Lauriston S. Taylor

(Chosen by John R. Cameron)

Published in
Physics & Society News April 1998

          Today, we know about all we need to know to adequately protect ourselves from ionizing radiation.  What is the problem and why is there one?  [The problem]  is not a scientific one.  Rather, it is a philosophical problem.  Perhaps it may be a political problem  or it may not be as much protecting ourselves against radiation as protecting us against ourselves (Ta57a) and from our penchant for self-torment through our obsession with health. 

          Collectively there exists a vast array of facts and general knowledge about ionizing radiation effects on animal and man. It cannot be disputed that the depth and extent of this knowledge are unmatched by that for most of the myriads of other toxic agents known to man. The public has come to expect sharp, clear, definitive, and undisputed answers to any questions involving  radiation. This leads to the difficulty that when there is a disagreement among scientists the public feels let down by the scientific community. A good example of this is the current so-called "controversy" within the protection community centering around the effects of radiation delivered in low doses at low dose rates.  Were it not for a few congressional committees, more interested in headlines than in facts, aided and abetted by a willing press and a few publicity seeking “scientists,” it is likely that the question would drone on in normal scientific meetings commensurate with its importance.  It’s not that it is unimportant but its priority should be low compared to many other insults man faces.

          Radiation effects are generally proportional to dose when delivered acutely in moderate amounts, say 100 rads and upwards, to the regions observed. Precise proportionality is difficult to establish. However for practical protection purposes, we postulate that for acute  doses of radiation to any part of body, the effect is proportionate to the dose.The problem becomes especially critical in the low dose region say below 25 or 50 rads, delivered acutely, for which the latent period may be 3 to 5 decades.

          During a long period any individual would be subjected to hundreds of other insults, any number of which might produce the same effect  as the radiation.  With all our available statistical techniques of today, the number of subjects needed to show a statistically significant result one way or the other to exposure of a few rads per year runs into the millions and hence becomes impractical (We71). Man has always lived in a radiation environment  which, except for a very small increment due to weapons testing has been essentially constant. There is uncertainty about the existence of threshold effects for ionizing radiation. There are very few threshold effects, although  there are clearly some.

        If one is concerned about the degree of hazard in the region where effects cannot be found or identified, to what extent should an attempt be made to further "reduce the hazard" to some fraction of what could not be found in the first place? The question is "how large is half of something that cannot be measured?"

          Dose effects are not cumulative. There must be some process of repair or recovery of cells, both of a genetic and somatic nature, if for no other reason, other than that based on modern radiation therapy techniques. It has been known for at least 50 years that the total amount of radiation delivered to a tumor and surrounding tissues can be enormously increased by the simple expedient of introducing “rest periods” between each treatment. Without some sort of recovery phenomena in play, there could be no reasonable radiation therapy today which, of course, is not the case.

        Today we know enough about dose-effect relationships to state unequivocally that at least for low-LET radiations the relationships cannot be strictly linear over the whole dose range  and that even for high doses they are probably not linear. The difficulty is that since we do not know the precise relationship - it is assumed as a matter of cautious procedure, that the dose-effect relationships are linear throughout the entire dose range. This assumption is constantly being subjected to hard scrutiny because, if taken too literally, it leads to unnecessary and unjustifiable restrictions on the use of ionizing radiations.

          In speaking of the risks attendant upon the use of ionizing radiation in the region of protracted radiation below 25 rads, we cannot find or define effects, nor can we define risks. From the mere fact that radiation may cause some identifiable effect, it does not follow that the effects are necessarily detrimental. To properly speak about radiation injury, it would appear that one should only refer to an effect which, in the eyes of proper medical authorities, is regarded as detrimental in some respect (Na 54).

          In the late 1940's it was clear to the NCRP, and probably to other bodies that non-scientific factors would be involved in establishing permissible dose standards. In 1957 I argued (Ta57b): “Radiation protection is not only a matter for science. It is a problem of philosophy, morality, and the utmost wisdom.” At later times I have added “economics, politics, and public involvement” but actually they are all segments of an overall ideological approach.

          Let us consider that risk, however we decide to describe it, is roughly proportional to radiation dose. Why are people willing to accept any risk at all? This argument applies practically to everything we  do in life, with radiation being perhaps one of the smallest risks that we normally have to contend with.

        Where has the past supply of wisdom has come from? Good or bad, it has come mostly from  the scientists themselves, who consciously or unconsciously, recognizing  the limits of their knowledge, have made strong and important judgment actions regarding the amount of radiation considered to be acceptable for radiation workers or the public or the patient. This has not been a bad thing because, after all, the scientists involved cover a wide range of disciplines, ways of living, nationalities, ethnic backgrounds, religions, and everything else that makes for an effective melting Pot. That this has been effective is evidenced by what I consider to be the fantastically  fine radiation safety records that they have accomplished. No one has been identifiably injured by radiation while working within the first numerical standards set first by the NCRP and then the ICRP in 1934. [Emphasis added. NCRP chose 0.1 r/day on 3/17/34; ICRP chose 0.2 r/day in July 1934. The latter is about a factor of 35 greater than the present recommendations.]

          Let us stop arguing about the people who are being injured by exposures to radiation at the levels far below those where any effects can be found. The fact is, the effects are not found despite over 40 years of trying to find them. The theories about people being injured have still not led to the demonstration of injury and, if considered as facts by some, must only be looked upon as figments of the imagination. [Emphasis added]

          I do not argue for leaving the philosophical decision process in the hands of the scientist where, by default if nothing else, it has largely rested for the past 60 years. Nor do I argue for removing the process entirely from his hands;  a combined scientific and non-scientific approach is indicated. A  difficulty here is the current public attitude that if a person has worked in a field (e.g. radiation) he must be suspected of some kind of conflict of interest if he becomes involved in any related decision-making  process. Actually, because of their basic training and their having to be imbued with a basic sense of objectivity, a good argument can be made that scientists, as such, are about as devoid of special interests as any group that may be found.

          On the other hand, we must  find an acceptable means for stopping or counteracting the endless prattlings by a few individuals, with whatever motives they may have for keeping the public stirred up, confused and alienated from the very technologists who are in the best position to properly inform and educate them (Br78b; Ta70).

          The second choice in standards setting would be to follow the practices used for many decades by the toxicologists. For permissible concentrations of some toxic substance, they would set a level somewhat below that at which any effect could be found. This carried the implication of a threshold but stopped short of saying there was a threshold.

          From about 1946 to 1977, practically all federal matters in the United States relating to ionizing radiation were handled through the  Joint Committee on Atomic Energy. The joint committee, with a stable membership from both the house and the senate, was dedicated to developing facts and an understanding of atomic energy, rather than looking for newspaper headlines and votes. In its place there are some two dozen congressional committees, lacking in stability and without an overview power. Rarely does the chairman or staff of these committees have any knowledge in depth of the broad subject of ionizing radiation.

        In spite of technical shortcomings in the political arena, both federal and state legislatures exert strong influences on the development of numerical radiation protection standards. Because of the likely influence on governmental  committees by vocal but prejudiced witnesses or witnesses having some personal case to plead, we are today faced with the possibility of unreasonably restrictive limitations being placed on legitimate uses of ionizing radiation.

One of the first political needs we must always recognize in dealing with groups of people is education.  The prime agent of education (outside of formal schools) in these times is in the radio-television, newspapers, comic books, books generally and books written by scientists. Of these, the "news media" clearly dominate, and here lies one of our most critical problems and the most fruitful area in which the radiation protectionist  must assist in the education of the public.  First, however, we have to persuade the media (and I use the term rather broadly now) that they have a national obligation to assist the country in educating its public about radiation matters.       

          Attacks on the news media for one reason or another are common as is their own defense under the First Amendment.  However, in my opinion, the First Amendment .. is an essential bulwark of freedom....[but]  the First Amendment also carries with it an obligation on the part of the press to completely and properly report the news.

        In the case of ionizing radiation there are constant and continuous violations of this principle.  The fact remains that we need greater responsibility on the part of the news media in the objective presentation of uneditorialized news.

