Inhibition of tumor cell proliferation by pulse-repetitive X-ray irradiation

The effect of X-ray irradiation given in pulse-repetitive regimen on the proliferation of P-815 mastocytoma and Ehrlich carcinoma tumor cells was studied. The antiproliferative effect was found to depend on the pulse-repetitive frequency and sum absorbed dose of irradiation. Irradiation at an impulse frequency in a range 13-16 Hz is appeared to completely inhibit tumor cell proliferation despite on the fact that absorbed doses are some fold less than those used in radiotherapy for cancer. The ability of pulse-repetitive X-ray to inhibit tumor growth rate in mice was shown. Mechanisms of the action of pulsed X-ray irradiation are discussed.