The increased use of advanced technologies generating new data and information, including algorithmic technologies and AI, has led to a renewed interest in the role of technologies in knowledge work. Some of these technologies act as epistemic technologies, a term derived from the work of Knorr Cetina on how sciences make knowledge. While previous studies provide important insights into how the outcomes of the technologies are used in expert work, the work needed to produce the outcomes in the first place is often overlooked and separated from use. The generation of new data and information is instead treated as both black-boxed and decontextualized. To highlight the work required to generate meaningful outcomes, and address the challenges posed by opaque algorithms, we present a longitudinal in-depth study of the medical imaging technologies of the Robotic X-ray and iMRI, used in combination with surgery. The study illustrates how technologies become epistemic through use: new data was produced by means of interactions within a relational and heterogeneous assemblage of people, technologies and devices. Through trained judgement, the experts made the data useful and possible to act upon in each specific situation. The study contributes to research into the use of algorithmic technologies in knowledge work by showing how opaque algorithms can be complemented by contextualized information, making it possible to interrogate and make trained judgements, in relation not only to outcomes, but also to their production. We conclude that epistemic technologies are involved in the ongoing construction of knowledge, during both the production and use of outcomes, and that enacting the technologies as epistemic includes a situational and material awareness. © The Author(s) 2025.