Part 1. Roentgenology Versus Radium Therapy
We are almost always speaking of radium-226 when we discuss radium therapy, although there are other nuclides of radium. Broadly speaking, there are no major differences between the health effects of x-rays and those of the gamma rays emitted from a source of radium-226. Both gamma rays and x-rays are photons, and photons are the agents which "kick" some electrons in tissue into high-speed travel.
There is one difference of consequence, however, in the interaction with tissue. The higher energy of the gamma photons from radium-226 "produces" some electrons in tissue which are much more energetic than the electrons "produced" by medical x-rays (a "ballpark" comparison would be 200 KeV initially vs. 40 KeV). The more energetic the electron, the greater the distance betweeen its interactions with tissue along its pathway. The electrons set in motion both by gamma rays and by x-rays gradually slow down, because they transfer energy to the molecules of tissue. On the average, the energies of electrons from gamma radiation are much higher than they are from medical x-rays, and therefore we assign about 2-fold less biological effect from a rad of gamma radiation than from a rad of medical x-radiation.
The Gamma Rays Associated with Radium-226
We have become accustomed to speaking about the gamma rays emitted by radium-226. In truth, only a small proportion of decaying radium nuclei give off a gamma ray (a few percent). Nonetheless, a source of radium-226 is a potent source of gamma rays primarily from the short-lived daughter products of radon-222. Radon-222 is the first decay product produced by emission of an alpha particle from radium-226. While the radium-226 has a half-life of some 1,600 years, the half-life of radon-222 is only approximately 3.8 days. In the decay of radon-222, there are some very short-lived daughter products which do indeed emit very energetic gamma rays. So long as the radon-222 does not escape the confinement with its radium-226 parent, the radon's daughter products build up quickly to a maximum value which determines the gamma ray intensity associated with its radium-226 source.
The Parent-Daughter Relationship of Radium-226 and Radon-222
The very long half-life of radium-226 and the very short half-life of radon-222 provided investigators and therapeutic radiologists with a tool widely used in the earlier days. If one pumped the gaseous radon-222 away from the solid radium-226, the greatest bulk (by far) of the gamma rays from short-lived daughters of radon-222 went with the radon-222. The combination of radon-222 and its daughters, having almost all of the highly energetic gamma rays, was taken off and used to treat patients. This in no way diminished the supply of gamma rays, since a new batch of radon-222 built up within a couple of weeks to nearly its full intensity. So one always had the radium source undiminished (except by its extremely slow decay), and one had short-lived gamma sources over and over again to use for therapy.
Any Contest Between Radium Therapy and Roentgen Therapy?
It is a fair statement to say that what we can accomplish in radiation therapy with the gamma rays from a radium source, we can also accomplish by having a source of x-rays. It is pretty much a matter of convenience and a question of which tissues and organs one wishes to irradiate.
We can quote from the text by Dr. George MacKee (1938, 3rd Edition, p.399):
"There appears to be little if any difference between the biologic and therapeutic action of x-rays and the gamma rays of radium. They seem to be equally efficacious, regardless of the disease, providing conditions are as suitable for the one as for the other. Gamma rays can be used in locations that are inaccessible to x-rays --- mouth, nose, vagina, and external auditory canal ... On the other hand, the x-rays are more suitable and more efficient in generalized dermatoses, or for the treatment of diseases that cover large areas."
We keep in mind one difference. A specified number of rads delivered by the gamma rays from radium-226 will be approximately one-half as effective in the biological effect as the same number of rads delivered by medical x-rays. In the parlance we are using in this book, one rad of gamma rays from a radium source (or the gamma rays from an atom-bomb source) is said to be equal to one-half a medical rad, delivered by medical x-rays.
A review of the radiation journals of the early decades in this century will show that roentgenologists were divided as the whether they preferred to use radium or x-rays in treating a specific disease. This division was largely because of personal convenience rather than because of any fundamental difference in efficacy. Many said explicitly that there was not much reason to choose one over the other in the therapy of benign disease.
An interesting exception is proposed in a paper by G.W. Grier (1925), concerning the treatment of enlarged thymus. We quote:
"Theoretically, then, radiation is an ideal treatment, and in practice this has been found to be the case. The rapid improvement of these cases after radiation is often astonishing. While the roentgen ray is widely used for this treatment, I have abandoned it in favor of radium, and for the last four years have treated all my cases in this way. The advantages of radium are that the response to treatment is somewhat quicker and that it can be more easily applied without disturbing the patient. It is very difficult to keep a baby accurately placed under an x-ray tube unless it is held by others who are in a certain amount of danger from exposure to the rays or to high voltage currents. The restraint of the child is also undesirable as it may precipitate paroxysms of strangulation from the crying and struggling incident to it. The radium can be applied in the baby's bed without any disturbance and the relief is surprisingly prompt."
