• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.223-230
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• 2023

This study attempted to concider the morphological change of red blood cells after whole body irradiation. Blood samples used red blood cells of white mice and mouse after irradiation. Transmission electron microscope observation results, Anisocytosis was observed in red blood cells 20 days after 5 Gy irradiation. Triangle and tetrapod were observed for small red blood cell types. Poikilocytosis, sickle-shaped Drepanocyte, and Acantocyte were observed in general-sized red blood cells. Schizocyte was observed in red blood cells 20 days after 7 Gy irradiation. Scanning electron microscope observation results, Dacryocyte was observed with microcytes. It was also confirmed that red blood cells were get tangled with each other. In addition, polygonal shapes and half-moon shapes were also observed. In conclusion, it is judged that the modified form of pathological study is more important than the numerical change in the study of red blood cells by radiation exposure. In conclusion, it was confirmed that modified morphological studies are more important than numerical changes in the study of red blood cells by radiation exposure.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.6
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• pp.464-468
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• 2008

Purpose: Effective half life of I-131 ($T_{eff}$) in patients with differentiated thyroid cancer treated by I-131 is must-know value for dose calculation and determination of release time from isolation room. There has been no report about $T_{eff}$ in Koreans. Thus, author tried to measure dose rate without radiation exposure to faculty members and calculated $T_{eff}$. Methods: Probe of radiation survey meter was fixed at the wall of isolation room, and body of survey meter was placed outside the room. With this simple arrangement, author could measure radiation frequently without radiation exposure to faculty members in 68 patient (F=55, M=13, age=$47{\pm}13.7$) treated by I-131 ($3.7{\sim}7.4\;GBq$) for differentiated thyroid cancer from Jan 2006 to Dec 2006. From this data, $T_{eff}$, 48 hr retention rate, and the time necessary to whole body retention of I-131 become less than 1.1 GBq were calculated. Serum creatinine levels were measured before and after thyroid hormone withdrawal. Results: $T_{eff}$ was $15.4{\pm}4.3\;hr$ ($9.4{\sim}32.5\;hr$). There was a loose correlation between $T_{eff}$ and serum creatinine concentration (r=0.45). 48hr retention was $4.9{\pm}4.2%$ ($1{\sim}23%$). Time necessary to whole body retention of I-131 become less than 1.1 GBq was calculated as $47.1{\pm}13.2\;hr$ for 9.25 GBq, $42.1{\pm}11.9\;hr$ for 7.4 GBq, $35.7{\pm}10.0\;hr$ for 5.55 GBq, and $26.7{\pm}7.5\;hr$ for 3.7 GBq dose of I-131. Conclusion: Author successfully measured radiation dose rates in isolated patients treated by high dose of I-131 without radiation exposure to the faculty members with simple arrangement of survey meter probe. Using those data, $T_{eff}$ and some other indices were calculated.

• Journal of the Korean Society of Radiology
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• v.1 no.3
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• pp.23-34
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• 2007

To find how much radiation was exposed the patients who visit emergency room, a measurement study was made for radiation amount toward 200 patients selected randomly among visitors to an emergency room in a university hospital from March 16 to 31st, 2006. The results are as follows ; 1. Among the subjects 50 person(25.0%) were transferred from other hospitals, 24 persons(8.3) come after traffic accident, 50 persons for other accident and 76 persons for general medical care. 2. The average frequency of X-ray taking was calculated as 6.4 time per person among transferred patients, 14.5 times per person among patients with traffic accident and 2.6 times per person among general medical care. 3. The radiation exposure amount by kind of X-ray showed 28.9mGyfor general X-ray diagnosis, 84.2mGy for CT scanning and 1.02mGy for other special radiation study. 4. Average radiation exposure amount was calculated as 24.6mGy by transferred patients, 55.2mGy by patients with traffic accident, 17.1mGy by patients with other accidents and 17.0mGy by general patients. 5. Through the comparison of radiation exposure amount among to subject with maximum allowance threshold by International Commission on X-ray Radium Protection, transferred patients exceeded 6 times than allowance in whole body except extremities and joints, blood forming organ, reproductive system, vitreous body of eye, bone, thyroid gland, skin and etc, Patient suffered from traffic accidents were exposed 10 times more than allowance. In conclusion, the radiation exposure amount during X-rat diagnosis re too much and exceeded allowance standard by International Commission on X-ray Radium Protection. So further study and preventive measure to decrease radiation exposure by patients who visit emergency room.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.58-60
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• 2007

