Biological effects of ionizing radiation: a perspective for Japan.
|Subject:||Nuclear accidents (Environmental aspects)|
|Publication:||Name: Journal of American Physicians and Surgeons Publisher: Association of American Physicians and Surgeons, Inc. Audience: Academic Format: Magazine/Journal Subject: Health care industry Copyright: COPYRIGHT 2011 Association of American Physicians and Surgeons, Inc. ISSN: 1543-4826|
|Issue:||Date: Summer, 2011 Source Volume: 16 Source Issue: 2|
|Geographic:||Geographic Scope: Japan Geographic Code: 9JAPA Japan|
Most of the world press assumes that all radiation is harmful. If
the Japanese government acts on this presumption in responding to the
nuclear reactor damage from the March 2011 earthquake and tsunami at
Fukushima, Japan's already reeling economy will be crushed by
tremendous unwarranted expense. Japan should learn from Chernobyl what
Mikhail Gorbachev understood too late: "The nuclear meltdown at
Chernobyl 20 years ago ... was perhaps the real cause of the collapse of
the Soviet Union five years later." (1)
Ionizing radiation is hormetic. The concept of hormesis, which is not generally understood by news media and governments, is that small doses are beneficial, while large doses are harmful. This effect is known to occur for about 40 essential nutrients, all drugs, and most other agents. Both chronic and acute exposures to ionizing radiation exhibit hormesis. Consideration of the full spectrum, beneficial as well as harmful, of the biological effects of ionizing radiation is vital to understanding the importance of nuclear fallout.
There are thousands of scientific papers showing benefit from low doses of ionizing radiation. (2,3,4) Japan could consult its own world renowned scientist, Dr. Sadao Hattori, (5) retired director of research for the Central Research Institute of Electric Power Industry of Japan. Instead, there is a tendency to rely on the Radiation Effects Research Committee (RERF) in Hiroshima, which spends millions of dollars searching for the harm from ionizing radiation, and is not a reliable source of information about the health benefits from ionizing radiation.
Ionizing Radiation Is Essential for Life
Experiments with appropriate shielding in brine shrimp, (6) protozoa, (7,8) and mice and rats (9) have produced convincing evidence that ionizing radiation is essential for life. In Luckey's study of protozoa and Kuzin's of mice and rats, researchers replaced natural (radioactive) potassium with the non-radioactive potassium-39 to produce radiation deficiency. These reports suggest that ionizing radiation is also an essential agent for humans.
[FIGURE 1 OMITTED]
The concept that we live with a radiation deficiency is supported by more than 2,000 scientific papers showing that low-dose irradiation stimulates the well being of laboratory animals and humans. (3,4) The data indicate that ambient levels of ionizing radiation throughout the world, 3 mSv/y, (10, p 198) are insufficient for vibrant health. For example, evidence suggests that if we received adequate ionizing radiation, cancer would be a raredisease.
A complete dose-response curve (Figure 1) shows the optimum ionizing radiation rate associated with the minimal cancer death rate and maximal life span: about 100 mGy/y. (11) The zero equivalent point (ZEP), the rate that divides healthful from harmful effects, is about 10,000 mGy/y. Exposure rates greater than ZEP may produce symptoms of radiation sickness and death.
Evidence for this concept comes from Taipei. (12) In 1982-1984, radioactive cobalt-contaminated steel was used for girders in an apartment complex. During the next two decades about 10,000 people lived in this enriched radioactive environment. The average dose received was 50 mSv/y. This dose is close to the optimum dose of 100 mSv/y. (Sv and Gy are about equal in the new evaluation.) (13) The cancer death rate for these apartment dwellers was only 3.5 per 100,000 person years; 116 deaths per 1,000 person years were anticipated from consideration of controls. Although thorough studies have not been made, it appears that chronic low-dose irradiation decreases cancer mortality rates. Lung cancer mortality rates as a function of indoor radon concentrations in the U.S. support this view. (14)
[FIGURE 2 OMITTED]
Conclusions about the effects of acute exposure are generally based on data on the Japanese survivors of the atomic bombs (see Figure 2). (15) The RERF compared the cancer mortality of Hiroshima and Nagasaki survivors with that of people who were 3-10 km from ground zero ("in-the-city controls"). These controls received some radiation from the bombs, and many went into the bombed areas while residual radiation was high. Total [all-cause] "mortality rates in 120,321 atomic bomb survivors were not increased at doses <490mSv." (16,p46)
The cancer mortality rate of the 7,430 survivors of Hiroshima and Nagasaki who received 10-19 mSv was 68.5% (P<.01) of that of controls. (17) The 28,423 survivors (69% of all survivors) who received <200 mSv had 76.6 cancer deaths per 1,000 people (see Figure 2). This was close to the value, 77 cancer deaths per 1,000 people, found for the unexposed people in villages northwest of Hiroshima. (18) Note that this "out of city" control population had more cancer deaths per 1,000 people than the RERF "in the city" control cohort, a comparison that RERF never makes.
Exposures greater than 200 mSv showed increased cancer death rates commensurate with increasing dose. Thus the ZEP for acute ionizing radiation was about 200 mSv. Radiation sickness was caused by exposures >2,000 mSv.
