Acoustic analog front-end for Bragg-Peak detection in hadron therapy

Abstract

Clinical proton and ions beams for cancer treatment provide maximum energy deposition (Bragg Peak, BP) at the end of their range and practically no dose behind. This enables a more efficient therapeutic option comparing with classical photon-based radiotherapy where maximum energy deposition occurs at the body/tissues interface. Obviously, optimum/minimum-error BP detection and calibration is thus a key aspect of this treatment. This work investigates a promising detection technique, based on the so called (proton) iono-acoustic effect. The BP energy deposition causes a small (mK) heating of the surrounding region that in turn induces a pressure variation. This propagates an ultrasound signal (MHz range) whose time-of-flight measurement aims to detect the BP position with very high accuracy (<1mm). This paper presents the simulation results of complete mixed-signals and mixed-energies model that starting from proton beam energy calculates the induced pressure variation in water, emulates the propagation of sound waves in the medium and finally provides a voltage signal (including noise) whose time evolution determines BP position.