CT generally refers to CT examination, CT examination is examined by parts, can check several parts at the same time. CT examination is a more advanced clinical medical imaging technology, which can be applied to any part of the body at the same time, including the diagnosis and differential diagnosis of lesions in several organs such as head, neck, chest, spine and limbs, etc. The purpose of CT examination is to help patients better diagnose the causes of diseases as well as tissue structure abnormalities. The purpose of CT examination is to help patients better diagnose the disease, understand the cause of the disease, the location of the disease and tissue structure abnormalities, etc., which provides a strong basis for subsequent treatment by doctors. The principle is to use X-rays to scan the patient’s body structure. After the scanning, the computer will convert the scanning information into image information for output, and then the radiologist will issue a diagnostic report. After an enhanced CT examination, a very small number of patients may experience adverse reactions such as hives and rashes. CT examinations are prohibited for pregnant women, people with iodine allergy, and during iodine restriction therapy for hyperthyroidism. If a patient has an adverse reaction such as rash after a CT, inform the doctor promptly and treat under the doctor’s guidance.