• Journal of the Korean Society of Radiology
• /
• v.14 no.6
• /
• pp.833-839
• /
• 2020

Globally, infection prevention and social awareness have been greatly changed by the severe acute respiratory syndrome coronavirus, and as a result, the infection control guidelines and procedures for patients with high exposure to hospital-acquired infection are further strengthened and management and monitoring are more thorough. In order to prevent infection, sterilization should be carried out with the highest priority, and we will find a sterilization method that is low in cost, easy to install, and easy to operate, to present appropriate sterilization effects. In this study, the UV sterilizer was used to contaminate the caries bacteria with an output of 4 W and irradiation time of 60, 150, and 300 sec, and the laser was irradiated with outputs of 0.8 and 1.5 W at wavelengths of 266 and 355 nm, respectively. Ultraviolet sterilizer showed safety in infection prevention at over 150 sec, and laser showed safety in prevention at 1.5 W, 0.8 W, and 266 nm. As a result, the higher the output and the wavelength closer to 253.7 nm, the better the sterilization effect.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.397.1-397.1
• /
• 2014

최근 방사선 진단 영역에 이용되고 있는 증감지는 입사된 방사선의 감도를 증가시키기 위해 형광체를 사용하고 있으며, 외부의 에너지를 흡수하여 빛으로 방출하는 역할을 한다. 이는 방사선 검출기, 디스플레이, 의료기기 등 다양한 분야에 활용되고 있다. 필름에 X선을 노출 할 경우 형광체의 사용 유무에 따라 방사선 흡수 효율에 영향을 미치며, 이는 발광 효율 및 감도에 주요한 인자로 작용한다. 현재 상용화되어 있는 형광체는 낮은 발광 효율로 인한 한계를 가지므로, 발광 효율 향상을 위하여 제작 구조에 대한 연구가 진행되고 있다. 이 중 반사막을 활용하는 연구가 활발히 진행되고 있다. 일반적으로 형광체의 제조를 위하여 보편적으로 이용하고 있는 스크린프린팅 방법에서 건조 공정을 수행 시 균일도가 감소하는 현상이 발생한다. 이러한 현상은 반사막의 증착을 불균일하게 만드는 원인으로 작용하고 빛의 산란을 초래하는 현상을 초래한다. 이에 본 연구에서는 증착 시 투명도 저하에 따라 반사율이 증가되는 반사막 성질을 가지며, 방수성 및 절연성과 같은 보호층 특성을 지닌 유기성 투명 박막 페를린에 대하여 연구하고자 한다. 본 연구에서는 화학적 증기 증착법(Chemical Vapor Deposition, CVD)을 이용하여 투명 필름의 상단에 페를린을 코팅한 시편과 코팅하지 않은 시편으로 구분하여 제작하였고, 상단에 스크핀프린팅 방법을 활용하여 형광체를 도포 하였다. 시편 제작 후 실험은 시편을 필름 상단에 위치시키고, 일반진단에너지 대역(Model-SF 80)의 X선을 조사하였다. 이 후 현상기(model-pro14)를 통해 현상된 필름에 나타난 광학적 농도(Optical Density, O.D)를 농도계(Fluke Biomedical Nuclear Associates Densitometer)로 측정하였는데, 불확실성을 줄이기 위하여 총 5회를 측정하여 그 중 2번째로 높은 값을 도출하였다. 측정 결과, 페를린을 코팅한 형광체에서는 1.71의 O.D 값이 측정되었고, 페를린을 코팅하지 않은 형광체에서는 1.43의 O.D 값이 측정되었다. 이를 이용하여 투명도를 산출한 결과 상대적으로 약 1.76% 차이가 나타났다. 이러한 결과는 페를린 활용 시 환자의 피폭 선량 저감화 및 해상력 개선을 도모할 수 있을 것으로 사료된다.

• Korean Journal of Environmental Biology
• /
• v.22 no.3
• /
• pp.472-477
• /
• 2004

To study the radiation related gene expression in mutants of Bacillus lentimorbus WJ5 induced by gamm radiation, the simultaneous gene expression was analyzed by DNA micro array. We constructed DNA chips including two thousand randomly digested genome spots of B. lentimorbus WJ5 and compared its quantitative aspect with seven mutants induced by gamma radiation $(^{60}/Co)$. From the cluster analysis of gene expression pattern, totally 408 genes were expressed and 27 genes were significantly upregulated by the gamma radiation in all mutants. Especially, genes involved in repair (mutL, mutM), energy metabolism (acsA, sdhB, pgk, yhjB, citB), protease (npr), and reduction response to oxidative stress (HMM) were simultaneously upregulated. It seems that the induction of the direct and/or indirect repair related genes in mutants induced by gamma radiation could be remarkably different from the adaptive responses against acute exposure to radiation.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.13 no.1
• /
• pp.27-34
• /
• 2020

