• Journal of the Korean Society of Radiology
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• v.10 no.5
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• pp.359-365
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• 2016

Fluoroscopy is performed when tissue or organ in the human body is examined, and it is used for diagnosis and procedure in back ailments. With regard to fluoroscopy equipment, distortion occurs on the peripheral part of fluoroscopic image rather than on its central part. This study measured distortion factors of vertical spacing ratio and distortion factor of diagonal spacing ratio before and after correction by applying a correction algorithm. According to measuring the vertical spacing ratio, post-correction standard deviation decreased by 0.04 in comparison with pre-correction one. Also measuring the diagonal spacing ratio, post-correction standard deviation decreased by 0.06 in comparison with pre-correction one. Consequently, the distortion of fluoroscopic image decreased after correction. A decrease in the distortion of image through the application of correction algorithm and the improvement of performance will be helpful in finding a correct position of lumbar puncture in nucleoplasty to treat lumbar disc herniation in the future.

• Journal of the Korean Society of Radiology
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• v.14 no.3
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• pp.313-318
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• 2020

Since radon is an inert gas and is a monoatomic molecule, the size of one particle represents the size of an atom, which means that it has a radius of approximately 1 to 100 nm. Therefore, if the mask has a radius smaller than the size of general fine dust and ultra fine dust, but it is possible to block the inhalation of radon more than a certain amount, it is considered that the exposure through the inhalation of radon can be reduced through normal indoor wear. Accordingly, we would like to find out the radon blocking effect of a mask worn in everyday life. Looking at the reduction rate of radon for each mask, cotton masks decreased by 33.45%, medical masks by 33.50%, KF 80 masks by 35.12%, and KF 94 masks by 37.72%. It was found that the radon blocking effect of the cotton and medical masks was somewhat inferior to that of the KF mask, but the difference was not so great that the introduction of radon into the air could be blocked to a certain level by wearing a mask.

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.383-389
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• 2011

This study offered a new method to calculate absorbed dose of actual patients through Monte Carlo Simulation by using the linkage of Geant4 and DICOM, and, the experimental value of absorbed dose at the center and Geant 4 simulation result according to the depth of PMMA mock phantom were compared by using MOSEF in order to verify Geant4 calculation code. In the area where there was no air space between the irregular gap due to incomplete compression of PMMA slab, the differences were $0.46{\pm}4.69$ percent and $-0.75{\pm}5.19$percent in $15{\times}15cm^2$ and $20{\times}20cm^2$ respectively. Excluding the error due to incomplete compression of PMMA mock phantom, the calculation values of the Monte Carlo simulation by linkage of Geant4 and DICOM was the same.

• Journal of the Korean Society of Radiology
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• v.9 no.2
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• pp.117-120
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• 2015

The number of campers has been consistently growing thanks to the introduction of a five-day work week and the time increase for a leisure. Thus, many types of facilities for camping are constructed. For instance, there are gravel camp site, which is called crushed stone, and normal soil camp site in case of private camp sites. The amount of natural background radiation, measured from site to site, was analyzed. The value of soil camp site was lower than that of crushed stone camp site. And the amount of natural background radiation from normal camp site was also lower than that from the artificial shade made by tarp. Consequently, it is noted that normal soil camp site with the plenty of woods should be chosen for camping place in order to avoid natural background radiation.

• Journal of the Korean Society of Radiology
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• v.6 no.6
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• pp.477-481
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• 2012

An X-ray diffractometer which has various X-ray optics can give qualitative and quantitative information for a sample using a nondestructive analysis method. A parallel beam optic passes the parallel beam and removes divergent beam generated from an X-ray tube. The parallel beam optic used in the X-ray diffractometer was fabricated by wire cut and grading of stainless steel plates and was evaluated its performance using an X-ray imaging system. The measured parallelization of 6.6 mrad for the fabricated the parallel beam optic was a very close to the expected value of 6 mrad. An X-ray imaging technique for evaluating the parallel beam optics can estimate parallelization for each plate and can be used to other X-ray optics.

