Time resolved properties of acoustic pulses generated in water and in soft tissue by pulsed proton beam irradiation--a possibility of doses distribution monitoring in proton radiation therapy.

Time-resolved acoustic pulses generated in water and in soft tissue by pulsed proton beam irradiation were observed. The spatial resolution of depth dose distribution in the clinically applied beam intensity is estimated about 3 mm by means of TOF measurement. The dependence of the acoustic signal intensity on the temperature of medium was examined. Proportionality of acoustic pulse intensity to absorbed dose per pulse was confirmed as well. These results suggest the possibility of clinical application to monitor dose distribution in the patient's body during irradiation of pulsed proton beam.