• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.904-906
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• 2005

본 논문에서는 뇌 CT 혈관조영영상에서 슬라이스 정보를 이용한 뇌 분할 방법을 제안한다. 뇌 분할 과정은 현재 슬라이스와 이전 슬라이스 간 분할 영역의 크기 정보를 가지고 영역 성장 단계와 전파 단계로 구분하여 수행된다. 영역 성장 단계에서는 이차원 영역성장법을 통해 뇌 분할을 수행하고 누출이 발생하는 슬라이스에 대하여 방사선 투과 기법을 통해 영역보정을 수행한다. 전파 단계에서는 이전 슬라이스에서 분할된 뇌 영역을 현재 슬라이스로 전파함으로써 장벽을 생성하고 장벽 내에서 이차원 영역성장법을 수행함으로써 누출을 최소화한다. 또한 뇌 영역과 유사한 밝기값을 형성하고 있는 미세 요소들을 제거하기 위해 이차원 연결화소군 레이블링 기법을 통해서 최종적으로 뇌 분할을 수행한다. 본 논문의 실험을 위하여 뇌 CT 혈관조영영상을 사용하여 정확한 뇌분할 결과를 얻었다.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.107-114
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• 2012

Purpose: Unlike the existing linear accelerator with photon, proton therapy produces a number of second radiation due to the kinds of nuclide including neutron that is produced from the interaction with matter, and more attention must be paid on the exposure level of radiation workers for this reason. Therefore, thermoluminescence dosimeter (TLD) that is being widely used to measure radiation was utilized to analyze the exposure level of the radiation workers and propose a basic data about the radiation exposure level during the proton therapy. Materials and Methods: The subjects were radiation workers who worked at the proton therapy center of National Cancer Center and TLD Badge was used to compare the measured data of exposure level. In order to check the dispersion of exposure dose on body parts from the second radiation coming out surrounding the beam line of proton, TLD (width and length: 3 mm each) was attached to on the body spots (lateral canthi, neck, nipples, umbilicus, back, wrists) and retained them for 8 working hours, and the average data was obtained after measuring them for 80 hours. Moreover, in order to look into the dispersion of spatial exposure in the treatment room, TLD was attached on the snout, PPS (Patient Positioning System), Pendant, block closet, DIPS (Digital Image Positioning System), Console, doors and measured its exposure dose level during the working hours per day. Results: As a result of measuring exposure level of TLD Badge of radiation workers, quarterly average was 0.174 mSv, yearly average was 0.543 mSv, and after measuring the exposure level of body spots, it showed that the highest exposed body spot was neck and the lowest exposed body spot was back (the middle point of a line connecting both scapula superior angles). Investigation into the spatial exposure according to the workers' movement revealed that the exposure level was highest near the snout and as the distance becomes distant, it went lower. Conclusion: Even a small amount of exposure will eventually increase cumulative dose and exposure dose on a specific body part can bring health risks if one works in a same location for a long period. Therefore, radiation workers must thoroughly manage exposure dose and try their best to minimize it according to ALARA (As Low As Reasonably Achievable) as the International Commission on Radiological Protection (ICRP) recommends.

• Journal of Radiation Industry
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• v.4 no.4
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• pp.359-364
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• 2010

PVDF-HFP (binder)/silylated alumina (inorganic particle)-coated PE (polyethylene) separators were with various compositions of binder and inorganic particle were prepared by a dip-coating process with humidity control (R.H. 25% and 50%) using electron beam irradiation. The morphology of the coated PVDF-$HFP/Al_2O_3$ layer with various compositions of PVDF-HFP and $Al_2O_3$, and humidity condition was found to be an important factor in determining ionic conductivity of the prepared separators. The PVDF-$HFP/Al_2O_3$ (5/5)-coated PE separator prepared at R.H. 50% followed by electron beam irradiation at 200 kGy was applied for lithium-ion polymer battery and the cell test results showed improved high-rate discharge performance and better cyclic stability compared to the cells with the bare PE and the PVDF-HFP-coated PE separators.

• Journal of radiological science and technology
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• v.45 no.6
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• pp.553-560
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• 2022

The purpose of this study is to evaluate the clinical risk according to the applicator heterogeneity, mislocation, and tissue heterogeneity correction through a dose verification program during brachytherapy of cervical cancer. We performed image processing with MATLAB on images acquired with CT simulator. The source was modeled and stochiometric calibration and Monte-Carlo algorithm were applied based on dwell time and location to calculate the dose, and the secondary cancer risk was evaluated in the dose verification program. The result calculated by correcting for applicator and tissue heterogeneity showed a maximum dose of about 25% higher. In the bladder, the difference in excess absolute risk according to the heterogeneity correction was not significant. In the rectum, the difference in excess absolute risk was lower than that calculated by correcting applicator and tissue heterogeneity compared to the water-based calculation. In the femur, the water-based calculation result was the lowest, and the result calculated by correcting the applicator and tissue heterogeneity was 10% higher. A maximum of 14% dose difference occurred when the applicator mislocation was 20 mm in the Z-axis. In a future study, it is expected that a system that can independently verify the treatment plan can be developed by automating the interface between the treatment planning system and the dose verification program.

