• Title, Summary, Keyword: Biological dosimetry

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Measuring the Light Dosimetry Within Biological Tissue Using Monte Carlo Simulation (Monte Csrlo 시뮬레이션을 이용한 생체조직내의 광선량 측정)

  • 임현수;구철희
    • Journal of Biomedical Engineering Research
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    • v.20 no.2
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    • pp.199-204
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    • 1999
  • As the correct measuring of the light dosimetry in biological tissues give the important affection to the effect of PDT treatment we used Monte Carlo simulation to measure the light dosimetry on this study. The parameters using in experiments are the optical properties of the real biological tissue, and we used Henyey-Greenstein phase function among the phase functions. As we results, we displayed the result the change of Fluence rate and the difference against the previous theory was at least 0.35%. Biological tissues using in experiment were Human tissue, pig tissue, rat liver tissue and rabbit muscle tissue. The most of biological tissue have big scattering coefficient in visible wavelength which influences penetration depth. The penetration depth of human tissue in visible region is 1.5~2cm. We showed that it is possible to measure fluence rate and penetration depth within the biological tissues by Monte Carlo simulation very well.

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Cytogenetic and Medical Examination Report of Accidental Exposure of Nuclear Power Plant Worker using Multiple Assays (원자력 발전소 피폭자 건강영향평가 사례보고)

  • Lee, Jung-Eun;Yang, Kwang-Hee;Jang, Yun-Kun;Jeong, Mee-Seon;Kim, Chong-Soon;Jin, Young-Woo
    • Journal of Radiation Protection and Research
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    • v.32 no.3
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    • pp.111-115
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    • 2007
  • A deuterium oxide leakage accident occurred on October 4, 1999, at nuclear power plant in Korea. The concentration of tritium in air increased and 22 workers were exposed by tritium at that time. It is well known that tritium causes internal exposure. Therefore, we examined complete blood cell count, physical and biological dosimetry fur 13 workers among whole 22 workers to check the health effect and to evaluate the dose estimation of tritium exposure. The leukocyte count test, one of general blood test, was normal. The estimated doses were 0 - 4.44 mSv by physical dosimetry and 0-37 mGy by biological dosimetry. This dose does not exceed radiation dose limit, and the clinical symptoms of the exposed workers were not shown. The consistency between clinical sign and estimated dose means that physical and biological dosimetry were very useful especially in accident evaluation.

Electric Field Effect on Numerical Dosimetry for Wireless Power Transfer System (무선전력전송의 조사량 평가 시 전기장 영향)

  • Park, Sang-Wook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.26 no.5
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    • pp.499-505
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    • 2015
  • The coupling effect of electric fields incident on the biological object is investigated in regards to dosimetry for a wireless power transfer(WPT) system using electromagnetic resonance phenomenon. The internal electric fields induced a biological sphere model exposed to a magnetic dipole are calculated with the finite-difference time-domain(FDTD) method considering both incident electric and magnetic fields, the impedance method considering only incident magnetic fields, and theoretical analysis. The results represent that the electric coupling effect on a biological object nearby the WPT system should be considered to conduct exact dosimetry.

Application of Physiologically Based Pharmacokinetic Modeling with Biological Monitoring Data for Risk Assessment (생물학적 모니터링 데이터를 기초한 PBPK 모델의 활용)

  • Yang, Mi-Hi;Yang, Ji-Yeon;Yi, Bit-Na;Lee, Ho-Sun
    • Environmental health and toxicology
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    • v.22 no.1
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    • pp.1-8
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    • 2007
  • Biological monitoring, analyses of internal dose for exposure to toxicants, has been thought as one of the belt approaches for risk assessment. As the amount detected in human samples is generally very low, typically in the parts-per-bilion (ppb) or parts-per-trillion (ppt) range, analytic technologies such at HPLC, GC/MS, LC/MS, and LC/MS/MS have been continuously developed. In addition, route specific and sensitive exposure biomarkers have been developed for proper biological monitoring. PBPK modeling, particularly reverse dosimetry, has been emphasized as an useful method via interpretation of biological monitoring results for regulation of toxicants. Thus, this review is focused on the use of PBPK dosimetry models for toxicology research and risk assessment in Korea.

Biological Dosimetry of In Vitro Irradiation with Radionuclides : Comparison of Whole Blood, Lymphocyte and Buffy Coat Culture (전혈, 림프구와 백혈구 연층 각각의 방사성 동위원소 체외 조사 후 배양을 이용한 생물학적 선량측정)

