Part 1. Radiotherapy of Bronchial Asthma Was Popular for Several Decades
In his 1965 book Radiotherapy of Benign Disease, Dewing commented as follows:
"Radiotherapy enjoyed a considerable popularity in the treatment of asthma during the first several decades of the twentieth century, and still lingers fleetingly in the recent literature, despite having been largely superseded by medical methods."
o - Item 1: Indeed, Eugene Leddy and Charles Maytum of the respected Mayo Clinic reported their largest therapeutic trial of roentgen therapy of bronchial asthma (over 1000 patients treated) in 1949, having published previous papers on trials by themselves at the Mayo Clinic conducted as far back as the 1931-1934 period. We shall derive our dose calculations for bronchial asthma therapy by ionizing radiation largely from their studies, although numerous other smaller studies are consistent with the Leddy-Maytum studies.
o - Item 2: Source of Data. Eugene T. Leddy and Charles K. Maytum (1949) "Roentgen Treatment of Bronchial Asthma," Radiology 52: 199-203.
o - Item 3: Doses. After their two early reports on radiation therapy of bronchial asthma, they felt that their usual technic of treatment entailed an excessive risk (p.202), so they cut the dose usually employed in half. And they stated, "In all the cases in which the patients were treated in this manner, the results were satisfactory. This experience led us to adopt the application of a dose of about 250 r to one large anterior and one large posterior mediastinal field. We have now used this method of treatment, which has been termed the `low-dosage' technic, in more than 1000 cases."
Dewing in his 1965 book lists this as the major study (in size) for bronchial asthma, and he does not suggest ineffectiveness.
Leddy and Maytum regard their results with some satisfaction, although they concede that the beneficial effects are only temporary (months in some cases). Poulsen (1952), in Denmark, cites the Leddy-Maytum work respectfully, and suggests in a 1952 paper that "palliation which may be obtained in roentgen treatment of asthma is utilized in this country to a smaller extent than it deserves, for which reason the following series of cases, although rather limited, is presented." He points out that "the striking beneficial effect obtained in the first two patients with bronchial asthma became known among doctors and patients in the district, and we now often see patients who have requested their doctor to refer them to the Radiological Clinic for roentgen treatment."
Part 2. The Calculations for X-Ray Therapy of Bronchial Asthma
Leddy and Maytum treated over 1,000 patients in their "low dosage" regimen starting about 1941, to about 1946. They estimate that those treated in this manner are about 6 % of the total number of asthmatic patients who have been treated at the Mayo Clinic. So their total number of asthmatic patients is (100 / 6) x 1,000, or 16,667 asthmatic patients in a period of about 5 years. About 70% of the patients "were middle-aged women."
Those asthmatics not treated with roentgen therapy (15,667) probably received just the radiation dose from a chest workup, which, compared with the roentgen therapy group, would be negligible. So we shall neglect any such dose to breasts.
Those in the 1,000 treated cases received radiation over two large fields, one anterior, and one posterior. Each field received an air dose of 256 R. We shall assume that this 16 cm square (16 cm by 16 cm) treated region, front and back, irradiated one-half of the breast tissue in each case. We will handle this as 128 R (half the dose) to the complete breasts.
From Gofman and O'Connor (1985):
For the anterior direction, rads / entrance roentgen = 0.693
For the posterior direction, rads / entrance roentgen = 0.037.Anterior Dose = 128 rads x 0.693 = 88.7 rads.
Posterior Dose = 128 rads x 0.037 = 4.7 rads.The anterior dose of 88.7 rads deserves adjustment for supra-linearity (Chapter 8).
The adjustment factor is 0.486.
The adjusted anterior dose = (88.7) rads x (0.486), or 43.1 rads.o - Item 4: Total Dose in therapy of asthma = 43.1 + 4.7 = 47.8 rads total.
o - Item 5: Person-rads at Mayo Clinic = (0.7 are women) x (1,000 patients) x 47.8 rads = 33,460 person-rads to female breasts.
The Mayo Clinic workers report that for purposes of testing, they studied only their severe asthmatics (about 6 % of their total asthmatic patients). Elsewhere, those physicians who believed in the therapy probably would have extended it to almost all their patients. But non-believers would have used no radiotherapy at all. For the sake of obtaining a "ballpark" estimate of contribution from this therapy to annual average breast-dose, we will estimate that nationwide, about 18 % (not 6 %) of asthmatic patients received such therapy. If this had been the case at the Mayo Clinic, the person-rads would have been (3 x 33,460), or 100,380 person-rads. The Mayo Clinic experience represented about five years, so per year, the person-rads would have been 20,076.
o - Item 6: Conversion to annual average population-dose. The next step is always to divide person-rads by total persons. How many persons would be appropriate?
