Cherenkov-light imaging of beta-particles emitted from daughter radionuclides of actinium-225 (Ac-225) using high sensitivity CCD camera

Abstract Actinium-225 (Ac-225) is a promising alpha emitter for radionuclide therapy due to its remarkable clinical efficacy in treating prostate cancer. The daughter radionuclides of Ac-225 emit beta particles with energies exceeding the Cherenkov-light threshold, making it possible to image them by detecting Cherenkov light. However, the performance of Cherenkov-light imaging for Ac-225's daughter radionuclides has not been assessed through experiments or simulations. To address this, we evaluated the performance of Cherenkov-light imaging for the daughter radionuclides of Ac-225 using both phantom experiments and simulations. A solution of Ac-225 and its daughter radionuclides was placed in an acrylic rod phantom, and Cherenkov-light images were acquired using a high-sensitivity CCD camera. We could obtain clear image of Cherenkov-light and the resulting images demonstrated a spatial resolution of less than 1 mm full width at half maximum (FWHM). Monte Carlo simulations indicated that the theoretical spatial resolution of Cherenkov light emitted from daughter radionuclides of Ac-225 was ∼0.026 mm FWHM, significantly finer than the experimental results, suggesting the blurring the experimental image. In conclusion, Cherenkov-light imaging of Ac-225's daughter radionuclides provides high spatial resolution and shows potential for applications requiring precise distribution measurement of Ac-225 and its daughter radionuclides.