Emission‐guided radiation therapy entails the use of radiation emitted by molecular imaging probes (SPECT for PET) to guide delivery directly, thus avoiding the need to wait for long acquisition times to collect sufficient count statistics. The potential of biological targeting in radiation treatment planning, taking advantage of advanced molecular imaging techniques in the form of hybrid SPECT/CT, PET/CT, or PET/MRI systems, is well established. The last three decades have witnessed abundant contributions indicative of the advantages of multiparametric molecular imaging in this framework. Ultimately, molecular imaging‐guided radiation therapy planning holds the promise of improved delineation of target volumes even in the presence of significant motion. Yet, despite significant advances to date, challenges remain limiting exploitation of the potential of this technology in the clinic to academic facilities with advanced technical support. Fortunately, these limitations are not preventing novel exciting developments to emerge with the aim to further boost the incorporation of multimodality imaging in the process of radiation therapy planning for various indications. In this regard, the conceptual basis of using on‐board PET to guide the radiation treatment process has been around since 2010. A small company based in the US (RefleXion Medical, Hayward, CA) pioneered the development of a device enabling commercial implementation of one approach to biologically guided radiation therapy. The product was displayed for the first time at the last ASTRO 2018 annual meeting. While some think that this is relevant technology that should soon be adopted for use in the clinic, others think that the concept is still in its infancy and not mature enough for clinical adoption. This is the topic addressed in this month's Point/Counterpoint debate.