• Korean Journal of Radiology
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• v.20 no.5
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• pp.844-853
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• 2019

Objective: To evaluate the learning curve for C-arm cone-beam computed tomography (CBCT) virtual navigation-guided percutaneous transthoracic needle biopsy (PTNB) and to determine the amount of experience needed to develop appropriate skills for this procedure using cumulative summation (CUSUM). Materials and Methods: We retrospectively reviewed 2042 CBCT virtual navigation-guided PTNBs performed by 7 novice operators between March 2011 and December 2014. Learning curves for CBCT virtual navigation-guided PTNB with respect to its diagnostic performance and the occurrence of biopsy-related pneumothorax were analyzed using standard and risk-adjusted CUSUM (RA-CUSUM). Acceptable failure rates were determined as 0.06 for diagnostic failure and 0.25 for PTNB-related pneumothorax. Results: Standard CUSUM indicated that 6 of the 7 operators achieved an acceptable diagnostic failure rate after a median of 105 PTNB procedures (95% confidence interval [CI], 14-240), and 6 of the operators achieved acceptable pneumothorax occurrence rate after a median of 79 PTNB procedures (95% CI, 27-155). RA-CUSUM showed that 93 (95% CI, 39-142) and 80 (95% CI, 38-127) PTNB procedures were required to achieve acceptable diagnostic performance and pneumothorax occurrence, respectively. Conclusion: The novice operators' skills in performing CBCT virtual navigation-guided PTNBs improved with increasing experience over a wide range of learning periods.

• Journal of the Korean Society of Radiology
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• v.81 no.3
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• pp.577-582
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• 2020

The Korean Society of Radiology and the Korean Society of Thoracic Radiology have prepared recommendations for the use of diagnostic imaging for COVID-19 in various clinical scenarios. We have tried to grasp the situation in the real world, aggregated opinions from the chest radiologists, and reviewed available references, in order to suggest the most reasonable recommendations possible at this moment. As circumstances change and new evidences emerge, the recommendations should immediately be modified accordingly.

• Proceedings of the Korean Society of Medical Physics Conference
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• 1999.11a
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• pp.238-239
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• 1999

• Journal of radiological science and technology
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• v.21 no.1
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• pp.35-39
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• 1998

We analyzed image factors to determine the characteristic factors that need for intelligent replenishment system of the auto film processor. We processed the serial 300 sheets of radiographic films of chest phantom without replenishment of developing and fixation replenisher. We took the digital data by using film digitizer which scaned the films and automatically summed up the pixel values of the films. We analyzed characteristic curves, average gradients and relative speeds of individual film using densitometer and step densitometry. We also evaluated the pH of developer, fixer, and washer fluid with digital pH meter. Fixer residual rate and washing effect were measured by densitometer using the reagent methods. There was no significant reduction of the digital density numbers of the serial films without replenishment of developer and fixer. The average gradients were gradually decreased by 0.02 and relative speeds were also gradually decreased by 6.96% relative to initial standard step-densitometric measurement. The pHs of developer and fixer were reflected the inactivation of each fluid. The fixer residual rates and washing effects after processing each 25 sheets of films were in the normal range. We suggest that the digital data are not reliable due to limitation of the hardware and software of the film digitizer. We conclude that average gradient and relative speed which mean the film's contrast and sensitivity respectively are reliable factors for determining the need for the replenishment of the auto film processor. We need more study of simpler equations and programming for more intelligent replenishment system of the auto film processor.

• Journal of The Korean Radiological Technologist Association
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• v.25 no.1
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• pp.33-34
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• 1999

As a result of execution of study through questionaries conerning the actual status of working being done by radiologises of the diagnostic radiation department, making 171 radioists who responded mon 200 radiogists City as of October 1998, as the subject

• Journal of The Korean Radiological Technologist Association
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• v.25 no.1
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• pp.264-274
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• 1999

As a result of execution of study through questionaires conerning the actual status of working being done by radiotechnologists of the diagnostic radiation department, making 171 radiotechnologists who responded among 200 radiotechnologists City as of Oct

• Journal of The Korean Radiological Technologist Association
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• v.28 no.1
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• pp.120-144
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• 2002

Purpose The quality assurance in a computed tomography gives a definition to be all the activity so as to optimize the performance of the device and keep an invariable quality of image, and it is to raise a high diagnostic efficiency to obtain a much info

• Journal of The Korean Radiological Technologist Association
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• v.28 no.1
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• pp.74-82
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• 2002

1. Purpose Presently, the service areas of those who we engaged in radiation works are being specialized. Thus, in this study, we propose a way for efficiently improving mutual relationship between the works of the radiation technicians(radiologists) and

• Imaging Science in Dentistry
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• v.34 no.1
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• pp.19-23
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• 2004

Purpose: To compare the diagnostic accuracy of Kodak Insight film with other intra-oral films in the detection of dental caries. Materials and Methods : Periapical radiographs of 99 extracted human teeth with sound proximal surfaces and interproximal artificial cavities were made on Kodak Ultra speed, Ektaspeed, Agfa Ektaspeed and Kodak Insight films and automatically processed. Six dentists examined the presence of dental caries using a five-point confidence rating scale and compared the diagnostic accuracy by ROC (Receiver Operating Characteristic) analysis and ANOVA test. Results: The sensitivity of Kodak Ultra speed, Ektaspeed, Agfa Ektaspeed and Insight film were 0.84, 0.77, 0.75 and 0.79 respectively. The specificity of Kodak Ultra speed, Ektaspeed, Agfa Ektaspeed and Insight film were 0.97. 0.95. 0.96 and 0.94 respectively. The mean ROC areas (Az) of Kodak Ultra speed, Ektaspeed, Agfa Ektaspeed and Insight film were 0.917, 0.910, 0.894, 0.909 respectively. There was no significant differences between Az of Insight film and other films (p = 0.178). Conclusion: Theses results suggested that Kodak Insight film have the comparative diagnostic accuracy of dental caries with Ultraspeed and Ektaspeed films.

• Korean Journal of Radiology
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• v.23 no.8
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• pp.777-784
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• 2022