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Manabe, Kentaro; Sato, Kaoru; Takahashi, Fumiaki
Journal of Nuclear Science and Technology, 59(5), p.656 - 664, 2022/05
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)It is known that internal doses depend on the physical characteristics of an evaluation subject. Internal dose coefficients provided by the International Commission on Radiological Protection (ICRP) are evaluated using the characteristics of the standard Caucasian. It is important to grasp the variations of doses due to the differences in characteristics between Japanese and Caucasian when the dose coefficients of ICRP are applied to Japanese. This study evaluated dose coefficients using specific absorbed fraction (SAF) data based on the average adult Japanese physique which was developed by modification of the existing Japanese SAF data with additional calculations to make the existing data fit to the current dosimetric methodology of ICRP and compared them to those provided by ICRP. As a result, the discrepancies in dose coefficients were smaller than plus or minus 10% in most intake conditions. However, some intake conditions indicated varieties over 40% due to the differences in organ masses, amount of adipose tissues around the thoracic cavity, and so on. This information is useful in application of ICRP's dose coefficients to population of which physical characteristics are different from those of Caucasian. Further, the Japanese SAF data is published as an appendix of this paper.
Manabe, Kentaro; Sato, Kaoru; Takahashi, Fumiaki
Journal of Nuclear Science and Technology, 56(5), p.385 - 393, 2019/05
Times Cited Count：3 Percentile：31.89(Nuclear Science & Technology)At high energy accelerator facilities, various radionuclides are produced by nuclear reactions of high energy particles with structure and/or ambient air of the facilities. Consequently, the radionuclides are potential sources of internal exposure for works of the facilities. However, the International Commission on Radiological Protection (ICRP) do not provide dose coefficients, which are committed effective doses per intake, for the short-lived radionuclides whose half-lives are shorter than 10 minutes in accordance with the ICRP 2007 Recommendations. Then, we estimated the dose coefficients for inhalation and ingestion of these short-lived radionuclides in accordance with the ICRP 2007 Recommendations. In addition, we compared the dose coefficients with those in accordance with the ICRP 1990 Recommendations. As a result, a decreasing tendency was shown in the dose coefficients for inhalation cases; an increasing tendency was observed in those for ingestion cases. It was found that these changes in dose coefficients were mainly caused by the revision of the dose calculation procedures, alimentary tract models. The result of this study will be useful for planning of radiation protection at the high energy facilities.
Endo, Akira
Hoken Butsuri, 52(1), p.39 - 41, 2017/03
Radiological protection requires the quantification of the extent of exposure of the human body to ionizing radiation. To this end, the International Commission on Radiological Protection (ICRP) and the International Commission on Radiation Units and Measurements (ICRU) developed a dosimetry system consisting of protection quantities and operational quantities. The existing dosimetry system has been successfully used in radiological protection practice and regulations. Nevertheless, the system has some limitations and needs further improvements to consider changes in the fields of radiological protection. ICRP and ICRU have been discussing the issues to propose an alternative system of radiation dosimetry. This presentation overviews recent discussion on the protection quantities and operational quantities by ICRP and ICRU and the proposed dosimetry system for radiological protection.
Endo, Akira
Isotope News, (736), p.34 - 37, 2015/08
Japanese translation of ICRP Publication 116 entitled "Conversion Coefficients for Radiological Protection Quantities for External Radiation Exposures" was published by the Japan Radioisotope Association in March 2015. The book gives fluence to dose conversion coefficients for both effective dose and organ absorbed doses for various types of external exposures, consistent with the 2007 Recommendations of the ICRP. A complete set of conversion coefficients is provided in an accompanying CD in ASCII format and Microsoft Excel software. This article overviews ICRP Publication 116 and its impact to practice of radiation protection.
Endo, Akira
no journal, ,
In 2007, the International Commission on Radiological Protection (ICRP) adopted new fundamental recommendations on radiation protection in ICRP Publication 103 (ICRP103). The recommendations revised procedure for the assessment of effective dose used for radiological protection. The revision required new dose conversion coefficients for external radiation exposures. The sets of conversion coefficients were compiled by the Task Group on Dose Calculations (DOCAL) of ICRP Committee 2, and published as ICRP116. This presentation reviews ICRP116 and discusses the impact of new dose conversion coefficients on radiation protection practice.
Endo, Akira
no journal, ,
Radiological protection requires the quantification of the extent of exposure of the human body to ionizing radiation. To this end, the International Commission on Radiological Protection (ICRP) and the International Commission on Radiation Units and Measurements (ICRU) developed a dosimetry system consisting of protection quantities and operational quantities. The existing dosimetry system has been successfully used in radiological protection practice and regulations. Nevertheless, the system has some limitations and needs further improvements to consider changes in the fields of radiological protection. ICRP and ICRU have been discussing the issues to propose an alternative system of radiation dosimetry. This presentation overviews recent discussion on the protection quantities and operational quantities by ICRP and ICRU and the proposed dosimetry system for radiological protection.
