Acoustic Pulse Generation in Water by Pulsed Proton Beam Irradiation and its Possible Application to Radiation Therapy

Acoustic pulse generation in water irradiated by pulsed proton beam was observed. The dose rate of the beam was 0.05 Gy/pulse and 0.0025 Gy/pulse. A hydrophone sensitive to the acoustic frequency band between 0 to 300 kHz was used for detection. The detected acoustic pulse in water was qualitatively the same shape as the depth dose distribution of the proton beam, when the depth scale is divided by the sound velocity. The intensity of the generated acoustic pulse is believed to allow monitoring of the radiation dose distribution in patients irradiated by pulsed heavy charged particle beam.