  • Kim, Jong-Ho;Lee, Dong-Soo;Choi, Chang-Woon;Chung, June-Key;Lee, Myung-Chul;Koh, Chang-Soon;Kim, Chong-Soon;Kim, Hee-Geun;Kang, Duck-Won;Song, Myung-Jae
    • The Korean Journal of Nuclear Medicine
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    • v.29 no.1
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    • pp.125-132
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    • 1995
  • The purpose of this study was to establish mononuclear cell cultures such as lymphocytes or buffy coat for the biological dosimetry of in vitro Irradiation of the radionuclide Tc-99m in order to exclude the effect of residual doses seen in the cultures of whole blood. Biological do simetry of Tc-99m on cultured mononuclear cells at doses ranging from 0.05 to 6.00 Gy, by scoring unstable chromosomal aberrations(Ydr) observed in cultured lymphocytes, were performed using peripheral venous blood of healthy normal person. The results showed that; (1) In vitro irradiation of radioisotope in separated lymphocyte or buffy coat showed trace amount of residual doses of isotope after washing. Residual doses of isotopes are increased in proportion to exposed time and irradiated dose without difference between I-131 and Tc-99m. (2) We obtained these linear-quadratic dose response equations in lymphocyte and buffy coat culture after in vitro irradiation of Tc-99m, respectively (Ydr = 0.001949 $D^2$ +0.006279D + 0.000185; Ydr= 0.002531 $D^2$-0.003274 D+0.003488). In conclusion, the linear quadratic dose-response equation from in vitro irradiation of Tc-99m with lymphocyte and buffy coat culture was thought to be useful for assessing Tc-99m induced biological effects. And mono-nuclear cell cultures seem to be the most appropriate experimental model for the assessment of biological dosimetry of internal irradiation of radionuclides.

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Characteristics of Specific Absorption Rate (SAR) in Electromagnetic (EM) Dosimetry

  • Hwang, Sun-Tae;Choi, Kil-Oung
    • Journal of Radiation Protection and Research
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    • v.25 no.2
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    • pp.109-114
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    • 2000
  • The SI unit of specific absorption rate (SAR) in W/kg in the electromagnetic (EM) field as non-ionizing radiation is exactly same as the SI unit of absorbed dose rate in Gy/s in the ionizing radiation field. The SI unit of both physical quantities can be expressed in $[m^{\cdot}s^{-3}]$. Where, the unit of absorbed dose, Gy stands for Gray. In EM biological interactions, the SAR equations are derived and the characteristics of EM field energy absorption in terms of the SAR are discussed and described on the mathematical basis.

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A Study on Photon Dosimetry System with Diode Defectors (다이오드를 이용한 광자선 선량측정에 관한 연구)

  • Lee, D.H.;Kang, J.K.;Jang, Y.G.;Jee, Y.H.;Hong, S.H.
    • Proceedings of the KOSOMBE Conference
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    • v.1992 no.05
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    • pp.148-151
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    • 1992
  • There is a definite requirement to continuously monitor the operating characteristics of radiation therapy machines. It is advisable to monitor the symmetry, flatness, and energy stability of x-ray beams. The semiconductor system was developed using commercially available rectifier diode for th assessment of quality assurance In radiation therapy, which is capable of the above measurements. The beam characteristics of 6MV, 10MV and 21MV photon of Microtron electron accelerator were measured using seven-diodes as detectors and the results were compared with that of using a film results dosimetry with a X-Y plotter. The seven-diode detetor is versatile enough to be used for checking beam profile, flatness, symmetry and energy.

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Children's Mobile Phone Use and Dosimetry

  • Lee, Ae-Kyoung;Kwon, Jong-Hwa
    • Journal of electromagnetic engineering and science
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    • v.15 no.3
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    • pp.167-172
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    • 2015
  • Research results on possible effects caused by radiofrequency fields in children are limited because most of the studies published so far have focused on adults, rather than children. Mobile phone use is now widespread, even among younger children. If a biological risk due to mobile phone exposure is found, it might be greater in children because their bodies might be more sensitive to radiofrequency energy. The issue of a possible difference in sensitivity between adults and children begins with whether any difference exists physically in terms of electromagnetic absorption. This paper presents a review of recent publications on dosimetric comparisons between children and adults with respect to radiation from mobile phones. The issue of the health effects of mobile phone use is beyond the scope of the present review. Most of the dosimetry research on possible differences in power absorption between children and adults has been based on numerical modeling and analysis. The understanding of the results so far is presented and needed studies are described.

High Energy Electron Dosimetry by Alanine/ESR Spectroscopy (Alanine/ESR Spectroscopy에 의한 고에너지 전자선의 선량측정)

  • Chu, Sung-Sil
    • Radiation Oncology Journal
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    • v.7 no.1
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    • pp.85-92
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    • 1989
  • Dosimerty based on electron spin resonance (ESR) analysis of radiation induced free radicals in amino acids is relevant to biological dosimetry applications. Alanine detectors are without walls and are tissue equivalent. Therefore, alanine ESR dosimetry looks promising for use in the therapy level. The dose range of the alanine/ESR dosimetry system can be extended down to 1 Gy. In water phantom the absorbed dose of electrons generated by a medical linear accelerator of different initial energies $(6\~21MeV)$ and therapeutic dose levels (1~60 Gy) was measured. Furthermore, depth dose measurements carried out with alanine dosimeters were compared with ionization chamber measurements. As the results, the measured absorbed doses for shallow depth of initial electron energies above 15 MeV were higher by$2\~5\%$ than those calculated by nominal energy $C_E$ factors. This seems to be caused by low energy scattered beams generated from the scattering foil and electron cones of beam projecting device in medical linear accelerator.

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