Abstract
A previously proposed theory of lymphoma pathogenesis is discussed and extended to assist in the formulation of a hypothesis for the mechanism of low dose systemic irradiation of lymphoma. It is proposed that masses of non-Hodgkin's lymphoma may not necessarily be truly autonomous neoplasms, and that low dose total body irradiation may be effective in such cases through a cytotoxic action on more radiation sensitive precursor cells in the peripheral blood and bone marrow.