• 대한방사선치료학회지
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• 제14권1호
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• pp.59-64
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• 2002

Purpose : In radiotherapy, various materials are used to located in treatment field unintentionally. It increases the dose delivered to the skin by interactions of the X-ray within the materials and occurs unwanted skin reaction.(due to the dose build-up effect) This aim of the this study is to measure the increase in skin dose when 13 materials are located in treatment field. Methods : Photon beam measurements were made using an plane-parallel chamber (Markus, PTW-Freiburg) in a polystyrene phantom. skin dose were measured using various overlaying 13 materials. a fixed geometry of a $10{\times}10cm$ field, a SSD=100cm and photon energy 4MV on Varian CLINAC 600C accelerator were used for all measurements. Results : There is an increase in skin dose for all materials($16.4{\sim}160.1\%$). As a percentage of maximum dose, the lowest skin dose were measured for the underwear with silk($43.2\%$) and the highest were measured for the 100m1 fluid-bag($96.6\%$) Conclusion : There is a significant increase in skin dose with 13 materials in the treatment field. a significant increase in skin dose can occur which could produce unwanted skin reaction. considerations for placement of 13 materials to be outside the treatment field whenever possible should be used to keep skin dose to a minimum level.

• 혜화의학회지
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• 제22권1호
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• pp.171-184
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• 2013

Single-and repeated-dose toxicities of Compound K (CK) were evaluated according to Toxicity Test Guidelines of Korea Food and Drug Administration using Sprague-Dawley rats. For single-dose toxicity study, CK was dissolved in drinking water, orally administered and examined for 14 days. As results, CK up to a dose of 5,000 mg/kg, the limited dose, neither induced death, clinical signs and necropsy findings, nor affected body weight gain and organ weights, in which 10% lethal dose could not be estimated. Based on the results of single-dose toxicity test, CK was administered at doses of 500, 1,000 or 2,000 mg/kg for 28 days for the evaluation of repeated-dose toxicity. All doses including the limited dose (2,000 mg/kg) of CK did not cause any abnormalities of rats, including mortality, clinical signs, body weight gain, feed/water consumption, necropsy findings, organ weights, hematology, blood biochemistry. Rather, high doses (1,000 - 2,000 mg/kg) of CK reduced the serum levels of alanine transaminase (ALT), aspartate transaminase (AST), creatinine phosphokinase (CPK), lactate dehydrogenase (LDH) and triglycerides, in addition to an increase in glucose, indicative of protective effects on hepatic and muscular injuries. Thus, both maximum tolerable dose (MTD) and no observed adverse effect level (NOAEL) were not determined. The results indicate that long-term intake of high-dose CK might not induce general adverse effects.

• 대한방사선기술학회지:방사선기술과학
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• 제42권1호
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• pp.47-51
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• 2019

This study was conducted from July 1 to September 30, 2018 using Optically Stimulated Luminescence Dosimeter(OSLD) and photoluminescent glass dosimeter(PLD) to measure the 3-month exposure dose and the cumulative dose in the active working area of the nuclear medicine worker Respectively. As a result, the cumulative dose for three months in the worker and work area was measured as 1.97 mSv and 2.02 mSv in the PLD. The mean surface dose and the mean depth dose of the OSLD were measured to be 2.04 mSv. The difference in the total surface dose measured by the PLD and the OSLD was 0.66mSv and the total mean surface dose was 0.07mSv. The difference between the total depth dose and the total depth dose was 0.1mSv and 0.02mSv, respectively. It was found that the dose value of the OSLD was higher than that of the PLD. In addition, it was found that the maximum difference of 0.01mSv was observed between the PLD and the OSLD of the worker. For the dose measurement of the two dosimetry systems, there was no significant difference between the PLD and the OSLD in the surface dose of 0.239 (p>0.05). Also, the significance of PLD and OSLD in the deep dose was 0.109, which was not statistically significant (p>0.05).

• Communications for Statistical Applications and Methods
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• 제29권4호
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• pp.421-439
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• 2022

Phase I dose-finding trials are essential in drug development. By finding the maximum tolerated dose (MTD) of a new drug or treatment, a Phase I trial establishes the recommended doses for later-phase testing. The primary toxicity endpoint of interest is often a binary variable, which describes an event of a patient who experiences dose-limiting toxicity. However, there is a growing interest in dose-finding studies regarding non-binary outcomes, defined by either the weighted sum of rates of various toxicity grades or a continuous outcome. Although several novel methods have been proposed in the literature, accessible software is still lacking to implement these methods. This study introduces a newly developed R package, UnifiedDoseFinding, which implements three phase I dose-finding methods with non-binary outcomes (Quasi- and Robust Quasi-CRM designs by Yuan et al. (2007) and Pan et al. (2014), gBOIN design by Mu et al. (2019), and by a method by Ivanova and Kim (2009)). For each of the methods, UnifiedDoseFinding provides corresponding functions that begin with next that determines the dose for the next cohort of patients, select, which selects the MTD defined by the non-binary toxicity endpoint when the trial is completed, and get oc, which obtains the operating characteristics. Three real examples are provided to help practitioners use these methods. The R package UnifiedDoseFinding, which is accessible in R CRAN, provides a user-friendly tool to facilitate the implementation of innovative dose-finding studies with nonbinary outcomes.

