• 대한방사선치료학회지
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• 제26권1호
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• pp.107-114
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• 2014

목 적 : 두경부 치료계획 CT영상에서 dental implant로 인한 metal artifact 발생 시 O-MAR(Metal artifact Reduction for Orthopedic Implants)(ver. 3.6.0, Philips, Netherlands)를 적용할 수 있을지 여부를 평가하고자 한다. 대상 및 방법 : 모든 CT영상은 Brilliance Big Bore CT(Philips, Netherlands)에서 관전압 120kVp, 2mm 두께로 촬영하였으며, O-MAR를 이용하여 Metal artifact reduction 후 전산화치료계획장비(Eclipse ver 10.0.42, Varian, USA)로 원본영상과 비교, 분석하였다. O-MAR의 기본적인 성능 테스트를 위해 Metal artifact가 발생하지 않은 영상과 발생한 영상에서 O-MAR 적용시, HU 변화를 검증하기 위해 원통형 팬텀과 cerrobend 막대, 불균질 팬텀을 이용하여 실험하였다. 각각의 원본 영상과 O-MAR 적용 영상에서 관심영역 내 HU 변화를 측정하였다. 이를 바탕으로 본 연구의 주목적인 dental implant로 인한 metal artifact 발생 영상을 재현하기 위해 팬텀을 제작하여 사용하였고, 실제 임상 환자 영상에 O-MAR를 적용한 영상과 원본 영상 그리고 artifact 부분을 보정한 영상의 선량 분포를 SNC Patient(Sun Nuclear Co., USA)로 비교하였다. 결 과 : 두경부에서의 metal artifact를 재현한 원본 영상과 O-MAR 적용영상의 선량 분포를 비교한 결과 gamma passing rate 는 2 mm / 2% 기준으로 99.8%, 일치를 보였다. 실제 임상 환자 영상을 바탕으로 O-MAR 적용 전후 영상과 density corrected CT 영상에 동일한 조건으로 치료 계획을 수립하여 선량 분포를 비교한 결과는 98.5% 일치로 비교적 높은 gamma passing rate를 보였다. 전체적인 선량 분포 차이는 모두 2% 이내로 팬텀 실험과 실제 임상 환자 영상 실험에서 비슷한 결과로 나타났다. 하지만 선량 편차가 적더라도 국소적으로 집중되어 있는 것은 문제의 소지가 될 가능성이 있다. 화질 개선 면에서는 모든 실험에서 O-MAR 적용영상이 원본에 비해 개선됨을 알 수 있었으나, 두경부 metal artifact를 재현한 팬텀 영상 air cavity 내에서 최대 HU 값이 상승하는 경우가 생겼고, 환자 영상에서는 air cavity가 tissue로 잘못 보정되는 경우 또한 발견할 수 있었다. 결 론 : 업체에서 제시한 사용제한 사항인 피부 근처와 저밀도 영역이 공존하는 두경부에서 O-MAR의 사용 가능성을 확인해 본 결과, 원본의 왜곡과 보정이 동시에 일어났다. 심지어 팬텀 실험보다 더 심한 artifact가 생긴 환자의 경우 air cavity가 tissue로 잘못 보정되는 경우도 발생하였다. 결과적으로 아직까지는 O-MAR 알고리즘이 air cavity와 photon starvation artifact를 정확히 구분하지 못하는 것으로 보인다. 선량 측면에서의 영향은 임상에서 배제될 만큼 큰 차이를 보이지는 않았다. 임상에서 원본과 O-MAR 적용 영상을 비교하며 작업한다면 contouring, artifact 보정작업, DRR 화질 개선 등에 도움을 받을 수 있을 것으로 사료된다.

• Advances in Traditional Medicine
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• 제8권3호
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• pp.279-285
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• 2008

