{"id":7936,"date":"2025-04-27T13:36:32","date_gmt":"2025-04-27T04:36:32","guid":{"rendered":"https:\/\/www.envraddb.go.jp\/entesttest\/?page_id=7936"},"modified":"2026-06-16T16:34:32","modified_gmt":"2026-06-16T07:34:32","slug":"committed-effective-dose","status":"publish","type":"page","link":"https:\/\/www.envraddb.go.jp\/en\/special\/committed-effective-dose\/","title":{"rendered":"What is Committed Effective Dose?"},"content":{"rendered":"
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What is Committed Effective Dose?<\/h2>\r\n <\/div>\r\n
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Radioactive materials taken into the tissues of our bodies gradually decrease\r\n over time by natural decay and are released to the outside of the body through metabolism.
Committed\r\n effective dose is a radiation dose assuming that the dose that is to be received over a committed period of 50\r\n years after intake is received in the first year, which is used as a standard for evaluating the long-term\r\n impact of internal exposure by food.<\/p>\r\n\r\n

\r\n \"\u9810\u8a17\u5b9f\u52b9\u7dda\u91cf\u3068\u306f\"\r\n <\/figure>\r\n
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In the case of internal exposure where tissues and organs of our bodies are\r\n irradiated by radiation due to decay of radionuclides taken into the body, the dose to the tissues and\r\n organs changes with time. This temporal change in dose rate depends on the type, physical and chemical\r\n nature of the radionuclide, how the radionuclide was taken in, and the tissues or organs the nuclide is\r\n mostly taken into.<\/p>\r\n <\/div>\r\n

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Usually, our bodies cannot selectively control the metabolism or the speed of\r\n excretion for radionuclides. Therefore, once a radionuclide is taken into our bodies, the effect (dose rate\r\n distribution and future cumulative dose) of the radionuclide in internal exposure is determined at the time\r\n of intake. The committed equivalent dose, H(\u03c4,T), received by a tissue or organ, T, is expressed by the\r\n following formula:<\/p>\r\n <\/div>\r\n

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H(\u03c4,T)\uff1d\u222bh(t)dt<\/p>\r\n <\/div>\r\n

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where the integration with respect to time is done fromt0<\/span>to t0<\/span>\uff0b\u03c4.<\/p>\r\n <\/div>\r\n

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In the formula above, h(t) is the dose rate the tissue or organ, T, receives at\r\n time t, and the committed period, \u03c4, is set to be 50 years for occupational exposure and for adults and 70\r\n years for children and infants.<\/p>\r\n <\/div>\r\n

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Figure 1 shows examples of h(t) in the formula above for radioactive materials\r\n with a long and short effective half-life (half-life that takes into account both the natural decay and\r\n discharge of radionuclides from the body) in a tissue or organ.<\/p>\r\n <\/div>\r\n

\r\n \"\u9810\u8a17\u5b9f\u52b9\u7dda\u91cf\u3068\u306f\"\r\n <\/figure>\r\n
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Committed effective dose, E(\u03c4), is the sum of the products of the equivalent\r\n dose that a tissue or organ, T, receives from intake of radioactive materials and the appropriate tissue\r\n weighting factors, W(T), as shown in the following formula:<\/p>\r\n <\/div>\r\n

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E(\u03c4)\uff1d\u03a3W(T)\u30fbH(\u03c4\uff0cT)<\/p>\r\n <\/div>\r\n

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where the summation is done for all tissues and organs in the body.<\/p>\r\n <\/div>\r\n

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However, if a radioactive material taken into our bodies adsorbs and remains in\r\n a tissue or organ, it is not easy to calculate the cumulative dose the tissue or organ receives. That is\r\n because calculation of the internal exposure dose requires measuring the amount of the radioactive material\r\n remaining in the tissues and organs and tracking the temporal change of the amount.<\/p>\r\n <\/div>\r\n

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To simplify the calculation, in the case of internal exposure, the relationship\r\n between the amount of radioactive materials taken and the amount of dose a tissue or organ receives is\r\n predetermined. Using this relationship, the dose a human body receives is calculated based on the intake\r\n amount of radioactive materials.<\/p>\r\n <\/div>\r\n

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The ratio of committed effective dose (mSv) of acute intake (or single dose\r\n intake) of 1 Bq of a radionuclide to 1 Bq of the radionuclide is called effective dose coefficient (mSv\/Bq),\r\n which is used to calculate committed effective doses. Table 1 shows examples of effective dose\r\n coefficients.
Committed effective dose is calculated by the following formula, using effective dose\r\n coefficient:\r\n <\/p>\r\n <\/div>\r\n

