Radiopharmacology: Hazard or/and Benefit^[*]

Summary

In the beginning of medical radiology, only the benefit of ionizing radiation was obvious, and radiation was handled and applied generously. After late effects had become known, the radiation exposure was reduced to doses following which no such effects were found. Thus, it was assumed that one could obtain an optimal medical benefit without inducing any hazard. Later, due to experimental findings, hypotheses arose (linear dose-effect response, no time factor) which led to the opinion that even low and lowest radiation doses were relevant for the induction of late effects. A radiation fear grew, which was unintentionally strengthened by radiation protection decrees: even for low doses a radiation risk could be calculated. Therefore, it was believed that there could still exist a radiation hazard, and the radiation benefit remained in question. If, however, all presently known facts are considered, one must conclude that large radiation doses are hazardous and low doses are inefficient, whereas lowest doses have a biopositive effect. Ionizing radiation, therefore, may cause both, hazard as well as benefit. Which of the two effects prevails is determined by the level of dose.

Zusammenfassung

Zu Beginn der medizinischen Radiologie sah man nur den großen Nutzen, der sich aus der Anwendung ionisierender Strahlen ergab, insbesondere seitens der Diagnostik. Deshalb ging man zunächst sehr großzügig mit der Strahlung um. Erst nachdem Spätwirkungen bekannt geworden waren, führte man Schutzmaßnahmen ein und setzte die Dosen so weit herab, daß Spätschäden nicht mehr nachweisbar waren. Man meinte, auf diese Weise den optimalen Nutzen ohne Induktion von Schäden erhalten zu können. Später wurden aufgrund neuer experimenteller Befunde Hypothesen aufgestellt (lineare Dosis-Wirkungsbeziehungen, kein Zeitfaktor), die zu der Auffassung führten, daß für die Induktion von Spätschäden auch kleine und kleinste Dosen berücksichtigt werden müßten. Es entstand eine Strahlenangst, die durch Strahlenschutzverordnungen verstärkt wurde: auch für kleine und kleinste Dosen ließ sich jetzt eine Strahlengefährdung errechnen. Man glaubte deshalb an das Bestehen einer Strahlengefährdung auch durch solche Dosen und bezweifelte jeglichen Nutzen. Wenn man jedoch alle zur Zeit vorliegenden Tatsachen berücksichtigt, kommt man zu dem Schluß, daß hohe Strahlendosen schädlich sind und kleine Dosen keine Wirkung haben, wohingegen kleinste Dosen biopositiv wirken. Ionisierende Strahlung kann also nicht nur schaden, sondern auch nützen. Es hängt von der Höhe der Dosis ab, welche Art der Wirkung auftritt.

^* 3rd International Symposium on Radiopharmacology, Freiburg i. Br., September 1983.

