• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.157-160
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• 2002

The dosage of intra-operative BNCT using near-threshold $^{7}$ Li(p,n)$^{7}$ Be direct neutrons was evaluated with the calculation method validated with the phantom experiment. The production of both neutrons by near-threshold $^{7}$ Li(p,n)$^{7}$ Be and gamma rays by $^{7}$ Li(p,p'gamma)$^{7}$ Li in a Li target was calculated using Lee's method and their transport in the phantom was calculated with MCNP-4B. As a result, the region satisfying the requirements of the protocol in intra-operative BNCT for brain tumors in Japan was acknowledged to be comparable to present BNCT, for the proton energy of 1.900 MeV for example. A boron-dose enhancer (BDE) introduced in this study to increase $^{10}$ (n,$\alpha$)$^{7}$ Li dose in a living body was effective. The void used to increase doses in deep regions was also valid with the BDE. It was found that intra-operative BNCT using near-threshold $^{7}$ Li(p,n)$^{7}$ Be direct neutrons is feasible.

• 약학회지
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• 제38권3호
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• pp.250-264
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• 1994

Omeprazole(OMZ)-cholestyramine(CHL) and various OMZ-Dowex resin complexes were prepared by reaction between OMZ and activated resins in 0.1N NaOH solution. And their physical properties were tested by means of infrared(IR), differential scaning caloimeter(DSC), X-ray diffraction. Chemical stability of OMZ-CHL was increased markedly compared with OMZ and the decomposition of OMZ-CHL followed the pseudo first-order kinetics and the rate constants were $2.743{\times}10^{-4}/day$ at $20^{\circ}C$, $7.83{\times}10^{-3}day^{-1}$ under 80% RH and $1.68{\times}10^{-2}day^{-1}$ under UV radiation, respectively. On the other hand, the rate constants of OMZ were $2.996{\times}10^{-4}day^{-1}$ at $20^{\circ}C$, $1.17{\times}10^{-2}day^{-1}$ under 85% RH, and $4.07{\times}10^{-2}day^{-1}$ under UV radiation, respectively. The rates of dissolution of OMZ-CHL bulk and OMZ-CHL tablet were 100% and more than 85% in 15 minutes, respectively, which were increased than OMZ base and OMZ-tablet. In the acute toxicological test, the value of oral $LD_{50}$(mouse) was 4.608 g/kg. OMZ-CHL was pelletized using lactose, polyethyle neglycol(PEG), D-sorbitol, Avicel PH 101, sodium laurylsulfate and polyvinylpyrrolidone(PVP) K-30, and enteric coated with HPMCP, Myvacet, acetone, ethanol and cetanol, of which dissolution rate was found to be more than 85% in 10 minutes. From the above results, it was found that OMZ-CHL is a useful means for development of new oral dosage forms of OMZ.

• 대한치과의사협회지
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• 제58권7호
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• pp.388-397
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• 2020

Objective: The purpose of the study was to calculate the effective and absorbed organ doses of cone-beam computed tomography (CBCT) in pediatric patient using personal computer-based Monte Carlo (PCXMC) software and to compare them with those measured using thermoluminescent dosimeters (TLDs) and anthropomorphic phantom. Materials and Methods: Alphard VEGA CBCT scanner was used for this study. A large field of view (FOV) (20.0 cm × 17.9 cm) was selected because it is a commonly used FOV for orthodontic analyses in pediatric patients. Ionization chamber of dose-area product (DAP) meter was located at the tube side of CBCT scanner. With the clinical exposure settings for a 10-year-old patient, DAP value was measured at the scout and main projection of CBCT. Effective and absorbed organ doses of CBCT at scout and main projection were calculated using PCXMC and PCXMCRotation software respectively. Effective dose and absorbed organ doses were compared with those obtained by TLDs and a 10-year-old child anthropomorphic phantom at the same exposure settings. Results: The effective dose of CBCT calculated by PCXMC software was 292.6 μSv, and that measured using TLD and anthropomorphic phantom was 292.5 μSv. The absorbed doses at the organs largely contributing to effective dose showed the small differences between two methods within the range from -18% to 20%. Conclusion: PCXMC software might be used as an alternative to the TLD measurement method for the effective and absorbed organ dose estimation in CBCT of large FOV in pediatric patients.

