Improved survival of non-Hodgkin’s Lymphoma patients was observed when they were subjected to 10 or 15 cGy total-body or half-body irradiation (TBI or HBI) interspersed between radiation treatments to the tumor (Total dose=1.5 Gy) (Sakamoto, 2004).
These data indicate that low radiation doses reduce the cancer risk consistent with radiation hormesis and contradicting the LNT model.
Tumors outside the HBI field also regressed in response to the repeated LDR exposures (Pollycove 2007), indicating that the the cancer therapeutic effect was due to a systemic response (e.g. immune enhancement), and not due to tumor cell-killing from the total dose of 1.5 Gy.
SAKAMOTO, K. Radiobiological basis for cancer therapy by total or half-body irradiation. Nonlinearity Biol Toxicol Med, v. 2, n. 4, p. 293-316, Oct 2004. https://www.ncbi.nlm.nih.gov/pubmed/19330149
Pollycove, M, Radiobiological basis of low-dose irradiation in prevention and therapy of cancer, Dose Response, 5(1):26-38, 2006. http://www.ncbi.nlm.nih.gov/pubmed/18648556