Measurements of the absolute gamma-ray emission intensities from the decay of 166Ho.

166Ho (T 1/2 ≈ 26.8 h) is an emerging theragnostic radionuclide of interest in nuclear medicine due to its peculiar decay scheme, featuring high-energy β− emission (≈ 1.8 MeV) coupled with the main gamma-ray emission (≈ 80.6 keV). Using the new 166Ho activity standard and the well-calibrated, high-energy resolution HPGe detector, both available at ENEA-INMRI, a new determination of several 166Ho gamma-ray emission intensities, I γ , was performed with low uncertainty. The new I γ values contributed to the Decay Data Evaluation Project. • 166Ho and its use in nuclear medicine as theragnostic radionuclide. • Absolute activity measurements by Triple-to-Double Coincidence Ratio (TDCR) technique. • Hidex and portable ENEA-INMRI TDCR counters. • Gamma-ray spectrometry technique. • 166Ho gamma-ray emission intensities. [ABSTRACT FROM AUTHOR]