• Imaging Science in Dentistry
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• 제42권4호
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• pp.237-242
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• 2012

Purpose: The objectives of this study were to survey the radiographic exposure parameters, to measure the patient doses for intraoral dental radiography nationwide, and thus to establish the diagnostic reference levels (DRLs) in intraoral dental X-ray examination in Korea. Materials and Methods: One hundred two intraoral dental radiographic machines from all regions of South Korea were selected for this study. Radiographic exposure parameters, size of hospital, type of image receptor system, installation duration of machine, and type of dental X-ray machine were documented. Patient entrance doses (PED) and dose-area products (DAP) were measured three times at the end of the exit cone of the X-ray unit with a DAP meter (DIAMENTOR M4-KDK, PTW, Freiburg, Germany) for adult mandibular molar intraoral dental radiography, and corrections were made for room temperature and pressure. Measured PED and DAP were averaged and compared according to the size of hospital, type of image receptor system, installation duration, and type of dental X-ray machine. Results: The mean exposure parameters were 62.6 kVp, 7.9 mA, and 0.5 second for adult mandibular molar intraoral dental radiography. The mean patient dose was 2.11 mGy (PED) and 59.4 $mGycm^2$ (DAP) and the third quartile one 3.07 mGy (PED) and 87.4 $mGycm^2$ (DAP). Doses at university dental hospitals were lower than those at dental clinics (p<0.05). Doses of digital radiography (DR) type were lower than those of film-based type (p<0.05). Conclusion: We recommend 3.1 mGy (PED), 87.4 $mGycm^2$ (DAP) as the DRLs in adult mandibular molar intraoral dental radiography in Korea.

• Imaging Science in Dentistry
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• 제37권2호
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• pp.87-92
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• 2007

Purpose: To measure the absorbed doses of cone beam computed tomography (CBCT), which is recently being more frequently used, and to compare them with those of panoramic radiography. Materials and Methods: To measure the absorbed doses of CBCT ($PSR-9000N^{TM}$, Asahi Roentgen Ind. Co., Japan), we placed TLD chips on the skin regions above the parotid and thyroid glands, and on the dorsum of tongue in a dental head phantom. We used two image acquisition modes of the Dental and Panoramic modes of CBCT, which differed in the field of view. Also, panoramic radiographs (Auto IIIN, Asahi Roentgen Ind. Co., Japan) were taken to compare with the absorbed doses of CBCT. Result: In the Dental mode of CBCT, the absorbed doses of the parotid gland, dorsum of tongue, and thyroid gland were 3.53, 3.13, and 0.36 mGy, respectively. In the Panoramic mode of CBCT, they were 9.57, 9.15, and 0.85 mGy, respectively. The panoramic mode showed higher absorbed doses than those of the Dental mode. In the panoramic radiography, the absorbed doses of the parotid gland, dorsum of tongue, and thyroid gland were 1.21, 1.19, and 0.16 mGy, respectively. And they were about 1/3 of the Dental mode and 1/9 of the Panoramic mode of CBCT. Conclusion: Absorbed doses of CBCT are higher than those of panoramic radiography, and dependent upon the field of view.

