Dermatitis due to these agents may be intentionally produced
by an accurately controlled technique when warranted in the treatment of
certain diseases, or may be accidentally incurred by ignorance or carelessness.
Accidental "burns" from x-rays and radium were closely associated
with the early use of them and, in the case of radium, first called attention
to its action upon living matter. About five years after the discovery and
medical use of roentgen rays, the first case of cancer arising upon chronic
radiodermatitis was reported in a roentgenologist. During the succeeding few
years numerous cases appeared in the literature. Although the x-ray industry
has since that time grown, the dangers are now more fully recognized and
precautions against them have been adopted.
Similarity
Between Radium and X-ray Dermatitis. Inflammatory reactions due to x-rays
and radium have many points of similarity, although the onset, course, and end
results vary greatly. These variations depend upon the intensity and
penetration of the radiation.Latent Period. An interval of several days intervenes between the exposure to radiation and the onset of visible skin reaction. This interval is called the latent period. The term is applied mostly when erythema doses are used, but a similar interval exists between exposure and functional or therapeutic manifestations when fractional or suberythema doses are employed. The duration of this interval is affected largely by the quality of the radiation, the skin tolerance of the subject, and the magnitude of the dose. In general, the softer the radiation and the larger the dosage, the shorter is the latent period.
The phenomena of
the latent period are difficult to explain. They belong to the field of general
biology and are not a specific radiation problem. Presumably the radiation
effects are immediate, and such grossly visible clinical changes as ultimately
appear are tissue reactions to them.