Do the Cases Treated with Radium Lead to Underestimation of Breast-Dose?
It is hard to know what actual dose in medical rads was utilized in the radium therapy of enlarged thymus. But we can suggest that each case treated with radium simply substitutes for a case treated with medical x-rays. And, roughly, we can approximate that the dose to breasts in medical rads might have been the same from both the x-ray treatments and the radium treatments.
If, however, there are cases treated with radium over and above those where radium was substituted for x-rays, then there really would have been an increment to breast-dose which we have not taken into consideration.
Also it is quite possible, for example, that in further searches we might encounter some dermatological cases where only radium was used, and where we might be able to determine the total national breast-dose increment from this source. Then we would surely wish to correct the underestimate in dose to breasts for the 1920-1960 period, since we had previously missed this application of radium therapy.Part 2. Handling of Radium in Hospitals: A Remarkable Report in 1941
The handling of radium sources is a totally different kind of problem from the handling of x-ray machines, with respect to hazard to patients, to relatives of patients, to medical personnel, and to "innocent" bystanders such as secretaries, stenographers, janitors, and others.
A remarkable publication in 1941 teaches us that in the very middle of the 1920-1960 period of our interest, the lessons of danger from handling radium were exceedingly poorly learned --- poorly learned in a number of hospitals where this would not have been expected so many years after the work of the Curies.
The Investigations of Drs. Cowie and Scheele in 1940-1941
Drs. Cowie and Scheele of the National Cancer Institute related their experiences in evaluating radiation protection in 48 hospitals (3 originally and 45 hospitals added to the list). This came about as follows. The National Cancer Institute Act authorized and directed the Surgeon General of the United States Public Health Service to purchase radium and to loan it to institutions for cancer research or for the treatment of patients. So, 9.5 grams of radium were bought in 1938 and were loaned to 48 hospitals in various parts of the United States.
Since it was necessary that most of the institutions to which radium had been sent be visited with reference to the renewal of the loans for a second year, it was decided that practices of protection ought to be looked at, in connection with renewal of the loans. The co-operation of the hospitals was sought and obtained in order to make the survey possible.
The "Quality" of the Hospitals Studied
The 45 hospitals surveyed, after a preliminary study of 3 hospitals, were scattered among 24 states all over the country. Twenty of them were state, county, city, or city-county institutions; 20 were operated by non-profit associations; and the remaining 5 were church-owned. Twelve of the institutions were university hospitals, and 3 more were teaching hospitals affiliated with medical schools. The hospitals were relatively large, 32 of the total having over 200 beds. The investigators pointed out that they felt this group of hospitals might show typical, if not slightly above average, equipment and practices in matters of protection against high-energy radiation.
The observations reported by Drs. Cowie and Scheele provide us with no basis for believing that unintentional breast irradiation, from the handling of radium, was a small problem at mid-century. Indeed, the findings may suggest a major, previously unestimated source of additional radiation exposure to breasts. We shall go over some of the details of the Cowie-Scheele findings in Part 3.Part 3. Storage Systems:
Protecting the Radium Rather Than the Personnel
In their survey, Drs. Cowie and Scheele investigated how radium was stored in the various hospitals. On storage methods, they rated 16 hospitals as excellent, thirteen as intermediate, and 16 as allowing "definite overexposure."
The Meaning of "Excellent" and "Tolerance Dose" in 1941
A rating of "excellent" meant that personnel were highly unlikely to receive more than the "tolerance dose" from normal work-habits around radium sources in the hospital. Drs. Cowie and Scheele pointed out, however, that such dose-levels were "nothing more than arbitrary guides" and were not any assurance of safety. We quote them from page 768:
"Various amounts of radiation have been set as `tolerance doses' for roentgen-ray and radium workers by protection committees. These vary from 0.1 to 0.2 Roentgens per day to the entire body. The commonly accepted standard in the United States is 0.1 Roentgen, but in reality little is known of the amount and timing of radiation necessary to cause the commonly recognized injuries. Much attention has been focused on blood changes as an index of exposure, and it is partly on this basis that the present official tolerance doses were set, with full recognition that they are nothing more than arbitrary guides. While exposure of the entire body to less than 0.1 Roentgen daily may not cause blood changes, it may cause other local damage. Genetic effects may have no threshold, and it is believed the number of changes increases with increase in dose above zero."
Readers will note that there was not a word about radiation-induced cancer from occupational doses up to 20 Roentgens every year --- and of course no worry about breast-cancer. All this activity was going on for decades before Dr. MacKenzie's ground-breaking paper of 1965.
