Radiobiological effects of highly charged ions Their relevance for tumor therapy and radioprotection in space

Abstract

Generally, radiobiology is mostly concerned with the influence of sparsely ionising radiation like X- or gamma-rays and electrons. In the last 50 years, however, the radiobiological action of heavy charged particles like protons or heavier ions has been studied with increasing intensity. This is for two reasons: first, heavy charged particles represent the best tool for an external radiotherapy of inoperable tumors. This is due to the favourable depth dose distribution where the dose increases with penetration depth and because of the small lateral and longitudinal scattering that allows irradiation of deep-seated target volumes with optimum precision. In addition, for particles heavier than protons, i.e. in the region of carbon, the biological efficiency increases at the end of the beam's range while it is low in the entrance channel, thus allowing a better inactivation of otherwise very radioresistant cells of deep-seated tumors. The second important field for particle radiobiology is the application in radiation protection in space research. In space outside the magnetic shielding of the earth, high-energy protons from the sun and heavier particles up to iron from interstellar sources pose a genetic and carcinogenic risk for man and can also influence and destroy semiconductor devices like computers. Because of the very high energies of these particles, shielding becomes difficult and extremely expensive. (orig.)To be published in: The Physics of Highly and Multiply Charged Ions. Currell, F.J. (ed.), Kluwer Academic Publ. (2002)Available from TIB Hannover: RO 801(2002-20) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman