High-precision gamma-ray spectroscopy of 61Cu, an emerging medical isotope used in positron emission tomography*

$^{61}$Cu ($t_{1/2}$ = 3.339h) is an important medical isotope used in positron emission tomography (PET) tumor hypoxia imaging scans; however, its beta-plus decay and the subsequent gamma decay of $^{61}$Ni has not been studied in over 30 years. Therefore, high quality decay data of $^{61}$Cu is desired to determine the overall dose delivered to a patient. In this study, $^{61}$Cu was produced at the University of Wisconsin - Madison cyclotron and then assayed using the Gammasphere array at Argonne National Laboratory. Consisting of 70 Compton-suppressed high-purity germanium (HPGe) detectors, Gammasphere provides precise decay data that exceeds that of previous $^{61}$Cu studies. $\gamma$-ray singles and coincident data were recorded and then analyzed using Radware gf3m software. Through $\gamma$-$\gamma$ coincidence techniques, new $\gamma$-ray transitions were identified and high precision determination of $\gamma$-ray intensities were made. These modifications and additions to the current decay scheme will be presented, and their impact on the resulting does estimates will be discussed.