Endo, Akira
no journal, ,
This presentation reports an overview of recent activities of the Committee 2 of the International Commission on Radiological Protection (ICRP) after its meeting held in Seoul, October 2015. The Committee 2 organized a symposium entitled "ICRP Symposium on Radiological Protection Dosimetry" in Tokyo, February 2016. The symposium aimed at reviewing the current work of ICRP and discussing research needed for the ICRP System of radiological protection dosimetry. The Committee 2 had its annual meeting in Oxford, the United Kingdom, September 2016. The committee reviewed progress of the development of ICRP Publications on development of computational phantom, dose coefficients for occupational and public intakes of radionuclides, use of effective dose as a risk-related radiological protection quantity, age dependent dose coefficients for external environmental exposures, and so on. Collaboration with the International Commission on Radiation Units and Measurements (ICRU) on revision of the operational dose quantities was also discussed.
Manabe, Kentaro; Sato, Kaoru; Takahashi, Fumiaki
no journal, ,
An effective dose coefficient is defined as a committed effective dose per unit intake, and it is a basic quantity for internal dose estimation and standards for radiation protection. In this study, we built a function to calculate effective dose coefficients based on the latest models and data in accordance with the 2007 Recommendations of International Commission on Radiological Protection (ICRP) as part of development of an internal dosimetry code. The methodology for dose calculation is summarized in a publication of ICRP. However, there is no description about concrete technics for solving a system of ordinary differential equations for activity distribution in the body, for interpolating specific absorbed fractions by radiation energies, and so on. Then, the best technics were searched for reproducing the effective dose coefficients recorded in the database provided by ICRP. In the presentation, we will report the result of comparison between the dose coefficients generated by the built function and those of the database and the validity of the selected technics.
Takahashi, Fumiaki; Manabe, Kentaro; Sato, Kaoru
no journal, ,
The International Commission on Radiological Protection (ICRP) has sequentially published radiation internal dose assessment models and data which are consistent with the ICRP Recommendation 2007. This study aims to develop a computation code that enables us to derive effective dose coefficients for revisions of reference values in radiation protection regulation by referring to the ICRP Recommendation 2007. In addition, the code will include a function to assess intakes of radionuclides from monitoring data. The code will be designed to correspond to the expanded data which will be published by ICRP, because the code will be applied to revise the reference value in regulations. Changes of radionuclide in a human body will be calculated by taking account for the use of this code in individual monitoring. This project will be made for 4 years under contraction with Nuclear Regulatory Authority (NRA) and overall plans are to be introduced in this title.
Yoshida, Hiroko*; Yasuda, Hiroshi*; Takahashi, Fumiaki; Dobashi, Ryuta*; Hattori, Takatoshi*
no journal, ,
The Japan Health Physics Society (JHPS) is a member of the International Radiation Protection Association (IRPA). Many researchers and technicians of radiation protection join JHPS in Japan. The international affairs committee in JHPS holds a session to introduce recent trends and information about radiation protection over the world in annual meeting. In the 51st Meeting, Dr. Yoshida (Tohoku Univ.) will talk about the recent activities of task groups in IRPA. Dr. Yasuda will explain radiation protection in aviation given by ICRP Publication 132. Dr. Dobashi will introduce recent discussions on the safety standards by IAEA. Takahashi (JAEA) will explain Occupational Intakes of Radionuclides (OIR) given by ICRP Publications 130, 134 and 137.
Manabe, Kentaro; Sato, Kaoru; Takahashi, Fumiaki
no journal, ,
no abstracts in English
Takahashi, Fumiaki; Sato, Kaoru; Shima, Yosuke*; Manabe, Kentaro
no journal, ,
JAEA has developed a computation code for internal dosimetry based upon the ICRP 2007 Recommendations. In this year, the dose coefficient calculation function is updated to calculate dose coefficients for elements in OIR part3 of ICRP and designed to incorporate new data. Some models (e.g., biokinetic models in OIR part 3) are newly incorporated to the function. The algorithm is also updated to calculate dose coefficients for nuclides in decay series (U, Th and so on). Effective dose coefficients by the updated function agreed well with the data in OIR Data Viewer for most cases. The function gives information of biokinetic models to be published by files with ID number and then can correspond to models and data that are to be published by ICRP in future. In addition, directories are prepared for files that can be used in internal dosimetry based upon the ICRP 1990 Recommendations and parameters for Japanese.
Manabe, Kentaro; Shima, Yosuke*; Sato, Kaoru; Takahashi, Fumiaki
no journal, ,
Intakes of radionuclides are estimated from monitoring results obtained by whole body counters or bioassay for personal dose management and internal dosimetry in case of an accident. In this study, we progressed the development of a function estimating intakes of radionuclides as part of development of an internal dosimetry code which is in accordance with the ICRP 2007 Recommendations. In FY2018, we built a basic function estimating intakes using the latest biokinetic models with a maximum likelihood method based on the conceptual design performed in HY2017. The quality of the basic function was assessed by comparison of the results by this function to literature data. In the presentation, we will report the method of estimating intakes and the result of quality assessment of this function.
