Korea Institute Of Radiological And Medical Sciences Research Articles

Production cross-sections of Mo-isotopes induced by fast neutrons based on the 9Be(p, n) reaction

We measured the flux-weighted average cross-sections of the 100Mo(n, 2n)99Mo and 92Mo(n, 3n)90Mo reactions with the average neutron energies between 14.0- and 31.8-MeV by using an activation and off-line γ-ray spectrometric technique. The fast neutrons were generated based on the 9Be(p, n) reaction with the proton energies of 25-, 35- and 45-MeV from the MC-50 Cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). The neutron flux was measured by using the 27Al(n, α)24Na monitor reaction, whereas the neutron spectra were simulated by using the MCNPX 2.6.0 code. The theoretical cross-sections of the 100Mo(n, 2n)99Mo and 92Mo(n, xn)91.90,89Mo reactions as a function of mono-energetic neutron were calculated by using the TALYS-1.9 code. The present results for the 100Mo(n, 2n)99Mo and 92Mo(n, 3n)90Mo reactions are compared with the calculated neutron flux-weighted average values based on the literature data and theoretical cross-sections as a function of mono-energetic neutron energy, and show a good agreement.

Measurements of production cross-sections of medical radioisotopes (57Ni, 55,57,58Co, 54Mn, 51Cr) and other by-products (56Ni, 56Co, 56Mn) from the 59Co(p,x) reactions

We studied the excitation functions of 59Co(p,x) reactions and measured the production cross-sections of medical radioisotopes (57Ni, 55,57,58Co, 54Mn, 51Cr) and other by-products (56Ni, 56Co, 56Mn) from their threshold to a proton energy of 43.7 MeV. The stacked-foil activation method was employed to irradiate the samples with an external beam from the MC-50 cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS), Korea. Off-line γ-ray spectrometry was used to measure the activities of the produced radionuclides. The integral yields for the thick target of the investigated radionuclides were also calculated from the measured excitation functions. The measured results were compared with the literature data as well as with theoretical values obtained from the TENDL-2017 library based on the TALYS-1.9 code.

A Simulation Study and Its Experimental Validation for the Detection of Neutrons with a Continuous Energy Spectrum by Using a MICROMEGAS Detector

A MICROMEGAS (MICRO Mesh GASeous) detector is developed to monitor neutrons with a continuous energy spectra generated by bombarding protons on a thick Be target at the MC-50 cyclotron of the Korea Institute of Radiological and Medical Sciences (KIRAMS). Two different neutron spectra are produced by protons of 20 and 40 MeV, and are detected by using the MICROMEGAS detector with a boron converter. Boron carbides (B4C) are deposited on the cathode of the detector and are used as a neutron-to-charged particle converter. α particles and 7Li nuclei produced by the 10B(n,α)7Li reaction are detected by using the MICROMEGAS detector. Monte Carlo simulations for the detector system are performed to compare the experimental data with the simulation results. For measuring the energies of the α particles and the 7Li nuclei, we vary the geometry of detector in both the simulations and the experiments to fully stop the α particles and the 7Li nuclei in the detector. The changes of the positions of the α and the 7Li peaks observed in the distribution of the deposited energy for different detector geometries agree more or less with those from the simulation results. The neutron conversion efficiency of the detector is studied.

Measurement of half-lives for 87m,gY and 196m,g,194Au produced from the photon and neutron induced reactions of 89Y and 197Au

We have measured the half-lives of 87mY and 87gY produced from the 89Y(γ, 2n) and 89Y(n, 3n) reactions with the bremsstrahlung end-point energy of 65 MeV and the average neutron energy of 37.2 MeV using an activation and an off-line γ-ray spectrometric technique, respectively. The bremsstrahlung photon was produced by using the 100 MeV electron linac of the Pohang Accelerator Laboratory (PAL), whereas the fast neutron was produced from the 9Be(p, n) reaction by using the 45 MeV proton of the MC-50 Cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). We have also measured the half-lives of 194Au and 196m2,gAu produced from the 197Au(γ, xn; x = 1, 3) and 197Au(n, xn; x = 2, 4) reactions with the bremsstrahlung end-point energy of 60 MeV and the average neutron energy of 37.2 MeV using the same technique and the same facilities as mentioned above. The induced γ-ray activities of the irradiated samples were measured by using an energy- and efficiency calibrated high purity germanium (HPGe) detector. The spectrum analysis has been done by using the ROOT software to separate signals from background. The measured half-lives are compared with the literature values and are in general agreement with each other within the uncertainties.

