Abstract
Cancer therapy with carbon ions at the HIMAC has started in 1994, more than 5,000 lesions have been treated by 2010, and fruitful results have been demonstrated. Following those results, few heavy-ion treatment facilities are working, some are under construction and many new facilities are planning all over the world now. To start treatments with HIMAC clinical experiences such as treatment planning, the beam quality at those new facilities must be very similar to the HIMAC in physics and biology. Biological results are easy affected by the biological conditions, techniques or so on. We tried to establish a standard biological protocol for this purpose.
Both C3H/He mice bred at NIRS (N) and Charles River Co. (C) were employed, and the crypt cell survival assay 3.5 days after the irradiation was performed with whole body single irradiation of carbon 290 MeV/u beam having 6 cm SOBP at HIMAC. Crypt survival data was taken from (N) and (C) mice. An expert and a new face measured crypt of the prepared slide.
The radio-sensitivity of the mice crypt was different by the breeders. The Dq values were similar between them (C and N), but the Do for (N) was higher than that for (C). Recognition level of the existing crypts at counting was different by the observers, but this technical difference was conquerable by simple training. Change in the recognition level with elapsed time could not found for an observer within 6 years.
Use of mice supplied by worldwide breeder with good quality control may be required for intercomparison of RBE. Short training could unify technique of new observer.
