PET-CT examination has a high accuracy rate. It can use radioactive elements to selectively localize certain tissues or organs and also to image functions, and it is mainly used to check whether there are tumors in various parts of the body, and it can further stage tumors and determine whether they are recurrent. However, the accuracy rate of any test is not 100%, and PET-CT is no exception. Therefore, no disease can be diagnosed by one test, and the doctor needs to combine the patient’s laboratory tests and other imaging tests to make a comprehensive judgment. It is up to the doctor to decide whether a patient needs a PET-CT test based on the patient’s specific condition, and it does not mean that everything will be fine once the PET-CT is done.