In a Patent Trial and Appeal Board (PTAB) decision issued on April 16, 2021, in Ex parte Bhalla, Luthra, Reid I, and Levason (Appeal 2021-001535, USSN 14/373,413), the PTAB was presented with the issue of the obviousness of an imaging agent comprising an 18F-labelled compound of a formula below, with the relevant moieties indicated. The main claim covered a moderate genus of compounds 1, and was rejected over a combination of three references. The PTAB noted that the rejection of the main claims was premised upon a primary reference which failed to describe the ligands at position Y 1 a...