This image is also known as a KUB (kidneys, ureters, bladder). It is a common imaging test and you should become familiar with its normal appearance. As you have seen in prior radiographs, the tissue boundaries will be identified by differences in the density of adjacent tissue. In the abdomen, often it is the adipose tissue that surrounds an organ which helps to define its boundaries. This image was obtained to ascertain the location of a swallowed pin.