QUANTITATIVE DESCRIPTION OF PARTICLE INTERACTIONS WITH BIOLOGICAL SAMPLES

Single particle microbeam irradiation systems provide the tool needed to investigate the response of cells and some other biological systems to extremely low doses of high LET radiation. However, the resulting exposure, which consists of specified numbers of charged particles thr ough specific portions of cells, cannot be described by conventional d osimetry concepts which were defined to characterise average energy de positions in a randomly irradiated population. In order to take advant age of the information provided by microbeam irradiation, it is import ant to describe the experimental irradiation in a way which can be cor related with the radiation interactions in individual cells in vivo wh ich can be calculated for many radiation exposures. An approach, based on characterising the response as a function of both the particle sto pping power and the path length through the cell or other defined targ et, is described.