• Title, Summary, Keyword: Beta-emitting radionuclides

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Fundamental approach to development of plastic scintillator system for in situ groundwater beta monitoring

  • Lee, UkJae;Choi, Woo Nyun;Bae, Jun Woo;Kim, Hee Reyoung
    • Nuclear Engineering and Technology
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    • v.51 no.7
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    • pp.1828-1834
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    • 2019
  • The performance of a plastic scintillator for use in an in situ measurement system was analyzed using simulation and experimental methods. The experimental results of four major pure beta-emitting radionuclides, namely $^3H$, $^{14}C$, $^{32}P$, and $^{90}Sr/^{90}Y$, were compared with those obtained using a Monte Carlo N-particle (MCNP) code simulation. The MCNP simulation and experimental results demonstrated good agreement for $^{32}P$ and $^{90}Sr/^{90}Y$, with a relative difference of 1.95% and 0.43% between experimental and simulation efficiencies for $^{32}P$ and $^{90}Sr/^{90}Y$, respectively. However, owing to the short range of beta particles in water, the efficiency for $^{14}C$ was extremely low, and $^3H$ could not be detected. To directly measure the low-energy beta radionuclides considering their short range, a system where the source could flow directly to the scintillator was developed. The optimal thickness of the plastic scintillator was determined based on the suggested diameter. Results showed that the detection efficiency decreases with an increase in the depth of the water. The detection efficiency decreased drastically to approximately 10 cm, and the tendency was gradually constant.

Beta particle energy spectra shift due to self-attenuation effects in environmental sources

  • Alton, Thomas Theakston;Monk, Stephen David;Cheneler, David
    • Nuclear Engineering and Technology
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    • v.49 no.7
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    • pp.1483-1488
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    • 2017
  • In order to predict and control the environmental and health impacts of ionizing radiation in environmental sources such as groundwater, it is necessary to identify the radionuclides present. Beta-emitting radionuclides are frequently identified by measuring their characteristic energy spectra. The present work shows that self-attenuation effects from volume sources result in a geometry-dependent shift in the characteristic spectra, which needs to be taken into account in order to correctly identify the radionuclides present. These effects are shown to be compounded due to the subsequent shift in the photon spectra produced by the detector, in this case an inorganic solid scintillator ($CaF_2:Eu$) monitored using a silicon photomultiplier. Using tritiated water as an environmentally relevant, and notoriously difficult to monitor case study, analytical predictions for the shift in the energy spectra as a function of depth of source have been derived. These predictions have been validated using Geant4 simulations and experimental results measured using bespoke instrumentation.

Development of Radiopharmaceutical DW-166HC for Anticancer drug

  • Man, Ryu-Jei
    • Proceedings of the Korean Society of Applied Pharmacology
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    • pp.53-61
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    • 1999
  • Radiation therapy has been used for the cancer treatment and radiation synovectomy$\^$1-3)/. There are two kinds of radiation therapy; the external radiation therapy and the internal radiation therapy. Hitherto, the external radiation therapy has been widely used, but for the lack of its selectivity it requires strong radiation dose and causes the irritation and damage of the normal tissue or organ. Therefore many researchers give their interests to the internal radiation therapy in which the radioactive materials are injected directly into the target organ or tissue. Many ${\beta}$-emitting radionuclides have been studied for the application of the internal radiation theraily. Among them, Holmium-166 has the many beneficial physical characteristics for the internal radiation therapy such as appropriate half life (26.8hr), high ${\beta}$ energy (max. 1.85 MeV(51%), 1.77 MeV (48%), mean 0.67MeV), and low ${\gamma}$ energy (0.081MeV) easily detected by ${\gamma}$-camera. In the internal radiation therapy, the administered radioactive materials should be retained in the target long enough to increase the therapeutic effects and avoid the damage in the normal tissue or organ. For this purpose, radionuclides are used as complex form with carriers. Carriers should have a high affinity with radionuclides in vivo and in vitro, so the complex can be evenly distributed in the lesion but can not be leaked out from the lesion.

