• 한국의학물리학회지:의학물리
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• 제15권3호
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• pp.140-148
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• 2004

본 연구에서는 PTRAN 전산코드를 사용하여 양성자에 대한 물 흡수선량의 분포를 계산하였다. 먼저 양성자와 물과의 상호작용에 대하여 정리하고 흡수선량의 계산과정에 대하여 기술하였다. 또한 PTRAN의 수송 알고리즘, 파일구조, 그리고 실행방법을 제시하였다. 본 결과에서는 양성자 에너지 60, 100, 150, 200, 250 WeV에 대하여 양성자에 의한 물 흡수선량의 분포가 쿨롱 상호작용과 핵반응의 합으로 주어지며, 브레그 봉우리의 형태가 에너지손실의 통계적 성질과 다중산란에 의존함을 보였다. 본 연구를 통하여 양성자에 대한 물 흡수선량의 구조 해석에 PTRAN 코드가 유용함을 알 수 있었다.

• 방사선산업학회지
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• 제7권2_3호
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• pp.109-113
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• 2013

In a previous study, a relatively high dose of gamma radiation (1 kGy) did not fully induce typical SOS genes such as sulA, recA, recN, and din in Salmonella Typhimurium (S. Typhimurium) (Lim et al. 2008, Gene expression profiles following high-dose exposure to gamma radiation in Salmonella enterica serovar Typhimuium. J. Radiat. Ind. 3:111-119). In this study, we examined changes in the transcriptional repertoire of S. Typhimurium after a dose of 10 Gy using DNA microarrays. It was found that more than half (~65%) of the 26 up-regulated genes belong to the SOS regulon: ten genes are typical SOS genes, and seven genes are Salmonella prophage genes, which are known to be activated by LexA cleavage. Among 29 down-regulated genes, the function of five genes with the most decreased expression is associated with carbohydrate transport and energy production. This suggests that upon exposure to gamma radiation cells may cease growing by reducing the metabolic activity, and repair DNA damage using a DNA repair system such as the SOS response system. The difference in expression of the SOS genes between a high (1 kGy) and low (10 Gy) dose of radiation shows the possibility that cells may opt for one of multiple regulatory circuits in response to the specific gamma radiation dose.

• Asian Pacific Journal of Cancer Prevention
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• 제14권9호
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• pp.5371-5374
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• 2013

Objective: Photodynamic therapy (PDT) is an emerging therapeutic procedure suitable for the treatment of cervical cancer. However, the side effects of PDT are severe, including skin ulceration, so we designed an experiment to examine the effects of multiple low-dose photodynamic therapy of 5, 10, 15, 20-tetrakis(1-methylpyridinium-4-yl) porphyrin (Tmpyp4) on tumour growth by utilizing a model in nude mice implanted with Hela cervical cancer cells. Materials and Methods: Female BALB/c nude mice (aged 5-6 weeks, weighing 18-20 g) were used. Hela cervical cancer cells were injected subcutaneously ($1{\times}10^7cells/200{\mu}L$). Ten days after injection, the mice were divided into three groups (n=6), the A group of controls without any treatment, the B group receiving a single-treatment with Tmpyp4 (10 mg/kg, intratumor injection) and irradiation (blue laser, $108J/cm^2$), and the C group given three-treatments with Tmpyp4 (10 mg/kg, intratumor injection) and irradiation at intervals of two days. After starting treatment, tumours were measured every two days, to assess growth. At 2 weeks after the last treatment of C group, tumour tissue and organs were collected from each mouse to evaluate tumor histology and organ damage. Results: Tumour growth in C group was significantly inhibited compared with A and B groups (P<0.05), without any injury to the skin and internal organs. Conclusion: Our novel findings demonstrated that multiple low-dose photodynamic therapy of Tmpyp4 could inhibit cervical cancer growth significantly with no apparent side effects.

• Clinical and Experimental Pediatrics
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• 제48권10호
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• pp.1090-1095
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• 2005

