Most of the time scintigraphy is used for orthopaedic examinations.

Therefore, horses get a radioactive (Tc99) injection which get concentrated in the skeleton.

For being able to see this parts a Gamma-Camera is used to create a picture out of the radiation. 

For instance an increased metabolism causes by an inflammation can get viewable through an intensive colouring. These parts are called hot-spots.

Moreover, the method makes areas viewable which are conventionally not or only difficult accessible like the head, back or bowel.