Currently, doctors can overlay the results of PET and CT scans performed separately to identify and locate tumors. However, because a patient may not be positioned identically for both scans, the two images can be difficult to line up exactly, degrading the accuracy of the diagnostic information. The combined PET/CT machine allows doctors to rapidly perform both scans in one session without having to move the patient. This means doctors can precisely overlay the metabolic data of the PET scan and the detailed anatomic data of the CT scan to pinpoint the location and stage of tumors.