Human access is restricted to environment where radiation sources are used, however observation equipment should be radiation-resistant as it is exposed. Therefore, if tungsten with the highest specific gravity and melting point and the lowest lead were selected to reduce the dose to the Cobalt 60 radiation source to 1/8, Tu had a volume of 432.6cm3, a thickness of 2.4cm, and Pb had a volume of 961cm3,, a thickness of 3.6cm. By applying this method, produced a radiation resistant CMOS camera with a camera module using a CMOS Image sensor and a radiation shielding structured housing. As a result of applying the head detachable 2M AHD camera (No. ①) that survived the experiment to select the optimal shielding thickness, when shielding the associated equipment such as cameras, adapters, etc. is achieved, it was confirmed that the design of the structure is appropriate by operating well at doses higher than 1.88×106rad. Therefore, it is expected to secure the camera technology and business feasibility that can be applied to high radiation environments.

• Journal of the Korean Society of Radiology
• /
• v.17 no.5
• /
• pp.717-723
• /
• 2023

Liver disease is highly associated with death, and other abdominal diseases are also important causes affecting a person's lifespan, and a CT scan is essential when treating abdominal diseases. High radiation exposure is essential to create images that are good for reading, but managing the patient's radiation exposure is also essential. In this study, a post-processing wavelet algorithm was proposed to improve the image quality of abdominal CT images. Wavelets have the disadvantage of having to set a threshold value depending on the type of input image. Therefore, we experimentally proposed the threshold value of the wavelet and evaluated whether the image quality was effective. As a result of the experiment, the optimal threshold value for abdominal CT images was calculated to be 50. In the case of image 1, noise was improved by 49% and in the case of image 2, by 29%, and the contrast also increased. if the results of this study are applied for post-processing after abdominal CT, image quality can be improved and it will be helpful in disease diagnosis.

• Journal of radiological science and technology
• /
• v.28 no.1
• /
• pp.13-17
• /
• 2005

In domestic nondestructive testing(NDT) field, there have recently been radiation exposure accidents due to a disregard for confirmation of the position of radioisotope during the test. In order to prevent these kinds of accidents, a scintillating film has been developed. The scintillating film that can convert gamma-ray to visible light has a function of the position detection of radioisotope in a opaque guide tube of an NDT apparatus. The aim of this study is to enhance the visibility performance of the scintillating film and find out the best configuration of the scintillating film. In order to find appropriate materials for the scintillating film, various inorganic scintillating materials were evaluated in this work. An absolute luminance of the scintillating films was measured by luminance meter for evaluation of visibility performance. Ir-192 gamma projector was used for NDT apparatus. The experiment shows that the scintillating film with reflective layer was the more effective performance for visibility. The higher mixing ratio of scintillating material to binding material, the higher luminance was measured. $Gd_2O_2S(Tb)$ inorganic powder as the scintillating materials had the best performance for visibility of the scintillating film. The developed scintillating film helps to ensure safer environment to the operators.

• Journal of radiological science and technology
• /
• v.44 no.3
• /
• pp.253-260
• /
• 2021

The purpose of this study is to measure of growth and chlorophyl in barley exposed by X-ray. Barley seed was soaked 24h duration in water, then was classified into two group; pre-seed germination group (Pre-G) or post-seed germination group (Post-G). Also, divided as control subgroup and experimental subgroup(10Gy, 20Gy, 30Gy) in each group. Experimental subgroups were exposed by X-ray using linear accelerator (Clinac IS, VERIAN, USA). Expose condition was 6 MV X-ray, SSD 100 cm, 18×10 cm, 600 MU/min. Length was measured every day for 10 days and 10th day for weight. Chlorophyl was analyzed using spectrophotometer(uv-1800, shimadzu, japan) in l0th day. Data analysis was performed using SPSS ver 22.0(Chicago, IL, USA), ANOVA test (Dunnett_T3) between control subgroup and experimental subgroup in group and Independent T-test between Pre-G and Post-G in subgroup. In Pre-G, length of barley was significantly difference between control and 30Gy in 4th day (4.3 vs. 1.5, p= 0.011). Length of 30Gy was statistical difference with control(10th day; 14.4 vs. 6.3, p < 0.01), and was not in 10Gy or 20Gy in all day. In experimental subgroup, length was shorter as increasing radiation dose. In Post-G, length of barley was not difference statistically between control and experimental subgroup in first day, but more difference between two subgroup with increasing duration after exposing. Length of experimental subgroup was shorter significantly compared with control in 10th day, and no significant difference between experimental subgroup. Density of chlorophyl was increasing with increasing radiation dose in Pre-G and Post-G. Chlorophyl density of control was lower than 30Gy; 0.26ppm in Pre-G, 0.29ppm in Post-G). Growth and chlorophyl of barley was effected by X-ray. It is expected to be used as basic data for future radiobiological research.

