Apart from ultrasound, what is the other type of wave that can be used to look inside the human body?

Apart from ultrasound, X-rays are another type of wave that can be used to look inside the human body. X-rays are a type of electromagnetic radiation, like light or radio waves, but are more energetic, so they can penetrate many materials to varying degrees. When X-rays are used for medical imaging, they are transmitted through the body and captured on the other side to create an image. The different tissues in the body absorb X-rays to different extents. For example, bones absorb much of the X-ray radiation and appear white on the image, while softer tissues absorb less and appear darker. This allows doctors to see inside the body without needing to make an incision.