Diospyros peregrina Gurke. (Ebenaceae) is a small middle sized tree grows luxuriantly in the plains of costal West Bengal, India. The objective of the study was to explore the antidiabetic activity of methanol extract of matured fruits of Diospyros peregrina to substantiate the folklore claim of traditional practitioners. It was also aimed to establish correlation with reduction of oxidative state associated with diabetes. Methanol extract of matured fruits of Diospyros peregrina was administered orally at doses of 150 and 300 mg/kg body weight for 12 consecutive days to normal and streptozotocin induced diabetic rats. Fasting blood glucose level was estimated in both normal and diabetic rats while serum lipid profiles, liver glycogen level and pancreatic thiobarbituric acid reactive substances (TBARS) were evaluated for diabetic rats. Initial and final changes in body weight were also recorded. Oral glucose tolerance test was performed during the course of study. Experimental findings showed significant antidiabetic potential of extract in term of reduction of fasting blood glucose level of both normal and diabetic rats. It was found that extract at the dose of 300 mg/kg body weight is more effective and percentage reduction (55.64) of elevated blood glucose level is comparable to that of standard drug glibenclamide (60.60) at a dose of 10 mg/kg body weight. Observed data found statistically significant in reduction of serum lipid and pancreatic TBARS levels whilst improvement was observed in liver glycogen level and body weight profiles in extract treated diabetic rats.

• Journal of Korean Neurosurgical Society
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• 제37권4호
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• pp.275-281
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• 2005

Objective: The prolactinoma is the most common pituitary tumor and sometimes shows severe invasiveness to the adjacent cavernous sinus, especially in the male patient. The dopamine agonist can be used as an alternative treatment modality to surgery. But, the transsphenoidal or transcranial approach for tumor removal has been more preferred treatment option of neurosurgeons in invasive prolactinoma. Especially rapid decompression of mass effect and resolution of the neurologic deficit is demanded. The prospective study is done in order to identify the therapeutic efficacy of bromocriptine as an initial treatment option for the invasive prolactionomas. Methods: Twenty patients with invasive prolactinoma were studied. Preoperative neurological and endocrinological evaluations were done, and size and invasiveness of the tumor was estimated on MRI. Bromocriptine was administrated by increasing dose planning reaching maximum dose at 1 month of treatment, with close neurological and endocrinological monitoring. At 3months after treatment, MRI was taken and decision was made whether to continue bromocriptine or to have surgical intervention. Results: Thirteen patients showed excellent result with only bromocriptine treatment. These patients showed not only marked reduction of tumor volume and prolactin level, but also, improving clinical symptoms and other hormonal deficits. 13patients who had visual field defect and decreased visual acuity had all improved visual symptoms. But, the remaining 4patients required surgical treatment due to insufficient reduction of tumor size inspite of normalized prolactin level within 3months. Remaining 2patients had $20{\sim}30%$ of tumor size reduction, but prolactin level was not normalized. One patient required radiation therapy. Conclusion: Bromociptine can be used as initial treatment for the invasive prolactinomas with careful monitoring of the neurological and endocrinological status. It should be carefully followed up for tumor size reduction within 3 months after initiation of treatment.

• Macromolecular Research
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• 제15권4호
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• pp.285-290
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• 2007

Ag nanoparticles were distributed onto polystyrene nanoparticle (PS-Ag) beads using two synthetic methodologies. In the first methodology, polystyrene (PS) beads were prepared via emulsion polymerization, with Ag nanoparticles subsequently loaded onto the surface of the PS beads. The polymerization of styrene was radiolytically induced in an ethanol (EtOH)/water medium, generating PS beads. Subsequently, Ag nanoparticles were loaded onto the PS beads via the reduction of Ag ions. The results from the morphological studies, using field emission transmission electron microscopy (FE-TEM), reveal the PS particles were spherical and nanosized, and the average size of the PS spherical particles decreased with increasing volume % of water in the polymerization medium. The size of the PS spherical particles increases with increasing radiation dose for the polymerization. Also, the amount of Ag nanoparticle loading could be increased by increasing the irradiation dose for the reduction of the Ag ions. In the second methodology, the polymerization of styrene and reduction of Ag ions were simultaneously performed by irradiating a solution containing styrene and Ag ions in an EtOH/water medium. Interestingly, the Ag nanoparticles were preferentially homogeneously distributed within the PS particles (not on the surface of the PS particles). Thus, Ag nanoparticles were distributed onto the surface of the PS particles using the first approach, but into the PS clusters of the particles via the second. The antimicrobial efficiency of a cloth coated with the Ag-PS composite nanoparticles was tested against bacteria, such as Staphylococcus aureus and Klebsiella pneumoniase, for 100 water washing cycles.

