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Endo, Akira
ESI-News, 43(2), p.37 - 41, 2025/04
The International Commission on Radiation Units and Measurements (ICRU) published ICRU Report 95 in 2020, revising the operational quantities for external exposure. This article provides an overview of the developments in the discussions within the ICRU, the International Commission on Radiological Protection (ICRP), and experts from Japan, and explores the background and process that led the ICRU to revise the operational quantities, as well as future responses and challenges. The article aims to enhance the understanding of the experts of the new operational quantities and to contribute to their smooth implementation in the future.
Endo, Akira
Radiation Protection Dosimetry, 200(13), p.1266 - 1273, 2024/08
Times Cited Count：0 Percentile：0.00(Environmental Sciences)This study examines the relationship between ambient dose 
, ambient dose equivalent 
, and effective dose for external neutron irradiation over 163 operational spectra from different workplaces. The results show that provides a reasonable estimate with a controlled margin, even if overestimated, to assess effective dose compared with , which can lead to a significant overestimation or underestimation of effective dose depending on the neutron spectra. The results highlight the limitations of and the superiority of in estimating effective dose according to the requirements of the operational quantity, especially in environments with high-energy neutrons.
Endo, Akira
JAEA-Research 2024-002, 90 Pages, 2024/05
JAEA-Research-2024-002.pdf:4.22MB
This report presents a comprehensive analysis of the relationship between three quantities used for area monitoring - ambient dose equivalent , maximum dose equivalent 
, and ambient dose - and effective dose for external irradiation by photons, neutrons, electrons, positrons, protons, muons, pions, and helium ions. For the analysis, calculations were performed using PHITS (Particle and Heavy Ion Transport code System) and the ICRU sphere. The analysis result shows that and can induce large differences in the estimation of effective dose over a wide energy range for various particle types covered by ICRP Publication 116 while can conservatively estimate effective dose within the acceptable range for area monitoring. In other words, and have limitations in estimating effective dose, and using is recommended as a more appropriate quantity for the purpose. This conclusion supports the proposal of ICRU Report 95 to use for estimating effective dose in various external exposure situations. The use of ambient dose is particularly important in situations where various types of radiation are encountered, such as the use of radiation in the medical and academic fields and exposure in aviation and can meet the evolving requirements of radiation monitoring for the expansion of the field of radiological protection.
Endo, Akira
Radiation Protection Dosimetry, 175(3), p.378 - 387, 2017/07
Times Cited Count：11 Percentile：67.12(Environmental Sciences)The International Commission on Radiation Units and Measurements (ICRU) has been discussing to propose a new system of the operational quantities for external radiations based on protection quantities. The aim of this study is to provide a set of conversion coefficients for use in defining personal dose equivalent for individual monitoring. Fluence-to-effective dose conversion coefficients have been calculated for photons, neutrons, electrons, positrons, protons, muons, pions and helium ions for various incident angles of radiations. The data sets comprise effective dose conversion coefficients for incident angles of radiations from 0 
to 90 in steps of 15 and at 180. Conversion coefficients for rotational, isotropic, superior hemisphere semi-isotropic and inferior hemisphere semi-isotropic irradiations are also included. The conversion coefficients are used to define the operational quantity personal dose equivalent which is being considered by ICRU and utilized for the design and calibration of dosemeters.
Endo, Akira
Annals of the ICRP, 45(1_suppl.), p.178 - 187, 2016/06
The protection quantities, equivalent dose in an organ or tissue and effective dose, were developed by ICRP to allow quantification of the extent of exposure of the human body to ionizing radiation to be used for the implementation of the limitation and optimization principles. The body-related protection quantities are not measurable in practice. Therefore, ICRU developed a set of operational dose quantities for use in radiation measurements for external radiations that provide assessment of the protection quantities. ICRU has examined the rationale for operational quantities taking into account the changes in the definitions of the protection quantities in the ICRP 2007 Recommendations. The committee has investigated a set of alternative definitions for operational quantities different to the existing quantities. The major change in the currently favoured set of quantities is the redefinition of the operational quantities for area monitoring from being based on doses at a point in the ICRU sphere to ones based on particle fluence and the relationship to the protection quantities.