Exposure of Stenographers: Storage of Radium in the Business Office
Drs. Cowie and Scheele reported the following observations (pp.769-770):
"Eleven of the forty-five hospitals visited stored their radium in main-business-office safes. This place was used because of the intrinsic value of the radium, the fact that these safes offered the best safeguard against theft, and because the superintendent or an office clerk could be made responsible for checking the radium as it was taken out or returned, thus helping to prevent its loss. In a few of these cases the amount of lead was adequate, but in many it was not and varied from one-eighth to one-half inch in thickness, with amounts of radium stored in excess of 100 milligrams, and as high as 500 milligrams. In these same instances, stenographers often worked from 7 to 8 hours per day within 5 to 6 feet of the radium." They continued:
"The use of main-business-office safes created another exposure hazard in several cases. As a rule, the night supervisor of nurses did not have the combination of the safe; hence, when radium was removed from a patient after the close of business hours, it often was kept in the nurse's desk inadequately protected. In other cases the radium was locked in wooden or steel drawers in the office to await the arrival of the hospital superintendent or someone else who would place it in the safe. In one instance, because of the failure to take 125 milligrams out of the drawer the first thing in the morning, a number of people worked near it for a half day without protection." And:
"In several additional hospitals the people responsible for the radium in the office admitted that they were often very busy and failed to put it away. In one of these hospitals, 150 mg. of radium in two small lead cylinders, each less than one-quarter inch in effective thickness and containing 75 mg., was returned at 9 in the morning by a nurse and was given to a stenographer who, because she was very busy and had not been instructed in the dangers of exposure to radium, placed the cylinders on her desk instead of putting them in the safe where there was an adequate lead container. She had been exposed for 5 hours on the occasion when the authors [of this report] discovered the situation and [she] stated that she often kept the radium on her desk but did not know that there was any danger of overexposure since it was in lead containers. In hospitals where adequate lead carriers were used, the storage of the radium in the office safe did not lead to overexposure, because the radium was placed in the carrier when it was removed from a patient at night." And:
In one hospital "500 mg. of radium was stored and assembled beside an ordinary plaster-and steel-lath wall on the opposite side of which was a desk at which a stenographer sat for 6 hours each day. She was 5 feet from the radium during this time and received a tolerance dose [0.1 Roentgen of whole-body exposure] each hour she spent at the desk."
Exposure of Nurses: Storage of Radium in the Medicine Cabinet
In addition to nightime exposure of some nurses, as described above, nurses would be exposed in other ways. "The worst example" was described by Drs. Cowie and Scheele as follows (pp.770-771):
"While the lead thickness of the storage container was adequate in many instances when the radium units were stored unassembled, the practice of placing assembled applicators outside the lead safe because the space in the lead container was not large enough to hold them, caused a number of cases of temporary overexposure. The worst example of this was the storage of a dental compound applicator, containing 100 mg. of radium and used for a few hours daily, in a small enameled basin in the medicine cabinet of the nurses' office. Nurses sat within 3 feet of this applicator when charting and stood within 1 foot of it when they prepared drugs for distribution, and they received over 0.5 Roentgens per hour of such work done."
This was equivalent to the full "tolerance dose" for five days --- in one hour.
Of course, the stenographers and nurses who were exposed in such ways by the careless handling of radium --- during years before and after the Cowie-Scheele survey --- did not have doses which would show up as entries in formal records available for study. But some of the genetic molecules in their breasts did accumulate a record of radiation exposure, unfortunately.Part 4. Transport Systems: Sometimes by Hand, Pocket, Towel, or Jar
Drs. Cowie and Scheele also reported on how radium should be --- and really was --- carried around in hospitals (p.775):
"Overexposure may occur during transportation of radium in a hospital ... Because the time involved in handling carriers containing radium is short and because they are heavy, recommended hand-carrier thicknesses are usually 0.5 inch or more of lead for quantities of radium up to 100 milligrams." And they provided a photo at p.775 of an "excellent hand carrier [with] lead 0.75 inch thick." They continued: "When larger amounts are to be carried, thicker transportation devices should be provided, and it is usually necessary to put wheels on such carriers because of their weight." And they provided a photo at p.776 of a "radium carrier on wheels with minimum lead thickness of 1.5 inches."
"In 21 institutions there were no carriers or they were 0.125 inch or less in thickness. Five [of the other 24 hospitals in the survey] had carriers 0.125 to 0.5 inch thick, and the other 19 had carriers 0.5 inch or more in thickness. However, the fact that an institution had an adequate carrier did not mean that this device was used. In 5, excellent carriers were provided, but because it was easier not to carry them and because no one had directed that radium should always be transported in them, they were unused."
