Delta-like ligand 3 (DLL3) has emerged as a promising target for imaging and therapeutic interventions because of its heightened expression in specific neuroendocrine cancers and its low expression in healthy tissues.1 In The Lancet Oncology, Salomon Tendler and colleagues2 report a pivotal milestone: the pioneering use of immunoPET imaging to visualise DLL3 expression in patients with neuroendocrine cancer, such as small-cell lung cancer (SCLC) and neuroendocrine prostate cancer. This research is notable for its scientific novelty and the potential to improve patient outcomes, enhance treatment effectiveness, and minimise treatment-related toxicity.