[Note: Book Review is reproduced from Health Phys. 79:207; 2000.]
Radiation from Medical Procedures in the Pathogenesis of Cancer and Ischemic Heart Disease: Dose-Response Studies with Physicians per 100,000 Population, by John W. Gofman, 1999, 699 pp., $35 hard cover, $27 soft cover, C.N.R. Book Division, Committee for Nuclear Responsibility, P.O. Box 421993, San Francisco, CA, 94142; ISBN 0-932682-98-9 (hard cover), 0-932682-98-7 (soft cover)
The book by John Gofman has as central tenets two hypotheses:
- Medical radiation is a highly important cause (probably the principal cause) of cancer mortality in the United States during the twentieth century.
- Medical radiation, received at very low doses and moderate doses, is an important cause of ischemic heart disease (IHD); the probable mechanism is radiation-induction of mutations in the coronary arteries, resulting in dysfunctional clones (mini-tumors) of smooth muscle.
The editor of the book also enclosed a two-part article by Gray on the subject of reducing patient exposure in diagnostic x-ray (Gray 1998a, b), ostensibly to validate the conclusions by Gofman. The cover letter from the editor included with the book went on to say: ". . . Dr. Gofman's new findings and recommended action will result in the employment of thousands of additional health physicists, wherever x-ray procedures are given. Their skills are badly needed . . ."
The book is an apparent scholarly treatment of two startling claims about health effects from medical x-rays that would have revolutionary ramifications if accepted by science and medicine. In short, Gofman did not prove the case nor were the conclusions (contained in part within the second hypothesis) demonstrated. The monograph is a rambling complex manipulation of cancer and other medical disease statistics that merely justifies a foregone conclusion stated in the preamble of the book. It is by no means objective science that reached an unavoidable conclusion due to the data.
The conclusions are reached by presenting a myriad of data plots that use an x-axis of Physicians per 100,000 Population, defined as "PhysPop." (To this reviewer, a very odd figure-of-merit from a standpoint of presenting scientific data.) The graphs support the notion that more physicians equate to more x-ray procedures and therefore more IHD. The author intends the readers to believe that plotting dependent variables as a function of increasing PhysPop is valid analogue to a dose effect relationship. A reader who is not trained in some form of radiological science or has some knowledge about methods used to perform radiation effects epidemiology might find the work quite convincing. But it is in reality junk science written in a manner that makes it very difficult to separate fact from contrived data. It is like saying that in the summer more ice cream is consumed than in the winter and in the summer, more people drown. Conclusion: Ice cream consumption is causally related to drowning. This book uses this basic tactic for 700 pages to "prove" both hypotheses.
The author would probably counter the above assessment by stating the book provides statistically rigorous presentation of supportive data. But Gofman fails to scientifically test the results for confounding factors that might negate the apparent rigor of statistical analysis. Some examples of what to this reviewer would seem to be obvious to ask:
- Why have no epidemiological human studies on radiation effects to date strongly linked IHD with x rays, and what articles in radiobiology already exist in the literature that would have a bearing on the validity of his conclusions, e.g., Lifespan Study of Hiroshima-Nagasaki Survivors?
- Have any "mini-tumors" been seen at autopsy in humans?
- Is there a reproducible analogue to describe "mini-tumors" in animals?
- According to the American Heart Association, the age-adjusted death rate per 100,000 from coronary heart disease (shown on page 287) has dropped over 50 percent from the mid-sixties to the year 1992. Given that the collective medical x-ray dose to the population increased over the same period this is a contradiction within the book itself.
- Why are there no radiobiological follow-up studies suggested by the author to verify the claim? It would seem prudent to be reserved about a scientifically revolutionary claim without an independent in-vitro study to demonstrate a cellular basis for the effect. Many radiation-induced health effects known to occur in humans have been demonstrated in non-human laboratory tests in conjunction with epidemiology.
- Why has there been no association between this increasing effect and concurrent rise in leukemia? A higher value for "PhysPop" should also result in concurrent, well-known, high probability radiation induced cancers.
- A recent study of Chernobyl Liquidators evaluated personnel who received much larger doses than those typically received on average in diagnostic radiology (Ivanov et al. 2000). The report showed some increase in some non-cancer diseases but IHD was one of the weaker effects identified. If Goffman were correct, the Liquidator population should have had relatively high rates of IHD if one assumes that their medical exposure is similar or lower than those blanketed by Gofman's theory. Since they did not express excessive rates consistent with his hypotheses, this particular data set appears to negate the conclusions of the book.
The juxtaposition of the articles by Gray also fails to support the case. There is a minor similarity, in that Gray and Gofman are both calling for reduced medical exposure to the population. Gray in a quite lucid manner argues that there is a significant amount of wasted dose in diagnostic radiology because some clinics are not using the most up-to-date technology, and some practitioners need additional training. In his two-part set of articles, Gray makes a convincing and well-founded analysis of those two points. The Health Physics Society, other professional organizations, regulatory authorities, and national and international recommending bodies all support the concepts of optimization and limiting doses in medicine to as low as reasonably achievable.
The lack of regulatory standards for patient exposure to aid in the control of medical exposure is a great ambiguity in our society and culture. If occupational workers were routinely subjected to the levels of wasted dose routinely found in medicine, the regulatory agencies would have to intervene. While it would be wrong to regulate physicians in the exact same manner as occupational exposure and thus regulate the quantity of dose for every procedure, some higher level of accountability for wasted dose due to obsolete technology, poor procedures and/or training should be open to regulation, or at the least accountability to the extent workers are protected. Certainly these problems transcend the line between medicine and regulation. Although Gray attempts to bring only the generic issues to our attention in the articles, these ideas deserve serious and scholarly consideration and should not be associated with Gofman's thesis.
Gray and Gofman depart soon after expressing their individual desire to lower exposure to medical x-rays for completely different reasons and endpoints. In conclusion, Gofman's monograph is not an objective scientific work supported by data but merely a lengthy exposition of guilt by association.
Stephen V. Musolino
Brookhaven National Laboratory
Radiological Control Division
Upton, NY 11973-5000
- Gray JE. Lower radiation exposure improves patient safety. Science and Technology 20:61–64; 1998a.
- Gray JE. Optimize x-ray systems to minimize radiation dose. Science and Technology 20:62–64; 1998b.
- Ivanov VK, Maksioutov MA, Chekin SYu, Kruglova ZG, Petrov AV, Tsyb AF. Radiation-epidemiological analysis of incidence of non-cancer diseases among the Chernobyl liqidators. Health Phys 78:495–501; 2000.