• Radiation Oncology Journal
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• 제35권2호
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• pp.121-128
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• 2017

Purpose: To report the results of a correlation analysis of skin dose assessed by in vivo dosimetry and the incidence of acute toxicity. This is a phase 2 trial evaluating the feasibility of intraoperative radiotherapy (IORT) as a boost for breast cancer patients. Materials and Methods: Eligible patients were treated with IORT of 20 Gy followed by whole breast irradiation (WBI) of 46 Gy. A total of 55 patients with a minimum follow-up of 1 month after WBI were evaluated. Optically stimulated luminescence dosimeter (OSLD) detected radiation dose delivered to the skin during IORT. Acute toxicity was recorded according to the Common Terminology Criteria for Adverse Events v4.0. Clinical parameters were correlated with seroma formation and maximum skin dose. Results: Median follow-up after IORT was 25.9 weeks (range, 12.7 to 50.3 weeks). Prior to WBI, only one patient developed acute toxicity. Following WBI, 30 patients experienced grade 1 skin toxicity and three patients had grade 2 skin toxicity. Skin dose during IORT exceeded 5 Gy in two patients: with grade 2 complications around the surgical scar in one patient who received 8.42 Gy. Breast volume on preoperative images (p = 0.001), ratio of applicator diameter and breast volume (p = 0.002), and distance between skin and tumor (p = 0.003) showed significant correlations with maximum skin dose. Conclusions: IORT as a boost was well-tolerated among Korean women without severe acute complication. In vivo dosimetry with OSLD can help ensure safe delivery of IORT as a boost.

• Asian Pacific Journal of Cancer Prevention
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• 제16권17호
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• pp.7795-7801
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• 2015

The aim of the present research was to establish primary characteristics of electron beams for a Varian 2100C/D linear accelerator with recently developed PRIMO Monte Carlo software and to verify relations between electron energy and dose distribution. To maintain conformity of simulated and measured dose curves within 1%/1mm, mean energy, Full Width at Half Maximum (FWHM) of energy and focal spot FWHM of initial beam were changed iteratively. Mean and most probable energies were extracted from validated phase spaces and compared with related empirical equation results. To explain the importance of correct estimation of primary energy on a clinical case, computed tomography images of a thorax phantom were imported in PRIMO. Dose distributions and dose volume histogram (DVH) curves were compared between validated and artificial cases with overestimated energy. Initial mean energies were obtained of 6.68, 9.73, 13.2 and 16.4 MeV for 6, 9, 12 and 15 nominal energies, respectively. Energy FWHM reduced with increase in energy. Three mm focal spot FWHM for 9 MeV and 4 mm for other energies made proper matches of simulated and measured profiles. In addition, the maximum difference of calculated mean electrons energy at the phantom surface with empirical equation was 2.2 percent. Finally, clear differences in DVH curves of validated and artificial energy were observed as heterogeneity indexes were 0.15 for 7.21 MeV and 0.25 for 6.68 MeV. The Monte Carlo model presented in PRIMO for Varian 2100 CD was precisely validated. IAEA polynomial equations estimated mean energy more accurately than a known linear one. Small displacement of R50 changed DVH curves and homogeneity indexes. PRIMO is a user-friendly software which has suitable capabilities to calculate dose distribution in water phantoms or computerized tomographic volumes accurately.

• Nuclear Engineering and Technology
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• 제45권1호
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• pp.1-12
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• 2013

This paper describes the radiation doses to human and non-human biota in the Republic of Korea, as a result of the Fukushima nuclear accident. By using the measured airborne activity and ground deposition, the effective and thyroid doses of five human age groups (infant, 5 years, 10 years, 15 years and adult) were estimated by the ECOSYS code, and the whole body absorbed dose rate of the eight Korean reference animals and plants (RAPs) was estimated by the K-BIOTA (the Korean computer code to assess the risk of radioactivity to wildlife). The first-year effective and thyroid human doses ranged from 5.7E-5 mSv in the infant group to 2.0E-4 mSv in the 5 years group, and from 5.0E-4 mSv in the infant group to 3.4E-3 mSv in the 5 years group, respectively. The life-time (70 years) effective and thyroid human doses ranged from 1.5E-4 mSv in the infant group to 3.0E-4 mSv in the 5 years group, and from 6.0E-4 mSv in the infant group to 3.5E-3 mSv in the 5 years group, respectively. The estimated maximum whole body absorbed dose rate to the Korean RAPs was 6.7E-7 mGy/d for a snake living in soil (terrestrial biota), and 2.0E-5 mGy/d for freshwater fish (aquatic biota), both of which were far less than the generic dose criteria to protect biota from ionizing radiation. Also, the screening level assessment for ERICA's (Environmental Risks from Ionizing Contaminants: Assessments and management) limiting organisms showed that the risk quotient (RQ) for the estimated maximum soil and water activity was significantly less than unity for both the terrestrial and freshwater organisms. Conclusively, the radiological risk of the radioactivity released into the environment by the Fukushima nuclear accident to the public and the non-human biota in the republic of Korea is considered negligible.

