A method and an x-ray system are disclosed for detecting and localizing a metabolic marker. In at least one embodiment, the method includes creating at least one absorption x-ray view of a patient or of a first region of a patient; creating at least one phase-contrast x-ray view of the patient or of a second region of the patient, with a quasi-coherent x-ray radiation being generated for the phase-contrast measurement with the aid of an x-ray grating arranged between the x-ray source and the patient, and the spatially dependent phase shift of the x-ray radiation in the patient being made visible with the aid of at least one grating between the patient and a detector; superposing the at least one absorption x-ray view and the at least one phase-contrast x-ray view; wherein orientation based on anatomical features is carried out with the aid of the at least one absorption x-ray view, and a spatial distribution of the metabolic marker present in the body of the patient is determined by the at least one phase-contrast x-ray view.