Comparative study of x-ray transmission in thorax and abdomen in living subjects.

In the course of multiple-field radiotherapy to twelve cases of bronchogenic carcinoma it became apparent that delivery of an adequate tumor dose entailed considerable damage to the lungs. Tumor doses ranging from an estimated 5,000 to 9,000 r were usually followed by clinical evidence of a severe pneumonitis, almost invariably terminal in nature. Postmortem evidence in the great majority of the cases indicated extensive bilateral pneumonitis, often with fibrosis, and there was a growing impression that death had been secondary to radiation damage. In an analysis of these unfavorable results, consideration was given to the possibility that estimation of the tumor dose had been in error and that an excessive amount had somehow been administered. In a previous study (1), to demonstrate the distribution of energy within the thorax during multiple field and rotational therapy, it was shown that a plywood phantom of 0.5 density is probably more accurate for obtaining depth dose data applicable to the human tho...