Validation of the dicentric chromosome assay for radiation biological dosimetry in South Korea.

The dicentric chromosome assay (DCA) is a well-established biodosimetry test to estimate exposure to ionizing radiation. The Korea Institute of Radiological and Medical Sciences (KIRAMS) established a DCA protocol as a medical response to radiation emergencies in South Korea. To maintain its accuracy and performance, intercomparison exercises with Health Canada (HC) have been conducted; herein, we aimed to validate our capacity of DCA analysis based on those results. Blood samples irradiated at HC were shipped to KIRAMS to assess the irradiation dose to blinded samples using conventional DCA full scoring and triage-based techniques (conventional DCA scoring in triage mode and DCA QuickScan method). Actual doses fell within the 95% confidence intervals of dose estimates for 70–100% of the blinded samples in 2015–2018. All methods discriminated binary dose categories, reflecting clinical significance. This DCA can be used as a reliable radiation biodosimetry tool in preparation for radiation accidents in South Korea.

Measurement of excitation functions of residual radionuclides from natTi(p,x) reactions up to 44 MeV

We studied the production of medically applicable scandium radioisotopes through the natTi(p,x) reactions with in the energy range of their threshold to 44 MeV. The excitation functions of natTi(p,x) reactions and thick target yield of scandium radioisotopes (43,44m,44g,46,47,48Sc) and by-product (48V) were also measured. For this purpose, pure thin titanium foils were stacked and irradiated with different proton energies by using the MC-50 cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS), Korea. The data acquisition and activation analysis was performed by using an off-line γ-ray spectrometry technique. The measured results were compared with literature data as well as the data from the TENDL-2017 library based on TALYS-1.9 code. The integral yields for the thick target using the measured cross section were also presented. The results reveal that natTi(p,x) reaction is one of the best route for the production of medical radioisotopes of 43,44m,44g,46,47,48Sc with controllable impurity of 48V.

SUSTAINABLE MEDICAL PREPAREDNESS AND RESPONSE SYSTEM FOR RADIATION EMERGENCIES IN THE REPUBLIC OF KOREA.

This paper provides information about the medical preparedness and response system for radiation emergencies in Republic of Korea. The National Radiation Emergency Medical Center (NREMC) oversees medical affairs in the Korean radiological disaster prevention system since its establishment in 2002. It has dedicated itself to set up a nationwide radiation emergency medicine network with 24 designated radiation emergency hospitals. NREMC, as one division under the Korea Institute of Radiological And Medical Sciences (KIRAMS), provides efficient medical care to patients suspected with radiation exposure by collaborating with professional medical staffs in Korea Cancer Center Hospital (KCCH). For prompt response to radiation accidents, NREMC has offered specialized trainings for medical staffs and first responders. It has also operated the 24-h on-call system to consult public concerns of radiation exposure, which can be switched into an emergency mode upon receiving accident reports. In addition, NREMC has conducted dose assessments of radiation exposure with high level of accuracy and implemented R&D programs for radiation injury therapeutics and low-dose radiation risks evaluation in daily life. NREMC supports global initiatives for strengthening medical preparedness and response for radiation emergencies with international organizations.

PINX1 promotes malignant transformation of thyroid carcinomas through AKT, MAPK, and β‐catenin signaling activation