• 방사선산업학회지
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• 제8권2호
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• pp.111-121
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• 2014

This study was aimed to select useful mutants of rapeseed (Brassica napus L.) and leaf mustard (Brassica juncea L.), the seeds of three lines S-14, S-27, and S-28 were treated with gamma-ray and EMS. The optimum ranges of gamma-ray dose and EMS concentration to enlarge the characteristic morphological variations were also separately investigated. The survival rates of S-28 only linearly decreased with increasing the gamma-ray dose. The overall growth parameters decreased of gamma-ray dose in all three lines of S-14, S-27, and S-28. The reduction dosage 50 of gamma-ray was identified as 1,200 Gy for S-14 leaf mustard, while those of S-27 and S-28 rapeseed lines were appeared as same 1,000 Gy. The emergence rates of S-14 and S-27 showed no significant differences by EMS treatment, while the growth of all three lines were significantly decreased. The reduction concentration 50 in S-14 could not be determined, demonstrating that this leaf mustard line is presumably insensitive to mutagenic EMS, while those in S-27 and S-28 were identified as 3.0 and 2.5%, respectively, showing that these rapeseed lines possess higher sensitivity to EMS than S-14. Various morphological characteristics of $M_1$ generation obtained from mutagen treatment were elaborately investigated for further maintenance of $M_2$ generation. In $M_2$ generation variants showing short stem, yellow color in seed coat, chlorophyll deficiencies in leaf or pod, abnormal flower color were selected as potentially useful mutants for breeding.

• The Korean Journal of Physiology and Pharmacology
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• 제27권1호
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• pp.31-38
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• 2023

Carboplatin, an advanced anticancer drug with excellent efficacy against ovarian cancer, was developed to alleviate the side effects that often occur with cisplatin and other platinum-based compounds. Our study reports the in vitro characteristics, viability, and activity of cells expressing the inducible nitric oxide synthase (iNOS) gene after carboplatin was conjugated with polysuccinimide (PSI) and administered in combination with other widely used anticancer drugs. PSI, which has promising properties as a drug delivery material, could provide a platform for prolonging carboplatin release, regulating its dosage, and improving its side effects. The iNOS gene has been shown to play an important role in both cancer cell survival and inhibition. Herein, we synthesized a PSI-carboplatin conjugate to create a modified anticancer agent and confirmed its successful conjugation. To ensure its solubility in water, we further modified the structure of the PSI-carboplatin conjugate with 2-aminoethanol groups. To validate its biological characteristics, the ovarian cancer cell line SKOV-3 and normal ovarian Chinese hamster ovary cells were treated with the PSI-carboplatin conjugate alone and in combination with paclitaxel and topotecan, both of which are used in conventional chemotherapy. Notably, PSI-carboplatin conjugation can be used to predict changes in the genes involved in cancer growth and inhibition. In conclusion, combination treatment with the newly synthesized polymer-carboplatin conjugate and paclitaxel displayed anticancer activity against ovarian cancer cells but was not toxic to normal ovarian cancer cells, resulting in the development of an effective candidate anticancer drug without severe side effects.

• Korean Journal of Radiology
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• 제21권1호
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• pp.68-76
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• 2020

Objective: To survey care providers' willingness to use 2-mSv computed tomography (CT) in their usual practice for adolescents and young adults with suspected appendicitis. Materials and Methods: An ethical committee approved this prospective study. We introduced 2-mSv CT in 20 hospitals through a pragmatic clinical trial. At the final phase of the trial, we invited 698 potentially-involved care providers in the survey regarding their willingness to use 2-mSv CT. Multivariable logistic regression analyses were performed to identify factors associated with willingness. Nine months after the completion of the trial patient recruitment, we surveyed whether the hospitals were using 2-mSv CT in usual practice. Results: The analyses included responses from 579 participants (203 attendings and 376 trainees; 221 radiologists, 196 emergency physicians, and 162 surgeons). Regarding the willingness to immediately change their standard practice to 2-mSv CT, 158 (27.3%), 375 (64.8%), and 46 (7.9%) participants responded as "yes" (consistently), "partly" (selectively), and "no", respectively. Willingness varied considerably across the hospitals, but only slightly across the participants' departments or job titles. Willingness was significantly associated with attendings (p = 0.004), intention to maintain the dedicated appendiceal CT protocol (p < 0.001), belief in compelling evidence on the carcinogenic risk of conventional-dose CT radiation (p = 0.028), and hospitals having more than 1000 beds (p = 0.031). Fourteen of the 20 hospitals kept using 2-mSv appendiceal CT in usual practice after the trial. Conclusion: Despite the extensive efforts over the years of this clinical trial, many care providers were willing to use 2-mSv CT selectively or not willing to use.