• Journal of the Korean Society of Radiology
• /
• v.6 no.6
• /
• pp.455-464
• /
• 2012

This study suggested evaluation of approximately exposure to low-dose ionization radiation from medical images using a computed radiography (CR) system in standard X-ray examination and experimental model can compare diagnostic reference level (DRL) will suggest on optimization condition of guard about medical radiation of low dose space. Entrance surface dose (ESD) cross-measuring by standard dosimeter and optically stimulated luminescence dosimeters (OSLDs) in experiment condition about tube voltage and current of X-ray generator. Also, Hounsfield unit (HU) scale measured about each experiment condition in CR system and after character relationship table and graph tabulate about ESD and HU scale, approximately radiation dose about head, neck, thoracic, abdomen, and pelvis draw a measurement. In result measuring head, neck, thoracic, abdomen, and pelvis, average of ESD is 2.10, 2.01, 1.13, 2.97, and 1.95 mGy, respectively. HU scale is $3,276{\pm}3.72$, $3,217{\pm}2.93$, $2,768{\pm}3.13$, $3,782{\pm}5.19$, and $2,318{\pm}4.64$, respectively, in CR image. At this moment, using characteristic relationship table and graph, ESD measured approximately 2.16, 2.06, 1.19, 3.05, and 2.07 mGy, respectively. Average error of measuring value and ESD measured approximately smaller than 3%, this have credibility cover all the bases radiology area of measurement 5%. In its final analysis, this study suggest new experimental model approximately can assess radiation dose of patient in standard X-ray examination and can apply to CR examination, digital radiography and even film-cassette system.

• Journal of the Korean Society of Radiology
• /
• v.18 no.3
• /
• pp.257-265
• /
• 2024

In this study, we applied AEC(Auto Exposure Control), which is used in many chest examinations, to evaluate whether medical devices inserted into the body affect the dose and image quality of chest images. After attaching three HIMD(Human implantable medical devices) to the ion chamber, the Monte Carlo methodology-based program PCXMC(PC Program for X-ray Monte Carlo) 2.0 was applied to measure the effective dose by inputting the DAP(Dose Ares Product) value derived from the Pacemaker and CRT and Chemoport Additionally, to evaluate image quality, we set three regions of interest and one noise region on the chest and measured SNR and CNR. The final study results showed significant differences in DAP and Effective dose. There was a significant difference between Pacemaker and CRT when AEC was applied and not applied. (p<0.05) When applied, the dose increased by 37% for Pacemaekr and 52% for CRT. Chemoport showed a 10% increase in effective dose depending on whether AEC was applied, but there was no significant difference. (p>0.05) In the image quality evaluation, there was no significant difference in image quality between all HIMD insertions and AEC applied or not. (p>0.05) Therefore, when the HIMD was inserted into the chest during a chest x ray and overlapped with the ion chamber sensor, the effective dose increased, and there was no difference in image quality even at a low dose without AEC. Therefore, when performing a chest X-ray examination of a patient with a HIMD inserted, it is considered that performing the examination without applying AEC is a method that can be considered to reduce the patient's radiation exposure.

• Journal of dental hygiene science
• /
• v.5 no.3
• /
• pp.105-112
• /
• 2005

In spite of relatively low level of radiation dose used at dental clinics, long term exposure may be harmful, so radiation workers at dental clinics must be well aware of its danger. This study was to analyze the factors to have an influence on safety management behavior in the radiography chamber by understanding the relationship among the knowledge, attitudes and behavior in regard with radiation safety management by dental hygienists in order to take preventive measures for dental hygienists and suggest ideas to develop radiation safety training programs. For this, we contacted dental hygienists working at the local dental clinics for 4 months from December of 2003 to march of 2004 and obtained the following findings. 1. Concering the knowledge level of radiation safety management, $8.59{\pm}2.36$ was average score with the highest of 13 and the lowest of 3 from 15-scale test. In addition, knowledge level of radiation safety management by general characteristics showed statistically significant difference according to working experience (p < 0.001), marital status (p < 0.001), attendance rate of radiation safety management training program (p < 0.001), and type of clinic (p < 0.001). 2. Concering the attitude level of radiation safety management, $4.08{\pm}0.50$ is average score with the highest of $4.31{\pm}0.73$ and the lowest of $3.82{\pm}0.89$ by item from 5-scale test. Besides, attitude level of radiation safety management by general characteristics showed statistically significant difference according to age (p < 0.001), working experience (p < 0.05), attendance rate of radiation safety management training program (p < 0.01), and type of clinic (p < 0.001). 3. Concering the behavior level of radiation safety management, $2.89{\pm}0.77$ is average score from 5-scale test, which was relatively low in comparison with the level of attitude and the highest score was $3.82{\pm}0.94$ and the lowest $2.37{\pm}1.04$ by item. Behavior level of radiation safety management by general characteristics showed statistically significant difference according to working experience (p < 0.001) and type of clinic (p < 0.001). 4. From the survey of relationship among knowledge, attitude and behavior of radiation safety management was, we found that the higher the knowledge level of radiation safety management, the higher the level of attitude and behavior, and the higher the attitude level was, the higher the level of behavior.