Calculation of carbon-ion beam’s range in different media used for radiation therapy

Carbon-ion radiotherapy (CIRT) is a new radiation modality with significant physical and biological advantages over photon irradiation. Range assessment is a major challenge and it is considered the key for using the full potential of carbon ion therapies. The purpose of this research is to develop a novel and practical method for monitoring accurately the carbon ion range in different types of tissue during treatment. The proposed method is based on the Doppler Shift Effect of Prompt Gammas (PGs), which give real–time information due to the instantaneous nuclear de-excitation, and thus PG shifted energy can quantify the mean carbon energy with respect to PG spectrum, and then the predicted range can be calibrated. We develop a mathematical model with initial carbon ion energies within the range of 100MeV/u-450 MeV/u for different detection angles of 0°-90°, and different target materials including water, air, and soft tissue. The results of our calculations are verified by Monte Carlo simulations.