Abstract
1) The pattern of dose response curves is not similar according to the mode of fractionation including single irradiation. Therefore, the shape of the curves don't coincide each other even if ordinates are modified by a certain ratio.
2) The curves from zero to a certain cumulative dose differ each other, and from a certain cumulative dose, the curves are not the same owing to the fractionation modes delivered previously.
3) The doses giving the same lethality in fractionated irradiations are corresponded to those in a single irradiation. Dose of single irradiation is the ordinate, and intergrated dose of fraction-ated irradiation is the abscissa. In these curves, we can define the amount of the ordinate to be‘cumulative dose’. By this procedure, the quantitative analysis is available in cumulative dose which is otherwise of an arbiturary nature in general.
4) The formula is invented to indicate that the decreased cumulative dose owing to the recovery is added to the succedding irradiation. The recovery rate is represented as μ.
5) μ is large in the region of low cumulative dose when one fractionated dose is small. This is believed to be due to its threshold effect.
6) In the region of 400-800 r, smaller fractionated dose resulted a large μ.
7) From the region of 400-800 r, μ is smaller in the case irradiated chronically than acutely.
8) The radiation effect is large when one fractionation dose is large even in the same over-all time.
9) The effect is large when one fractionated dose is large in the case of same interval.
