• Journal of Yeungnam Medical Science
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• 제28권2호
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• pp.173-179
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• 2011

Polymyositis is diffuse, inflammatory myopathy with proximal-muscle weakness due to lymphocyte infiltration to the muscle layer. The exact cause of the muscle weakness is unclear but may be related with an immunologic mechanism. Using high-dose steroid is the treatment of choice for polymyositis. It is difficult to distinguish steroid-resistant polymyositis from steroid myopathy, however, in the course of high-dose steroid therapy. These authors encountered a steroid myopathy patient during polymyositis treatment with high-dose steroid. A 57-year-old woman was diagnosed with polymyositis and was treated with high-dose steroid. Her condition was initially improved, but in the course of the treatment, her symptom was aggravated without increasing the muscle enzymes. Her muscle weakness was improved by reducing the steroid dosage.

• Nutrition Research and Practice
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• 제3권2호
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• pp.122-127
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• 2009

Folate is generally considered as a safe water-soluble vitamin for supplementation. However, we do not have enough information to confirm the potential effects and safety of folate supplementation and the interaction with vitamin $B_{12}$ deficiency. It has been hypothesized that a greater methyl group supply could lead to compensation for vitamin $B_{12}$ deficiency. On this basis, the present study was conducted to examine the effects of high-dose folic acid (FA) supplementation on biomarkers involved in the methionine cycle in vitamin $B_{12}$-deficient rats. Sprague-Dawley rats were fed diets containing either 0 or $100{\mu}g$ (daily dietary requirement) vitamin $B_{12}/kg$ diet with either 2 mg (daily dietary requirement) or 100 mg FA/kg diet for six weeks. Vitamin $B_{12}$-deficiency resulted in increased plasma homocysteine (p<0.01), which was normalized by dietary supplementation of high-dose FA (p<0.01). However, FA supplementation and vitamin $B_{12}$ deficiency did not alter hepatic and brain S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) concentrations and hepatic DNA methylation. These results indicated that supplementation of high-dose FA improved homocysteinemia in vitamin $B_{12}$-deficiency but did not change SAM and SAH, the main biomarkers of methylating reaction.

• 방사선산업학회지
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• 제11권3호
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• pp.123-130
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• 2017

Concerns about high radiation exposure to the hands of radiation workers who may contact with radioactive contamination on surfaces in a nuclear power plant (NPP) had been raised, and the Korean regulatory body required the extremity dose estimation during contact tasks with radioactive materials. Korean NPPs conducted field tests to identify the incident radiation to the hands of radiation workers who may contact with radioactive contamination during maintenance periods. The results showed that the radiation fields for contact tasks are dominated by high energy photons. It was also found that the radiation doses to the hands of radiation workers in Korean NPPs were much less than the annual dose limits for extremities. This approach can be applicable to measure and estimate the extremity dose to the hands of medical workers who handle the radioactive materials in a hospital.

• 방사성폐기물학회지
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• 제21권4호
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• pp.543-558
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• 2023

Currently, Japan is undertaking a nationwide project to measure and map radioactive contamination around Fukushima, as part of the efforts to restore normalcy following the nuclear accident. The Japan Atomic Energy Agency (JAEA) manages the Fukushima Environmental Safety Center, located approximately 20 km north of the Fukushima Daiichi nuclear power plant in Minamisōma City, Fukushima Prefecture. In collaboration with the JAEA, this study involved conducting comparison experiments and analyses with radiation detectors in high radiation environments, a challenging task in Korean environments. Environmental radiation surveys were conducted using three types of detectors: CZT, NaI(Tl), and LaBr₃(Ce), across two contaminated areas. Dose rate values were converted using dose rate conversion factors for each detector type, and dose rate maps were subsequently created and compared. The detectors yielded similar results, demonstrating their feasibility and reliability in high radiation environments. The findings of this study are expected to be a crucial reference for enhancing the verification and supplementation of procedures and methods in future radiation measurements and mobile surveys in high-radiation environments, using these three types of radiation instruments.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.681-688
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• 2022

