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NCRP Report No. 116 Limitation of Exposure to Ionizing Radiation
Book Review
NCRP Report No. 116: Limitation of Exposure to Ionizing Radiation National Council on Radiation Protection and Measurements Bethesda, Md: NCRP Publications, 1993. Paper, $25.00; pp 88. This long-awaited publication describes the newest recommendations of the National Council on Radiation Protection and Measurements (NCRP) concerning occupational and public radiation dose limits. NCRP Report No. 116 supercedes NCRP Report No. 91, published in 1987. In the intervening years, a major reevaluation of the effects of radiation on the atomic bomb survivors was completed and published in 1990 as the Biological Effects of Ionizing Radiations (BEIR) V report (1).The conclusion of the BEIR V report was that cancer risk from exposure to low linear energy transfer radiation (ie, x rays and gamma rays) is two to four times greater than was previously believed. Subsequent to the BEIR V report, the International Commission on Radiological Protection (ICRP), the body looked to by many other nations for dose limit guidelines, revised its recommendations concerning dose limits (2). The current NCRP document takes into account the conclusions of the BEIR V report and ICRP Publication 60. This publication marks an important step in the philosophy of the NCRP regarding occupational exposure. Short-term occupational dose limits remain as we are accustomed to: 50 mSv (5,000 mrem) as the annual effective dose limit, 150 mSv as the annual equivalent dose limit to the lens of the eye, and 500 mSv as the annual equivalent dose limit to the skin, hands, and feet. Three important changes do, however, exist. First, the "guidance" of 1987 stating that one's lifetime cumulative dose limit should be 10 mSv multiplied by the age in years has been strengthened to a recommended limit. With current record-keeping methods, many interventional radiologists will exceed this limit. Second, the embryo-fetal dose limit of 5 mSv during gestation has been changed to 0.5 mSv per month after the pregnancy is known. The current docu-
96
Journal of Vascular and Interventional Radiology
ment includes no total gestational dose limit. Finally, the council recommends that "consideration be given to establishing special dose limits for those selected occupational groups requiring higher exposures to accomplish needed activities" (page 42). This may have application to interventional radiology-particularly if regulating agencies continue to consider the over lead collar dosimeter reading to be equivalent to the total body dose (which is the case in many states). As is usual with NCRP publications, the text is well organized, concise, and written in clear, conversational English. Chapters have clear titles, making it easy to find topics of interest. Table 1.1on pages 3-5 is particularly useful, providing a direct comparison between the current NCRP recommendations, the current ICRP recommendations, and the 1987 NCRP dose limits. Chapters 2 and 3 provide background information on the philosophy of radiation safety. Later chapters deal with cancer risk estimates and multiple specific aspects of occupational radiation exposure. Limits to public exposure and remedial action levels are discussed briefly. Because all interventional radiologists should know what the rules are, I recommend that all interventional radiology groups own a copy of NCRP Report No. 11 6 as a reference.
-Reviewed by M. Victoria Marx, MD References 1. National Academy of SciencesINational Research Council. Health effects of exposure to low levels of ionizing radiation: report of the Committee on the Biological Effects of Ionizing Radiations (BEIR V). Washington, DC: National Academy Press, 1990. 2. International Commission on Radiological Protection. 1990 recommendations of the International Commission on Radiological Protection. ICRP Publication 60. Annals of the ICRP 21. Elmsford, NY: Pergamon Press, 1991.
January-February 1995
NCRP Report No. 116: Limitation of Exposure to Ionizing Radiation National Council on Radiation Protection and Measurements Bethesda, Md: NCRP Publications, 1993. Paper, $25.00; pp 88. This long-awaited publication describes the newest recommendations of the National Council on Radiation Protection and Measurements (NCRP) concerning occupational and public radiation dose limits. NCRP Report No. 116 supercedes NCRP Report No. 91, published in 1987. In the intervening years, a major reevaluation of the effects of radiation on the atomic bomb survivors was completed and published in 1990 as the Biological Effects of Ionizing Radiations (BEIR) V report (1).The conclusion of the BEIR V report was that cancer risk from exposure to low linear energy transfer radiation (ie, x rays and gamma rays) is two to four times greater than was previously believed. Subsequent to the BEIR V report, the International Commission on Radiological Protection (ICRP), the body looked to by many other nations for dose limit guidelines, revised its recommendations concerning dose limits (2). The current NCRP document takes into account the conclusions of the BEIR V report and ICRP Publication 60. This publication marks an important step in the philosophy of the NCRP regarding occupational exposure. Short-term occupational dose limits remain as we are accustomed to: 50 mSv (5,000 mrem) as the annual effective dose limit, 150 mSv as the annual equivalent dose limit to the lens of the eye, and 500 mSv as the annual equivalent dose limit to the skin, hands, and feet. Three important changes do, however, exist. First, the "guidance" of 1987 stating that one's lifetime cumulative dose limit should be 10 mSv multiplied by the age in years has been strengthened to a recommended limit. With current record-keeping methods, many interventional radiologists will exceed this limit. Second, the embryo-fetal dose limit of 5 mSv during gestation has been changed to 0.5 mSv per month after the pregnancy is known. The current docu-
96
Journal of Vascular and Interventional Radiology
ment includes no total gestational dose limit. Finally, the council recommends that "consideration be given to establishing special dose limits for those selected occupational groups requiring higher exposures to accomplish needed activities" (page 42). This may have application to interventional radiology-particularly if regulating agencies continue to consider the over lead collar dosimeter reading to be equivalent to the total body dose (which is the case in many states). As is usual with NCRP publications, the text is well organized, concise, and written in clear, conversational English. Chapters have clear titles, making it easy to find topics of interest. Table 1.1on pages 3-5 is particularly useful, providing a direct comparison between the current NCRP recommendations, the current ICRP recommendations, and the 1987 NCRP dose limits. Chapters 2 and 3 provide background information on the philosophy of radiation safety. Later chapters deal with cancer risk estimates and multiple specific aspects of occupational radiation exposure. Limits to public exposure and remedial action levels are discussed briefly. Because all interventional radiologists should know what the rules are, I recommend that all interventional radiology groups own a copy of NCRP Report No. 11 6 as a reference.
-Reviewed by M. Victoria Marx, MD References 1. National Academy of SciencesINational Research Council. Health effects of exposure to low levels of ionizing radiation: report of the Committee on the Biological Effects of Ionizing Radiations (BEIR V). Washington, DC: National Academy Press, 1990. 2. International Commission on Radiological Protection. 1990 recommendations of the International Commission on Radiological Protection. ICRP Publication 60. Annals of the ICRP 21. Elmsford, NY: Pergamon Press, 1991.
January-February 1995