The rapid progress of medical sciences has brought about novel effective medications, new techniques that make surgery less traumatic, artificial materials that serve to replace tissues and organs, and robotic prostheses. Still, treatment success is largely a question of timely and accurate diagnosis and proper patient monitoring. Here, various imaging techniques come in handy. Those are often thought of as tools for anatomy visualization, but in fact, they are often highly effective for the assessment of the functional state of organs and tissues. Imaging techniques are so diverse that it is impossible to cover them all in one review. Therefore, we have decided to touch upon the most common and interesting ones, such as ultrasound imaging, tomography, oximetry and fluorescence imaging.