Dose monitoring in CT patients requires accurate dose estimation but most of the CT dose calculation tools are based on Caucasian computational phantoms. We established a library of organ dose conversion coefficients for Korean adults by using four Korean adult male and two female voxel phantoms combined with Monte Carlo simulation techniques. We calculated organ dose conversion coefficients for head, chest, abdomen and pelvis, and chest-abdomen-pelvis scans, and compared the results with the existing data calculated from Caucasian phantoms. We derived representative organ doses for Korean adults using Korean CT dose surveys combined with the dose conversion coefficients. The organ dose conversion coefficients from the Korean adult phantoms were slightly greater than those of the ICRP reference phantoms: up to 13% for the brain doses in head scans and up to 10% for the dose to the small intestine wall in abdominal scans. We derived Korean representative doses to major organs in head, chest, and AP scans using mean CTDI_vol values extracted from the Korean nationwide surveys conducted in 2008 and 2017. The Korean-specific organ dose conversion coefficients should be useful to readily estimate organ absorbed doses for Korean adult male and female patients undergoing CT scans.

• Toxicological Research
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• 제18권4호
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• pp.375-384
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• 2002

Repeated-dose toxicity of hyrubicin ID6105, a novel anthrarycline anticancer agent, was investigated in Sprague-Dawley rats. ID6105 was injected intravenously to rats at dose levels of 0.04, 0.2 or 1.0 mg/kg/day for 4 week. As a result, there were no dose-related mortality and specific clinical signs of all animals treated with the drug. However body weight gain of both male and female rats treated with a high dose (l.0 mg/kg/day) of ID6105 significantly decreased compared to control. Interestingly, the numbers of RBC and platelets, and concentration of hemoglobin remarkably increased, while protein synthesis was suppressed, which may be related to the atrophy of spleen, thymus and liver. Moreover there were severe lymphocytic depletion in spleen and thymus as well as decrease in the number of hematopoietic cells in bone marrow. Also, degeneration of cardiac muscles and testicular germinal epithelia were observed. Taken together, it is suggested that Long-term administration of ID6105 at high doses over 0.2 mg/kg/day might cause hematopoietic and male reproductive system injuries, in addition to hepatic dysfunction.

• Journal of Radiation Protection and Research
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• 제3권1호
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• pp.6-22
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• 1978

High energy electron beams took effect for tumor radio-therapy, however, had a lot of problems in clinical application because of various conversion factors and complication of physical reactions. Therefor, we had experimentally studied the important properties of high energy electron beams from the linear accelerator, LMR-13, installed in Yonsei Cancer Center. The results of experimental studies on the problems in the 8, 10, 12 Mev electron beam therapy were reported as following. 1. On the measurements of the outputs and absorbed doses, the ionization type dosimeters that had calibrated by $^{90}Sr$ standard source were suitable as under 3% errors for high energy electrons to measure, but measuring doses in small field sizes and the regions of rapid fall off dose with ionization chambers were difficult. 2. The electron energy were measured precisely with energy spectrometer consisted of magnet analyzer and tele-control detector and the practical electron energy was calculated under 5% errors by maximum range of high energy electron beam in the water. 3. The correcting factors of perturbated dose distributions owing to radiation field, energy and material of the treatment cone were checked and described systematically and variation of dose distributions due to inhomogeneous tissues and sloping skin surfaces were completely compensated. 4. The electron beams, using the scatterers; ie., gold, tin, copper, lead, aluminium foils, were adequately diffused and minimizing the bremsstrahlung X-ray induced by the electron energy, irradiation field size and material of scatterers, respectively. 5. Inproving of the dose distribution from the methods of pendulum, slit, grid and focusing irradiations, the therapeutic capacity with limited electron energy could be extended.

• Korean Journal of Radiology
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• 제19권6호
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• pp.1031-1041
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• 2018

