An Experimental Study on the Time Factor in Radiation Treatment of Cancer

抄録

Subcutaneous tumor was produced with Ehrlich ascites tumor in the subcutaneous tissue of the right shin of a mouse. X-ray irradiation to the area of tumor transplantation was carried out using the total dose of 5, 000 R, i.e., 500 R daily, 500 R every 3 days, 500 R every 5 days, 200 R daily; 3, 000 R in a single dose; and 5, 000 R in a single dose. Inhibition of tumor growth was more pronounced as a period of irradiation became shorter, and less effective as it became longer. Life prolongation effect was poor when a period of irradiation was extremely short or long as the total dose was kept constant. Those with marked inhibition of tumor growth did not always exhibit good life prolongation effect. No rectilinear relationship was found between these two. When the period of irradiation and total dose are same and the dose for a single irradiation is different; in other words, the interval and frequency of fractional irradiation are different, the effect varies. Even in a single irradiation, a considerable effect may be expected when an adequate dose is used.