Relation of dose-fractionation of x-rays and its spacing in time to skin damage. Experimental studies.

摘要: Prolongation of fractionation times greatly modifies the intensity reations, irrespective number and size fractions delivered. This is due to a perturbation cell population dynamics time factors involved in onset reactive hyperplasia. The results indicate that iso-effect dose formulae for fractionated treatments radiotherapy, based on experimental animal survival data, are doubtful validity if dose-time which modify repopulation ignored. particularly applies limited large used. For increments range 1,200-1,800 rads, spacings excess 14 days between successive do not improve tissue tolerance but decreases progressively as interval reduced approximately 6 days, below further decrease has little effect modifying damage. Doses 600 rads produced similar effects prolongation such with betw...