Hadron therapy has well known advantages with respect to conventional radiation therapy using photons. The ion beam energies can be chosen in such a way that the Bragg peak, the sharp peak of the released dose at the end of the ion range, falls inside the tumour, while sparing surrounding normal tissues. Compared to proton therapy, hadron therapy using 12C beams has further advantages, among these are a sharper lateral dose fall-off and a higher potential to treat radioresistant tumours due to its increased linear energy transfer (LET) at the end of the particle range. However, since the secondary fragments produced by the nuclear interactions of the beam with the tissue significantly contribute to the absorbed dose, fragmentation effects cannot be neglected. Currently, treatment planning systems for hadron therapy are generally based on deterministic codes for dose calculations which are relatively fast. These deterministic dose engines are often benchmarked against Monte Carlo simulations in order to test and improve their accuracy. The predictions of various theoretical models for the fragmentation process differ up to an order of magnitude for double-differential quantities (in energy and angle). Several measurements were made in the past of fragment yields and total cross sections, but double-differential cross section (DDCS) measurements are scarce. Accurate knowledge of fragmentation cross sections would also be important in the field of radiation protection in space missions.
Recently, NASA completed a large database of nuclear fragmentation measurement and observed that there are ion types and kinetic energy ranges where such measurements are missing. In particular, DDCS measurements for light ions in the energy range of interest for hadron therapy applications are lacking. The FIRST (Fragmentation of Ions Relevant Space and Therapy) experiment at SIS accelerator of GSI laboratory in Darmstadt, has been designed for the measurement of different ions fragmentation cross sections at different energies between 100 and 1000 MeV/nucleon, filling the current experimental gap and hence allowing an improvement of TPS softwares, that are heavily relying on that experimental input.
Details in the collaboration web site.
Who: V. Patera, A. Sarti, A. Sciubba, M. Toppi
Collaborators: FIRST collaboration (~ 60 members from France, Spain, Germany, Italy)
Analysis Meeting Slides: are linked in the indico TPS page