Recently, a high efficiency regime of acceleration in laser plasmas has been discovered, allowing table top equipment to
deliver doses of interest for radiotherapy with electron bunches of suitable kinetic energy. In view of an R&D program
aimed to the realization of an innovative class of accelerators for medical uses, a radiobiological validation is needed.
At the present time, the biological effects of electron bunches from the laser-driven electron accelerator are largely
unknown. In radiobiology and radiotherapy, it is known that the early spatial distribution of energy deposition
following ionizing radiation interactions with DNA molecule is crucial for the prediction of damages at cellular or
tissue levels and during the clinical responses to this irradiation. The purpose of the present study is to evaluate the
radio-biological effects obtained with electron bunches from a laser-driven electron accelerator compared with bunches
coming from a IORT-dedicated medical Radio-frequency based linac's on human cells by the cytokinesis block
micronucleus assay (CBMN). To this purpose a multidisciplinary team including radiotherapists, biologists, medical
physicists, laser and plasma physicists is working at CNR Campus and University of Pisa. Dose on samples is
delivered alternatively by the "laser-linac" operating at ILIL lab of Istituto Nazionale di Ottica and an RF-linac
operating for IORT at Pisa S. Chiara Hospital. Experimental data are analyzed on the basis of suitable radiobiological
models as well as with numerical simulation based on Monte Carlo codes. Possible collective effects are also
considered in the case of ultrashort, ultradense bunches of ionizing radiation.