Magnetic Resonance Imaging(MRI) has become a very widely used medical procedur e. Clo.sed and open systems are typically used with static magnetic fields at or below 2 Tesla. BWhole body SAR(specific absorbsion rate) is the value of SAR averaged over the entire body of the patient over any period of 15 minutes. Head SAR is the value of SAR averaged over the head of the patient for any period of 10 minutes. SAR is a measure of the absorption of electromagnetic energy in the body' (typically in watts per kilogram (W/kg)). The normal operating mode comprises values of head SAR not higher than 3 W/kg. The second level controlled operating mode comprises values higher than 3 W/kg. Current FDA guidance limits the SAR in the whole body. including the head to a range of 1.5 to 4.0 W/kg, depending on the patient's clinical condition. SAR, limit restrictions are incorporated in all MRI systems. and domestic' s guidance limits the SAR in a part body. including the head to 3.2w/kg and less. The purpose of this study is to evaluate on change of head SAR in using MRI pulse sequence and to check if exceed 3.2(w/kg) level in domestic a part exposure through measured head SAR. 23 patient's the average head SAR of pulse sequence is that T2WI sagittal is 0.5375. T2WI axial(FSE) is 0.4817, T1WI axial(SE) is, 0.8179. FLAIR axial is 0.4580. GRE axial is 0.0077, Diffusion is 0.0824w/kg. The head SAR exposed per patient was proved 2.3845w/kg less than the international standard. Coefficient of correlation for the relations body weight and SAR or for the relations ETL(echo train length) and SAR is 1 value. Coefficient of correlation for the relations between TR(time to repeat) and SAR is -0.602 value. so SAR increased relative to weight body and ETL. But the relations between TR and SAR is negative definite.

• Progress in Medical Physics
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• v.21 no.2
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• pp.137-144
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• 2010

The purpose of this study was to evaluate the usefulness of reducing of craniofacial radiation dose using automatic exposure control (AEC) technique in the 64 multi-detector computed tomography (MDCT). We used SOMATOM Definition 64 multi-detector CT, and head of whole body phantom (KUPBU-50, Kyoto Kagaku CO. Ltd). The protocol were helical scan method with 120 kVp, 1 sec of rotation time, 5 mm of slice thickness and increment, 250 mm of FOV, $512{\times}512$ of matrix size, $64{\times}0.625\;mm$ of collimation, and 1 of pitch. The evaluation of dose reducing effect was compared the fixed tube current of 350 with AEC technique. The image quality was measured the noise using standard deviation of CT number. The range of craniofacial bone was to mentum end from calvaria apex, which devided three regions: calvaria~superciliary ridge (1 segment), superciliary ridge~acanthion (2 segment), and acanthion~mentum (3 segment). In the fixed tube current technique, CTDIvol was 57.7 mGy, DLP was $640.2\;mGy{\cdot}cm$ in the all regions. The AEC technique was showed that 1 segment were 30.7 mGy of CTDIvol, 340.7 $mGy{\cdot}cm$ of DLP, 2 segment were 46.5 mGy of CTDIvol, $515.0\;mGy{\cdot}cm$ of DLP, and 3 segment were 30.3 mGy of CTDIvol, $337.0\;mGy{\cdot}cm$ of DLP. The standard deviation of CT number was 2.622 with the fixed tube current technique and 3.023 with the AEC technique in the 1 segment, was 3.118 with the fixed tube current technique and 3.379 with the AEC technique in the 2 segment, was 2.670 with the fixed tube current technique and 3.186 with the AEC technique in the 3 segment. The craniofacial radiation dose using AEC Technique in the 64 MDCT was evaluated the usefulness of reducing for the eye, the parotid and thyroid with high radiation sensitivity particularly.

• Journal of Magnetics
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• v.21 no.3
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• pp.442-449
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• 2016

In this paper, an effective numerical analysis method is proposed for calculating dosimetry of the wireless power transfer system operating low-frequency ranges. The finite-difference time-domain (FDTD) method is widely used to analyze bio-electromagnetic field problems, which require high resolution, such as a heterogeneous whole-body voxel human model. However, applying the standard method in the low-frequency band incurs an inordinate number of time steps. We overcome this problem by proposing a modified finite-difference time-domain method which utilizes a quasi-static approximation with the surface equivalence theorem. The analysis results of the simple model by using proposed method are in good agreement with those from a commercial electromagnetic simulator. A simulation of the induced electric fields in a human head voxel model exposed to a wireless power transmission system provides a realistic example of an application of the proposed method. The simulation results of the realistic human model with the proposed method are verified by comparing it with the conventional FDTD method.