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[Committed effective dose (mSv)]\uff1d[Effective dose coefficient (mSv\/Bq)]\u00d7[Nuclide\r\n intake per year (Bq)]\u00d7[Market dilution factor]\u00d7[Correction for reduction by cooking, etc.]<\/p>\r\n <\/div>\r\n

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[Nuclide intake per year (Bq)]\uff1d[Annual average nuclide concentration in\r\n environmental samples]\u00d7[Annual intake of the food, drink, etc.]<\/p>\r\n <\/div>\r\n

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* The market dilution factor and correction for reduction by cooking, etc., are\r\n applied where necessary.<\/p>\r\n <\/div>\r\n

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In Japan, committed effective doses are added to effective doses of external\r\n exposure in the control of exposure of individuals by the Act on the Regulation of Nuclear Source Material,\r\n Nuclear Fuel Material and Reactors and other radiation control-related laws (so that the sum of the\r\n committed effective dose assuming received in one year after intake and the effective dose of external\r\n exposure for the year does not to exceed the annual dose limit).<\/p>\r\n <\/div>\r\n

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Table 1 Examples of effective dose coefficients for converting intake of\r\n radionuclide to internal exposure dose<\/p>\r\n <\/div>\r\n

\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n
Column 1<\/td>\r\n Column 2<\/td>\r\n Column 3<\/td>\r\n <\/tr>\r\n
Type of radioactive material<\/td>\r\n Effective dose coefficient for inhalation
\r\n (mSv\/Bq)<\/td>\r\n 		Effective dose coefficient for inhalation
\r\n (mSv\/Bq)<\/td>\r\n <\/tr>\r\n
Nuclide<\/td>\r\n Chemical form, etc.<\/td>\r\n <\/tr>\r\n
3<\/span>H<\/td>\r\n Water<\/td>\r\n 1.8\u00d710-8<\/span><\/td>\r\n 1.8\u00d710-8<\/span><\/td>\r\n <\/tr>\r\n
60<\/span>Co<\/td>\r\n Compounds other than oxides, hydroxides, and inorganic compounds\r\n (ingestion)<\/td>\r\n <\/td>\r\n 3.4\u00d710-6<\/span><\/td>\r\n <\/tr>\r\n
60<\/span>Co<\/td>\r\n Oxides, hydroxides, and inorganic compounds (ingestion)<\/td>\r\n <\/td>\r\n 2.5\u00d710-6<\/span><\/td>\r\n <\/tr>\r\n
60<\/span>Co<\/td>\r\n Compounds other than oxides, hydroxides, halides, and nitrates<\/td>\r\n 7.1\u00d710-6<\/span><\/td>\r\n <\/td>\r\n <\/tr>\r\n
60<\/span>Co<\/td>\r\n Oxides, hydroxides, halides, and nitrates<\/td>\r\n 1.7\u00d710-5<\/span><\/td>\r\n <\/td>\r\n <\/tr>\r\n
90<\/span>Sr<\/td>\r\n Compounds other than strontium titanate<\/td>\r\n 3.0\u00d710-5<\/span><\/td>\r\n 2.8\u00d710-5<\/span><\/td>\r\n <\/tr>\r\n
90<\/span>Sr<\/td>\r\n Strontium titanate<\/td>\r\n 7.7\u00d710-5<\/span><\/td>\r\n 2.7\u00d710-6<\/span><\/td>\r\n <\/tr>\r\n
131<\/span>I<\/td>\r\n Steam <\/td>\r\n 2.0\u00d710-5<\/span><\/td>\r\n <\/td>\r\n <\/tr>\r\n
131<\/span>I<\/td>\r\n Methyl iodide<\/td>\r\n 1.5\u00d710-5<\/span><\/td>\r\n <\/td>\r\n <\/tr>\r\n
131<\/span>I<\/td>\r\n Compounds other than methyl iodide<\/td>\r\n 1.1\u00d710-5<\/span><\/td>\r\n 2.2\u00d710-5<\/span><\/td>\r\n <\/tr>\r\n
137<\/span>Cs<\/td>\r\n All compounds<\/td>\r\n 6.7\u00d710-6<\/span><\/td>\r\n 1.3\u00d710-5<\/span><\/td>\r\n <\/tr>\r\n
239<\/span>Pu<\/td>\r\n Compounds other than nitrates and insoluble oxides (ingestion)<\/td>\r\n <\/td>\r\n 2.5\u00d710-4<\/span><\/td>\r\n <\/tr>\r\n
239<\/span>Pu<\/td>\r\n Nitrates (ingestion)<\/td>\r\n <\/td>\r\n 5.3\u00d710-5<\/span><\/td>\r\n <\/tr>\r\n
239<\/span>Pu<\/td>\r\n Insoluble oxides (ingestion)<\/td>\r\n <\/td>\r\n 9.0\u00d710-6<\/span><\/td>\r\n <\/tr>\r\n
239<\/span>Pu<\/td>\r\n Compounds other than insoluble oxides<\/td>\r\n 3.2\u00d710-2<\/span><\/td>\r\n <\/td>\r\n <\/tr>\r\n
239<\/span>Pu<\/td>\r\n Insoluble oxides<\/td>\r\n 8.3\u00d710-3<\/span><\/td>\r\n <\/td>\r\n <\/tr>\r\n <\/tbody>\r\n <\/table>\r\n <\/div>\r\n
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From Japan Radioisotope Association (ed.): Public Notice of the Science and\r\n Technology Agency, No. 5, October 23, 2000 (Specifying Standards for the Quantities, etc. of\r\n Radiation-Emitting Isotopes) Appended Table 2. Isotope Statute Book (I) 2005 Edition (October 2005), p375\r\n <\/p>\r\n <\/div>\r\n

