• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2247-2257
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• 2024

To investigate the impact of the recently released pediatric reference voxel phantoms (0-, 1-, 5-, 10-, 15-year-old males and females) of the International Commission on Radiological Protection (ICRP) on organ dose estimates for radioactive iodine (RAI) treatment in pediatric patients, we calculated and analyzed pediatric-specific iodine131 S values (r_T ← thyroid) for the 30 radiosensitive organs by conducting Monte Carlo simulations using the Geant4. The gender dependency in the S values was frequently seen for the 15-year-old phantoms with higher S values of female than male. In addition, the age dependency in the S values was observed for most target organs; that is, the S values tend to decrease for older ages (e.g., ~120 times for the gonads between the adult and newborn) due mainly to the inter-organ distances generally longer for older ages. Moreover, we observed that the iodine-131 S values tend to be significantly greater by up to ~145.5 times than those of the stylized phantoms that have been widely used for organ dose estimates of pediatric RAI patients. We believe that the pediatric-specific iodine-131 S values (r_T ← thyroid) of the ICRP pediatric reference voxel phantoms should be beneficial to improve the dosimetry of pediatric RAI patients.

• Translational and Clinical Pharmacology
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• v.26 no.4
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• pp.150-154
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• 2018

This tutorial reviews the principles of dose individualisation with an emphasis on target concentration intervention (TCI). Once a target effect is chosen then pharmacodynamics can predict the target concentration and pharmacokinetics can predict the target dose to achieve the required response. Dose individualisation can be considered at three levels: population, group and individual. Population dosing, also known as fixed dosing or "one size fits all" is often used but is poor clinical pharmacology; group dosing uses patient features such as weight, organ function and comedication to adjust the dose for a typical patient; individual dosing uses observations of patient response to inform about pharmacokinetic and pharmacodynamics in the individual and use these individual differences to individualise dose.

• Journal of Radiation Protection and Research
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• v.28 no.3
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• pp.199-206
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• 2003

Because the MIRD phantom, the representative mathematical phantom was developed for the calculation of internal radiation dose, and simulated by the simplified mathematical equations for rapid computation, the appropriateness of application to external dose calculation and the closeness to real human body should be justified. This study was intended to modify the MIRD phantom according to the comparison of the organ absorbed doses in the two phantoms exposed to monoenergetic broad parallel photon beams of the energy between 0.05 MeV and 10 MeV. The organ absorbed doses of the MIRD phantom and the Zubal yokel phantom were calculated for AP and PA geometries by MCNP4C, general-purpose Monte Carlo code. The MIRD phantom received higher doses than the Zubal phantom for both AP and PA geometries. Effective dose in PA geometry for 0.05 MeV photon beams showed the difference up to 50%. Anatomical axial views of the two phantoms revealed the thinner trunk thickness of the MIRD phantom than that of the Zubal phantom. To find out the optimal thickness of trunk, the difference of effective doses for 0.5 MeV photon beams for various trunk thickness of the MIRD phantom from 20 cm to 36 cm were compared. The optimal thunk thickness, 24 cm and 28 cm for AP and PA geometries, respectively, showed the minimum difference of effective doses between the two phantoms. The trunk model of the MIRD phantom was modified and the organ doses were recalculated using the modified MIRD phantom. The differences of effective dose for AP and PA geometries reduced to 7.3% and the overestimation of organ doses decreased, too. Because MIRD-type phantoms are easier to be adopted in Monte Carlo calculations and to standardize, the modifications of the MIRD phantom allow us to hold the advantage of MIRD-type phantoms over a voxel phantom and alleviate the anatomical difference and consequent disagreement in dose calculation.

• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.4019-4025
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• 2023

Recently, a new monkey computational phantom, called Visible Monkey, was developed for non-ionizing radiation studies in animal research. In this study, we extended its applications to ionizing radiation studies by implementing the voxel model of the Visible Monkey into three general-purpose Monte Carlo (MC) codes: MCNP6, PHITS, and Geant4. The implementation work for MCNP and PHITS was conducted using the LATTICE, UNIVERSE, and FILL cards. The G4VNestedParameterisation class was used for Geant4. Then, organ dose coefficients (DCs) for idealized photon beams in the antero-posterior direction were calculated using the three codes and compared, showing excellent agreement (differences <3%). Additionally, organ DCs in other directions (postero-anterior, left-lateral, and right-lateral) were calculated and compared with those of the newborn and 1-year-old reference phantoms. Significant differences were observed (e.g., the stomach DC of the monkey was 5-fold greater than that of the 1-year-old phantom at 0.03 MeV) while the differences tended to decrease with increasing energy (mostly <20% at 10 MeV). The results of this study allows conducting MC simulations using the Visible Monkey to estimate organ-level doses, which should be valuable to support/improve monkey experiments involving ionizing radiation exposures.

• Journal of Oriental Neuropsychiatry
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• v.23 no.2
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• pp.99-120
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• 2012

Objectives : The oriental medicine Jangwonhwan, a boiled extract of 12 medicinal herbs/mushrooms, has been prescribed to patients with cognitive dysfunction, as originally described in the Korean medical text, DonguiBogam(amnesia chapter). Recently, a modified formula of Jangwonhwan (LMK02-Jangwonhwan) consisting of seven medicinal plants/mushrooms, was shown to reduce the ${\beta}$-amyloid deposition in the brain of Tg-APPswe/PS1dE9 mouse model for Alzheimer's disease. The toxicity of LMK02-Jangwonhwan was investigated in SD rats, by a daily oral administration for 13 weeks and NOAEL(No observed adverse effect dose), a definite toxic dose and target organ, as well. Methods : Quality control of the tablet form of LMK02-Jangwonhwan was established by estimating the indicative components, Ginsenoside Rg3 of Red Ginseng and Decursin of Angelicagigas Nakai. The toxicity of LMK02-Jangwonhwan was investigated in 6 week old, specific pathogen free (SPF), Sprageu-Dawley rats by oral administration. Each test group consisted of 10 male and 10 female rats. The groups received doses of 500, 1,000 or 2,000 mg/kg/day of test substance for 13 weeks. The clinical signs, death rate, body weight, food consumption, ophthalmic examination, urinalysis, hematological and serum biochemistry, organ weight and pathological changes were examined and compared with those of the control group. Results : The 13-week repeated oral treatment doses didn't result in any specific symptoms or death. There were no significant changes in the rat's weight and food consumption. Further, ophthalmic examination, urinalysis, hematological, serum biochemistry test and organ weight revealed no significant differences. Conclusions : The no-observed-adverse-effect level(NOAEL) of LMK02 for male and female Sprague-Dawley rats was determined as 2,000mg/kg/day and the target organ wasn't confirmed. Because no significant adverse effects were observed, the target organ could not be determined.

• Journal of radiological science and technology
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• v.41 no.2
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• pp.141-148
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• 2018

This study examined the properties of photons and the dose distribution in a human body via a simulation where the total body irradiation(TBI) is performed on a pediatric anthropomorphic phantom and a child size water phantom. Based on this, we tried to find the optimal photon beam energy and material for beam spoiler. In this study, MCNPX (Ver. 2.5.0), a simulation program based on the Monte Carlo method, was used for the photon beam analysis and TBI simulation. Several different beam spoiler materials (plexiglass, copper, lead, aluminium) were used, and three different electron beam energies were used in the simulated accelerator to produce photon beams (6, 10, and 15 MeV). Moreover, both a water phantom for calculating the depth-dependent dosage and a pediatric anthropomorphic phantom for calculating the organ dosage were used. The homogeneity of photon beam was examined in different depths for the water phantom, which shows the 20%-40% difference for each material. Next, the org an doses on pediatric anthropomorphic phantom were examined, and the results showed that the average dose for each part of the body was skin 17.7 Gy, sexual gland 15.2 Gy, digestion 13.8 Gy, liver 11.8 Gy, kidney 9.2 Gy, lungs 6.2 Gy, and brain 4.6 Gy. Moreover, as for the organ doses according to materials, the highest dose was observed in lead while the lowest was observed in plexiglass. Plexiglass in current use is considered the most suitable material, and a 6 or 10 MV photon energy plan tailored to the patient condition is considered more suitable than a higher energy plan.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.115-118
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• 2004

