Particle dependence of quenching effect in an optical-fiber-type optically stimulated luminescence dosimeter

Abstract

To monitor an actual dose in a patient's body during radiotherapy treatment, we have developed a small-size dosimeter of an optical fiber probe mounting optically stimulated luminescence (OSL) materials at the tip. The OSL materials show a quenching effect when they are irradiated by charged particles with high linear energy transfer (LET). We evaluate the particle dependence on the quenching effect in the small-size OSL dosimeter probe. Eu:BaFBr and Ce:CaF2 were adopted as OSL materials, and two types of small-size dosimeter were fabricated. We irradiated 290 MeV/u carbon ions, 150 MeV/u helium ions, and 225 MeV protons and measured the Bragg peak. The Eu:BaFBr small-size dosimeter showed the quenching effect in these three types of particle irradiation. The Ce:CaF2 small-size dosimeter showed the quenching effect only in carbon ion irradiation. The luminescence efficiencies of Eu:BaFBr were compared among these three charged particles. The quenching effect of Eu:BaFBr is independent of the irradiated particles.