A device and method for using X-rays to highlight soft-tissue parts in medical imaging are provided. The device may be implemented in radiotherapy equipment or used in radiotherapy. A control of the radiation dose needed for the therapy may involve phase-contrast imaging using X-rays to highlight soft-tissue parts. The result of the imaging by highlighting soft-tissue parts can be used for real-time and non-real-time planning of therapy and for adapting the treatment plan or the radiation dose. The radiation dose control may include anatomical imaging for locating tumours before, during and after irradiation and/or real-time adaptation of the treatment plan based on imaging that highlights soft-tissue parts. The positioning and arrangement of the combination of X-ray sources and detector in such a radiotherapy apparatus and of an accelerator may be independent of one another. The accelerator makes it possible to cover the entire body of the patient with X-rays.