More evidence comes from 23 young Japanese fishermen who received fallout from the explosion of a hydrogen bomb at Bikini Island in March 1954. All suffered severe radiation sickness. Whole body doses were 170-590 cSv (1,700-5,900 mSv), according to Eisenbud's Table 12.1. (10) Thyroids received 300-1,000 cSv. The man who received the largest dose died 206 days following exposure. The others survived for more than two decades with no cancers.
Triage for Radiation
The above information provides a tentative guide for the treatment of people exposed to different amounts of chronic and/or acute ionizing radiation. Triage following a nuclear accident or explosion provides the most good for the most people. Triage for people with acute radiation exposures usually involves consideration of other problems also, such as psychological reactions, physical disabilities, injuries from flying debris, and/or in adequate food, water, and housing.
The major concern here is trauma caused by direct irradiation; this contributes about 5% of the total harm from atomic bombs. (19) Triage also includes radiation from many external and internal radionuclides; this accounts for about 10% of the total harm from a nuclear explosion. Blast and heat cause about 80% of the total harm. These guidelines are of limited value in nuclear accidents.
Radiation triage is relatively simple for people with chronic exposures from external sources. People exposed to less than 10 Gy/y (about 1 mGy/h) from external radiation can immediately help those less fortunate. People exposed to 2-10 mGy/h for prolonged periods should be placed under observation. Reddening of the skin (as in sunburn) is symptomatic of minor excess radiation. People exposed to 11-100 mGy/h for an extended time will have radiation sickness and should be placed under medical care. People who receive more than 1 Gy/h will have serious radiation sickness. People exposed to more than 10 Gy/h should be placed in a hospice with care and a blessing.
The combined data from Hiroshima and Nagasaki (17) indicate that people exposed to less than 1,000 mSv acute radiation should be recruited to help those who are disabled and sick. People exposed to 1,000-2,000 mSv acute radiation may require treatment for radiation sickness. People exposed to 2,000-6,000 mSv need immediate hospitalization. People with more than 6,000 mSv should be placed in a hospice with care and a blessing. The quality factor (Q) of nuclear explosions needs to be re-examined. (13)
(1) Jaworowski Z. Observations on the Chernobyl disaster and LNT. Dose Response 2010;8:148-171.
(2) Luckey TD. Hormesis with Ionizing Radiation. Boca Raton, Fla.: CRC Press; 1980.
(3) Luckey TD. Radiation Hormesis. Boca Raton, Fla.: CRC Press; 1991.
(4) Muckerheide J. Low-Level Radiation Health Effects: Compiling the Data. Needham, Mass.: Radiation Science and Health; 2003.
(5) Hattori S. State of research and perspective on radiation hormesis in Japan. Am J Occup Med Toxicol 1994;3:203-217.
(6) Eugaster J. Weltraumstrahlung. Berlin: Hans Huber; 1955.
(7) Planel H, Soleilhavoup JP, Tixador R, et al. Influence on cell proliferation of background radiation or exposure to very low, chronic gamma radiation. Health Physics 1987;52:571-581.
(8) Luckey TD. Ionizing radiation promotes protozoan reproduction. Radiat Res 1986;108:215-219.
(9) Kuzin AM, Natural atomic radiation and the phenomenon of life. Byulleten Eksperimental noi Biologiil Meditsiny 1997;123:364-366.
(10) Eisenbud M, Gesell T. Environmental Radioactivity. 4th ed. Academic Press; 1997.
(11) Luckey TD. The health effects of low-dose ionizing radiation. J Am Phys Surg 2008;13:35-42.
(12) Chen WL, Luan YC, Shich MC, et al. Effects of cobalt-60 exposure on health of Taiwan residents suggest new approach needed in radiation protection. Dose Response 2007;5:63-75.
(13) Luckey TD. Sv has a negative Q. Health Physics News, submitted March, 2011.
(14) Cohen BL Test of the linear no-threshold theory of radiation carcinogenesis for inhaled radon decay products. Health Physics 1995;68:157-174.
(15) Luckey TD. Atomic bomb health benefits. Dose-Response 2008;6:369-382.
(16) Sanders CL. Radiation Hormesis and the Linear-No-Threshold Assumption. Berlin:Springer; 2010.
(17) Shimizu Y, Kato H, Schull WJ, Mabuchi K. Dose-response analysis among atomic-bomb survivors exposed to low-level radiation. In: SugaharaT, Sagon LA, Aoyama T. Low Dose Irradiation and Biologic Defense Mechanisms. London: Excerpta Medica; 1992:71-74.
(18) Mifune M, Sobue T, Arimoto H, et al. Cancer mortality survey in a spa area (Misasa, Japan) with a high radon background. Jpn J Can Res 1992;83:1-5.
(19) Kondo S. Health Effects of Low-level Radiation. Madison, Wis.: Medical Physics Publishing; 1993.
Sir Samurai T.D. Luckey, Ph.D., is honorary professor, Free University of Herborn, Germany, and retired professor, University of Missouri, Columbia. In 1984 he was knighted in Germany for two decades of world leadership in intestinal microecology. In 2003 he was awarded an honorary Samurai for his work in radiation hormesis. Contact: email@example.com.
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