• 문화기술의 융합
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• 제10권3호
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• pp.819-825
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• 2024

진단용방사선발생장치를 사용함에 있어서 선량데이터를 기록하는 이유는 의료진 및 환자의 피폭선량을 기록하고 관리하기 위함이다. 진단용방사선발생장치를 사용함에 있어서 방사선량의 차이를 검증하고 위험성과 차폐체 착용의 유무의 상황에서 피폭선량에 대한 측정과 분석을 통해 사용자의 피폭선량 경감에 대한 인식을 알리고자 하였다. 에스레이튜브와 II튜브에 따라 구분하여 장비를 한국 C-arm 2대, 독일 C-arm 2대장비를 대상으로 각 장비별 선량분석결과 한국 FPD type C-arm 이 가장 높은 선량값이 측정되었고, 독일 I.I type C-arm, 독일 FPD type C-arm, 한국, I.I type C-arm 순서로 피폭선량값이 측정되었다. 차폐체 유무에 따른 피폭선량 분석결과 일반적인 대기상태에 인체팬텀을 놓고 측정결과 산란선에 의해 피폭선량이 약 2배 증가하였으나 차폐체(0.5mm/납앞치마)를 착용하니 약 5배의 피폭선량 감소하는 결과가 나타났다. 피폭선량과 차폐체를 통해 피폭선량의 관리가 중요한 역할을 하며 방사선 피폭을 줄이는 방법을 유추할 수 있다. 또한, 장비마다 출력되는 피폭선량이 다른 특성을 갖고 있음으로 차폐체를 유무를 선별하는데 선량정보로 제공을 할 것으로 기대 한다.

• 한국콘텐츠학회논문지
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• 제10권2호
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• pp.258-267
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• 2010

방사선피폭에 대한 관심이 높아지면서 X선 검사시에 환자에게 조사되는 피폭선량을 정확히 알고 있다는 것은 환자의 불안을 해소하고 또 방사선사나 의사가 피폭선량 경감의식을 향상시키는 데 중요하지만, 임상에서 측정기를 보유하고 있는 시설은 극소수에 불과하다. 본 연구에서는 bit system 및 NDD-M법의 특징을 살려서 우리나라에 사용되고 있는 진단용 X선장치의 출력선량을 직접 측정하여 도표화 하고, X선 출력선량을 아는 경우 또는 모르는 경우 모두에서 적절히 적용할 수 있게 두 가지 방법을 제시하여 실측선량과 비교 실험을 하였다. 그 결과 bit system 및 NDD-M법보다 정확도가 우수한 결과를 나타내어 임상에서 환자가 받는 선량을 더욱 쉽게 알 수 있게 됨으로 방사선관련 종사자들의 의료피폭에 대한 관심이 더욱 높아지고 의료선량감소에 한층 더 노력하는 계기가 될 것으로 사료된다.

• Journal of Radiation Protection and Research
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• 제30권3호
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• pp.113-119
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• 2005

전산화단층촬영(Computed Tomography, CT)은 높은 품질의 인체 단층 영상을 제공하지만 기존의 진단 X선 촬영에 비해 상당히 높은 선량을 환자에게 부여한다. 더욱이 CT 촬영의 수요는 계속적인 증가추세를 보이고 있어 CT 촬영 환자의 선량에 대한 관심이 높아지고 있다. 이에 본 연구에서는 물리적 실측 팬텀과 열형광 선량계를 이용하여 CT 촬영으로 인한 환자의 피폭 선량을 측정을 통해 평가해 보았다. 촬영방식을 기존의 축방향 스캔과 현재 주류를 이루고 있는 나선형 스캔으로 구분하여 선량 측정을 수행하였으며 그 결과 환자의 유효선량이 각각 17.78mSv, 10.01mSv으로 평가되었다. 또한 나선형 스캔 시 환자 선량의 감축 정도는 pitch에 의존한다는 기존의 연구결과를 재확인할 수 있었다. 본 연구에서 사용한 실측 기법은 CT 기술 발전에 기인한 촬영 프로토콜의 변화가 있는 경우 환자 선량 재평가에 응용할 수 있다.

