• Journal of the Korean Society of Radiology
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• v.16 no.3
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• pp.217-223
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• 2022

In this study, images taken using a grid and images taken using Air Gap Technique were evaluated in X-ray chest radiography. Subjective Evaluation The ROC (Receiver Operating Characteristic) evaluation was evaluated by 5 radiologists who had worked for more than 10 years in the radiology department of a university hospital. Objective evaluation SNR (Signal to noise ratio) was evaluated. As a result of the analysis, the Cronbach Alpha value was 0.714, which was significantly higher. In the Air Gap Technique, the distance between the phantom and the subject was set at 20 cm, and the image was taken with a tube voltage of 100 kVp, a tube current and a recording time of 8 mAs. In the ROC (Receiver Operating Characteristic) evaluation, the highest score was obtained with 18 score and an objective evaluation SNR (signal to noise ratio) of 6,149 scored. Also, in the imaging method using a grid, when the distance between the phantom and the constant receptor is 15 cm apart, and the tube voltage is 110 kVp, the tube current and the recording time are taken at 8 mAs, the ROC evaluation score is 19 and the objective evaluation SNR (Signal to noise ratio) is the highest with 6.622 scored. Therefore, if the Air Gap Technique imaging method is used, which overcomes the shortcomings such as delay in reading, increase in patient's exposure dose, and shortening of mechanical lifespan, as well as re-radiography due to the cut-off phenomenon of the grid that appears using the grid, the It is thought that it will be very helpful for chest imaging, including the case of using a portable X-ray imaging device.

• Korean Journal of Digital Imaging in Medicine
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• v.9 no.1
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• pp.37-43
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• 2007

1. Purpose : This study is to present effective exposure conditions to acquire the best image of simple abdomen in Film Screen (F.S) system and Computed Radiography (C.R) system. 2. Method : In the F.S system, while an exposure condition was fixed as 70kVp, images of a patients simple abdomen were taken under the different mAs exposure conditions. Among these images, the best one was chosen by radiologists and radiological technologists. In the C.R system, the best image of the same patient was acquired with the same method from the F.S system. Both characteristic curves from F.S system and C.R system were analyzed. 3. Results : In the F.S system, the best exposure condition of simple abdomen was 70kVp and 20mAs. In the CR system, with the fixed condition at 70kVp, the image densities of human organs, such as liver, kidney, spleen, psoas muscle, lumbar spine body and iliac crest, were almost same despite different environments (3.2mAs, 8mAs, 12mAs, 16mAs and 20mAs). However, when the exposure conditions were over or under (below) 12mAs, the images between the abdominal wall and the directly exposed part became blurred because the gap of density was decreased. In the C.R system, while the volume of mAs was decreased, an artifact of quantum mottle was increased. 4. Conclusion : This study shows that the exposure condition in the C.R system can be reduced 40% than in the F.S system. This paper concluded that when the exposure conditions are set in CR environment, after the analysis of equipment character, such as image processing system(EDR : Exposure Data Recognition processing), PACS and so on, the high quality of image with maximum information can be acquired with a minimum exposure dose.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.725-733
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• 2023

The purpose of this study is to evaluate the effectiveness of virtual grid software (VGS). The purpose of this study is to evaluate the changes in energy and object thickness by dividing the use of VGS into two cases (Without-VGS) without using a movable grid. We attempted to determine the effectiveness of VGS by acquiring images using a chest phantom and a thigh phantom and analyzing SNR and CNR. In the chest phantom and femoral phantom, the tube flow was fixed at 2.5 mAs, and the tube voltage was changed by 10 kVp from 60 to 100 kVp to measure SNR and CNR, and SNR was about 1.09 to 8.86% higher in the chest phantom than in Without-VGS, and CNR was 4.18 to 14.56% higher in the VGS than in Without-VGS. And in the femoral phantom, SNR was about 9.78 to 18.05% higher in VGS than in Without-VGS, and CNR was 21.07 to 44.44% higher in VGS than in Without-VGS. The tube voltage was fixed at 70 kVp in the chest phantom and the femoral phantom, and the amount of tube current was changed at 2.5 to 16 mAs, respectively, and after X-ray irradiation, SNR and CNR were measured in the chest phantom, which was about 1.49 to 11.11% higher in VGS than in Without-VGS, and CNR was 4.76 to 13.40% higher in VGS than in Without-VGS. And in the femoral phantom, SNR was about 2.22 to 17.38% higher in VGS than in Without-VGS, and CNR was 13.85 to 40.46% higher in VGS than in Without-VGS. Therefore, if an inspection is required with a mobile X-ray imaging device, it is believed that good image quality can be obtained by using VGS in an environment where it is difficult to use a mobile grid, and it is believed that the use of mobile X-ray devices can be increased.

