-4~Assuming that this formula is appropriate for the continuous alpha particle irradiation from internal alpha emitters, with very high LET, short track in tissue, and high cell sterilizing and killing efficiency and effect within short distances of the sources, and applying to it various dose rates (R), a given constant time of exposure (t) and a given constant mean life of normal cell and singly mutated cell (I,), the formula seems to indicate that for varying internally administered amounts of alpha emitter (continuous alpha irradiation), i.e., different doses and associated dose rates, “the tumor incidence would be proportional to the square of the dose or the square of the dose rate, and the incidence per unit dose would increase in proportion to increasing dose or increasing dose rate. This is compatible with the dose-incidence relationship for alpha radiation-induced bone tumor incidence in dogs cited by the author in lines 13-16, page 4 (see comments on that sentence above). This kind of dose-incidence relationship for alpha emitters (involving continuous irradiation) indicates decreasing effectiveness of doses in the rising portion of the dose-incidence curve with the decreasing dose rate that is associated with decreasing dose. It is difficult to reconcile these findings with the author's next statement, as follows: ‘ Page 4, line 28 to Page 5, line 3 - "This tumor risk relationship makes it abundantly clear that a linear extrapolation to low dose rates is not only conservative for alpha radiation induced tumors, but rather that there is a marked increase dose-rate vs. risk relationship." Comments; comments. Reference is made to the immediately preceding set of For varying amounts of internally administered alpha emitter