• Archives of Pharmacal Research
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• 제20권3호
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• pp.212-217
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• 1997

Induction of an adaptive response to ionizing radiation in mouse lymphoma (EL4) cells was studied by using cell survival fraction and apoptotic nucleosomal DNA fragmentation as biological end points. Cells in early log phase were pre-exposed to low dose of ${\gamma}$-rays (0.01 Gy) 4 or 20 hrs prior to high dose ${\gamma}$-ray (4, 8 and 12 Gy for cell survival fraction analysis; 8 Gy for DNA fragmentation analysis) irradiation. Then cell survival fractions and the extent of DNA fragmentation were measured. Significant adaptive response, increase in cell survival fraction and decrease in the extent of DNA fragmentation were induced when low and high dose .gamma.-ray irradiation time interval was 4 hr. Addition of protein or RNA synthesis inhibitor, cycloheximide or 5,6-dichloro-1-.betha.-d-ribofuranosylbenzimidazole (DRFB), respectively during adaptation period, the period from low dose ${\gamma}$-ray irradiation to high dose ${\gamma}$-ray irradiation, was able to inhibit the induction of adaptive response, which is the reduction of the extent DNA fragmentation in irradiated EL4 cells. These data suggest that the induction of adaptive response to ionizing radiation in EL4 cells required both protein and RNA synthesis.

• 대한방사선기술학회지:방사선기술과학
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• 제21권1호
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• pp.29-34
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• 1998

The purpose of simple abdomen erect projection is to see the fluid level which indicates gastrointestinal ileus or free air due to perforation. we do not have to insist on low kVp technique in simple abdomen erect position as long as we can detect the fluid level and free air shadow. Therefore, the author tried to decrease patient dose by high kVp technique and to improve the image quality due to motion artifact by reduction of exposure time. [Methods] Experiment 1. * screen/film SRO1000/HRH * exposure factor : $140\;kvp{\pm}5\;kv$ with added filters, 200 mA, 0.01 sec * phantom : Acryles : 15.0 cm(equivalent to 17 cm body thickness) 17.5 cm(equivalent to 21 cm body thickness) 20.0 cm (equivalent to 25 cm body thickness) With the exposure factor for same film density($D=0.8{\pm}0.1$) and with the materials above, we tried to find out entrance skin dose and gonad dose for both male and female. Experiment 2. Burger's phantom radiography were checked to see whether there was any change of image quality according to the kVp and the added filters. Experiment 3. Using rotating meter(self made), we examined the motion artifact and the exposure time limitation. [Results and conculution] 1. Using high voltage technique of 140 kVp with added filter, Skin dose, testicle dose and ovary dose decrease to 89.3%, 47% and 71.4% respectively compare to 70 kVp technique, 2. No great changes of Burger's phantom image has detected as from 70 kVp to 140 kVp and the air hole size of Burger's phantom over 0.028 cc(Diameter 3 mm, hight 4 mm) can be distinghished. 3. 0.01 sec(1 pulse) exposure time is possible in the single phase full wave rectification that why we can quitely reduce the unsharness caused by patient's movement.

• 한국발생생물학회지:발생과생식
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• 제25권4호
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• pp.245-255
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• 2021

The spermatozoa become mature in the epididymis which is divided into initial segment and caput, corpus, and cauda epididymis. The water movement across the epididymal epithelium is important for creating luminal microenvironment for sperm maturation. Aquaporins (Aqps) are water channel proteins, and expression of Aqps is regulated by androgens. The current research was focused to examine expressional regulation of Aqp1 and Aqp9 by an androgenic-anabolic steroid, nandrolone decanoate (ND). The ND at the low dose (2 mg/kg body weight/week) or high dose (10 mg) was subcutaneously administrated into male rats for 2 or 12 weeks. Transcript levels of Aqp1 and Aqp9 were determined by quantitative real-time polymerase chain reaction (PCR) analyses. In the initial segment, level of Aqp1 was decreased with 12 week-treatment, while Aqp9 level was decreased by the high dose treatment for 12 weeks. In the caput epididymis, Aqp9 expression was decreased by the low dose treatment. The 2 week-treatment resulted in an increase of Aqp1 level but a decrease of Aqp9 expression in the corpus epididymis. In the corpus epididymis, the 12 week-treatment at the low dose caused the reduction of Aqp1 and Aqp9 levels, but the high dose treatment resulted in an increase of Aqp1 expression and a decrease of Aqp9 level. In the cauda epididymis, Aqp1 expression was decreased by 2 and 12 week-treatments, while increases of Aqp9 levels was detected with the high dose treatment for 2 weeks and with 12 week-treatment. These findings indicate differential regulation of Aqp1 and Aqp9 expression among epididymal segments by ND.