Proton and carbon ion therapy is an emerging technique used for the treatment of solid cancers. The monitoring of the dose delivered during such treatments and the on-line knowledge of the Bragg peak position is still a matter of research. A possible technique exploits the collinear 511 key photons produced by positrons annihilation from beta(+) emitters created by the beam. This paper reports rate measurements of the 511 keV photons emitted after the interactions of a 80 MeV/u fully stripped carbon ion beam at the Laboratori Nazionali del Sud (LNS) of INFN, with a poly-methyl methacrylate target. The time evolution of the beta(+) rate was parametrized and the dominance of C-11 emitters over the other species (N-13, O-15, O-14) was observed, measuring the fraction of carbon ions activating beta(+) emitters to be (10.3 +/- 0.7) x 10(-3). The average depth in the PMMA of the positron annihilation from beta(+) emitters was also measured, D beta+ = 5.3 +/- 1.1 mm, to be compared to the expected Bragg peak depth D-Bragg = 11.0 +/- 0.5 mm obtained from simulations. (C) 2012 Elsevier B.V. All rights reserved.
|Titolo:||Study of the time and space distribution of beta(+) emitters from 80 MeV/u carbon ion beam irradiation on PMMA|
|Data di pubblicazione:||2012|
|Appare nelle tipologie:||1.1 Articolo in rivista|