Speaker
Dr
Cecilia Voena
(INFN Roma)
Description
Hadron therapy is a technique for cancer treatment that exploits ion
beams (mostly protons and carbons). A critical issue is the monitoring
accuracy of the dose released by the beam to the tumor and to the
surrounding tissues. We present the design of a dual-tracking device
capable of online dose monitor through the detection of prompt
photons and charged particles produced by the interactions of the beam in the patient tissues. Both the neutral and charged emission shapes can be correlated with spatial dose release and the Bragg peak position. The device will be able to provide a fast response
on the dose pattern.
I will briefly review the measured flux and energy spectra for
secondary particles produced by 12C beams at therapeutical
energies impinging on PMMA phantoms and their relation with the Bragg
peak. I will then describe the dual mode dosimeter whose design has
been optimized using Monte Carlo simulations.
The operation uses the information provided by 6 planes of
scintillating fibers with orthogonal views followed by a plastic
scintillator (electron absorber) and a small calorimeter made by a
pixellated lyso crystal. A first tracker layer has already been
assembled and the detector performances have been estimated with
cosmic rays. The fiber system efficiency and cross-talk will be
reviewed.
A complete simulation and event reconstruction has been performed to determine
the achievable spatial resolution. Charged particles are reconstructed
using the scintillating planes and those identified by protons are
back-traced to determine the point of origin. Prompt photons are
reconstructed exploiting their Compton interactions by combining the
spatial and energy measurements from the tracker for the electron and
from the lyso for the photon.
For a real hadrotherapeutic treatment the achievable
resolution is of the order of ten (few) millimeters using the neutral
(charged) component.
Primary author
Dr
Cecilia Voena
(INFN Roma)