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Optimal Monitoring Intervals and MDA Requirements for Routine Individual Monitoring of Occupational Intakes Based on the ICRP OIR

  • Ha, Wi-Ho;Kwon, Tae-Eun;Jin, Young Woo
    • Journal of Radiation Protection and Research
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    • v.45 no.2
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    • pp.88-94
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    • 2020
  • Background: The International Commission on Radiological Protection (ICRP) has recently published report series on the occupational intakes of radionuclides (OIR) for internal dosimetry of radiation workers. In this study, the optimized monitoring program including the monitoring interval and the minimum detectable activity (MDA) of major radionuclides was suggested to perform the routine individual monitoring of internal exposure based on the ICRP OIR. Materials and Methods: The derived recording levels and the critical monitoring quantities were reviewed from international standards or guidelines by the International Atomic Energy Agency (IAEA), the International Organization for Standardization (ISO), and the European Radiation Dosimetry Group (EURADOS). The OIR data viewer provided by ICRP was used to evaluate the monitoring intervals and the MDA, which are derived from the reference bioassay functions and the dose coefficients. Results and Discussion: The optimal monitoring intervals were determined taking account of two requirement conditions on the potential intake underestimation and the MDA values. The MDA requirement values of the selected radionuclides were calculated based on the committed effective dose from 0.1 mSv to 5 mSv. The optimized routine individual monitoring program was suggested including the optimal monitoring intervals and the MDA requirements. The optimal MDA values were evaluated based on the committed effective dose of 0.1 mSv. However, the MDA can be adjusted considering the practical operation of the routine individual monitoring program in the nuclear facilities. Conclusion: The monitoring intervals and the MDA as crucial factors for the routine monitoring were described to suggest the optimized routine individual monitoring program of the occupational intakes. Further study on the alpha/beta-emitting radionuclides as well as short lived gamma-emitting nuclides will be necessary in the future.

Minimum detectable activity of plastic scintillator for in-situ beta measurement system in ground water

  • Choi, Woo Nyun;Lee, UkJae;Bae, Jun Woo;Kim, Hee Reyoung
    • Nuclear Engineering and Technology
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    • v.51 no.4
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    • pp.1169-1175
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    • 2019
  • The minimum detectable activity (MDA) value was derived according to the flow rate of the sample and degree of amplification of the device by sending the sample directly from the collection site to the detection part through a pump. This method can lead to reduction in time and cost compared to the existing measurement method that uses a pre-treatment process. In this study, experiments were conducted on $^3H$ and $^{90}Sr$, which are the major pure beta-emitting radionuclides, by setting the sample flow rate and the amplification gain as factors. The MDA values were derived according to the flow rates, considering that the flow rate can affect the MDA values. There were no change in the MDA under different flow rates of 0, 600, 800, and 1000 mL/min. Therefore, it was confirmed that the flow rate may not be considered when collecting samples for monitoring in actual field. As the degree of amplification of the amplifier increased, the time required to reach the target MDA decreased. When the amplification was quadrupled, the detection efficiency increased by approximately 23.4 times, and the time to reach the MDA decreased to approximately 1/550 times. This method offers the advantage of real-time on-site monitoring.

Recovery of C-14 in the Cement Waste Form (농축폐액 시멘트 고화체로부터 C-14 회수 특성)

  • Ahn Hong-Joo;;Lee Jeong-Jin;Pyo Hyung-Yeal;Han Sun-Ho;Jee Kwang-Young
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • pp.284-289
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    • 2005
  • According to the nuclear safety regulation policy including the administration of radionuclides in low level radwastes, the evaporator bottoms were mixed with cement to form a stable solidification for identifying the recovery possibility of the C-14. The chemical oxidation method was applied for the extraction of C-14 from the cement waste form. The emitting beta ray of the C-14 extracted from the radwastes was measured with the liquid scintillation counter and calculated by using the quenching correction curves. Only the beta emitting radioactive nuclides of the C-14 in the radwastes was showed the radioactivities with the range of $2.7E+00\;{\sim}\;3.07E+02$ Bq/g.

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Simulation of Beta Ray Spectra in Liquid Scintillation Counting System by means of Monte Carlo Method (Monte Carlo 계산에 의한 액체섬광계수기의 베타선 스펙트럼 Simulation)

  • Yi, Chul-Young;Jun, Jae-Shik
    • Journal of Radiation Protection and Research
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    • v.18 no.2
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    • pp.17-25
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    • 1993
  • Beta ray spectra of $^3H,\;^{14}C\;and\;^{36}Cl$ in liquid scintillation counting system have been calculated using the Monte Carlo method by which physical behaviors of particle transport in medium were simulated. The calculations have been carried out on the basis of beta rays being slowing down according to the continuous slowing down approximation(CSDA) model. Beta rays generated in simulation geometry were traced until they lost their energy below 0.3keV that in known to be the detection limit in the liquid scintillation counter. Scintillator solution in which pure beta emitting radionuclides were dissolved uniformly was assumed to be bottled in the shape of right circular cylinder with 12.5mm in radius and 35mm in height. The comparison of the calculated and measured results showed satisfactory agreement between those two, with slight discrepancy due to self quenching in the case of lower energy of emitted beta particles in the solution.