목 적 : 신생아 호흡곤란증후군에서 폐 표면활성제 보충요법으로 생존률이 향상되고 있다. 신생아 호흡곤란증후군에서 폐 표면활성제 단일 투여군(S군)과 재투여군(M군)의 임상양상을 비교 관찰하기 위하여 본 조사를 실시하였다. 방 법 : 2002년 1월부터 2004년 3월까지 경희의대 부속병원 신생아 중환자실에서 호흡곤란증후군으로 진단받고 폐 표면활성제 보충요법을 실시하였던 48례를 대상으로, 이 중 S군 32례, M군 16례의 임상경과를 비교 검토하였다. 결 과 : 1) 평균 출생체중과 평균 재태기간은 S군이 $1,577{\pm}708g$, $30{\pm}3$주, M군이 $1,755{\pm}921g$, $31{\pm}4$주였다. 출생 초기 pH는 각각 $7.25{\pm}0.15$와 $7.26{\pm}0.08$로 의미 있는 차이가 없었다. 출생당시 소생술을 실시했는지의 여부와 산전 산모에 있어 스테로이드 투여 유무의 경우도 두 군간에 유의한 차이가 없었다. Bomsel 기준에 의한 호흡곤란증후군 분류로 볼 때에도 두 군간에 grade II, III, IV의 경우 통계적으로 유의한 차이가 없었다. 폐 표면활성제 투여 전의 VI는 S군에서 $0.075{\pm}0.08$, M군에서 $0.096{\pm}0.06$으로 M군에서 더 나쁘나 통계적으로는 유의하지 않았고, a/A $PO_2$는 S군에서 $0.22{\pm}0.13$, M군에서는 $0.15{\pm}0.07$로 M군에서 의미있게 나쁜 소견을 보였다(P<0.05). 2) 72시간까지의 VI와 a/A $PO_2$의 변동은 S군에서 M군에 비해 지속적인 개선을 관찰할 수 있었고, M군은 재발양상이 관찰되어 재투여를 한 후 호전되는 소견을 보였다. 3) 평균 인공호흡기 기간은 S군에서 9.7일, M군에서 6일로 유의한 차이가 없었다. 예후에 있어 28일 이내의 사망률은 두 군 모두 6.3%로 동일하였다. 합병증으로 뇌실내출혈, 미숙아 망막증, 괴사성장염, 기관지폐 이형성증, 패혈증 및 파종성 혈관내 응고증은 두 군간에 의미있는 차이를 보이지 않았다. 결 론 : 신생아 호흡곤란증후군에서 S군과 M군의 임상경과에서 VI와 a/A $PO_2$의 지속적 호전은 S군에서 현저하였고, M군은 재발양상이 관찰되어 재투여의 필요성이 있었다. 이러한 재발된 경우에도 적극적인 재투여를 실시함으로써 사망률과 합병증의 빈도가 S군과 M군 사이에 차이가 없는 것으로 보아, 재발되는 경우 폐 표면활성제 재투여가 예후의 개선을 가져오기에 재투여의 필요성이 강조되었다.

• 한국응급구조학회지
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• 제10권1호
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• pp.51-60
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• 2006

Background: The toxicity of paraquat has been known to be caused by oxygen free radicals which leads to the lipid peroxidation and multiple organ failure. High dose vitamin C has been known to be a effective antioxidant activities against the paraquat intoxication. This study was designed to evaluate the effect of regular injection of high dose vitamin C on liver damage in paraquat poisoned rat model. Method: Fifty five rats of Sprague-Dawley strain were divided into three groups: control group, only intraperitoneally injected saline; paraquat group, single dose intraperitoneally injected paraquat(24.5%, 40 mg/kg) and every 8 hours injected saline; paraquat and vitamin C group, single dose intraperitoneally injected paraquat(24.5%, 40 mg/kg) and every 8 hours injected vitamin C(72 mg/kg). Rats were sacrificed on the 12 hours, 1st day, 2nd day, 4th day, 7th day after injection and liver tissue was obtained. H&E(Hematoxylin & Eosin) stain and Masson's trichrome stain for collagen fiber detection were undertaken. The results were observed using the microscope. Results: 1. There were no differences between control and experimental group at the 12hours after regular injection of high dose vitamin C. 2. There were significantly decreased liver damage in experimental group in the 1st day after regular injection of high dose vitamin C. 3. There were significantly increased recovery of liver damage with time in experimental group after regular injection of high dose vitamin C. Conclusion: These results suggest that regular injection of high dose vitamin C is effective in decreasing liver damage in paraquat intoxication.

• Radiation Oncology Journal
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• 제8권1호
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• pp.125-131
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• 1990

방사선조사시 선량분포에 영향을 미치는 여러가지 요소들 중에서 조직불균등성은 선량을 상당히 변화시킨다. 특히, 중뇌강은 여러골조직으로 구성되어 있어 조직 불균등성에 따른 상당한 선랑감쇠가 예상된다. 6 MV X-선 조사후 중두개와에서의 선량분포측정은 LiF TLD 소자를 이용하였으며 같은 측정장소에서, 계산에 의한 예상선량과 실측선량의 비교를 시도하였다. 계산에 의하면, 골조직 1 cm당 예상선량감쇠는 $3.74\%$를 나타내었다. 한편, 골조직을 고려한 예상선량과 실측선량의 차이는 매우 적었으며 $\pm0.21\%$의 오차범위내에서 일치됨을 나타내었다.