• 한국방사선학회논문지
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• 제11권5호
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• pp.387-392
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• 2017

영 유아는 사건, 사고 및 교통사고 또는 질병으로 인해 머리에 골절 및 혈관파열, 피부에 상처를 받아 병원에 내원하여 영상의학과에서 머리 검사인 전 후(Skull AP) 및 측면(Skull LAT) 촬영을 받게 된다. 머리검사에서 성인 머리(Skull) 촬영은 격자를 이용하여 촬영에 적용하면 방사선 2차선을 제거하여 영상의 대조도를 높인다. 그러나 방사선 노출조건 중 관전압을 8~10 kVp 높게 주어야 하며 환자피폭이 증가한다. 본 연구는 영 유아 머리촬영시 격자(grid)를 이용하지 않고 동등한 영상을 얻을 수 있다면 피폭선량 감소 및 Grid Cut off에 의한 아티팩트를 방지할 수 있어 연구해 보았다. 연구자는 방사선계측기 이용 방사선선량을 측정 하고 의료영상평가 방법 중에서 주관적 평가(ROC,receiver operationg characteristic)을 해 보았다. 결과에서 격자를 이용하지 않고 촬영하면 환자 피폭선량 감소와 영상 평가에서도 영 유아의 머리 촬영시 격자를 이용하지 않고 촬영을 하게 되면 머리 전 후촬영에서 0.019 mGy 와 측면촬영 0.02 mGy 피폭선량 감소가 있었고 영상평가에서도 4점을 높게 받았다. 결론으로 병원에 내원한 영 유아 머리촬영은 격자를 이용하지 않고 촬영하면 피폭 선량 감소 및 영상 아티팩트인 Grid Cut off을 방지 할 수 있고 엑스선관 수명이 연장되리라 사료된다.

• 한국방사선학회논문지
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• 제14권2호
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• pp.97-104
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• 2020

방사선이 조사된 흰쥐의 간에서 아로니아의 방사선 방호효과가 나타나는가를 혈청검사를 통하여 알아보고자 하였다. 실험동물은 (체중 200~250g) 수컷 흰쥐 5마리씩, 1군으로 정상군, 5 Gy 방사선대조군은 2군, 5 Gy 방사선조사 아로니아 실험군은 3군으로 설정하였다. 정상군 1군(A)은 일반식을 투여하고 방사선 조사를 실시하지 않고, 대조군 2군(B)은 일반식을 투여하여 방사선 조사를 하였고, 실험군 3군(C)는 방사선조사 전 14일 동안 아로니아, 경구투여량(100 mg/kg/day)로 1일 2회씩 50 mg/kg/day로 증류수에 희석하여 각각 흰쥐에 14일 동안 쥐용 존데를 이용하여 경구투여 후 방사선조사를 실시하였다, 이 연구를 위해서 Linac (선형가속기) 6 MV X선 치료장치를 사용하여 5 Gy 방사선이 1회 전신조사 된 흰쥐의 혈액을 채취하여 간에 관련된 5가지 혈청검사를 실시하였으며, 통계분석은 분산분석(ANOVA test)를 실시하였다. 결론적으로 실험분석을 확인한 결과는 아로니아의 간에 대한 방사선방호 효과가 없는 것으로 나타났다. 그러나 통계적으로 ALB (P > 0.05)는 유의성이 없고, TP (P < 0.05)는 유의한 차이가 있다고 확인되었다. 향후에는 다양한 검사가 이루어져야 할 것으로 사료된다.