• 한국방사선학회논문지
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• 제6권3호
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• pp.217-226
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• 2012

본 연구는 PACS에서 JPEG200을 이용하여 AAPM CT Performance Phantom 영상을 다양한 비율로 압축 한 후 영상의 질 변화를 알아보았다. 원 영상을 기준으로 압축된 영상을 비교했을 때 물의 CT 계수 측정에서는 압축률 15:1에서 1.93%의 변화, 절편 두께 측정에서는 15:1에서 0.81% 의 변화를 보였다. 균일도는 규칙적인 변화나 통계적으로 유의한 차이가 나타나지는 않았다. 노이즈 측정의 경우 10:1에서 1.47%의 변화를 보이나 15:1에서 10.99%로 증가한 후 변화율 증가 폭이 확대되어 40:1에서 81.68%의 변화율을 보였다. CT 계수, 균일도, 절편 두께, 공간 분해능, 대조도 분해능의 경우 압축률 증가에 따라 영상의 화질 변화율도 증가하나 영향은 크지 않은 것으로 나타났다. 상대적으로 노이즈는 압축에 따른 영향을 많이 받는 것으로 나타났다. JPEG2000 압축 기법으로 AAPM CT Performance Phantom 영상을 평가한 결과 CT영상의 압축을 시행하는 경우 10:1정도의 압축률이 적정한 것으로 판단된다.

• 약학회지
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• 제58권3호
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• pp.151-157
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• 2014

Water extracts of rice grasshopper (Oxya japonica japonica Thurnberg) were prepared and their antitumor and immunostimulatory activities were investigated using a flow cytometer. When LCT-CT was ip injected into ICR mice at the dose of 33.3 mg/kg before and after the implantation of $4{\times}10^5$ cells/mouse of sarcoma 180 tumor cells, it inhibited the growth of the tumor cells by 96.6%, showed lymphoblstogenic activities on the splenic lymphocytes and increased the expression of CD25 molecules on the splenic T lymphocytes. When co-cultured with the splenic lymphocytes of a BALB/c mouse, LCT-CT showed strong immunostimulatory activities at the concentration of $25{\sim}100{\mu}g/ml$ by significantly increasing lymphoblasts ratio and CD25 expression.

• 한국콘텐츠학회논문지
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• 제10권9호
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• pp.259-266
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• 2010

고해상도 엑스선 영상장치인 마이크로 CT를 이용, 흰쥐 간의 전체적인 문맥상과 각 간엽(lobe)의 미세혈관구조를 관찰하여 4개 분절 간엽의 구조를 영상화 하였고, 단축면상의 데이터를 3D영상으로 재구성한 미세혈관 구조의 입체적인 영상을 획득할 수 있는 마이크로 CT에 대한 유용성을 알아보고자 하였다. 5마리의 간 중에서 손상이 가장 적은 1개의 간을 4 개의 분절 간엽으로 각각 절단하여 문맥의 미세구조를 이차원으로 구성하였으며, MIP기법을 이용하여 간 문맥 전체 미세혈관의 3D영상을 얻었으며, 각 간엽의 미세혈관은 6분지까지 관찰할 수 있었다. 6 분지까지의 크기를 측정한 결과 평균치는 1 branch : $0.51mm{\pm}0.08$, 2 branch : $0.32mm{\pm}0.12$, 3 branch : $0.23mm{\pm}0.11$, 4 branch : $0.19 mm{\pm}0.08$, 5 branch : $0.13mm{\pm}0.06$, 6 branch : $70.5{\mu}m{\pm}14.1$ 로 측정되었다. 본 연구의 실험 결과에서 획득한 3차원의 입체 영상과 미세혈관 구조의 발견은 향후 고해상력의 영상을 얻을 수 있는 마이크로 CT가 많이 이용될 수 있을 것으로 기대된다.

• 대한방사선기술학회지:방사선기술과학
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• 제42권3호
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• pp.209-215
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• 2019