Objective: To compare image quality and radiation dose of high-pitch dual-source spiral cardiothoracic computed tomography (CT) between non-electrocardiography (ECG)-synchronized and prospectively ECG-triggered data acquisitions in young children with congenital heart disease. Materials and Methods: Eighty-six children (${\leq}3$ years) with congenital heart disease who underwent high-pitch dual-source spiral cardiothoracic CT were included in this retrospective study. They were divided into two groups (n = 43 for each; group 1 with non-ECG-synchronization and group 2 with prospective ECG triggering). Patient-related parameters, radiation dose, and image quality were compared between the two groups. Results: There were no significant differences in patient-related parameters including age, cross-sectional area, body density, and water-equivalent area between the two groups (p > 0.05). Regarding radiation dose parameters, only volume CT dose index values were significantly different between group 1 ($1.13{\pm}0.09mGy$) and group 2 ($1.07{\pm}0.12mGy$, p < 0.02). Among image quality parameters, significantly higher image noise ($3.8{\pm}0.7$ Hounsfield units [HU] vs. $3.3{\pm}0.6HU$, p < 0.001), significantly lower signal-to-noise ratio ($105.0{\pm}28.9$ vs. $134.1{\pm}44.4$, p = 0.001) and contrast-to-noise ratio ($84.5{\pm}27.2$ vs. $110.1{\pm}43.2$, p = 0.002), and significantly less diaphragm motion artifacts ($3.8{\pm}0.5$ vs. $3.7{\pm}0.4$, p < 0.04) were found in group 1 compared with group 2. Image quality grades of cardiac structures, coronary arteries, ascending aorta, pulmonary trunk, lung markings, and chest wall showed no significant difference between groups (p > 0.05). Conclusion: In high-pitch dual-source spiral pediatric cardiothoracic CT, additional ECG triggering does not substantially reduce motion artifacts in young children with congenital heart disease.

• 한국방사선학회논문지
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• 제17권6호
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• pp.801-808
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• 2023

소아 두부 CT 검사 시 방사선 피폭 최소화와 진단적 가치가 높은 영상을 확보하기 위하여 Volume Axial Mode, High Pitch Mode, Helical Mode 간 피폭 선량과 영상의 비교 분석을 통하여 Volume Axial Mode의 유용성을 평가하였다. 1세 미만의 소아 두부 CT Helical Mode, High Pitch Mode, Volume Axial Mode에서 70, 80, 100 kVp의 관전압에 따라 영상평가와 선량평가를 시행하였다. 영상평가는 각 영상에 ROI를 설정해 SNR과 CNR을 산출하여 영상평가를 진행하였으며 일원배치 분산분석(ONE-WAY ANOVA)을 사용하여 통계적 유의성을 평가하였고, 선량평가는 검사 후 장비에서 직접 제공하는 Dose Report에 표시되는 DLP값을 이용하여 비교 분석하였다. Volume Axial Mode를 사용하여 검사하였을 때, DLP 값은 전체적으로 낮게 나왔고, SNR과 CNR은 각각 ROI와 kVp별 차이를 가졌다. Volume Axial Mode가 다른 Scan Mode와 비교하여 영상의 질을 평가하였을 때, 그 차이 값이 균일하지 않아 특정 Mode가 우수하다고 볼 수 없었으나 선량 측면에서는 가장 피폭선량을 줄일 수 있었다. 또한 Volume Axial Mode의 짧은 스캔 시간과 Table의 이동 없이 제자리에서 검사 할 수 있는 점은 방사선 감수성이 높은 1세 미만 소아 CT검사에서 유용하게 적용된다.

• Radiation Oncology Journal
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• 제1권1호
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• pp.29-36
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• 1983

The treatment of tumors along curved surfaces with stationary electron beams using cone collimation may lead to non-uniform dose distributions due to a varying air gap between the cone surface and patient. For large tumors, more than one port may have to be used in irradiation of the chest wall, often leading to regions of high or low dose at the junction of the adjacent ports. Electron-beam arc therapy may elimination many of these fixed port problems. When treating breast tumors with electrons, the energy of the internal mammary port is usually higher than that of the chest wall port. Bolus is used to increase the skin dose or limit the range of the electrons. We invertiaged the effect of various arc beam parameters in the isodose distributions, and combined into a single arc port for adjacent fixed ports of different electron beam eneries. The higher fixed port energy would be used as the arc beam energy while the beam penetration in the lower energy region would be controlled by a proper thickness of bolus. We obtained the results of following: 1. It is more uniform dose distribution of electron to use rotation than stationary irradiation. 2. Increasing isocenter depth on arc irradiation, increased depth of maximum dose, reduction in surface dose and an increasing penetration of the linear portion of the curve. 3. The deeper penetration of the depth dose curve and higher X-ray background for the smaller field sized. 4. If the isocenter depth increase, the field effect is small. 5. The decreasing arc beam penetration with decreasing isocenter depth and the isocenter depth effect appears at a greater depth as the energy increases. 6. The addition of bolus produces a shift in the penetration that is the same for all depths leaving the shape of the curves unchanged. 7. Lead strips 5 mm thick were placed at both ends of the arc to produce a rapid dose drop-off.