First application of the BIANCA biophysical model to carbon-ion patient cases.

Objective.The main objective of this work consists of applying, for the first time, the BIANCA (BIophysical ANalysis of Cell death and chromosome Aberrations) biophysical model to the RBE calculation for C-ion cancer patients, and comparing the outcomes with those obtained by the LEM I model, which is applied in clinics. Indeed, the continuous development of heavy-ion cancer therapy requires modelling of biological effects of ion beams on tumours and normal tissues. The relative biological effectiveness (RBE) of heavy ions is higher than that of protons, with a significant variation along the beam path. Therefore, it requires a precise modelling, especially for the pencil-beam scanning technique. Currently, two radiobiological models, LEM I and MKM, are in use for heavy ions in scanned pencil-beam facilities.Approach.Utilizing an interface with the FLUKA Particle Therapy Tool, BIANCA was applied to re-calculate the RBE-weighted dose distribution for carbon-ion treatment of three patients (chordoma, head-and-neck and prostate) previously irradiated at CNAO, where radiobiological optimization was based on LEM I. The predictions obtained by BIANCA were based either on chordoma cell survival (RBEsurv), or on dicentric aberrations in peripheral blood lymphocytes (RBEab), which are indicators of late normal tissue damage, including secondary tumours. The simulation outcomes were then compared with those provided by LEM I.Main results.While in the target and in the entrance channel BIANCA predictions were lower than those obtained by LEM I, the two models provided very similar results in the considered OAR. The observed differences betweenRBEsurvandRBEab(which were also dependent on fractional dose and LET) suggest that in normal tissues the information on cell survival should be integrated by information more closely related to the induction of late damage, such as chromosome aberrations.Significance.This work showed that BIANCA is suitable for treatment plan optimization in ion-beam therapy, especially considering that it can predict both cell survival and chromosome aberrations and has previously shown good agreement with carbon-ion experimental data.

FLUKA particle therapy tool for Monte Carlo independent calculation of scanned proton and carbon ion beam therapy.

While Monte Carlo (MC) codes are considered as the gold standard for dosimetric calculations, the availability of user friendly MC codes suited for particle therapy is limited. Based on the FLUKA MC code and its graphical user interface (GUI) Flair, we developed an easy-to-use tool which enables simple and reliable simulations for particle therapy. In this paper we provide an overview of functionalities of the tool and with the presented clinical, proton and carbon ion therapy examples we demonstrate its reliability and the usability in the clinical environment and show its flexibility for research purposes. The first, easy-to-use FLUKA MC platform for particle therapy with GUI functionalities allows a user with a minimal effort and reduced knowledge about MC details to apply MC at their facility and is expected to enhance the popularity of the MC for both research and clinical quality assurance and commissioning purposes.

Beam parameters optimization and characterization for a TUrning LInac for Protontherapy.

TULIP (TUrning LInac for Protontherapy) is a novel compact accelerator system for protontherapy mounted on a rotating gantry (Amaldi et al., 2013, 2010, 2009). Its high-energy Linac has the unique property of being able to modulate the beam energy from one pulse to the next, in only a couple of milliseconds. The main purpose of this study is to optimize the properties of the beam exiting the Linac to make them compatible to medical therapy and to characterize their medical physics properties for later implementation in a Treatment Planning System. For this purpose, multi-particle tracking and Monte Carlo (MC) simulations are used to follow the particles through their path up to the treatment isocenter, following the so-called phase-space method. The data compiled includes particle fluences in air and depth-dose curves and provides the basis for a specific model of the TULIP beam.