The Mayo Clinic is a special place, attracting patients from all over the country and the world, so we can not derive the number of persons from data for the local county (as we did in Chapter 8, for example). It is difficult to estimate what fraction of the United States population really supplied the asthma-patients for the Mayo Clinic, but we shall use 2 % as a "ballpark" estimate.
Since Leddy and Maytum said that about 70 % of their patients were middle-aged women, we will approximate the age-range as age-30 through age-54. The national number of such women (from the Master Table, Column A) was 21,543,144 for one calendar-year of the 1920-1960 period, and 2 % of that total is 430,863 women. We shall divide the estimated person-rads by that number. So, we have 20,076 person-rads / 430,863 persons, = 0.0466 rads.
The last step is to distribute this population dose among 25 different age-years (age-30 through age-54). Per age-year, the annual average breast-dose would be (0.0466 rads / 25), or 0.0019 rads, a relatively minor contribution to breast-dose. There is no basis for assuming that any correction for duration is indicated.
Thus, we make 25 identical entries into the Master Table, Column J, for this source of breast-irradiation.
Part 3. Some Words of 1949 for Contemplation by a Later Generation
As we complete this book in 1995 we realize that a current generation of young physicians might find it laughable that anyone should have thought of treating infections and bronchial asthma with roentgen-rays. The danger is that he who laughs may be doing much worse for his patients.
The Mayo Clinic in the 20th Century is certainly to be regarded as a pacemaker institution. So the reader will find the close of the article by Leddy and Maytum of interest. We quote their words written in 1949:
"Our experience in the treatment of asthma with roentgen rays has been similar in all essentials to our experience in the treatment of inflammatory and infectious lesions, in which our results have improved as the doses of roentgen rays have been lowered. For this reason, we think that a lower dose, possibly in the neigborhood of 100 r, or even less, may be worth a trial in another series of cases of chronic severe, intractable asthma."
Is the reader ready to be sure that Doctors Leddy and Maytum were having an illusion in all that experience? Our use of the data do not depend in any way on whether the therapy had any effect or had none, but we find it interesting in the extreme that at the Mayo Clinic a series of 1,000 patients with severe asthma were treated with roentgen rays --- and few today would believe that the physicians really saw any improvement.
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Part 1
Preview of Another Use: Well-Baby Check-Ups
From Dr. Hanson Blatz, we first learned the following:
"Those of you who have been in the field a long time know that it was once the practice of pediatricians to fluoroscope babies and young children every month and when they had the annual checkup. When we questioned this practice, pediatricians would say, `Well, the parents expect it. They think if I don't fluoroscope the patients, they are not getting a complete examination'."
Statement in 1970 by Dr. Hanson Blatz, Director of the Office of Radiation Control, New York City Department of Health.
Find that far beyond the credible? Look below. New York City is not the only place where this occurred.
Part 2
Preview of Another Use: Well-Baby Check-Ups
Confirmed by Dr. James Pifer and Colleagues!
Dr. James Pifer and co-workers (1963) have described the case material, radiation factors, and study methods in the investigations of enlarged thymus therapy with x-rays in the Rochester studies (see our Chapter 8). Where they described the circumstances which led certain children to become involved in such therapy, Pifer and colleagues stated the following (1963, p.1358):
" ... Also, the indications for treatment differed with each radiologist, pediatrician, or general practitioner. Frequently parents insisted that their child be treated. Some pediatricians fluoroscoped all infants routinely, but probably most children treated in private offices had symptoms at presentation which prompted a radiologic examination ... "
That is an eye-opener of the first magnitude. "Some pediatricians fluoroscoped all infants routinely."
That is precisely what Dr. Blatz was telling us had been his experience, too. Well-babies getting fluoroscopy. Regularly. And the information fits the experience of a woman who wrote to me about her own experience as a child in New York City. She could remember being fluoroscoped at every visit to the pediatrician from age 4 through age 12. She had no recall of medical attention, one way or the other, before age 4.
Had this pediatric practice at least been confined to New York State? No way. We then found the same practice, possibly worse, on the other side of the country. Part 3 of this Preview is on page 124.