State-of-the-art gamma-ray assay of Y-86 for medical imaging

An emerging direction in nuclear medicine is the coupling of a therapeutic isotope with an imaging isotope to form a so-called theranostic pair, which allows one to quantitatively track and image the delivery of the therapeutic isotope. Y-90 is used in several therapy applications and a convenient candidate imaging partner is the positron emitter Y-86. A 27.6 MBq source of Y-86 was produced at the University of Wisconsin and assayed with the Gammasphere array at Argonne National Laboratory. Over 200 gamma-ray transitions were identified, more than double that which was previously known. The positron emission probability inferred from the present level scheme leads to 27.9(12)%, an important (approximate to 14%) reduction with respect to the previously recommended value.