Effect of low doses of whole body irradiation on spontaneous lung metastasis of NFSA2ALM1 mouse tumors.

The effect of low-dose (10-50 cGy) irradiation, delivered as single or fractionated doses, on metastatic development was investigated using NFSA2ALM1 fibrosarcoma and the C3H/HeNrs mouse. Spontaneous lung metastases from tumors transplanted into the leg were suppressed in those mice irradiated with low doses of radiation 12 days after tumor cell inoculation. Abbreviations used: LCFE = lung colony forming efficiency through i.v. injection of tumor cells; SLME = spontaneous lung metastasis efficiency from leg tumors; TD50 = cell number which produces tumors in 50% of inoculated sites; WBI = Whole body irradiation.