Comparison of the effective dose of the chest and the equivalent dose of the lens site in the radiation workers working at four medical institutions with the PET / CT room located in one metropolitan city and province from April 1 to June 30, 2018 Respectively. Radioactive medicine were measured at the time of dispensing and at the time of injection. In this experiment, the average dispensing time per patient was 5.7 minutes and the average injection time was 3.1 minutes. The equivalent dose at the lens site was $0.78{\mu}Sv/h$ for 1 mCi, and the effective dose for chest was $0.18{\mu}Sv/h$ per 1 mCi. The equivalent dose at the lens site during injection was $0.88{\mu}Sv/h$ per mCi and the effective dose of chest was $0.20{\mu}Sv/h$ per mCi. The daily effective dose of the chest was $0.9{\pm}0.6{\mu}Sv$ and the equivalent dose of the lens site was $3.6{\pm}1.4{\mu}Sv$ during daily dosing for 20 days. The effective dose of the chest during the day was $0.6{\pm}0.5{\mu}Sv$ and the equivalent dose of the lens was $2.2{\pm}1.0{\mu}Sv$. At the time of dispensing, the equivalent dose of the lens was $0.187{\pm}0.035mSv$, the effective dose of the chest was $0.137{\pm}0.055mSv$, the equivalent dose of the lens was $0.247{\pm}0.057mSv$, and the effective dose of the monthly chest was $0.187{\pm}0.021mSv$. As a result of the corresponding sample test, the equivalent dose and the effective dose of the chest, the effective dose of the chest, the effective dose of the chest, the effective dose of the chest, The equivalent dose of the lens and the effective dose of the chest were statistically significant (p<0.05) with a significance of 0.000. However, there was no statistically significant difference (p>0.05) between the equivalent dose and the effective dose of the chest, the equivalent dose of the lens at the time of injection, and the effective dose of the chest at 0.138 and 0.230, respectively.

• Imaging Science in Dentistry
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• 제40권1호
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• pp.15-23
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• 2010

Purpose : This study was designed to compare the effective doses from low-dose and standard-dose multi-detector CT (MDCT) scanning protocols and evaluate the image quality and the spatial resolution of the low-dose MDCT protocols for clinical use. Materials and Methods : 6-channel MDCT scanner (Siemens Medical System, Forschheim, Germany), was used for this study. Protocol of the standard-dose MDCT for the orthodontic analysis was 130 kV, 35 mAs, 1.25 mm slice width, 0.8 pitch. Those of the low-dose MDCT for orthodontic analysis and orthodontic surgery were 110 kV, 30 mAs, 1.25 mm slice width, 0.85 pitch and 110 kV, 45 mAs, 2.5 mm slice width, 0.85 pitch. Thermoluminescent dosimeters (TLDs) were placed at 31 sites throughout the levels of adult female ART head and neck phantom. Effective doses were calculated according to ICRP 1990 and 2007 recommendations. A formalin-fixed cadaver and AAPM CT performance phantom were scanned for the evaluation of subjective image quality and spatial resolution. Results : Effective doses in ${\mu}Sv$ ($E_{2007}$) were 699.1, 429.4 and 603.1 for standard-dose CT of orthodontic treatment, low-dose CT of orthodontic analysis, and low-dose CT of orthodontic surgery, respectively. The image quality from the low-dose protocol were not worse than those from the standard-dose protocol. The spatial resolutions of both standard-dose and low-dose CT images were acceptable. Conclusion : From the above results, it can be concluded that the low-dose MDCT protocol is preferable in obtaining CT images for orthodontic analysis and orthodontic surgery.

• 한국방사선학회논문지
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• 제13권4호
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• pp.523-530
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• 2019

본 연구의 목적은 광자계수검출기 기반 스펙트럼 전산화단층촬영을 이용하여 K-각 영상을 획득하고, 이를 통해 3차원 융합진단영상을 구현하여 임상적 이용 가능성을 평가하고자 하였다. 실험을 통한 K-각 영상획득을 위해 스펙트럼 전산화단층촬영 시스템을 이용하였다. 희석된 iodine과 gadolinium 조영제가 주입된 6개의 튜브를 돼지고기에 삽입하여 팬텀을 제작하였다. 100 kVp 관전압과 $500{\mu}A$ 관전류 조건에서 발생된 X-선을 이용하였으며, iodine과 gadolinium의 K-각 흡수에너지를 고려한 35 및 52 keV에 저 에너지 문턱값을 설정하여 K-각 영상을 획득하였다. 융합진단영상은 일반적인 전산화단층촬영 영상과 스펙트럼 전산화단층촬영을 통해 획득한 iodine 및 gadolinium 영상을 정합하여 획득하였다. 두 가지 조영제 기반 융합진단영상의 CNR은 일반적인 CT보다 평균적으로 6.76-14.9배 높았으며, 3차원 융합진단영상은 각 조영제의 물질 지도 정보를 제공할 수 있었다. 따라서 본 연구에서 제안하는 방법을 통해 전산화단층영상의 화질을 향상시킬 수 있으며 특정 물질의 추가적인 정보를 제공을 통해 진단의 효율성을 증가시킬 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.96-98
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• 2005

In this paper, an algorithm to compensate the distorted signals due to Current Transformer(CT) saturation is suggested, First, DWT which can be easily realized by filter banks in real-time applications is used to detect a start point and an end point of the saturation. Secondly, For enough Datas those need to use the least-square curve fitting method, the distorted current signal is compensated by the AR(autoregressive) model using the data during the previous healthy section until pick point of Saturation. Thirdly, the least-square curve fitting method is used to restore the distorted section of the secondary current. Finaly, this algorithm had a Hadware test using DSP board(TMS320C32) with Doble test device. DWT has superior detection accuracy and the proposed compensation algorithm which shows very stable features under various levels of remanent flux in the CT core is also satisfactory. And this algorithm is more correct than a previous algorithm which is only using the LSQ fitting method. Also it can be used as a MU involving the compensation function that acquires the second data from CT and PT.

