1568P - Development of laser-driven proton beam therapy

Abstract

ABSTRACT Aim: Proton beams by their advantageous dose profile over conventional photon and electron beams may provide higher dose conformity and better healthy tissue sparing. But due to high costs and huge size of existing facilities, proton therapy is limited to few centers. A novel proton acceleration, on µm scale by ultra-intense lasers, promises compact accelerators and beam delivery systems. Unlike conventional proton beams, laser-accelerated proton (LAP) beam is characterized by short ultra-intense pulses with peak dose rates exceeding conventional values by ∼9 orders of magnitude but low repetition rate, broad energy spread and large divergence. They require completely new techniques of beam transport, dose delivery and quality assurance along with radiobiological characterization. Methods: The presented work is an ongoing joint translational research project of several institutions in Germany aiming to establish LAP therapy. In parallel to the development of high power laser systems and laser targets to generate stable and reproducible LAP beams, a dedicated radiation oncology focused research program is being followed. Results: Laser-based technology was established for cell and small animal irradiation. The high power laser system DRACO was setup and optimized for long-term stable proton acceleration. A dedicated fixed-beam transport system with integrated energy selection and field shaping as well as real time dose monitoring was established. The suitability and reliability of all components was proven in systematic radiobiological studies over months. No overall difference in the biological effectiveness between laser-accelerated and conventional beams was detected to date. For translation towards patient irradiation, increase of proton energy from ∼25 to ∼230 MeV by increasing the laser power from ∼100 TW to ∼1 PW is required and the development of PW laser is in progress. Furthermore, a compact 360° isocentric proton gantry was designed, based on novel light-weight high-field pulsed magnets. This gantry is ∼2.5x smaller than conventional proton gantries. The necessary pulsed magnets are being developed together with novel dose delivery strategy for LAP. Conclusions: LAP therapy is a promising alternative, yet require substantial development with a clinical prototype in some years. Supported by German BMBF, no. 03Z1N511. Disclosure: All authors have declared no conflicts of interest.