Assess the Feasibility of Cone Beam CT to Localize Liver Metastases Immediately Prior to Radiotherapy

The purpose of this study is to test a new and possibly more accurate method of positioning patients with liver tumors in preparation for radiation treatment. The positioning of patients with liver cancer is important because the tumor moves a bit when you breathe and makes it hard to determine the right position of the tumor at the time of treatment. Also, depending upon what is in your stomach at the time of treatment, it may change the shape of the liver and make it difficult to plan the radiation treatment. As part of this study, we will take a new type of image of your liver in addition to the standard portal images. This new type of image is called a cone-beam image. It shows a much more detailed picture of the liver tumors than the standard portal images. Normally, marker seeds need to be placed near the liver metastasis for radiation treatment. If the results of this study show that the tumor can be positioned as accurately with the new images as with the old images, then future patients with liver tumors would not have to have marker seeds placed into their liver. The use of cone beam imaging for the setup of patients with liver tumors is new.