Biological Effectiveness of Particle Beams in Cancer Treatment

Abstract:  Radiation therapy plays an important role in cancer treatment, with more than 50% of cancer patients receiving radiation therapy as a part of their treatment plan. The advent of new heavy ion treatment facilities, being planned around the world, marks the beginning of an increased use of heavy ions in cancer treatment. Currently, protons are the most common ion in use for radiotherapy; and carbon ions are a distant second. Each has important differences from the clinical perspective, and offer differing advantages and disadvantages. The quantification of the biological effectiveness of the particle beams is expressed in terms of the relative biological effectiveness (RBE). Current in-vivo and in-vitro RBE studies using particle beams are limited in number and cell-type. This hinders the possibility of utilizing full potential offered by the particle beams in patient treatment planning systems. Our efforts in measuring the RBE for particle beams led to an experimental investigation using a novel experimental design that enabled rapid gathering of massive amount of data. Monte Carlo simulations were carried out for accurate determination of particle transport variables for this experimental setup. This investigation highlights the key role of physics-based modeling for heavy ion therapies, and the results will be presented for proton, helium and carbon ion beams.