Yoshizawa, Michio
Hokeikyo Nyusu, (23), p.2 - 4, 1999/03
no abstracts in English
Yamaguchi, Yasuhiro
Hoken Butsuri, 33(1), p.12 - 15, 1998/00
no abstracts in English
Yoshizawa, Michio
Hoken Butsuri, 33(1), p.7 - 11, 1998/00
no abstracts in English
Yoshizawa, Michio; Yamaguchi, Yasuhiro
IRPA9: 1996 International Congress on Radiation Protection, Proceedings, 3, p.41 - 43, 1996/00
no abstracts in English
Sakamoto, Yukio; Tanaka, Shunichi; ; W.Pairsuwan*; Yoshizawa, Nobuaki*; ; Furihata, Shiori*; Uehara, Takashi*; Iwai, Satoshi*
JAERI-Conf 95-007, 0, p.48 - 56, 1995/03
no abstracts in English
spherical NaI(Tl) scintillation detector for estimating effective dose equivalentTsutsumi, Masahiro; Moriuchi, Shigeru; Saito, Kimiaki
JAERI-M 89-196, 30 Pages, 1989/11
no abstracts in English
Endo, Akira
no journal, ,
The International Commission on Radiation Units and Measurements (ICRU) defines a set of operational quantities for use in radiation measurements that provides assessment of the protection quantities recommended by International Commission for Radiological Protection (ICRP). The ICRU operational quantities in current use was defined in 1980s. ICRU Report Committee 26 has examined the rationale for operational quantities taking into account the changes in the definitions of the protection quantities and the changes in the fields of application of the operational quantities. The considerations have included the range of types and energies of particles contributing to doses to workers and members of the public. Based on the analysis, the committee has proposed a set of operational quantities which differs from the previous quantities. This presentation describes an overview of ICRU Report Committee 26's discussion on the definitions, deficiencies, and limitations of the current system, and its proposals for an alternative system of operational quantities.
Yoshitomi, Hiroshi
no journal, ,
no abstracts in English
Takahashi, Fumiaki; Sato, Kaoru; Satoh, Daiki
no journal, ,
In 2010, the International Commission on Radiological Protection (ICRP) indicated that the current operational quantities would underestimate effective doses based upon ICRP 2007 Recommendations. The International Commission on Radiation Unit and Measurement (ICRU) published new operational quantities in 2020. It can be required to use radiations instruments and dosimeters that correspond to the current operation quantities, even after Japanese standards for radiation safety are revised by taking account for ICRP 2007 Recommendations. Thus, we have analyzed relationships between current operational quantities and effective doses (current and new) for external neutron exposure by using spectra compiled in IAEA report. It is cleared that the current operational quantities can safely estimate the new effective dose. In addition, ratio of the new effective dose to the current operational quantity strongly depends on energy spectra in neutron fields.
Yoshitomi, Hiroshi; Tsuji, Tomoya; Fukami, Tomoyo; Nishino, Sho; Tanimura, Yoshihiko
no journal, ,
no abstracts in English
Yoshitomi, Hiroshi
no journal, ,
no abstracts in English
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, ,
The International Commission on Radiation Units and Measurements (ICRU), an international organization dedicated to providing internationally accepted recommendations on radiation-related quantities and units, has published ICRU Report 95, which revises the operational quantities for external radiation monitoring in 2020. This presentation will review the evolution of the discussions among the ICRU, the International Commission on Radiological Protection (ICRP), and national and international experts that led to the revision of the operational quantities, and will highlight key points of consideration in the preparation of the ICRU Report 95. This presentation will deepen the understanding of the new operational quantities and enable their smooth implementation in the future.
Yoshitomi, Hiroshi; Tsuji, Tomoya; Nishino, Sho; Fukami, Tomoyo; Tanimura, Yoshihiko
no journal, ,
no abstracts in English
Takahashi, Fumiaki
no journal, ,
This lecture focus on the evaluation of equivalent doses in radiation applications other than the medical field. Equivalent dose limits are established based on the recommendations of the International Commission on Radiological Protection (ICRP) in radiation safety standards of Japan. The equivalent doses of workers are evaluated with the operational quantities defined by the International Commission on Radiation Units and Measurements (ICRU). Domestic safety standards are based on the concept of the ICRP's 1990 recommendations, but data used for dose evaluations in accordance with the 2007 recommendations, which replaced these recommendations, have also been made public. In addition, many issues have been pointed out regarding the use of dose in radiation protection, and ICRP published Publ. 147, which clarifies these issues. Efforts are currently underway internationally to resolve the issues presented here. However, consideration and improvement measures are required about issues clarified in Publ.147 within the current protection system.
Yoshitomi, Hiroshi; Tanimura, Yoshihiko; Tsuji, Tomoya; Nishino, Sho
no journal, ,
no abstracts in English