Although a large proportion of thyroid cancers, specifically papillary thyroid carcinomas (PTCs), generally show indolent biological behavior, some patients present with aggressive clinical manifestations such as distant metastasis and recurrence. It was also shown that PTC could be progressed to more malignant subtype, anaplastic thyroid carcinomas (ATCs), through specific gene mutation and signaling activation. However, the key modulators regulating malignant transformation of PTCs still remain to be identified. In the current study, we found that PIN2/TERF1 interacting telomerase inhibitor 1 (PINX1) was highly expressed in ATC patient tissues and cell lines compared to PTC patient tissues and cell lines. To investigate the effects of PINX1 on proliferation and migration, we checked colony formation capacity, cell migration, and EMT markers expression after regulation of PINX1 expression. Knockout of PINX1 using specific siRNAs decreases cell proliferation and inhibits cell cycle progression in ATC cell lines, whereas PINX1 gene transfection increases cell proliferation and promotes cell cycle progression in PTC cell lines. Moreover, downregulation of PINX1 in ATC cells reduces cell migration and EMT‐related markers expression, while upregulation of PINX1 in PTC cells increases cell migration and EMT‐related markers expression. To verify whether PINX1 is involved in anaplastic progression, we investigated AKT, MAPK, and β‐catenin signaling activation which were reported to play major roles in anaplastic progression of thyroid carcinomas. Decrease of PINX1 expression repressed the phosphorylation of AKT, p38, and ERK and reduced the expression level of β‐catenin in ATC cell lines. Moreover, increase of PINX1 expression promoted the phosphorylation of AKT, p38, and ERK and upregulated the expression level of β‐catenin in PTC cell lines. These results showed that PINX1 might promote cell proliferation, migration and anaplastic progression of thyroid carcinomas through the activation of AKT, MAPK, and β‐catenin signaling pathways.Support or Funding InformationThis study was supported by a grant from the Korea Institute of Radiological and Medical Sciences (KIRAMS), funded by the Ministry of Science and ICT (MSIT), Republic of Korea. (No. 50476‐2018)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Measurement of 99Mo production cross-section from the 100Mo(n,2n) reaction with quasi monoenergetic neutron based on the 9Be(p,n) reaction

The production cross-section of the medical isotope, 99Mo from the enriched 100Mo(n,2n) reaction with the average neutron energies of 21.9 and 26.5 MeV has been determined for the first time by using an off-line γ-ray spectrometric technique. The average neutron energies were generated by using the 9Be(p,n) reaction with the proton energies of 35 and 45 MeV from the MC50 cyclotron of the Korea Institute of Radiological and Medical Sciences (KIRAMS) at Seoul, South Korea. The 100Mo(n,2n) reaction cross-section as a function of neutron energy was also calculated theoretically by using the computer code TALYS-1.8 and EMPIRE-3.2 Malta. The experimental results are in close agreement with the theoretical values from TALYS-1.8. However, the present data at the neutron energy of 21.9 MeV is slightly lower and at 26.5 MeV is higher than the values from EMPIRE-3.2 Malta.

Neutron-induced reaction cross-sections of 93Nb with fast neutron based on 9Be(p,n) reaction

The cross-sections of the 93Nb(n,2n)92mNb, 93Nb(n,3n)91mNb and 93Nb(n,4n)90Nb reactions with the average neutron energies of 14.4 to 34.0 MeV have been determined by using an activation and off-line γ-ray spectrometric technique. The fast neutrons were produced using the 9Be(p,n) reaction with the proton energies of 25-, 35- and 45-MeV from the MC-50 Cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). The neutron flux-weighted average cross-sections of the 93Nb(n,xn;x=2–4) reactions were also obtained from the mono-energetic neutron-induced reaction cross-sections of 93Nb calculated using the TALYS 1.8 code, and the neutron flux spectrum based on the MCNPX 2.6.0 code. The present results for the 93Nb(n,xn;x=2–4) reactions are compared with the calculated neutron flux-weighted average values and found to be in good agreement.

Medical RI development plan of KOMAC

Many kinds of radioisotopes (RIs) produced by the high energy (100 ~ 200 MeV) proton accelerators are developed by the foreign R&D institutes and the worldwide demands are being increased continuously. The RI production using high energy proton beam higher than 50 MeV was not considerable because of the limit of the proton beam energy from existing proton accelerator facilities in Korea before 2013. The available maximum proton energy was 50 MeV from MC-50 cyclotron of Korea Institute of Radiological and Medical Sciences (KIRAMS) at that time. After the construction of a 100 MeV high-current and high-energy proton accelerator and a new irradiation facility for the RI production in 2013 and 2016 by the Korea Multi-purpose Accelerator Complex (KOMAC) at Korea Atomic Energy Research Institute (KAERI), we can make a plan for the new RI production of Cu-67, Sr-82 and so on. In the medical application fields, the worldwide demand of Sr-82 is being increased rapidly during last several years and the domestic demand of Cu-67 is also expected to be increased in near future. And alpha-emitters, such as Ac-225 and Ra-223, are becoming attractive to the users in the medical science fields in the future. The RI development plan of KOMAC was specified recently reflecting the recent environment changes and requirements from the users. In this paper, the results and present status of RI production and R&D facilities, calculation results related to the RI production yields, and future plans is presented.

