Energy-resolved imaging ofαparticles emitted by the decay products of Pb-212 using a YAP(Ce)-based imaging detector for targeted radionuclide therapy.

Objective.Lead-212 (Pb-212) is attracting considerable interest as a radionuclide fortargeted α-therapy, yet energy-resolved imaging ofαparticles originating from its decay chain has been technically difficult.Approach.To address this issue, we employed a YAP(Ce)-basedα-particle imaging detector to perform energy-resolved imaging ofαparticles emitted from Pb-212 progeny and evaluated its performance for energy-discriminativeα-particle imaging.Main results.The system provided a spatial resolution better than 1.0 mm full width at half maximum (FWHM) and an energy resolution of approximately 14.9% (FWHM) forαparticles. This performance made it possible to distinguish the two principalα-energy components emitted by the daughter nuclides of Pb-212, even in the presence of partial interference fromβparticles. To suppress thisβ-particle contribution, a 1 mm-thick acrylic plate was inserted between the Pb-212 source and the detector to selectively acquireβ-particle images, which were then subtracted from the mixed images. Theβ-particle contribution was partially reduced using the proposed subtraction approach, although the contrast to noise ratio decreased after subtraction.Significance.The results demonstrate that practical energy-resolved imaging ofαparticles from Pb-212 progeny is achievable and that the proposed subtraction approach has the potential to reduceβ-particle interference.