Cell death and mutation induction on cultured cells by irradiation of heavy ions and X-rays

Abstract

The cell-killing effects and mutation induction have been investigated in order to evaluate the biological effects of heavy-ion beams and X-rays on cultured cells. Human breast cancer origin has been used to evaluate the biological effects of carbon and neon ion beams as well as the effect of X-rays. The biological effect of fractionated irradiation of three hours interval on cell survival rate and mutation frequency against V79 cell has been studied. It was found that carbon beams and neon beams had much more powerful cell-killing effects than X-ray, and that neon beams have a smaller mutation induction effect than that of carbon beams under a certain condition. Carbon beams had no significantly different effects on cell-killing between single and fractionated irradiation, however, the mutation frequency at the fractionated irradiation was reduced. In the case of X-rays, the cell survival rate was increased by fractionation, but mutation frequency was not changed.

培養細胞に及ぼす重イオンビームとX線の生物学的効果を評価するため細胞致死効果および突然変異誘発を検討した。炭素イオンビームとネオンイオンビームならびにX線の生物学的効果を評価するためにヒトの乳癌細胞を用いた。3時間間隔の分割照射時のV79細胞に対する細胞生存率と突然変異率に及ぼす生物学的効果を研究した。炭素ビームとネオンビームはX線よりもかなり強力な細胞致死効果を持ち、また或る一定の条件下ではネオンビームの突然変異誘発効果は炭素ビームよりも小さいことが分かった。炭素ビームは1回照射と分割照射との間の細胞致死効果に際だった差はないが、分割照射の場合の突然変異率は低下した。X線の場合には、細胞生存率は分割照射により増加したが突然変異率に変化はなかった。