Through his work developing the National Oncologic PET Registry, he helped to greatly expand Medicare coverage for PET. More recently, he serves as co-chair of the Imaging Dementia—Evidence for Amyloid Scanning (IDEAS) Study, a national study designed to demonstrate the clinical value of brain amyloid PET in patients with mild cognitive impairment or dementia.

In 2021, Siegel received the ACR Gold Medal Award for his more than 40 years of leadership in the nuclear medicine community. The Gold Medal, the society's highest honor, recognizes his accomplishments in helping develop PET into a major clinical and research tool and elevating the quality of imaging clinical trials.