• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.827-833
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• 2023

CT(Computed Tomography) contrast agents are commonly used in general hospitals and university hospitals when taking radiographic examinations. The CT contrast medium contains a mixture of a substance called "Iodine", which absorbs radiation energy and makes it appear white in the CT image, further improving the image quality. In addition, the CT contrast agent, which moves like blood in the blood vessels, clearly differentiates it from muscle and water, so CT contrast agents are widely used in hospitals. These CT contrast agents absorb X-rays, but in order to absorb X-rays, they must have a high density or a high radiation absorption coefficient. Since the CT contrast agent is injected into the blood vessels, if the density is high, the blood vessels are strained and the patient is in shock. For this reason, it is necessary to match the density similar to that of water and always pay attention to side effects. In addition, the amount of CT contrast medium is adjusted according to the patient's body shape, and the remaining contrast medium is discarded. However, This study tried to find out the idea of recycling it as a radiation shielding material. Since the CT contrast medium has a high radiation absorption coefficient at a density similar to that of water, the amount to absorb radiation is adjusted, the amount of contrast medium and the amount of water are adjusted, and the amount of radiation absorbed is determined by mixing with water. In addition, a study was conducted to find out the result of the difference in radiation absorption in various ways by comparing the radiation quality coefficient and absorption coefficient with other substances or materials in an environmentally friendly method harmless to the human body by mixing CT contrast medium and water.

• Progress in Medical Physics
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• v.12 no.2
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• pp.155-160
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• 2001

We developed a new method that the radiation field shape and intensity could be controlled automatically with a insertion of the liquid shielding material box having a rotatable model imitated the 3-dimensional target volume within. The molded box filled with the mercury was mounted to the tray. A acrylic model imitated the 3-dimensional target volume was fixed into the center of the interior of the box. Although the gentry rotate, the acrylic model can be returned to the original direction of the target due to the action of the gravity. The film measurements at the gantry rotation angle 0$^{\circ}$, 45$^{\circ}$, and 90$^{\circ}$, respectively were shown that the radiation intensities were modulated properly and the field shapes were conformed to the target. We verified the dose distribution for our method with a cylindrical acrylic phantom inserted a film within. In the case of the 8-field irradiation, the 80% isodose line was enclosed the target shape properly. This results show the realization of a new intensity-modulated radiation therapy(IMRT).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.807-810
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• 2003

금속 평행판 전극 사이에 주입된 액체 유전체의 움직임에 의해서 발생되는 차동 전기용량 변화를 이용하여 기울기 측정센서를 개발하였다. 기울기 $0^{\circ}{\sim}{\pm}90^{\circ}$의 범위에서 직선에 대한 상관계수가 0.999 99로 분석이 되어 우수한 선형성을 보였다. 센서의 전극구조를 완벽한 3-전극형 전기용량기로 설계하였기 때문에 외부로부터의 전자기 잡음 및 전기장의 영향에 관계없이 기울기를 정밀하게 측정할 수 있었다. 또한 안정된 디지털 출력을 이용하여 기울기의 정밀측정 뿐만 아니라 장치나 구조물 등의 기울기를 원격조정 또는 monitoring에도 적용이 가능하다.

• Clean Technology
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• v.14 no.2
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• pp.110-116
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• 2008

The radioactive wastes generated from the nuclear industry can be divided into the forms of solid, liquid, or gas. Radioactive methyl iodide, a gaseous radioactive waste, is absorbed by activated carbon with 5 wt% of Trietylenediamine (1,4-diazania-bicycle[2.2.2]octane, TEDA) impregnated on the surface. Methyl Iodide ($CH_3I$) is combined chemically with TEDA (the final product : I-TEDA). To recycle radioactive activated carbon, removal of I-TEDA from activated carbon is needed. A wet method for recycling impregnated active carbon was developed to remove radioactive I-TEDA using an acetonitrile solution, which produces lots of secondary wastes. We suggest the removal of I-TEDA by supercritical carbon dioxide with co-solvents. In this experiment, we used a quartz crystal microbalance (QCM) for measuring the removal rate of the I-TEDA. From the experimental results, methanol was found to be the optimum co-solvent, and the optimum conditions such as temperature, pressure, and co-solvent flow rate were obtained. Possibility of using supercritical fluid in the removal of I-TEDA from radioactive activated carbon was also discussed.