• Pediatric Infection and Vaccine
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• v.11 no.1
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• pp.59-72
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• 2004

Purpose : Rotaviruses are the major cause of gastroenteritis in infants and young children worldwide. It is important to get the epidemiologic data of rotavirus genotype for the application of rotavirus vaccine. So we tried to investigate the distribution of rotavirus genotypes with RT-PCR. Methods : A total of 120 rotavirus latex agglutinin test positive stool samples were collected continually from 120 children from Sep. 2000 to Apr. 2001. Rotavirus P(VP4), G (VP7) genotypes were determined by RT-PCR. Results : The genotype was identified in 116 stool samples of total 120 samples(96%). The incidence of G genotype was as follow; G1 17(14.2%), G2 74(61.7%), G4 1(0.8%), G9 1(0.8%). There were four cases of multiple genotypes; G1/G2, G1/G4, G1/G9, G8/G9 and genotype of G3, G8 were not found. Twenty three(19.2%) samples were nontypeable. The incidence of P was as follow; P[4] 77(64.2%), P[6] 22(18.3%), P4/P6 12(10%), P[4]/P[8] 1(0.8%) p[8] 1(0.8%). Seven(5.9%) samples were nontypeable. Conclusion : Various combinations of G and P genotypes were observed. Most rotavirus strains were P[4]G2 62(51.74%), followed by P[6]G2 7(5.8%), and P[6]G1 7(5.8%), P[4/P[6] G1 4(3%), P[4]/P[6]G2 4(3%), P[4]G1 3(2.5%), P[8]G2 1(0.8%), P[4]G4 1(0.8%) in Kyoungsangnamdo, Korea during 2000~2001.

• Advances in pediatric surgery
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• v.16 no.2
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• pp.196-202
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• 2010

Abdominal cerebrospinal fluid pseudocyst is an uncommon complication of ventriculoperitoneal shunt (VPS) performed for hydrocephalus. The incidence of VPS complications in children is higher than in adults. There are controversies and difficulties in the treatment of the abdominal pseudocyst. We report a case of abdominal pseudocyst complicating VPS in a boy. Partial excision of pseudocyst and replacement of the VP shunt were effective during a followup of 18 months postoperatively with no recurrence.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.2
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• pp.10-17
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• 2009

Transillumination system used by radiation is widely applied to industrial imaging system. In this study, the linear detector array constructed with scintillator and pin diode, and a multi-channel data acquisition system was developed for precision inspection of end-milling. The detector module consists of $16-CdWO_4$crystal scintillator and photodiode array. The detector and data acquisition system was applied to precision inspection of end-mill and the images of the end-mill were successfully reconstructed. The total system can analyze the Detector Quantum Efficiency(DQE) of each system. The performance of developed photodiodes equipment was compared with each other for different crystal geometry and its characteristics. Finally fine details of the end-mill phantom were constructed for industrial application. The image acquired contains several objects on a real time data transfer and the linear X-ray scanning system can be applied to many fields of a industry.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.9
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• pp.130-139
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• 2007

The disaster from functional gastrointestinal disorders (FGID) has detrimental impact on the quality of life of the affected population. There are, however, rare diagnostic methods for FGID. Our research group identified recently that the gastrointestinal tract well of the patients with FGID became more rigid than that of healthy people when palpating the abdominal regions overlaying the gastrointestinal tract. The objective of the current study is, therefore, to identify feasibility of a diagnostic system for FGID based on ultrasound technique, which can quantify the characteristics above. Two-dimensional finite difference (FD) models (one normal and two rigid models) were developed to analyze the reflective characteristic (displacement) on each soft-tissue layer responded after application of ultrasound signals. Based on the results from FD analysis, the ultrasound system for diagnosis of the FGID was developed and clinically tested via application of it to 40 human subjects with/without FGID who were assigned to Normal and Patient Groups. The results from FD analysis showed that the maximum displacement amplitude in the rigid models (0.12 and 0.16) at the interface between the fat and muscle layers was explicitly less than that in the normal model (0.29). The results from actual specimens showed that the maximum amplitude of the ultrasound reflective signal in the rigid models $(0.2{\pm}0.1Vp-p)$ at the interface between the fat and muscle layers was explicitly higher than that in the normal model $(0.1{\pm}0.0Vp-p)$. Clinical tests using our customized ultrasound system showed that the maximum amplitudes of the ultrasound reflective signals near to the gastrointestinal tract well for the patient group $(2.6{\pm}0.3Vp-p)$ were generally higher than those in normal group $(0.1{\pm}0.2Vp-p)$. These findings suggest that our customized ultrasound system using the ultrasound reflective signal may be helpful to the diagnosis of the FGID.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.1
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• pp.26-30
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• 2009

