욱근 신 - Academia.edu (original) (raw)
욱근 신
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Université Blaise-Pascal, F- Clermont-Ferrand
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For in-vivo range verification in proton therapy, attempts have been made to measure the spatial ... more For in-vivo range verification in proton therapy, attempts have been made to measure the spatial distribution of the prompt gammas generated by the proton-induced interactions and to determine the proton dose distribution. However, the high energies of prompt gammas and background gammas are still problematic in measuring the distribution. In this study, we suggested a new method for determining the in-vivo range by utilizing the time structure of the prompt gammas formed during the rotation of a range modulation wheel (RMW) in passive scattering proton therapy. To validate the Monte Carlo code simulating the proton beam nozzle, we compared the axial percent depth doses (PDDs) with the measured PDDs for varying beam range from 4.73 to 24.01 cm. Also, we assessed the relationship between the proton dose rate and the time structure of the prompt gammas in a water phantom. The results of the PDD showed agreement within relative errors of 1.1% in the distal range and 2.9% in the modulation width. The average dose difference in the modulation was assessed as less than 1.3% by comparison with the measurements. The time structure of prompt gammas was well-matched, within 0.39 ms, with the proton dose rate, and this enabled an accurate prediction of the in-vivo range.
Radiation portal monitor using plastic scintillator was modeled and the energy spectra of six rad... more Radiation portal monitor using plastic scintillator was modeled and the energy spectra of six radionuclides were assessed. Energy-weighted algorithm which enables radionuclide analysis with plastic scintillator was suggested and evaluated. The cases of moving and shielding effect were evaluated and simultaneous radionuclide identification was carried out. Analysis of the simulated spectra with suggested method shows clear results to enable the radionuclide identification. a b s t r a c t Nuisance and false alarms due to naturally occurring radioactive material (NORM) are major problems facing radiation portal monitors (RPMs) for the screening of illicit radioactive materials in airports and ports. Based on energy-weighted counts, we suggest an algorithm that distinguishes radioactive nuclides with a plastic scintillation detector that has poor energy resolution. Our simulation study, using a Monte Carlo method, demonstrated that man-made radionuclides can be separated from NORM by using a conventional RPM.
For in-vivo range verification in proton therapy, attempts have been made to measure the spatial ... more For in-vivo range verification in proton therapy, attempts have been made to measure the spatial distribution of the prompt gammas generated by the proton-induced interactions and to determine the proton dose distribution. However, the high energies of prompt gammas and background gammas are still problematic in measuring the distribution. In this study, we suggested a new method for determining the in-vivo range by utilizing the time structure of the prompt gammas formed during the rotation of a range modulation wheel (RMW) in passive scattering proton therapy. To validate the Monte Carlo code simulating the proton beam nozzle, we compared the axial percent depth doses (PDDs) with the measured PDDs for varying beam range from 4.73 to 24.01 cm. Also, we assessed the relationship between the proton dose rate and the time structure of the prompt gammas in a water phantom. The results of the PDD showed agreement within relative errors of 1.1% in the distal range and 2.9% in the modulation width. The average dose difference in the modulation was assessed as less than 1.3% by comparison with the measurements. The time structure of prompt gammas was well-matched, within 0.39 ms, with the proton dose rate, and this enabled an accurate prediction of the in-vivo range.
Radiation portal monitor using plastic scintillator was modeled and the energy spectra of six rad... more Radiation portal monitor using plastic scintillator was modeled and the energy spectra of six radionuclides were assessed. Energy-weighted algorithm which enables radionuclide analysis with plastic scintillator was suggested and evaluated. The cases of moving and shielding effect were evaluated and simultaneous radionuclide identification was carried out. Analysis of the simulated spectra with suggested method shows clear results to enable the radionuclide identification. a b s t r a c t Nuisance and false alarms due to naturally occurring radioactive material (NORM) are major problems facing radiation portal monitors (RPMs) for the screening of illicit radioactive materials in airports and ports. Based on energy-weighted counts, we suggest an algorithm that distinguishes radioactive nuclides with a plastic scintillation detector that has poor energy resolution. Our simulation study, using a Monte Carlo method, demonstrated that man-made radionuclides can be separated from NORM by using a conventional RPM.