• References

• 1 Baum J. W. Population heterogenity hypothesis on radiation induced cancer. Health Phys 1973; 25: 97.
• 2 BEIR Report: The effects on populations of exposure to low levels of ionizing radiation. U. S. Dept, of Commerce, PB 1972; 239: 735.
• 3 Committee on Genetic Effects of Atomic Radiation. 1956, Biologic Effects of Atomic Radiation, Summary Reports. Washington, D. C.: National Academy of Science and the National Research Council; 23 28: (cit.) Wesley J. P.. 1960.
• 4 Dublin L. I., Spiegelmann M. Mortality of medical specialists, 1938-1942. J. Am. med. Assn 1948; 137: 1519.
• 5 Eichholz G. G. Trivial dose levels. Health Phys 1983; 45: 180-1.
• 6 Freire-Maja A., Krieger H. Human genetic studies in areas of high natural radiation-IX. Effects on mortality, morbidity and sex ratio. Health Phys 1978; 34: 61-5.
• 7 Frigerio N. A., Stowe R. S. Carcinogenic and genetic hazard from backround radiation. In: Biological Effects of Low-Level Radiation. Vol. 2 385-93 IAEA; Vienna: 1976.
• 8 Grahn D., Sacher A. G., Rust J. H., Fry R. J. M. Duration of life with daily ⁶⁰Co gamma irradiation: Report on survival and incidence of tumors, Annual Report ANL-7635. 1-8 (Argonne Nat. Lab.) 1969;
• 9 Hutchison G. B. Late neoplastic changes following medical irradiation. Radiology 1972; 105: 645.
• 10 Ichimaru M., Ishimaru T., Belsky J. L. Incidence of leukemia in atomic bomb survivors belonging to a fixed cohort in Hiroshima and Nagasaki. J. Radiat. Res 1978; 19: 262.
• 11 ICRP, Publication 8:. The Evaluation of Risks from Radiation. Pergamon Press, Oxford. Braunschweig, 1966; Health Phys 1966; 12: 239-302.
• 12 ICRP, Publication 26:. Recommendations of the International Commission on Radiological Protection. Pergamon Press; Oxford - New York - Frankfurt: 1977.
• 13 Jacobson A. P., Plato P. A., Frigerio N. A. The role of natural radiations in human leukemogenesis. Amer. J. Publ. Health 1976; 66: 31-7.
• 14 Kato H., Schull W. J. Studies of the mortality of A-bomb Mortality survivors. 7, 1950-1978: Part I. Cancer Mortality. Radiat. Res 1982; 90: 395-432.
• 15 Krebs A. Strahlenbiologie. Springer; Berlin - Heidelberg - New York: 1968.
• 16 Lisco H., Ducoff H. S., Baserga R. The influence of total body X-irradiation on the response of mice to methylcholanthrene, Bull. Johns Hopkins Hosp 1958; 103: 101-13.
• 17 Luckey T. D. Hormesis with ionizing radiation. CRC; Boca Raton: 1980.
• 18 Luckey T. D. Physiological benefits from low levels of ionizing radiation. Health Phys 1982; 43: 771.
• 19 Mason T. H., Miller R. W. Cosmic radiation at high altitudes and U. S. cancer mortality 1950-1969. Radiat. Res 1974; 60: 302-6.
• 20 Mewissen D. H., Rust J. H. Reticuloendothelial neoplasma in c57 black mice after fast neutron irradiation at low doses. In: Hanford Biology Symposium on Radiation and the Lymphatic System. 230-238 Oak Ridge: U. S. Atomic Energy Commission; AI 1976. Vol 7 255-518
• 21 Mole R. H. Radiation Effects in Man: Current views and Prospects. Health Phys 1971; 20: 485-90.
• 22 Muller H. J. Artificial transmutation of the gene. Science 1927; 66: 84.
• 23 Murphy J. B., Morton J. J. The effect of Roentgen rays on the rate of growth of spontaneous tumours in mice. J. exp. Med 1915; 22: 800-3.
• 24 Pauling L. Genetic and somatic effects of carbon-14. Science 1958; 128: 1183.
• 25 Peterson A. V., Prentice R. L., Ishimaru T., Kato D., Mason M. Investigation of circular asymmetry in cancer mortality of Hiroshima and Nagasaki A-bomb survivors. Radiat. Res 1983; 93: 184-99.
• 26 Planel G., Soleilhavoup J. P., Tixador R., Croute F., Richoilley G. Demonstration of a stimulating effect of natural ionizing radiation and of very low radiation dose on cell multiplication. In Biological and Environmental Effects of Low Radiation. Vol. 1 127-40 IAEA; Vienna: 1976;
• 27 Rotblat J. The puzzle of absent effects. New Sei 1977; 75: 475.
• 28 Schull W., Otake M., Neel J. V. Genetic effects of the atomic bombs: A reappraisal. Science 1981; 213: 1220.
• 29 Schulz H. Über Hefegiste. Arch. Ges. Physiol 1888; 42: 517.
• 30 Segall A. Leukemia and background radiation in northern New England. Blood 1964; 23: 250-61.
• 31 Segall A., MacMahon B., Hannigan M. Congenital malformations and background radiation in northern New England. J. chron. Dis 1964; 17: 915.
• 32 Seltser R., Sartwell P. E. The influence of occupational exposure to radiation on the mortality of American radiologists and other medical specialists. Amer. J. Epidemiol 1965; 81: 2.
• 33 Storer J. B. Late somatic effects of ionizing radiation as a function of dose, dose rate and radiation quality. Radiat. Res 1974; 59: 313.
• 34 Tuschl H., Altmann H., Kovac R., Topaloglou A., Egg D., Günther R. Effects of low-dose radiation on repair processes in human lymphocytes. Radiat. Res 1980; 81: 1-9.
• 35 Tuschl H. Die Wirkung niederer Dosen ionisierender Strahlung auf DNA-Reparturvorgänge, Abstrakt, Strahlenschutz 1/ 1983; Strahlenschutz in Forschung und Praxis. 25. 1983 in press
• 36 Ullrich R. L., Jernigen M. C., Cosgrove G. E., Satterfield L. C., Bowles N. D., Storer J. B. The influence of dose and dose rate on the incidence of neoplastic disease in REM mice after neutron irradiation. Radiat. Res 1976; 68: 115-31.
• 37 UNSCEAR Report: Ionizing Radiation: Levels and Effects. Vol. II Effects. United Nations; New York: 1972.
• 38 UNSCEAR Report: Sources and Effects of Ionizing Radiation. United Nations; New York: 1977.
• 39 Upton A. C., Randolph M. L., Conklin J. W. Late effects of fast neutrons gamma rays in mice as influenced by the dose rate of irradiation: induction of neoplasia. Radiat. Res 1970; 42: 467-91.
• 40 Van Bekkum D. W., Bentvelzen P. The concept of gene transfer-misrepair mechanism of radiation carcinogenesis may challenge the linear extrapolation model of risk estimation for low radiation doses. Health Phys 1983; 43: 231-7.
• 41 Wakabayashi T., Kato H., Ikeda T., Schull W. J. Studies of the mortality of Abomb survivors, Report 7. Part III. Incidence of cancer in 1959-1978, based on the tumor registry. Nagasaki. Radiat. Res 1983; 93: 112.
• 42 Warren S. Longevity and causes of death from irradiation in physicians. J. Amer. med. Assn 1956; 162: 464.
• 43 Warren S., Lombard O. M. New data on the effects of ionizing radiation on radiologists. Arch, environ. Health 1966; 13: 415.