Low-dose radiation, when applied
multiple times to the whole body during several weeks, has been
observed to produce a cancer therapeutic effect. The survival of
cancer patients treated with low-dose radiation was better than
the survival of patients treated with chemotherapy (Choi et al.,
1979; Pollycove, 2007) (see the Figure below).

Note: Difference between the two curves in the above graph is not statistically significant.
Since cancer patients treated with chemotherapy have better survival compared to untreated cancer patients (Huchcroft and Snodgrass, 1993), it is clear that chemotherapy has a cancer therapeutic effect. Hence, low-dose radiation applied repeatedly also has a cancer therapeutic effect and not a carcinogenic effect.
There is also additional evidence which shows the cancer therapeutic effect of repeated applications of low-dose radiation to the whole body or half of the body, e.g. (Mendenhall et al., 1989).
All of these data contradict the LNT model, according to which cancer risk would increase following exposure to low radiation doses.