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References<\/p>\r\n <\/div>\r\n

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\uff08\uff11\uff09Japan Radioisotope Association (ed.): ICRP Publ. 42, A Compilation of the\r\n Major Concepts and Quantities in Use by ICRP, Maruzen (June 1986)<\/p>\r\n <\/div>\r\n

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\uff08\uff12\uff09Japan Radioisotope Association (transl.): ICRP Publ. 60, 1990\r\n Recommendations of the International Commission on Radiological Protection, Maruzen (July 1991)<\/p>\r\n <\/div>\r\n

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\uff08\uff13\uff09Guidance for Environmental Radiation Monitoring (Nuclear Safety\r\n Commission, partially amended in March 2001)<\/p>\r\n <\/div>\r\n

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\uff08\uff14\uff09Glossary of Basic Terms in Nuclear Emergency Prevention<\/p>\r\n <\/div>\r\n

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\uff08\uff15\uff09Atomic Energy Encyclopedia ATOMICA    https:\/\/atomica.jaea.go.jp\/index.html<\/a>*Japanese<\/p>\r\n <\/div>\r\n <\/div>\r\n <\/div>\r\n <\/section>\r\n

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Committed Effective Dose Calculation Formula<\/h2>\r\n <\/div>\r\n
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Committed effective dose is calculated using the formula below (*1).<\/p>\r\n <\/div>\r\n

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Committed effective dose H(mSv) \uff1d 0.001\u00d7m\u00d7d\u00d7p\u00d7a\u00d7f1<\/span>\u00d7f2<\/span>\r\n <\/p>\r\n <\/div>\r\n

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m: Intake of food and drink (g\/day)
\r\n The values of the intake of nutrition, etc., by food group (nationwide) in the National Health and Nutrition\r\n Survey 2005 conducted by the Ministry of Health, Labour and Welfare will be used. The values are provided in a\r\n table summarizing the intake (g) per person per day, arranged by food group.
\r\n d: Number of days of intake (days)
\r\n It will be 365 days, since we are looking to obtain dose per year.
\r\n p: Effective dose coefficient (mSv\/Bq)
\r\n Dose coefficients for ingestion are specified in ICRP Publ. 72 for each nuclide, which will be used.
\r\n Example: 2.8\u00d710-5<\/span>for Sr-90,1.3\u00d710-5<\/span>for Cs-137
\r\n a: Radioactivity concentration (Bq\/kg)
\r\n Data of radioactivity analysis for food samples collected in prefectures summarized by nuclide will be\r\n used.
\r\n f1<\/span>\uff1aMarket dilution factor
\r\n f2<\/span>\uff1aCorrection for reduction by cooking, etc.
\r\n These values vary depending on the conditions, such as the distribution channel and cooking method. Here, we\r\n use the value of 1 as the most severe condition.<\/p>\r\n <\/div>\r\n

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(*1) Guidance for Environmental Radiation Monitoring (Nuclear Safety Commission,\r\n partially amended in March 2001)<\/p>\r\n <\/div>\r\n

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Committed Effective Dose Calculation Example<\/h3>\r\n <\/div>\r\n
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As an example, the committed effective dose is calculated below for Japanese jack\r\n mackerel.<\/p>\r\n <\/div>\r\n