Professor Röntgen, can you help me? This book clearly illustrates how doctors can obtain images from inside the body today: using X-rays, radio waves in magnetic resonance imaging, sound waves in ultrasound, and radioactively labeled substances in nuclear medicine. Modern imaging allows us to represent entirely new realities and, thanks to modern physics, to look inside people in ways that differ from what our eyes can see. This enables us to depict various densities of tissue in the human body, visualize the magnetic properties of different organs, and illustrate glucose metabolism or brain changes in Alzheimer's disease. In addition to clearly presenting fundamental physical principles, it also explains which procedure is best suited for the most common diseases at what point in time.