X-rays and CT scans—also called CAT scanning—are non-invasive medical exams that help doctors to diagnose certain medical conditions. Doctors will usually start with an x-ray to view the inside of the chest, including the lungs and internal organs. If the x-ray comes back abnormal or inconclusive, a CT scan will generally be ordered as the next step to try and diagnose the condition or abnormality. CT scans use special x-ray equipment to produce multiple images of the inside of the body. From this, the internal organs, bones, tissue and vessels can be viewed with better clarity leading to an accurate diagnosis.