Cherenkov real-time monitor for proton flash therapy

Abstract Flash therapy with ultra-high dose rate beams opens up the possibility of significantly reducing radiation damage to normal tissues. But that type of radiotherapy requires the development of new methods for dosimetry and monitoring of beams, since many conventional detectors are not fully suitable for these purposes. In this work, the characteristics of a new proton beam monitor that detects Cherenkov radiation from secondary delta electrons were studied in flash mode of irradiation. This monitor is applicable for proton beams of any intensity, very transparent for fast protons, and can provide real-time control of the absorbed dose and beam position. To record Cherenkov radiation, generated in a thin glass radiator located in the beam in front of the target, we used single-channel and multichannel photomultipliers. Proton beams with an energy of 160 MeV and a current of 1 mA were studied. The readings of a Cherenkov monitor, EBT-XD films, and a beam current transformer were compared and consistency of these detectors was found. The linearity of the Cherenkov monitor readings vs dose is very high ( R 2 = 0.9995). This monitor can be used for real-time control of the absorbed dose and of the beam position in flash therapy for any intensity of proton beams.