An X-ray of the chest is a safe and painless test to visualise the structures of the chest wall which includes the collar bone, breastbone, ribs, shoulder blade and surrounding muscles. It also helps to visualise the internal organs of the chest which includes the lungs, airways, heart, food pipe and diapragm. The image is recorded on a special X-ray film using small amount of radiation. The X-ray image is black and white. Dense structures such as the bones, appear white and softer body tissues, such as the skin and muscles appear darker. The actual exposure time to radiation is usually less than a second, although the overall test may take 15-20 minutes.