This study will look at how tumors in the chest and abdomen move when you breathe. Your doctors are studying if extra 4D CT scans and instructions on how to breathe can help predict this type of movement and improve the accuracy of radiation treatment. 4D CT scans are approved by the FDA. A 4D CT scan is different from a regular CT because it moves slower and takes more pictures. It takes pictures of the way your body moves when you breathe. This gives doctors more pictures of your body so that they can match your pictures to the way you breathe.