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Performance Evaluation of a Plastic Scintillator for Making a In-situ Beta Detector (현장 적용형 베타검출기 제작을 위한 플라스틱 섬광체의 성능 평가)

  • Nam, Jong Soo;Kim, Yong Uhn;Hong, Sang Bum;Seo, Bum Kyung;Kim, Ki Hwan
    • New Physics: Sae Mulli
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    • v.67 no.9
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    • pp.1080-1085
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    • 2017
  • In this study, a plastic scintillator was fabricated to design a radiation detector for in-situ measurement of radioactivity at a site contaminated with radionuclides emitting beta-rays, such as $^{90}Sr$ or $^{238}U$, in a nuclear power plant at the end of its life cycle or a nuclear accident such as that at Fukushima. The performance of the fabricated plastic scintillators was evaluated. The plastic scintillator PS-0201 fabricated by mixing 0.2 wt% of PPO and 0.01 wt% of POPOP in epoxy was found to have good beta-ray absorption, as well as light emission and transmittance, characteristics comparable to thoose of commercial plastic scintillator BC-40004. Scanning electron microscope images confirmed that the homogeneity of the surface and the cutting plane of the plastic scintillator PS-0201 fabricated in this study was superior to that of BC-40004.

188Re Labeled liver therapeutic drugs for hepatic carcinoma (HCC)

  • Seelam, Sudhakara Reddy;Banka, Vinay Kumar;Lee, Yun-Sang;Jeong, Jae Min
    • Journal of Radiopharmaceuticals and Molecular Probes
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    • v.5 no.1
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    • pp.26-35
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    • 2019
  • $^{188}Re$ is one of the most readily available generator derived and useful radionuclides for therapy emitting ${\beta}^-$ particles (2.12 MeV, 71.1% and 1.965 MeV, 25.6%) and imageable gammas (155 keV, 15.1%). The $^{188}W/^{188}Re$ generator is an ideal source for the long term (4-6 months) continuous availability of no carrier added (NCA) $^{188}Re$ suitable for the preparation of radiopharmaceuticals for radionuclide therapy. Rhenium-188 has been used for the preparation of therapeutic radiopharmaceuticals for the management of diseases such as bone metastasis, rheumatoid arthritis and primary cancers. Several early phase clinical studies using radiopharmaceuticals based on $^{188}Re$ -labeled phosphonates, antibodies, peptides, lipiodol and particulates have been reported. In this review, we addressed the current development status of $^{188}Re$ radiopharmaceuticals for liver cancer therapy and their applications.

Assessment of Effective Doses in the Radiation Field of Contaminated Ground Surface by Monte Carlo Simulation (몬테칼로 시뮬레이션에 의한 지표면 오염 방사선장에서의 유효선량 평가)

  • Chang, Jai-Kwon;Lee, Jai-Ki;Chang, Si-Young
    • Journal of Radiation Protection and Research
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    • v.24 no.4
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    • pp.205-213
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    • 1999
  • Effective dose conversion coefficients from unit activity radionuclides contaminated on the ground surface were calculated by using MCNP4A rode and male/female anthropomorphic phantoms. The simulation calculations were made for 19 energy points in the range of 40 keV to 10 MeV. The effective doses E resulting from unit source intensity for different energy were compared to the effective dose equivalent $H_E$ of previous studies. Our E values are lower by 30% at low energy than the $H_E$ values given in the Federal Guidance Report of USEPA. The effective dose response functions derived by polynomial fitting of the energy-effective dose relationship are as follows: $f({\varepsilon})[fSv\;m^2]=\;0.0634\;+\;0.727{\varepsilon}-0.0520{\varepsilon}^2+0.00247{\varepsilon}^3,\;where\;{\varepsilon}$ is the gamma energy in MeV. Using the response function and the radionuclide decay data given in ICRP 38, the effective dose conversion coefficients for unit activity contamination on the ground surface were calculated with addition of the skin dose contribution of beta particles determined by use of the DOSEFACTOR code. The conversion coefficients for 90 important radionuclides were evaluated and tabulated. Comparison with the existing data showed that a significant underestimates could be resulted when the old conversion coefficients were used, especially for the nuclides emitting low energy photons or high energy beta particles.

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