Dr. Tilo Reinert

University of North Texas, Physics

The Proton-Boron-Reaction 11B(p,a)2a as a Possible Dose Enhancer in Proton Therapy

Abstract: Proton therapy is an emerging radiotherapy that targets tumors with a beam of high energetic protons. The advantage in using protons instead of X-rays relies on the physical effect that a proton's energy loss per unit path length (LET), and thus the dose delivered in a human body, is highest a few micrometers before the end of the proton's range. This maximum, which we call Bragg-peak, is positioned inside the tumor. It happens that the proton energy in the Bragg-peak shows also a largely increased cross section for the nuclear reaction with boron-11. The reaction results in the emission of three a-particles with in total fourteen times more energy. The boron nuclei can be provided by tumor-seeking particles. Whether the reaction is significantly contributing to the dose depends on the size of the particles which in turn affects the number and energy of a-particles that irradiate the tumor. The a-particle energy product is a measure for the optimum particle size. I will present theoretical estimates of the optimum particle size and the design of an experimental approach. I will address the advantage of using a multi-detector setup and digital pulse processing for coincidence alpha-spectrometry to extract the cross-sections for the individual reaction channels.

Refreshments at 3:15 P.M.