Local soft tissue infiltration is the slow infiltration of fluid into soft tissue, the infiltration of abnormal cells into human tissue or the appearance of body cells that should not appear under normal circumstances, and the expansion of certain diseased tissue into the surrounding area. So, what is the process of CT examination when a patient has symptoms of local soft tissue infiltration? The following is a brief introduction: 1, drug intravenous injection: according to the different purposes of the examination, the use of different imaging agents. After injection, please rest quietly, do not talk to people, and avoid tense body position. The waiting time after injection is different for different examination items (basically more than 40 minutes). 2.Empty urine before PET/CT examination (for tumor screening) to avoid urine contamination of body surface and clothes. 3.During the PET/CT examination of the body, both arms need to be raised, and the examination time is usually about 20 minutes; the brain examination does not require both arms to be raised, and the examination time is usually about 10 minutes. Usually, family members are not allowed to enter the scanning room during the scanning process. 4. When the examination is completed, the doctor on duty will observe whether the image quality meets the requirements and notify the patient to leave after approval; depending on the condition, some patients may need delayed imaging or CT-enhanced scanning, and an informed consent form must be signed before CT-enhanced examination.