Respiratory motion in the thorax and abdomen is an important limiting factor in high-precision radiation therapy. The lung tumor and tumor(pancreas, stomach) in abdomen therefore are internal motion due to breathing. We will perform to measurement of dose distributions for these moving tumors. In preliminary study, we investigated displacement of moving tumor such as liver, lung tumor in abdomen with previously reported papers. With reference data, internal movements of tumor are displayed with phantom and moving control device(MCD), which appear three dimension (3-D) motion such as x, y and z axis. These devices are used to access dose delivered in tumor with and without internal motion. The MCD and phantom were used to evaluate a delivered dose under similar condition, although there are not same internal tumor motion. In future, we will obtain the exact evaluation of dose if improved in programed software of moving control device and measure precise internal motion using image modality such as fluoroscopy, simulator in based on this study.

• The Journal of Internal Korean Medicine
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• v.33 no.1
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• pp.62-68
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• 2012

Objectives : This study aimed to evaluate the single oral dose toxicity of Seonpyejeongcheon-tang (SJT) in male and female Sprague-Dawley rats. Methods : In this single oral toxicity study, rats were orally administrated in a single dose of 0 or 5,000 mg/kg SJT. There were 7 rats in each group. After single administration, mortality, clinical signs, body weight changes and gross pathological findings were observed for 14 days. Organ weight, clinical chemistry and hematology were tested after 14 days. Results : There was no mortality or other clinical signs for 14 days. There were also no significant differences in body weight, organ weights, hematological and serum chemical parameters between the SJT and control groups. Conclusions : The results obtained in this study suggest that the 50% lethal dose of SJT is over 5,000 mg/kg, so this finding can be expected to provide scientific evidence for the safety of SJT.

• The Journal of Internal Korean Medicine
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• v.31 no.3
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• pp.539-553
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• 2010

Objectives : The object of this study was to obtain accurate information (single oral dose toxicity) of Lonicerae Flos (LF; Dried flower bud parts of Lonicera japonica Thunb (Caprifoliaceae)), which has traditionally been used in Korean medicine for treating various inflammatory diseases. Methods : In order to observe the 50% lethal dose (LD 50), approximate lethal dosage (ALD) and target organs, test articles were once orally administered to female and male ICR mice at dose levels of 2,000, 1,000, 500 and 0 (control) mg/kg (body weight.). The mortality and changes on body weight, clinical signs and gross observation were monitored for 14 days after single oral treatment of LF aqueous extracts with organ weights and histopathological observations of 12 types of principle organs. Results : 1. After single oral treatment of LF aqueous extracts, we could not find any mortality and toxicological evidences up to 2,000 mg/kg treated group, the limited dosages in rodents at body and organ weights, clinical signs, gross and histopathological observations. 2. Slight diarrhea was detected in most mice treated with 2,000 mg/kg of LF aqueous extracts and male mice of LF aqueous extracts 1,000 mg/kg within 2 days after end of treatment, respectively. Conclusion : The results obtained in this study suggest that the LD 50 and ALD of LF aqueous extracts in both female and male mice after single oral treatment were considered as over 2,000 mg/kg because no mortalities were detected up to 2000 mg/kg, the highest dose recommended by KFDA and OECD. However, we also observed the possibility of digestive disorders like diarrhea when over 1,000 mg/kg of LF aqueous extracts were administered in the present study.

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.4
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• pp.453-459
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• 2013

The objective of this study was to evaluate the single oral dose toxicity of Polygalae Radix (PR) in male and female mice. PR extract (yield = 18.6%) was administered to ICR mice as an oral dose of 2,000, 1,000 and 500 mg/kg (body weight) according to the recommendation of Korea Food and Drug Administration (KFDA) Guidelines (2009-116, 2009). Animals were monitored for the mortality and the changes in body weight, clinical signs and gross observation during 14 days after dosing. Upon necropsy, organ weight and histopathology of 14 principal organs were examined. It was observed that there were no mortalities, clinical signs, changes on the body and organ weights, gross and histopathological observations against 14 principal organs related to PR extract up to 2,000 mg/kg. Therefore, 50% lethal dose ($LD_{50}$) and approximate LD of PR aqueous extracts after single oral treatment in female and male mice were considered over 2000 mg/kg the limited dosages recommended by KFDA Guidelines, respectively.