Abstract: To test the validity of radio-surgery of heavy ion beams, which inactivate a specific organ through local irradiation, silkworms (Bombyx mori) were whole-body exposed or locally irradiated with carbon ion beams (¹²C⁵⁺; 18.3 MeV/u). Between controls and larvae locally irradiated at the wandering stage, no significant differences in either survival or cocoon quality were observed . Only localized effects were observed, depending on both dose and site of irradiation, but this was not true for whole-body irradiated larva. After local irradiat ion of the hemopoietic organs at the 4th instar premolting stage, the hemocyted ensities were clearly reduced and the hemopoietic organs capacity was disrupted. The results show that radio-surgery utilizing heavy ion beams can destroy a specific organ or tissue in a larva of insect.

Key words: Bombyx mori, heavy ion beam, local irradiation, organ