Proton hypoxiradiotherapy of Ehrich's carcinoma with different dose rates

An experimental evaluation of the effeciency of hypoxiradiotherapy with irradiation of tumors by protons at different dose rates is discussed. In experiments performed at ITEP synchrotron it has been shown that the use of the hypoxic gas mixture containing 6% O2 for breathing appreciably diminishes the degree of skin reactions with only weak tumor protection. It is concluded that the use of hypoxic hypoxia during proton irradiation afford the same advantages as during γ- or x-ray therapy. The skin protection can be also achieved by use of ultra-high dose rate and in this case it is associated with radiochemical depletion of oxygen. This effect may be used for the improvement of radiotherapy of malignant tumors