at one university hospital in Busan in 2007. As a result, the largest groups of the patients were as follows. 52.4% of the patients were male when classify by gender; 28.0% of the patients were 50's by age; 45% of the patients got when it was spring(April and March); 75.6% of the patients had a side effects when the speed of injection is 2.5mL/sec; 58.5% of the patients were suffered when the volume of injected contrast medium is over 130mL. Urticaria was the main symptom of side effect as 26.8%. And the main treatment for the effect was alleviating the symptoms before making patients to return home. Thus, practical preventive measures are needed as follows : use the OCS system to observe warning signs at risky patients, secure warming spaces for patients to cope with season changing, prepare enough emergency kits for the patients in danger, and establish CPR call systems, explain the risk of contrast medium and get agree about using contrast medium.

• Journal of the Korean Society of Radiology
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• v.10 no.6
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• pp.419-425
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• 2016

The purpose of this study is to produce a shielding material to reduce a dose on the genital gland, one of the superficial organs, at a CT scan on the whole abdomen and hardly affect picture quality and examine its utility. This research made 22 mm silicone and 7.3 mm aluminum having the similar material quality and effect of previous bismuth. By using the non-shield, bismuth, 22 mm silicone, and 7.3 mm aluminum shielding materials, this author conducted a comparative experiment measuring the decay rate of the genital gland's exposure to radiation, change of the CT number and noise in the image, and the CT number, noise, and uniformity in the AAPM phantom. According to the results, exposure to radiation is reduced in bismuth as 29.96%, silicone 22 mm as 13.10%, and 7.3 mm aluminum as 18.27%. In bismuth, however, the image's CT number varies a lot, and uniformity is measured to be inappropriate in the AAPM phantom scan; therefore, it indicates great change in terms of picture quality in superficial organs like the genital gland. Concerning superficial organs like the genital gland, if 22 mm silicone and 7.3 mm aluminum are used as shielding materials, it will be helpful in reducing variation in picture quality and also decreasing radiation exposure to radiation.

• Journal of the Korean Society of Radiology
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• v.10 no.6
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• pp.395-401
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• 2016

Upper gastrointestinal series is a diagnostic test that X-ray passes through the stomach after administering contrast media such as barium or gastrografin. Upper gastrointestinal series with an advantage of no side effect except temporary constipation or abdominal pain has been widely used to diagnose diseases of the gastrointestinal system. However, image degradation and diagnostic accuracy frequently occurred when improper movement and breath control were carried out by lack of understanding the overall inspection process for the upper gastrointestinal series. The movie of the upper gastrointestinal series was made for improving inspection accuracy and image quality. The examinees encouraged to see the movie for waiting time before doing upper gastrointestinal series. In this study, image quality and diagnostic accuracy was examined for the effect of the movie about upper gastrointestinal series. 60 patients composed of each 10 people from 30s to 80s were selected randomly among both 2,940 examinees in 2014 and 3,076 examinees in 2015. Image quality was evaluated by the full width at half maximum of profile for each image using the Image J. The measurement of the full width at half maximum showed 0.208 mm and 0.133 mm for after and before seeing the movie. Thus it was verified that the movie education could improve the image quality and diagnostic accuracy for upper gastrointestinal series.

• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.615-621
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• 2018

Recently, various environmentally friendly products have been developed for improving the indoor air quality while pursuing a well-being nature-friendly healthy life as a core value. In this research, we not only solve the problems of existing environmentally friendly paints, but also developed a charcoal composite seats that can reduce radon, which is a natural radioactive substance, and evaluated the reduction effect of radon, formaldehyde and volatile organic compounds. In the charcoal composite seats, a sodium silicate emulsion and charcoal were mixed to prepare an charcoal liquid coating material, and the composite seats was fabricated by air-spray coating method. In order to analyze the hazardous substance reduction performance of the fabricated charcoal composite seats, radon was designed to comply with the Ministry of the Environment standard, formaldehyde and volatile organic compounds were designed to comply with KCL-FIR-1085 standard. As a result of the experiment, the fabricated charcoal composite seats was evaluated as having a radon reduction capability of about 90.8% from 20 hours, formaldehyde and volatile organic compounds were 3 hours, and the reduction capability of 96.7% and 96.6% was found respectively. It is considered that these results can be utilized as basic data at the time of product development for improvement of indoor air quality.

• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.637-643
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• 2018

A depth of interaction(DOI) detector module using a block scintillator and a pixellated scintillator was designed, and layer discrimination ability was calculated using DETECT2000. The block scintillator was used to improve the sensitivity and the spatial resolution was improved by measuring the DOI. The DOI was measured by analyzing the signal characteristics of each channel of the changed distribution of light. The detector module was composed to the block scintillator in the top layer and the pixellated scintillator in the bottom layer, which changes the distribution of light generated from a scintillator interacting with a gamma ray. In the flood image, the top layer was able to acquire the image at the position similar to the position of the bottom layer because the bottom layer consist of the pixellated scintillator. By using the Anger algorithm, the 16 channel signal was reduced to 4 channels to facilitate the analysis of the signal characteristics. The layer discrimination was measured using a simple algorithm and the accuracy was about 84% for each layer. When this detector module is used in preclinical PET, the spatial resolution at the outside of the field of view can be improved by measuring the DOI.

• Journal of the Korean Society of Radiology
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• v.9 no.4
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• pp.239-247
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• 2015

It should be accurate dose calculation to increase the efficiency of radiation therapy, and it is priority to figure out the beam characteristics for this purpose. The target and primary collimator in head components of the linear accelerator have the greatest influence on determining the beam characteristics which is caused by backscatter and it is the factor to consider the shielding structures and equipment management. In this study, we made modeling of the linear accelerator through the Geant4 Monte Carlo simulation and investigated backscatter according to the change of the size and shape in head components. For the scattered electrons, it showed the greatest number of distributions inside of the inner radius at primary collimator. But, for the scattered photons which have the high energy, it was mostly located outside of the inner radius at primary collimator. Scattered positrons showed a small occurrence in about 0.03%. According to the change of the inner radius at primary collimator, it was great changes in the inside of inner radius for all three scattered particles. According to the change of the outer radius at primary collimator, it was shown some considerable effects from more than 60 mm outer radius. It was no significant effect according to the change of target thickness. In this study, we found that backscatter should be considered, and figured out that geometric size and shape of the peripheral components are the factors that influences the backscatter effect.

• Journal of radiological science and technology
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• v.40 no.2
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• pp.213-218
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• 2017

Recently, as the number of high-risk pregnancies increases, the use of new techniques such as Doppler, which have higher acoustic power than in the past, has been increasingly used in prenatal diagnosis and guidelines have been set up by various organizations to prevent excessive exposure. Therefore, in this study, we tried to investigate the temperature change of the body surface for each test mode according to the long time ultrasound examination and to examine the exposure time which is not influenced by the thermal effect. B mode, C mode, and PD mode according to time, and the temperature difference between exposed and unexposed sites were compared. As a result, the B mode showed a significant difference in the temperature change from 10 minutes, 50 minutes after exposed, 20 minutes from the C mode, and 30 minutes from the PD mode (p<0.01). In all three modes, the temperature difference was different (p<0.000), and PD mode was the most sensitive to temperature change. Also, it was found that the temperature rise time was shortened with the increase of the ultrasonic exposure time. Therefore, it is recommended that ultrasonography to observe the embryo or fetus should be used only for diagnostic purposes, avoiding excessive test time.