Until today, X-ray based imaging modalities play a central role in medical care. They are primary touchpoints in cancer detection and trauma diagnosis, guide physicians through interventional procedures like surgical operations, cardiac catheterization, or radiotherapy, and support the medical follow-up after disease treatment. In this presentation, we provide an overview of the clinical applications and discuss the resulting requirements for the X-ray imaging chain of the various modalities. We set a special spotlight on innovative detector technologies and detection methods with potential of future use in commercial devices, such as the recently released photon counting technology for Computed Tomography.