          There are at least fourteen agencies of which six have regulatory responsibilities. Six have research and development responsibilities and three have advisory roles. In the legislative branch of the government, there may be some twenty-four House or Senate committees playing some role in radiation matters (the exact identification of these is not easy).

          There is constant pressure to lower protective standards by some radiation protectionists as well as "consumer advocates" and generally concerned members of the public. Too often their arguments are based mainly on theoretical arguments of effects that have never been observed ....  So this is a case of reducing by some factor something that you did not know in the first place. If someone were today to decide on a reasonable de minimis level for radiation exposure, it would probably be found that most of our radiation installations are already well below it. 

          In education we need two things: (1) better communication within and between scientific and technical groups on the one hand, and the general public on the other; and (2) much broader education of information to the public. These communication and educational projects should be carried out basically by non-governmental  organizations, aided and assisted, however, by some limited government support. in the matter of communication, the radiation protectionist profession must play a stronger role.

        It is my belief that much of the blame for the public's fears and apprehensions with respect to radiation matters are due to our media.  There is another criticism that must be directed to the media, namely, their constant use of a small number of individuals who are clearly out of step with the radiation protection community. In the U.S. alone there are some 3500 health physicists and 1800 radiological physicists. [In 1997 the numbers are about 6,000 and 4,000 respectively.]  Yet the media will, for some newly breaking news story, seek out some of a half a dozen individuals who are willing to make willfully deceptive statements regarding radiation.

          Of a collection of "popular" books published over the last decade or so dealing with radiation matters there is not a single one which is not riddled with half-truths, untruths, and evidence of basic lack of knowledge of nuclear energy or radiation. Another insidious practice designed to keep the public alarmed about radiation matters is the constant linkage made between the atomic bomb and any discussions about radiation, including medical and industrial applications.

        I plead that we cease the seemingly endless procession of studies, congressional committees, and hearings on the problem of "low level ionizing radiation" .. About this we know what we know and we know what we do not know; there is reasonable and rational agreement as to the degree of disagreement. We know that the full and final solution to the dose-effect relationship for low doses (less than, say, 5 or even 10 rads) delivered at any dose rate, is not in sight and will not be attainable within any of the capabilities that can be visualized today. We also know that regardless of the precise relationship between the effect and doses below, say 5 rads, whatever the effects may be, they are minuscule if they exist at all; and they cannot be identified as radiation effects among all the other similar effects that occur due to otherwise unidentified sources.

          Either we forget the whole “problem” or we theorize or postulate a dose-effect relationship. The latter has, in effect, been done for the past two decades or more, and is used by radiation protection scientists as a theoretical upper limit to the theoretical effects.

          However, this is what has led to our present dilemma because of the fact that our technical verification has boundaries of limitation.  [Various groups  have]  interpreted and treated the theoretical estimates as if they were experimentally established facts rather than as the scientific speculations and provisional  pragmatic solutions which they are.  Thus has been opened the door to wildly imaginative statements as to what may be happening at the low doses where no effects can be found.

          For the failures of the public to recognize the situation outlined above, we are forced, in part, to blame the media. Although the scientific community is not without blame of its own.

(2484 words)

REFERENCES:

Br78b Bross, I. D. J., 1978, “Hazards to Persons Exposed to Ionizing Radiation (And to Their Children) from Dosages Currently Permitted by the Nuclear Regulatory Commission”, NRC Public Meeting, 4-7-78 (7590-01) 5 USC-552(a)); see also comments by K. J. Rothman and letter comments by Lauriston S. Taylor, both of which are part of the public hearing record.

Na 54  National Committee on Radiation Protection, 1954, Permissible Dose from External Sources of Ionizing Radiation, p. 27.

Ta57a  Taylor, L. S., 1957 “The Philosophy Underlying Radiation Protection”, Am J. Roent. 77, 914 (from address on 7 Nov. 1956).

Ta57b Taylor, L. S., 1957  “Radiation Exposure and the Use of Radioisotopes” Impact 7, 210.

Ta70 Tamplin, A. R., and Gofman, J. W., 1970 Population Control Through Nuclear Power (Chicago: Nelson-Hall).

We71  Weinberg, A. M., 1971 Letter to Editor, Science 174, 546.