High-Precision γ-ray spectroscopy of the PET imaging agent ⁷²As

Radioisotopes are used for imaging or therapeutic purposes in millions of procedures annually. The future of nuclear medicine is to pair a therapeutic agent with a positron emitting isotope to perform simultaneous PET imaging of the therapy agent. One of the most promising new theranostic pairs is ⁷²As. The decay of ⁷²As was last studied in 1971 using a primitive Ge detector system. To provide higher-quality decay data, a source of ⁷²As was assayed at Argonne National Laboratory with the Gammasphere array. This allowed previously-observed cascades to be confirmed and new γ-rays to be identified. The revised level scheme and high-precision intensities will be presented and their impact on the dose of γ and β radiation will be discussed.