High Linear Energy Transfer Radiation in Cancer Therapy with Accelerators

KREINER AJ; DURÁN H; MOLINARI B; SCHUFF JA; POLICASTRO L; MAZAL A; BURLÓN A; DAVIDSON J; DAVIDSON M; DEBRAY ME; EDREIRA M; KESQUE JM; OZAFRÁN M; RIVERA E; SOMACAL H; VALDA A; VÁZQUEZ M

Buenos Aires, Argentina

Workshop; Workshop on Clinical Applications of the Concept of Oxidative Stress in Radiobiology and Cancer Radiotherapy. XII Meeting of the International Society for Free Radical Research; 2004

High Linear Energy Transfer (LET) radiation, namely radiation for which the energy deposited in tissue per unit length of traversed path is significantly higher than for conventional gamma radiation or high energy protons, is known to have significant radiobiological advantages for cancertherapy. The LET depends on the nuclear charge or atomic number Z (as Z2) and on the velocity (as 1/v2) of the projectile. Hence, the higher Z and/or the smaller v, the higher the LET which means a higher ionization and excitation density leading to higher local doses. This in turn implies a monotonically increasing relation between the Relative Biological Effectiveness (RBE) and the LET (in the LET range from 0 to @150 keV/mm the RBE reaches values as high as 5). The main radiotherapy modalities which are taking advantage of these facts are hadrontherapy and Boron Neutron Capture Therapy (BNCT). In order to start an activity in this field external proton, a and Li beams, were produced and characterized dosimetrically at the Tandem accelerator TANDAR in Buenos Aires and used for radiobiology studies on cancer cells. RBE10 (at 10% survival) values have been measured as functions of projectile energy for protons, a and Li ions for different cell lines.