SU‐E‐T‐423: Feasibility and Parameter Study on the Radiation Therapy with Laser‐Accelerated Electrons Using a Sharp Density Transition Scheme

Abstract

Purpose: In the cancer therapy using laser‐accelerated VHEE (very high energy electron) beams, stability of the beam generation is a very important issue. Generation of stable mono‐energetic electron beam is affected by the conditions of electron injection. We used the sharp density transition scheme for the stable generation of the VHEE beams and investigate the characteristics of the mono‐energetic electron beams with a laser focal spot size. Methods: To generate sharp density transition structure experimentally, a study on the generation of plasma shock structure was performed at Korea Electrotechnology Research Institute. The characteristics of VHEE beams generated from laser‐plasma interaction via linearly polarized intense laser pulses are investigated using two‐dimensional particle‐in‐cell simulations. To investigate the feasibility of the cancer therapy with VHEE beams with a sharp density transition scheme, Monte‐Carlo simulations are performed for calculating the dosimetric properties. Results: The sharp density transition structure can be generated using a pre‐pulse propagating orthogonal to the main laser pulse. 200 ps and 400 mJ pre‐pulse can generate the plasma shock structure with a sharp density transition under 10㎛. The charge of the electron bunch is related to the area of the phase‐mixing region. The electron bunch with the maximum charge was produced in the maximum area of the mixing region for the specific laser focal size. Energy spread of electron bunch increases with the increasing focal spot size and transverse bunch size decrease with increasing focal spot size. Dose distributions have also been calculated with the GEANT4 code and we present the feasibility of the particle therapy with sharp density transition scheme based VHEE beams for the deep seated tumor. Conclusions: In this paper, we present the superior feasibility of the cancer therapy using laser‐accelerated VHEE beams with a sharp density transition scheme.