Speaker
Description
The accurate evaluation of the dose distribution is an open issue in Hadrontherapy.
MONET (Model of ioN dosE for Therapy) is a code for the computation of the 3D dose distribution for protons and Helium beam in water. MONET accounts for all the physical interactions and is divided in two part: the lateral and longitudinal distribution.
For the lateral profile, MONET is based on the Molière theory of multiple Coulomb scattering (Embriaco et al, Phys. Med. Biol. 62 (2017) 6290–6303). To take into account also the nuclear interactions, we add the Cauchy-Lorentz function, where the two parameters are obtained by a fit to a FLUKA simulation (Bellinzona et al., Phys. Med. Biol. 61 (2016) N102–N117) (Embriaco et al., Physica Medica 40 (2017) 51–58). We have implemented the Papoulis algorithm for the passage from the projected to a 2D lateral distribution (Embriaco et al, Physica Medica 38 (2017) 66–75).
For the longitudinal profile, we have implemented a new calculation of the average energy loss that is in good agreement with simulations and other formulas. The inclusion of the straggling is based on the convolution of energy loss with a Gaussian function. In order to complete the longitudinal profile, also the nuclear contributions are included in the model using a linear parametrization with only two parameters (Embriaco et al, Physica Medica 38 (2017) 66–75).
The total dose profile is calculated in a 3D mesh by evaluating at each depth the 2D lateral distributions and by scaling them at the value of the energy deposition.
We have compared MONET results with the FLUKA simulation in two cases: a single Gaussian beam and a lateral scan as a sum of many beams in order to estimate the accuracy of the model focusing on the tails of the distribution that give rise to the low-dose envelope. In both cases, we have obtained a good agreement for different energy of protons and Helium beam in water.
The advantages are the physical foundation, the fast calculation time and the accuracy. A possible development is the creation of a dose database of clinical interest and an online fast dose evaluation tool.