• The Korean Journal of Ecology
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• v.24 no.6
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• pp.349-352
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• 2001

The beekeeping pest insect Galleria mellonella larvae(greater wax moth) were reared on an artificial diet contaminated indipendently with cadmium chloride($CdCl_2$) at different concentrations(1.25, 2.50, 5.00, 10.0 20.0, 40.0 ${\mu}g/g$ food fresh weight). Results of these studies suggested that Cd exposure of G. mellonella may influence its whole body lipid contents. We decided, therefore, to analyze lipid content of G. mellonella exposed to different concentrations of Cd. Lipid concentrations were measured photometrically by phosphovanillin method. Significant decrease in the total lipid content was found in Cd-contaminated larvae and pupae. In this study, six kinds of lipids were separated, and they were phospholipid, monoglyceride, diglyceride, sterol, fatty acids, triglyceride. And fatty acids were proved to consist of palmitic acid, stearic acid, oleic acid and linolenic acid. Palmitic acid, linoleic acid and oleic acid were found high rate in all groups, but stearic acid was low. In conclusion, lipid contents decreased in Cd-contaminated groups in comparison to the control group.

• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.829-834
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• 2016

Free radicals originate due to the radiolysis of cytoplasmic water with low "Linear Energy Transfer" (LET) radiations. Naringenin (Ng) is a natural antioxidative compound found in citrus fruits. This study revealed that Naringenin (Ng) reduced the radiation damage of critical organs by scavenging oxidative free radicals. In the study, Ng was orally administrated to rats daily for 7 consecutive days, prior to whole body exposure to gamma-rays. The scavenging efficacy was evaluated biochemically by measuring the concentration of cytotoxic byproducts and the activity of enzymes relevant to oxidative free radicals, after extracting the organs from the exposed rat. We observed increased levels of malondialdehyde (MDA) concentration, and decrease in the activities of superoxide dismutase (SOD) and catalase (CAT) in the exposed control group. However, pretreatment with Ng significantly reduced the MDA concentration, and increased the activities of SOD and CAT, as compared to the control group, due to the free radical scavenging by Ng. The results indicate that Ng administration prior to irradiation could protect critical organs from radiation damage.

• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.943-953
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• 2012

Because of their unique properties, nano-sized metallic nanomaterials (NMs) have been used in extensive applications of biomedicine, electronics, optics, engineering, and personal care products. Accordingly, with the increasing release of NMs into the environment, numerous studies of nanoecotoxicity have been conducted. Fish embryo toxicity test (FET) has many benefits in evaluating toxicity of NMs as an alternative to a whole-body test in fish. In this study, we collected and analyzed the toxicity studies of metallic NMs on freshwater fish embryos. Most studies have demonstrated that metallic NMs are highly toxic during the early development of fish embryos. However, it should be noted that the results for the same NMs on the same test species show variation due to differences in the size or surface properties of the test NMs and exposure conditions. For the safe use of metallic NMs, we need to analyze their effects based on their properties, test species, environmental media, and diverse conditions.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.2
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• pp.218-224
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• 1998

Long-term exposure of cigarette smoke or air pollutants to human can induce damages in the airway mucociliary function and can be closely related to the irritation and sputum formation in the respiratory system. This study was undertaken to investigate whether rat trachea can be used as a tool for evaluating the cigarette smoke quality. It was identified that, through the examination with inverted microscope, ciliary beating in 1 mm long cut of nat trachea ring was continued for at least 48 hours in saline solution at $25^{\circ}C$. The ciliostasis time in a KCN solution as a positive control was decreased with increasing the concentration of KCN. There were no significant differences in the ciliostasis time by body weight and individual variation of rats. Ciliotoxicity of whole smoke trapped in saline was not significantly changed by aging for more than 6 hrs. The ciliostasis time was in inverse proportion to the number of sample cigarettes applied. As moisture in the cigarette was increased, ciliostasis time was linearly increased. Therefore, these data indicate that the ciliotoxicity test using rat trachea in vitro can be applied to evaluate the cigarette smoke quality and to search factors for the irritation and sputum formation by cigarette smoke as well as air pollutants.