Manabe, Kentaro; Sato, Kaoru; Takahashi, Fumiaki
no journal, ,
Evaluation of internal doses based on intake estimation from monitoring results such as external counting and bioassay is important for dose control in atomic or radiation facilities and incorporation of radionuclides caused by radiation accidents. When the 2007 Recommendations of the International Commission on Radiological Protection (ICRP) is implemented in the regulatory standards, intake and dose estimation will be carried out based on the models and data in accordance with the ICRP 2007 Recommendations. In this study, we are constructing a function for estimating intakes from monitoring results by using the current biokinetic models in the internal dosimetry code development in accordance with the 2007 Recommendations. We compared the result generated by the function with reference values as a verification of the function. In a sample examination of IDEAS guideline, we confirmed the results generated by our function were consistent with the reference values. In the presentation, we will report the results of verification including other examples.
Manabe, Kentaro; Sato, Kaoru; Takahashi, Fumiaki
no journal, ,
no abstracts in English
Manabe, Kentaro; Sato, Kaoru; Takahashi, Fumiaki
no journal, ,
Radioactivity in the body becomes in an equilibrium level after a certain period of time from a start of chronic intakes. In order to study the influence of revisions of biokinetic models by the International Commission on Radiological Protection on internal dose estimation for chronic intakes of soluble aerosols of 
Cs, we calculated the time course of radioactivity in the whole body and effective dose rates per year using the new and old sets of biokinetic models. It was found that the radioactivity at the equilibrium state increased 13% by the revision of the clearance model in the respiratory tract and that the dose rate increased 41% at the state by the revision of the systemic model for cesium.
Takahashi, Fumiaki; Sato, Kaoru; Manabe, Kentaro
no journal, ,
The Nuclear Regulatory Authority (NRA) of Japan has proceeded discussions to incorporate the ICRP 2007 Recommendation into radiation regulations in Japan. If regulations are revised, the standards for radiation protection are to be also changed. JAEA has developed internal dosimetry code to check whether new dose coefficients are correctly derived according to dosimetry model and data based upon the 2007 Recommendations. The code equips new dosimetry model and data based on the 2007 Recommendations and is designed to add new models which are to be published in future. Verification studies are performed by referring to new dose coefficients by ICRP. In addition, a function is also equipped to estimate intake of radionuclides by monitoring.
Manabe, Kentaro; Tokashiki, Yuji*; Sato, Kaoru; Takahashi, Fumiaki
no journal, ,
Nuclear Safety Research Center of Japan Atomic Energy Agency has been processing a 4-year research project from FY2017 to FY2020 to develop a computation code for internal dosimetry based upon the ICRP 2007 Recommendations contracted from Nuclear Regulation Authority of Japan. A beta ware of the code was completed by developing a graphical user interface to set calculation conditions with combining the two functions: dose coefficients calculation function and intake estimation function in this fiscal year which is the 3rd year of this project. We will report the summary of the beta ware and the future plan to finish the development project and to make the code open to the public.
Endo, Akira
no journal, ,
In December 2020, the International Conference on Recovery After Nuclear Accidents: Radiological Protection Lessons from Fukushima and Beyond is organized by the International Commission on Radiological Protection (ICRP) and hosted by Japan Atomic Energy Agency (JAEA) in association with several Japanese and international organizations. Collaboration between the ICRP and Japan Atomic Energy Research Institute (JAERI), the predecessor of JAEA, started in the early 1990s for the development of ICRP Publication. Since then, the ICRP and JAERI/JAEA have been continuing to cooperate in various tasks of radiation protection including response to the TEPCO Fukushima Daiichi Nuclear Power Plant Accident. For the recovery of Fukushima, continued cooperation of people involved in the accident, the ICRP and JAEA is required. This presentation looks back on the interaction of the ICRP and JAERI/JAEA over the past three decades and looks to future cooperation for the restoration of Fukushima.
Takahashi, Fumiaki; Manabe, Kentaro; Takubo, Kazuya*; Sato, Kaoru
no journal, ,
JAEA has developed an internal dosimetry code based on the ICRP 2007 recommendation in a four-year plan from FY 2017 to FY 2020 through a project commissioned by the Nuclear Regulation Authority. In this year, we heard comments on operability and functions for the prototype code developed up to last from experts of institutions with knowledge and experience in radiation monitoring. After that, the GUI screen for input was improved and a new output function was added by reflecting the result of hearing. In addition, the new dose evaluation models released as ICRP Publ.141 in 2020 were investigated and implemented in the code. The improved code was verified to calculate effective dose coefficient correctly for the newly added models. In this presentation, we report the overall of the code and its utilization.