• 대한방사선기술학회지:방사선기술과학
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• 제44권5호
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• pp.489-494
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• 2021

In this study, radioactivity quantitative analysis was performed on radon contained in cigarette, and the effective dose was calculated using the result value to determine the amount of exposure caused by smoking. A total of 5 types of cigarettes were sampled. Cigarette smoke was collected by using activated carbon, and tobacco were measured by homogenizing for quantitative analysis. For each sample, Bi-214 and Pb-214 were subjected to gamma nuclide analysis to observe the uranium-based radioactive material contained in cigarette, and a measurement time of 30,000 seconds was set for the sample based on the results of previous studies. As a result of measuring the radioactivity of tobacco, a maximum of 0.715 Bq/kg was derived, and in the case of cigarette smoke measured using activated carbon, a maximum of 3.652 Bq/kg was derived. Using this measurement, the average effective dose to the lungs is 0.938 mSv/y, and it was found that there is a possibility of receiving exposure up to 1.099 mSv/y depending on the type of tobacco. It was found that the exposure dose due to cigarette occupies a large proportion of the annual effective dose limit for the general public. Therefore, more diverse studies on radioactive substances in cigarette are needed, and measures to monitor and reduce the incidental exposure to radon should be established.

• Nuclear Engineering and Technology
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• 제53권8호
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• pp.2767-2773
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• 2021

We used the GEANT4 Monte Carlo MC Toolkit to simulate carbon ion beams incident on water, tissue, and bone, taking into account nuclear fragmentation reactions. Upon increasing the energy of the primary beam, the position of the Bragg-Peak transfers to a location deeper inside the phantom. For different materials, the peak is located at a shallower depth along the beam direction and becomes sharper with increasing electron density NZ. Subsequently, the generated depth dose of the Bragg curve is then benchmarked with experimental data from GSI in Germany. The results exhibit a reasonable correlation with GSI experimental data with an accuracy of between 0.02 and 0.08 cm, thus establishing the basis to adopt MC in heavy-ion treatment planning. The Kolmogorov-Smirnov K-S test further ascertained from a statistical point of view that the simulation data matched the experimentally measured data very well. The two-dimensional isodose contours at the entrance were compared to those around the peak position and in the tail region beyond the peak, showing that bone produces more dose, in comparison to both water and tissue, due to secondary doses. In the water, the results show that the maximum energy deposited per fragment is mainly attributed to secondary carbon ions, followed by secondary boron and beryllium. Furthermore, the number of protons produced is the highest, thus making the maximum contribution to the total dose deposition in the tail region. Finally, the associated spectra of neutrons and photons were analyzed. The mean neutron energy value was found to be 16.29 MeV, and 1.03 MeV for the secondary gamma. However, the neutron dose was found to be negligible as compared to the total dose due to their longer range.

• 대한본초학회지
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• 제22권4호
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• pp.45-50
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• 2007

Objectives : The purpose of this study is to determine dose of Gypsum and Natrii sulfas in Shanhanlun and Geumgyeyoryak Methods : We measured the egg size Gypsum, and Natrii sulfas 1 Seong(升), and Results : 1. The weight of GYPSUM, egg is about $48{\pm}4g$, it will end up with 104g, when applying egg gravity of 1.055 and Gypsumls weight of 2.3. 2. One Ryang(兩) is equal to 6.5g in Sanghanlun and Gumgyeyoryak, and therefore the weight of ones gypsum is equal to 1 Keun(斤). 3. Compare to a dose of Gypsum is equal to one egg in Mokbanggitang. 4. Maximum dosage of Gypsum is equal to half an egg, 8Ryang(兩) of Sanghanlun, which is 52g. 5. Daily dosage of One Keun(斤) of Natrii sulfas is 8 Ryang(兩), of sanghanlun, which is 52g, Maximum dosage of Sanghanlun is 4 Ryang(兩), which is 26g. Conclusion : As stated above we may acknowledge that a dosage of Gypsum and Narii sulfas in either Sanghanlun and Keumgyeyoryak is applicable range in practical clinic.