Then the really casual treatment of radium is revealed:
"A nurse and radiologist in one institution carried applicators in their hands; and at another, for lack of a carrier, a resident carried applicators in his pocket. In several instances radium was transported in towels or carried by threads intended for use in anchoring the applicator after insertion. In a few cases the applicators were carried to and from the place of use by thumb forceps."
And Drs. Cowie and Scheele provided a third photo:
"Figure 5 shows a bottle used as a carrier in one of the institutions visited." The photo, showing what many people would call a glass jar with a lid, is captioned "Small glass bottle used for carrying radium."
Assembly of Radium Applicators: Participation by Nurses and Technicians
Another way in which radium exposed hospital personnel was during its assembly into applicators. Drs. Cowie and Scheele reported (p.772):
"The Advisory Committee on X-ray and Radium Protection has recommended that preparation of radium applicators and similar operations should be done behind a lead L-block of a minimum thickness of 2 inches (5 cm). The authors found that 14 hospitals in the 45 had no L-blocks. Of those remaining, all had blocks; however, 4 were from 0.0625 to 0.25 inch thick, 6 were from 1 to 2 inches thick, and 21 were 2 or more inches thick." Moreover (p.773):
"The average person assembling applicators is not adept at this work. As a rule, applicator assembly is an occasional job, therefore no one works at it sufficiently often to develop any real skill." And:
"The assembly of applicators is a task usually assigned to residents, internes, technicians, and nurses. These people frequently had little knowledge of the dangers of overexposure and occasionally had too little direct supervision. In six cases, the lumen of rubber tubing used for tandems was so small that considerable time was spent inserting radium units covered with lubricating jelly into it. It was found that such procedures could not be carried out without holding the rubber tubing or radium unit in the fingers or in the very short forceps."Part 5. Radium-Handling's Contribution to Breast-Cancer
Need we even wonder whether radium-handling contributed to the breast-dose in the 1920-1960 era? If Drs. Cowie and Scheele could uncover so much ignorance and mal-handling of radium sources at hospitals in one on-site survey, what was the aggregate effect from years of such behavior?
How large? Since most of the doses were unrecorded, there is no way to generate meaningful information for the Master Table.
But there is no doubt at all that radium-handling made some contribution to breast-cancer among the irradiated hospital personnel. And many years after their exposure, when some of these unfortunate women were having mastectomies, their histories might give no hint about occupational radiation exposure --- because their prior occupation might well say "Stenographer."
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1931: "There Is No Such Thing as `Minor Roentgenology' ... Secondary
In 1931, Professor Dr. George Fedor Haenisch of the University of Hamburg, Germany, was honored by the American Roentgen Ray Society to deliver the Annual Eugene Caldwell Lecture. (American Journal of Roentgenology, Vol.26, No.6: 821-833, December, 1931.) Some excerpts from it, additional to those on page 218, are presented below.
Dr. Haenisch described the consequences of x-ray machines in the hands of the general practitioner (p.829):
"He cannot afford to install large and complete roentgen equipments, because that would not pay, besides he would not be able to operate them or obtain the utmost service from them. He must therefore be content with small, nay the smallest, apparatuses such as are incessantly produced and zealously offered for sale by the manufacturers in their efforts to increase their business [emphasis added]. The small apparatuses are sufficient for definite purposes and are useful in the hands of the experienced, otherwise they aid in the production of incapable roentgenologists." And:
"When roentgenology will have become universal among the general practitioners the consequent lowering of the demands upon apparatus and upon the operator's skill and knowledge will result in a deterioration of the quality and in an arrest of the progress and of the development of the art. It is imperative, however, that roentgen diagnosis and therapy be developed to the highest perfection so that they may be of benefit to the patient. We must not be content with incompetent mass production. The advocates of universalized roentgenology must come to a realization of the responsibility which they are assuming by prematurely placing roentgenology in the hands of every general practitioner. The resulting injury may perhaps never be remedied." And:
"We roentgenologists, however, who can foresee the consequences must energetically combat the indiscriminate distribution of inferior apparatus and the consequent deterioration of roentgenologic work because ours is the responsibility for the development of roentgenology." And:
"The physician must recognize that there is no such thing as `minor roentgenology' in analogy to minor surgery. The difficulties are not readily apparent, the inexperienced does not realize the sources of error, the pitfalls and obstacles which might cause his downfall even in the simplest roentgenogram of a hand or foot, to the detriment of his patient! The nature of roentgenology is such that secondary or superficial attention to it will not do."
Similar warnings in this book can be re-located from the Index under "Danger (potential danger) of x-rays" and under "Unqualified users of x-ray equipment."
The point: There is ample reason to think that non-recorded x-ray doses were very high in the 1920-1960 period.