• Journal of the Korean Society of Radiology
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• v.2 no.1
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• pp.5-10
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• 2008

This study developed a PDA based wireless communication radiation measuring instrument using Bluetooth. The proposed system is composed of Student Radiation Monitor of Vernier using GM (Geiger Mueller) counter tube as a radiation measuring sensor, LabPro of Vernier as a module for data collection, Promi SD 101 of Initium, which can make Bluetooth communication up to 30 m, for wireless data transmission, and HP 5550 embedded with Pocket PC 2003 as OS for data storage and display. Because GM counter tube is used as a radiation measuring sensor, the system cannot measure radiation energy but measures count volume and count rate. When the result of natural radiation measuring by the PDA based system was compared with that by a PC based system, it was found that the proposed system transmits and receives data without distortion.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.691-698
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• 2019

The patients who visited the Health Promotion Center were compared between the visceral fat area according to CT fat measurement position and the visceral fat area measured by Inbody. In the CT measurement, the visceral fat area measured at the L4-5 and CT Umbilicus positions was not different regardless of gender. In addition, there was no difference between CT visceral fat area and Inbody visceral fat area in the correlation between visceral fat area according to CT measurement position and visceral fat area measured by Inbody. The highly correlated CT measurement position were male L4-5, L5-S1, female L3-4, L4-5, L5-S1, and Umbilicus. In addition, when studying the relationship between the inbody visceral fat area and CT visceral fat area regardless of gender, it is suggested to compare the visceral fat area at the CT L4-5 position.

• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.833-839
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• 2021

The Possibility of Denuclearization Verification of Korean peninsula is mentioned. Considering the geographical and linguistic advantages, it is necessary to show willingness to participate in the denuclearization verification. In this study, investigation about nuclear facilities, characteristic of facilities, core resource, operation history, geographic/weather environment were performed. Transport route accessibility analysis and risk analysis for development of transport scenario were performed. Accessibility analysis was classified into airport, port, and vehicle transport. Distance by route, estimated time required, and transit roads were analyzed. In this process, it was possible to confirm the suitability of the vehicle transport scenario. Through follow-up studies, we intend to develop an optimal transport scenario.

• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.227-232
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• 2019

MRI examination for patients with metal objects has in poor image quality. Metallic implants can result in poor image because magnetic susceptibility causes signal loss and distortion and makes poor imaging, which is called magnetic susceptibility artifact or metal artifact. There are several approaches to reduce metal artifacts. In this study, we study the reduction of metal artifact by VAT and SEMAC techniques. A metal implant used for orthopedic surgery was attached to the phatom and the distortion caused by the artifact was measured under T1WI and T2WI protocols. Several techniques of VAT only and VAT and SEMAC for the reduction of metal artifact were compared. The metal artifact showed a reduction of at least 8% to a maximum of 26% in the VAT-SEMAC. The VAT-SEMAC technique can be applied to patients with orthopedic implants to improve image quality. If scan time and image quality are simultaneously considered in VAT-SEMAC technique, metal artifact will be reduced in clinical practice.

• Journal of the Korean Society of Radiology
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• v.16 no.3
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• pp.289-294
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• 2022

In this study, the accuracy and usefulness of volume measurement were investigated as a phantom experiment using CT and USG scan data and a clinical trial using patient scan data. As a result, there was no significant difference between the volume of the actual round phantom of various volumes for both the CT and ultrasound devices (p>0.05). As a result of statistical analysis, it was analyzed that there was no significant difference (p>0.05). Clinical application of this result requires more clinical trials, but if a CT or ultrasound device is selected and applied in consideration of patient radiation exposure, the examiner's scanning technology, and CT reconstruction experience, the basic data in terms of the usefulness of volume measurement using CT scan image is considered to have application value.