Optimization of In-vivo Monitoring Program for Radiation Emergency Response

This study was supported by a grant of the Korea Institute of Radiological and Medical Sciences (KIRAMS), funded by Ministry of Science, ICT and Future Planning, Republic of Korea (1711031804/50445-2016).

SU‐F‐T‐149: Development of the Monte Carlo Simulation Platform Using Geant4 for Designing Heavy Ion Therapy Beam Nozzle

Purpose:The significant issue of particle therapy such as proton and carbon ion was a accurate dose delivery from beam line to patient. For designing the complex delivery system, Monte Carlo simulation can be used for the simulation of various physical interaction in scatters and filters. In this report, we present the development of Monte Carlo simulation platform to help design the prototype of particle therapy nozzle and performed the Monte Carlo simulation using Geant4. Also we show the prototype design of particle therapy beam nozzle for Korea Heavy Ion Medical Accelerator (KHIMA) project in Korea Institute of Radiological and Medical Science(KIRAMS) at Republic of Korea.Methods:We developed a simulation platform for particle therapy beam nozzle using Geant4. In this platform, the prototype nozzle design of Scanning system for carbon was simply designed. For comparison with theoretic beam optics, the beam profile on lateral distribution at isocenter is compared with Mont Carlo simulation result. From the result of this analysis, we can expected the beam spot property of KHIMA system and implement the spot size optimization for our spot scanning system.Results:For characteristics study of scanning system, various combination of the spot size from accerlator with ridge filter and beam monitor was tested as simple design for KHIMA dose delivery system.Conclusion:In this report, we presented the part of simulation platform and the characteristics study. This study is now on‐going in order to develop the simulation platform including the beam nozzle and the dose verification tool with treatment planning system. This will be presented as soon as it is become available.

Design study of the KIRAMS-430 superconducting cyclotron magnet

Design study of superconducting cyclotron magnet for the carbon therapy was performed at the Korea Institute of Radiological and Medical Science (KIRAMS). The name of this project is The Korea Heavy Ion Medical Accelerator (KHIMA) project and a fixed frequency cyclotron with four spiral sector magnet was one of the candidate for the accelerator type. Basic parameters of the cyclotron magnet and its characteristics were studied. The isochronous magnetic field which can guide the 12C6+ ions up to 430MeV/u was designed and used for the single particle tracking simulation. The isochronous condition of magnetic field was achieved by optimization of sector gap and width along the radius. Operating range of superconducting coil current was calculated and changing of the magnetic field caused by mechanical deformations of yokes was considered. From the result of magnetic field design, structure of the magnet yoke was planned.

Analysis of Trends in Dose through Evaluation of Spatial Dose Rate and Surface Contamination in Radiation-Controlled Area and Personal Exposed Dose of Radiation Worker at the Korea Institute of Radiological and Medical Sciences (KIRAMS)

Analysis of Trends in Dose through Evaluation of Spatial Dose Rate and Surface Contamination in Radiation-Controlled Area and Personal Exposed Dose of Radiation Worker at the Korea Institute of Radiological and Medical Sciences (KIRAMS)

Cross Sections for the \(^{nat}\)Zr\((p,xn)^{89,90}\)Nb Reactions Induced by 27.7 MeV Protons

The cross-sections for the formation of \(^{89}\)Nb and \(^{90}\)Nb radionuclides in proton induced nuclear reactions on zirconium were measured by using the well known activation method. The natural zirconium (\(^{nat}\)Zr) target and copper (\(^{nat}\)Cu) monitor foils were irradiated by 27.7 MeV proton beam at the MC50 Cyclotron of the Korea Institute of Radiological and Medical Science (KIRAMS), Korea. The induced gamma activities of the reaction products were measured by a coaxial high purity germanium (HPGe) detector coupled to a PC-based multichannel analyzer. The obtained cross sections for each nuclide are compared with those existing in literature and with the theoretical cross sections calculated by the TALYS - 1.4 code.