• Nuclear Engineering and Technology
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• 제42권6호
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• pp.670-679
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• 2010

In this paper, a new approach using a pixel-based correction method was developed to fix the non-uniform responses of flat-bed type scanners used for radiochromic film dosimetry. In order to validate the method's performance, two cases were tested: the first consisted of simple dose distributions delivered by a single port; the second was a complicated dose distribution composed of multiple beams. In the case of the simple individual dose condition, ten different doses, from 8.3 cGy to 307.1 cGy, were measured, horizontal profiles were analyzed using the pixel-based correcton method and compared with results measured by an ionization chamber and results corrected using the existing correction method. A complicated inverse pyramid dose distribution was made by piling up four different field shapes, which were measured with GAFCHROMIC$^{(R)}$EBT film and compared with the Monte Carlo calculation; as well as the dose distribution corrected using a conventional method. The results showed that a pixel-based correction method reduced dose difference from the reference measurement down to 1% in the flat dose distribution region or 2 mm in a steep dose gradient region compared to the reference data, which were ionization chamber measurement data for simple cases and the MC computed data for the complicated case, with an exception for very low doses of less than about 10 cGy in the simple case. Therefore, the pixel-based scanner correction method is expected to enhance the accuracy of GAFCHROMIC$^{(R)}$EBT film dosimetry, which is a widely used tool for two-dimensional dosimetry.

• Nuclear Engineering and Technology
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• 제51권8호
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• pp.1991-1997
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• 2019

In this manuscript, we present a method for the direct calculation of an ambient dose equivalent (H^* (10)) for the external gamma-ray exposure with an energy range of 40 keV to 2 MeV in an electronic personal dosimeter (EPD). The designed EPD consists of a 3 × 3 ㎟ PIN diode coupled to a 3 × 3 × 3 ㎣ CsI (Tl) scintillator block. The spectrum-to-dose conversion function (G(E)) for estimating H^* (10) was calculated by applying the gradient-descent method based on the Monte-Carlo simulation. The optimal parameters for the G(E) were found and this conversion of the H^* (10) from the gamma spectra was verified by using ²⁴¹Am, ¹³⁷Cs, ²²Na, ⁵⁴Mn, and ⁶⁰Co radioisotopes. Furthermore, gamma spectra and H^* (10) were obtained for an arbitrarily mixed multiple isotope case through Monte-Carlo simulation in order to expand the verification to more general cases. The H^* (10) based on the G(E) function for the gamma spectra was then compared with H^* (10) calculated by simulation. The relative difference of H^* (10) from various single-source spectra was in the range of ±2.89%, and the relative difference of H^* (10) for a multiple isotope case was in the range of ±5.56%.

• 약학회지
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• 제40권1호
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• pp.84-89
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• 1996

This study was done to investigate the effect of glycyrrhizin on the lethality induced by galactosamine and lipopolysaccharide coadministration in mice. Glycyrrhizin was injecte d intravenously as a multiple dose at 20, 15, 10, 5, and O hr before galactosamine and lipopolysaccharide coadministration. Lethality and tumor necrosis factor (TNF${\alpha}$) level in serum were surveyed as markers of glycyrrhizin effect. Glycyrrhizin had no effect on the lethality induced by galactosamine and lipopolysaccharide when glycyrrhizin was administered as a single dose. Glycyrrhizin reduced the lethality induced by galactosamine and LPS in dose-dependent manner when glycyrrhizin was administered as a multiple dose at 20, 15, 10, 5 and O hr before galactosamine and lipopolysaccharide coadministration. Glycyrrhizin reduced the serum TNF${\alpha$ level.

• 약학회지
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• 제42권4호
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• pp.431-436
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• 1998

The pharmacokinetics of CKD-602, a new camptothecin anticancer derivative, were studied in mice, rats and dogs following a single or multiple intravenous administration, and the following results were obtained. The blood levels of CKD-602 declined in biphasic fashions with peak plasma levels $(C_0)$ of $2.63{\mu}g/ml$ in mice, $2.27{\mu}g/ml$ in tumor bearing mice, $2.84{\mu}g/ml$ in rats at a dose of 20mg/kg, and of 0.02mcg/ml in dogs at a dose of 0.5mg/kg. The plasma half-lives $(t_{1/2}{\beta})$ were 9.55hr in mice, 9.94hr in tumor bearing mice, 9.98hr in rats and 12.75hr in dogs. AUC of CKD-602 was increased linearly with the dose at a range from 5 to 20mg/kg. Moreover, Cltot and Vdss were also not significantly changed with increasing the dose. On the other hand, after 5 daily intravenous bolus injection of CKD-602 (5mg/kg) in rats, $t_{1/2}{\beta}$, AUC and MRT of CKD-602 were 11.90hr, $3.19{\mu}g{\cdot}hr/ml$, and 11.61hr, respectively, which were slightly higher than after the single bolus injection.