Part 1. Fluoroscopy Can Diagnose
Pulmonary Tuberculosis When Physical Exam Fails
We need to keep reminding readers who are relatively young about how important the issue of pulmonary tuberculosis was in the first half of the 20th Century. Two important publications from the Metropolitan Life Insurance Company, one in 1928, and the other in 1929, appeared with some potentially ominous connotations about radiation dose to the breasts.
The paper by Fellows and Ordway (1928) outlined the problem concisely. A number of employees of the Metropolitan Life Insurance Company were diagnosed as having advanced tuberculosis within a year after acceptance for employment, despite a thorough physical examination. It was therefore suspected that cases of unrecognized tuberculosis were being accepted for employment in spite of rigid physical examination and careful questioning.
The Metropolitan Life Insurance Company did not find this to be an acceptable result for a variety of obvious reasons. Casting about for a more accurate means of detecting latent tuberculous disease, the company hired skilled roentgenoscopists [fluoroscopists], well-trained in this type of work, to examine each applicant. This means was employed with a consecutive series of 800 applicants for positions.
From these 800 applicants, accepted after history and physical examination, 8 cases of well-developed pulmonary tuberculosis were found by the roentgenoscopic examinations. Two of these showed calcified lesions, while 6 were classified as having active tuberculosis. These applicants shown roentgenographically to have definite tuberculosis then had repeat physical exams by trained physicians qualified to diagnose tuberculous lesions. In 4 of the 6 cases, these physicians again failed to find abnormal signs in the persons with a definite roentgenoscopic diagnosis of tuberculosis.
This preliminary report indicated that roentgenoscopic examination of chests made by well-trained physicians experienced in this type of work detects tuberculous lesions which otherwise are unrecognized by physical examination alone.
It occasions no surprise that Metropolitan Life Insurance Company pursued the question further. Indeed, one year later, Ada Chree Reid (1929) published a much more detailed account of the Metropolitan Life experience with this problem.
In the years 1924 to 1927, 53 cases of tuberculosis were admitted to a sanatorium for tuberculosis within eighteen months after they began to work for the Metropolitan Life Insurance Company. Presumably, they had tuberculosis at the time of their employment despite a negative physical examination at that time. Reid stated that it is admitted by a number of competent observers that physical examination may miss early tuberculosis in 5 to 10 % of individuals. Cavities may be missed in as high as 50 % of the cases according to Reid's account. The presence of persons with tuberculous cavities in a work force is an open invitation to spread tuberculous disease to healthy individuals (See Chapter 15).
Metropolitan Life Insurance Company reasoned that it would be much more costly to make roentgenograms of everyone to be employed than to have the persons roentgenoscoped. It was felt that the roentgenoscope is a valuable adjunct to physical diagnosis and was employed in the home office of the Metropolitan Life Insurance Company beginning October 1, 1927. From October 1, 1927 to September 30, 1928, 4,883 applicants successfully passed their physical examination. Of these, 59, or 1.214 per cent, were found by roentgenoscopic examination to have tuberculosis. This was confirmed by roentgenograms. Of the 59 cases, 35 reported back in one year. Sixteen were found to have active progressive tuberculosis. The lesions demonstrated varied from minimal to advanced lesions.
There are several points to make concerning these observations. From the human point of view, the major point is to emphasize how lucky those applicants were to have the services of an experienced, well-trained roentgenoscopist and availability of a functioning roentgenoscope. We have no doubt whatever that the lives of a high proportion of those diagnosed with tuberculosis in this manner were saved. Yes, they had an increase in the risk of future cancer, but the roentgen-ray and its use made it possible for them to be alive for decades beyond the discovery of tuberculosis. We have made this point before in describing what collapse therapy of tuberculosis, aided by fluoroscopy, meant in saving lives. This is a different facet of the same problem.
From the radiation exposure point of view, we would need to know how widespread the practice described for Metropolitan Life became in the United States. Surely, other industries must have heard the message and undoubtedly some other industries used the same approach to weeding out prospective employees with active tuberculosis. Unless there is some central recording somewhere concerning how many persons received such fluoroscopic examination, we are unable to ascertain any proper entry into our Master Tables for this radiation source.Part 2. The Demand for Chest X-rays in Employment Situations
Whatever the case might have been for industries with respect to screening which used the services of a trained expert roentgenoscopist, it certainly was true that employers broadly demanded that new employees have chest films before being accepted for a position. And tuberculosis was the disease of concern in such exams.
In numerous school districts throughout the country, school teachers had to have an annual chest film in order to receive permission to teach. Unfortunately, the expertise with which such employment examination chest films were read hardly was any match for the type of ability shown by those who did the roentgenoscopy for Metropolitan Life.
The dose received by millions of young women in school systems and in other employment situations is not easily known. To the extent that photofluorography was not employed, the average dose may well have been quite low, per examination. The doses, in the main, were not part of those accounted for in hospital x-ray departments or in doctor's offices. As a result, the doses received in such employment examinations are not represented anywhere in our Master Tables. They simply represent a source of breast irradiation for which there is no accounting ---- and hence they represent an underestimate in radiation doses received by the breasts of women in the 20th century.
The number of new cases of pulmonary tuberculosis in U.S.A. decreased steadily in the decades beyond 1950, but that hardly was sufficient for the school board bureaucracies to give up their demand for the annual chest film for school teachers. As a result, school teachers received an unnecessary annual dose of chest irradiation long after the medical need for tuberculosis screening was over. It is a little early to say whether the resurgence in tuberculosis in the 1980s and 1990s will change this screening requirement once again. Diseases such as tuberculosis can hardly ever really be said to be eradicated.
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- Bernard Berenson, 1865-1959,