• Journal of radiological science and technology
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• v.33 no.2
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• pp.133-141
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• 2010

The evaluation of Varian enhanced dynamic wedges (EDW) were performed in terms of quality assurance in external radiotherapy. The seven (10, 15, 20, 25, 30, 45, 60 deg.) EDW angles were evaluated for 6 and 15 MV x-rays in Varian Linac. The STT (segmented treatment table) for a field were calculated and compared with actual movement of the jaw using Dynalog files in order to evaluate mechanical operation. Two dimensional array detector and an ionization chamber were used to measure dose distributions in phantom from Linac. The mechanical movement of jaw was agreed with its expectation and two dimensional dose distributions including beam profiles were in agreement with RTP data approximately. In comparison with RTP calculations the percentage difference of output dose values for 100 MU irradiation was less than 2.9% and measured wedge factor was less than 2.6%. These results are shown that there is no problem in clinical applications of EDW equipped on this linac.

• Radiation Oncology Journal
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• v.23 no.3
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• pp.157-160
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• 2005

Purpose: To investigate the effect of low dose radiation on neuronal cell proliferation In diabetic rats. Materials and Methods: A group of rats (first group) were divided into three subgroups (nondiabetic control, nondiabetic 0.1 Gy and nondiabetic 10 Gy groups) to determine the effect of radiation on normal hippocampal neuronal ceil proliferation. A further group of rats (second group) were divided into six subgroups (nondiabetic control, diabetic control, diabetic 0.01 Gy, diabetic 0.1 Gy, diabetic 1 Gy and diabetic 10 Gy groups) to determine the effect of radiation on hippocampal neuronal cell proliferation under diabetic conditions. Using immuno-histochemistry for 5-bromo-2'-deoxyuridine (BrdU), the number of neuronal cells in the dentate gyrus of all the groups was counted. Results: The number of BrdU-positive cells in the dentate Gyrus of the nondiabetic control, nondiabetic 0.1 Gy and nondiabetic 10 Gy subgroups of the first group were $45.95{\pm}3.42,\;59.34{\pm}5.20\;and\;19.26{\pm}2.98/mm^2$, respectively. The number of BrdU-positive cells in the dentate gyrus of the diabetic control, diabetic 0.01 Gy, diabetic 0,1 Gy, diabetic 1 Gy and diabetic 10 Gy subgroups of the second group were $55.44{\pm}8.57,\;33.33{\pm}6.46,\;67.75{\pm}10.54,\;66.63{\pm}10.05,\;23.59{\pm}6.37\;and\;14.34{\pm}7.22/mm^2$, respectively. Conclusion: Low dose radiation enhances cell proliferation in the dentate gyrus of STZ-induced diabetic rats.

• Journal of the Korean Arthroscopy Society
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• v.10 no.2
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• pp.165-172
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• 2006

Purpose: The purpose of this study is to evaluate the effects of intratunnel fixation in the tibial side on the arthroscopic ACL reconstruction with quadruple hamstring tendon at the second look arthroscopy. Materials and Method: From Dec 1999 to May 2005, we arthroscopically reexamined 32 cases who had been done arthroscopic ACL reconstruction with quadruple hamstring tendons. Hamstring tendons of all cases were fixed at femoral side with RigidfixTM. At the tibial side hamstring tendons were fixed only Post-tie (Group I) or Post-tie combined with IntrafixTM (Group II). At the time of second look arthroscopy mean age of cases was 30 years and mean duration for second look arthroscopy was 21.3 months. We analyzed the results with IKDC score, KT-1000 arthrometer under anesthesia, Telos stress radiography, tibial tunnel widening on the radiography and second look arthroscopic findings. Results: Group II had more superior than group I at side to side differences with KT-1000 and Telos stress radiograph, IKDC score, but the differences were insignificant. At arthroscopic evaluation, Group ll also had more superior than group I at graft tension and graft appearance, graft synovialization, but the differences were insignificant. Tibial tunnel widening in the knee AP radiograph was 2.3 mm in Group I and 1.7 mm in Group II and the difference was significant. (P=0.042) Conclusions: Additional procedure of tibial intratunnel fixation in arthroscopic ACL reconstruction with autogenous hamstring tendon significantly prohibited from tibial tunnel widening but clinical results, radiologic joint stability, findings in second look arthroscopy were insignificantly different. We concluded that Post-tie itself induced satisfactory clinical results, joint stability and graft maturation and that tibial tunnel widening did not affect the results.

