Three Main Benefits of Low Level Radiation

1-DNA repair (Mollecular level)
According to this theory, low doses of ionizing radiation induce the production of special proteins, that are involved in DNA repair processes (Ikushima 1996). Studies using two dimensional gel electrophoresis indicated new proteins in cells irradiated with low doses of radiation. Also, it was further shown that cycloheximide, a protein synthesis inhibitor blocks this hormetic effect. The function and importance of these radiation induced proteins is still unknown. Also it was foud that inhibitors of poly ADP-ribose polymerase, an enzyme implicated in DNA strand break rejoining could prevent the induction of adaptive response (for a review see Wolff 1998).

2-Free radical detoxification (Molecular level)
In 1987 Feinendengen and his co-workers indicated that low doses of ionizing radiation cause a temporary inhibition in DNA synthesis (the maximum inhibitionat 5 hours after irradiation). This temporary inhibition of DNA synthesis would provide a longer time for irradiated cells to recover (Feinendengen et al. 1987). This inhibition also may induce the production of free radical scavengers, so irradiated cells would be more resistant to any further exposures.

3-Stimulation of immune system (Cellular level)
Despite the fact that high doses of ionizing radiation are immunosupressive, many studies have indicated that low doses radiation may stimulate the function of the immune system. In 1909 Russ first showed that mice treated with low-level radiation were more resistant against bacterial disease (Russ VK 1909).Later in 1982 Luckey published a large collection of references supporting immunostimulatory effects of low doses of ionizing radiation (Luckey TD 1982).

I would also add that other observed benefits include but are not limited to elimination of yeast/fungus/mold/candida in your body, anti-aging/longer life span, and alkalizing effect on the body.