Dose-time Relationship in the Radiation Therapy of Metastatic Lung Cancer

Abstract

The relationship between radiation effect and fraction number was studied in a case of metastatic lung cancer. Three radiotherapeutic fields were taken from multiple pulmonary metastatic foci of squamous-cell carcinoma from the lower jaw. The same total dose was given to each field with the same over-all time, but with three different daily doses. In each radiation field several nodular shadows of metastases were contained, one of which was measured for diameter periodically. Radiation effects were summarized in the formula:
log R_n/R_o=(α/t-β)T
Where R_o is the tumor size before treatment, Rn is that after irradiation, t the interval of time between fractions, T the over-all time, and α and β constants related to the daily dose.