• Korean Journal of Cleft Lip And Palate
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• v.3 no.1
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• pp.1-9
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• 2000

목적 : 치조파열 환자에 있어서 이차 치조골 이식술을 시행한 후 그 결과를 알아보고자 방사선학적 분석을 통하여 평가하였다. 본 연구의 목적은 수술전 골결손부 인접치아의 치조정 높이와 수술후 골결손부 인접치아의 치조정 높이를 근심측과 원심측에서 각각 측정함으로써 치조정의 높이가 과연 통계적으로 유의성 있게 증가하는지와 치조골 이식술의 성공률이 치조열의 너비와 상관관계가 있는지의 여부를 알아보는 것이다. 환자 및 방법 : 1991년부터 1999년까지 서울대학교병원 구강악안면외과에서 자가장골 채취 후 분쇄피질망사골 형태 또는 block 피질망상골 형태로 이식한 편측성 치조열을 가진 환자 중 최소한 6개월이 경과한 환자 56명을 연구대상으로 하였고 두 술자에 의해 시술되었다. 수술전 골결손부 인접치아의 치조정의 높이와 치조열의 너비 및 수술후 이식한 골의 높이와 절흔의 양은 치과용 파노라마 방사선 사진을 이용하여 측정하였고, 치조열의 너비는 모델이나 환자의 골결손부 근심치아의 근원심 폭경을 이용하여 환산하였다. 그리고 이식한 골의 높이와 절흔의 양을 1995년 Long이 제시한 방법으로 측정하여 술전의 측정치와 비교하였다. 결과 : 치조열의 너비는 평균 6.9mm(1.9mm-12.1mm) 였다. 근심에서의 치아는 골이식 당시 중절치가 52개(92.9%), 측절치가 4개(7.1%)였고, 49명의 환자에서 완전맹출을, 6명의 환자에서 부분맹출(측절치 2개, 중절치 4개)을 보였다. 원심측에서의 치아는 골이식 당시 측절치가 25개(44.6%), 견치가 29개(51.8%), 소구치가 2개(3.6%)였고, 완전 맹출이 32.1%, 부분 맹출이 57.2%, 미맹출이 10.7%로서 완전히 맹출하기 전에 골이식한 경우가 67.9%였다. 모든 환자에 있어서 bony bridge가 나타났고, 절흔이 인접치 아래로 연장되지 않았으며, 치조골 이식술 후 oronasal fistula를 보인 환자는 한 명도 없었으므로 성공률은 100%였다. 술후 근심측에서의 치조정의 높이는 근심측 치아 치근길이의 79%(평균), 원심측에서의 치조정의 높이는 원심측 치아 치근길이의 87%(평균)로서 통계적으로 유의성 있게 증가하였다. 결론: 이차 치조골 이식술을 시행한 후 치조정의 높이는 골결손부 근심측과 원심측에서 모두 유의성있게 증가하였고, 근심측에서보다 원심측에서 통계학적으로 더 유의성 있게 증가하였다. 치조열의 너비와 절흔의 양, 치조정의 높이 및 치조골이식 성공률과는 유의성 있는 관련성이 없었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.13 no.1
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• pp.9-15
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• 1991

The cleft alveolus occurs about 75% of cleft lip and palate patients. The purpose of bone grafting is improve the maxillary growth, rehabilitation of continuty of maxillary arch and providing bone for periodontal support for unerupted teeth. The bone grafting for alveolar cleft defect repair are classsified; primary bone grafting, early secondary bone grafting secondary bone grafting and late secondary bone grafting. In this article, we reported the cases of PMCB grafts for repair of the alveolar clefts showed potential benifit to the patient to induce a normal maxillary growth and providing bone foor periodontal support of unerupted teeth.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1978.10a
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• pp.205.2-205
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• 1978

우리나라 전국명지에서 약 1400여점의 토양시료를 채취하여 이 토양 시료에서 방사선균 1635균주를순수분리 배양하고, 명 균주를 배양하여 생산되는 항생물질 중 paper disk method에 의해 벼문고 병균 Pellicularia sasakii에 대한 항균력을 나타내는 균주를 선발하고, 이차선발로서 Dendroid test method와 최종적 선발방법으로 벼를 대상으로 문고병 발생에 대한 green house test에 의하여 우수한 균주를 취득하였다.