Determination of positron emission intensity in the decay of 86gY.

The β+- emitting radionuclide 86gY (t1/2 = 14.7 h) forms a matched-pair with the β--emitting therapeutic radionuclide 90Y (t1/2 = 2.7 d) for theranostic application in medicine. Precise knowledge of the positron emission probability of the PET nuclide is very important, which was rather uncertain for 86gY until recently. In this work, an 86gY source of high radionuclidic purity was prepared and the positron emission intensity per 100 decay of the parent (hereafter "positron emission intensity") was determined by measuring the 511 keV annihilation γ-ray using high-resolution HPGe detector. The total source activity was obtained from known γ-ray emission probabilities. The electron capture (EC) intensity was also determined as an additional check by measuring the Kα and Kβ X-rays of energies 14.1 and 15.8 keV, respectively, using a low energy HPGe detector. From those measurements, normalized values of 27.2 ± 2.0% for β+ -emission and 72.8 ± 2.0% for EC were deduced. These results are in excellent agreement with values recently reported in the literature based on a detailed decay scheme study. [ABSTRACT FROM AUTHOR]