Histological examination of the effect of differently fractionated irradiations on transplanted mouse-tumours. II. Observations with Harding-Passey melanoma.

: Comparing the histological effects of differently fractionated X-ray irradiations, using always the same total dose, it seems that Harding-Passey melanoma suffers in the early time points more severe damage by relatively high radiation fractions given with 3 to 4 day intervals than from daily applied smaller fractions of radiation. The daily several times given ultra-fractionation may promote the tumour destroying effect of X-ray irradiation from some points of view.