Background and Objectives: To determine the anatomic position of the inferior alveolar nerve (IAN) canal in patients with mandibular prognathism using the cone-beam CT (CBCT). Materials and Methods: Fifty rami from 25 patients were evaluated. The images were taken by i-CAT and reconstructed 3-dimensionally using the Simplant 11 program. The linear distances between the IAN canal to the buccal cortex (a, $a^{\dag}$ and $a^{\ddag}$), from the IAN canal to the alveolar crest (b and $b^{\dag}$) and the anterior margin ($b^{\ddag}$) and finally the buccal cortical thickness (c, $c^{\dag}$ and $c^{\ddag}$) were measured at three reference planes (VP, OP and HP). Results: On the left side, the average distance of a, b and c were 7.12, 15.96 and 3.60 mm on the VP plane, respectively. On the OP, the distance of $a^{\dag}$, $b^{\dag}$ and $c^{\dag}$ was 6.11, 8.83 and 2.63 mm. For the HP, the distance of $a^{\ddag}$, $b^{\ddag}$ and $c^{\ddag}$ was 4.84, 10.11 and 2.30 mm. On the right side, the distance of a, b and c, on the VP, was 7.10, 16.13 and 3.42 mm, respectively. On the OP, the distance of $a^{\dag}$, $b^{\dag}$ and $c^{\dag}$ was 4.77, 8.75 and 2.68 mm. On the HP, the distance of $a^{\dag}$, $b^{\dag}$ and $c^{\ddag}$ was 4.55, 9.84 and 2.38 mm. Regarding the difference between genders, the distance in male's was longer than female's on the VP (p=0.019), and was thicker in males than females on the HP (p=0.002). Conclusion: The CBCT data provided accurate information about the location and course of the IAN.

• Journal of the Korean Society of Radiology
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• v.11 no.6
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• pp.423-428
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• 2017

In this study, the calculation of the effective spatial dose distribution of the diagnostic imaging laboratory of K university was performed by the Monte Carlo simulation. The radiation generator has a maximum tube voltage of 150 kVp and a maximum current of 700 mA. Using the results, we compared the spatial effective dose distributions of diagnostic imaging laboratory when the shielding door was closed and opened. In conclusion, it was found that the effective dose in the operating room of the diagnostic imaging laboratory does not exceed the annual dose limit (6 mSv/y) of the student (occasional visitor) even when the door is opened. However, since the effective dose when the door is open is about 16 times higher in front of the lead glass window and about 3,000 times higher in front of the doorway than the case when the door is closed, closing the shielding door at the time of the practical exercising reduces unnecessary radiation exposure by great extent.

• YAKHAK HOEJI
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• v.35 no.3
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• pp.203-215
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• 1991

Using the calorimetric [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT)assay, we evaluated the chemosensitivity of 8 anticancer drugs{vincristine(VCR), vinblastine(VBL), adriamycin(ADR), cisplatin(CPDD), etoposide(VP-16), cytosine arabinoside(ara-C), bleomycin (Bleo) and cyclophosphamide(CYC)} and the cytotoxicity-enhancing effects of ($\pm$)-ar-turmerone and the extracts of the crude drugs {Lithospermum eythrorhizon(LE) and Scutellaria baicalensis (SB)} on the above mentioned anticancer drugs against HL-60 and KG-1 cells among 8 anticancer drugs, VCR, VBL, ADR, and CPDD inhibited the growth of both cell lines by more than 50%, while VP-16, ara-C, Bleo, and CYC were less effective. ($\pm$)-ar-Turmerone had significant inhibitory effects against both cell lines, showing the ID$_{50}$ values of 11.730 $\mu\textrm{g}$/ml and 0.292 $\mu\textrm{g}$/ml for HL-60 and KG-1 cells. respectively. But the extracts of LE and SB roots showed no significant cytotoxic effects. According to ID$_{50}$ values, the cytotoxicities of VCR, VBL and ADR against HL-60 were enhanced two, eight and three times by mixing ($\pm$)-ar-turmerone, five, seven and three times by adding the extract of LE root, and twenty, six and three times by mixing the extract of SB root, respectively. The cytotoxicities of the above mentioned drugs against KG-1 cell were enhanced two, seven and three times by mixing ($\pm$)-ar-turmerone, two, three and three times by combining wilth the extract of LB root, and two, five and two times by adding the extract of SB root, respectively. The cytotoxicity-potentiating effects of ($\pm$)-ar-turmerone and the extracts of LE and SB roots against HL-60 cell were greater than KG-1 cell.