• 대한방사선치료학회지
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• 제14권1호
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• pp.35-39
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• 2002

Introduction : It is essential to input patients external contour in 3D treatment plan. We would like to see changes in depth and dose when 3D RTP is operating auto contouring when windows value (Width/Level) differs in this process. Material & Methode : We have analyzed the results with 3D RTP after CT Scanning with round CT Phantom. We have compared and analyzed MU values according to depth changes to Isocenter changing external contour and inputting random Window value. We have watched change values according to dose optimization in 4 directions(LAO, LPO, RAO, RPO), We plan 100 case for exact analyzation. We have results changing window value random to each beam in 100 cans. Result : It showed change between minimum and maximum value in 4 beam is Depth 0.26mm, MU $1.2\%$ in LAO. It showed LPO-Depth 0.13mm, MU $0.9\%$, RAO-Depth 0.2mm MU $0.8\%$, RPO-Depth 0.27mm, MU $1.1\%$ Conclusion : Maximum change in depth 0.27 mm, MU error rate is $0.12\%$ according to Window change. As we can see in these results, it seems Window value change doesn't effect in treatment. However, it seems there needs to select appropriate Window value in precise treatment.

• 한국환경보건학회지
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• 제32권1호
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• pp.8-18
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• 2006

The aim of this study is to evaluate the emission characteristics of mercury, lead, arsenic, and selenium from medium size municipal solid waste incinerators(MSWIs) in Korea. The concentrations of mercury, lead, arsenic, and selenium emitted from medium size MSWI stack were $2.67\;{\mu}g/Sm^3,\;0.38\;mg/Sm^3,\;1.33\;{\mu}g/Sm^3,\;0.28\;{\mu}g/Sm^3$, respectively. The concentration levels of mercury, lead, arsenic in flue gas from medium size MSW incinerator stacks selected were nearly detected under the Korea criteria level. Removal efficiencies of mercury, lead, arsenic, and selenium in waste heat boiler(WHE) and cooling tower(CT) were $90.36\%,\;69.76\%,\;43.04\%,\;40.64\%$, respectively. In general, the removal efficiencies of mercury and lead in WHE were higher than those of arsenic and selenium in WHE. Emission gas temperature reduction from waste heat boiler(WHB) and cooling tower(CT) can control mercury and lead of medium size MSWIs. To evaluate the relationship between mercury, lead, arsenic, selenium of fly ash and those of flue gas, it was carried out to correlation analysis of each metal concentration in the fly ash and in the flue gas from medium size MSWIs. From the correlation analysis, the coefficients of mercury, lead, arsenic, and selenium were 0.61, -0.38, 0.87, 0.28, respectively. The results of correlation analysis revealed that it should be highly positive to the correlation coefficients of mercury and arsenic in the fly ash and those of the flue gas emitted from medium size MSWIs. As it were, the concentrations of mercury and arsenic of flue gas from medium size MSWIs are high unless mercury and arsenic in fly ash are properly controlled in dust collection step in medium size MSWIs. It was also concluded that mercury, lead, arsenic, and selenium from MSWIs stacks could be controlled by waste heat boiler(WHE) and dust collecting step in medium size MSWIs.

• 한국정밀공학회지
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• 제27권5호
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• pp.92-101
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• 2010

This study evaluated the structure and quality of osteoporotic vertebral bone. To induce osteoporosis, eight rats were ovariectomized (OVX). All rats were divided into two groups (Normal group: 4, OVX group: 4). Total lumbar vertebrae for each rat were scanned by in-vivo ${\mu}CT$ at 0, 4 and 8 weeks. Morphological characteristics (BV/TV, Tb.Th, Tb.N, Tb.Sp and SMI) were calculated by in-vivo ${\mu}CT$ image analyzer. Three dimensional finite element models were analyzed to investigate bone strength of OVX and Normal groups. Moreover, the elastic modulus was quantitatively analyzed to evaluate the quality changes of osteoporotic bone. In the OVX group, BV/TV, Tb.Th and Tb.N were significantly decreased at all the lumbar over time (p<0.05). We also investigated a contrary tendency in Tb.Sp and SMI, compared to the above results in each group. A degree of alteration of mechanical characteristics in OVX group was decreased over measuring time (p<0.05). Bone quality presented by distribution of elastic modulus was improved in the Normal group more than OVX group. The findings of the present study indicated that both bone structure and quality of whole lumbar could be tracked and detected by analyzing the morphological and biomechanical characteristics of bones, based on a nondestructive method.