Preliminary results, obtained by using a proton beam, for an active scanning system to installed on the KHIMA

The active scanning technique is a pencil beam delivery method in particle therapy. The active scanning beam delivery system consists of a beam scanner, beam monitor, energy modulator, and related programs, such as the irradiation control and planning programs. A proposed prototype active scanning system was designed and installed on MC-50 at the Korea Institute of Radiological and Medical Science (KIRAMS) with a 45-MeV proton beam. The laminated magnetic yoke of the scanning magnet supported fast ramping. The beam intensity and the beam profile monitors were designed for measuring the beam’s properties. Both the range shifter and the ridge filter modulate the incoming beam energy. The LabVIEW®-based beam-irradiation-control program operates the system in a sequential operation manner for use with the MC-50 cyclotron. In addition, an in-housecoded irradiation-planning program generates an optimal irradiation path. A scanning experiment was successfully completed to print the logo of the Korea Heavy Ion Medical Accelerator (KHIMA) on GaF film. Moreover, the beam’s position accuracy was measured as 0.62 mm in the x-direction and as 0.83 mm in the y-direction.

Suggestion for Comprehensive Quality Assurance of Medical Linear Accelerator in Korea

294 This study was supported by a grant of the Korea Institute of Radiological and Medical Sciences (KIRAMS), funded by Ministry of Science, ICT and Future Planning, Republic of Korea (1711022077/ 50575-2015, 1711021932/50557-2015). Received 7 December 2015, Revised 21 December 2015, Accepted 22 December 2015 Correspondence: Dong Oh Shin (ohsd32@gmail.com) Tel: 82-2-958-8665, Fax: 82-2-958-9469 cc This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Suggestion for Comprehensive Quality Assurance of Medical Linear Accelerator in Korea

Radiation tests for a single-GEM-loaded gaseous detector

We report on a systematic study of a single-gas-electron-multiplier (GEM)-loaded gaseous detector developed for precision measurements of high-energy particle beams and for dose verification in particle therapy. In the present study, a 256-channel prototype detector having an active area of 16 × 16 cm2 and operating using a continuous current-integration-mode signal-processing method was manufactured and tested with X-rays emitted from a 70-kV X-ray generator and 43-MeV protons provided by the MC50 proton cyclotron at the Korea Institute of Radiological and Medical Science (KIRAMS). The amplified detector response was measured for X-rays with an intensity of about 5 × 106 Hz cm−2. The linearity of the detector response to the particle flux was examined and validated by using 43-MeV proton beams. The non-uniform development of the amplification for the gas electrons in space was corrected by applying a proper calibration to the channel responses of the measured beam-profile data. We conclude from the radiation tests that the detector developed in the present study will allow us to perform quality measurements of various high-energy particle beams and to apply the technology to dose-verification measurements in particle therapy.

Measurement of cross-sections for 89Y(n,xn) reaction at average neutron energies of 15–36 MeV

We measured neutron-induced reaction cross-sections for 89Y(n,2n)88Y, 89Y(n,3n)87Y, and 89Y(n,4n)86Y reactions with the average neutron energy region from 15.9 to 36.3 MeV by using an activation and off-line γ-ray spectrometric technique. High energy neutrons were produced from the 9Be(p,n) reaction with 25-, 35- and 45-MeV proton beam from the MC-50 Cyclotron at Korea Institute of Radiological and Medical Sciences (KIRAMS). The neutron-induced reaction cross-sections of 89Y as a function of neutron energy were calculated using the TALYS 1.6. The flux-weighted average cross-sections for 89Y(n,xn; x = 2–4) reactions are also calculated from the TALYS values based on mono-energetic neutron and by using the neutron spectrum from MCNPX 2.6.0 code. The present results for 89Y(n,xn; x = 2–4) reactions are compared with the flux-weighted values of TALYS and are found to be in good agreement.