Precautions for a lung CT include avoiding metal jewelry, wearing loose clothing as much as possible, and contraindications to the test. Lung CT is chest CT, which is a commonly used test to diagnose lesions of the chest wall, lung tissue, and chest cavity. 1. Avoid wearing metal jewelry: metal jewelry can cause artifacts in the CT image, which may affect the normal reading of the film, so metal jewelry should be avoided, and female patients should not wear metal bras. 2. Try to wear loose clothing: Wearing loose clothing is easy to put on and take off, which is convenient for examination operation. 3. Examination contraindications: preparation for pregnancy, pregnancy or suspected pregnancy, prohibit CT examination; in addition, due to the need for intravenous injection of iodine contrast agent for enhanced CT examination, which may cause allergies, renal function damage, etc., need to be clear before the examination of the injection of the contrast agent caused by the uncomfortable situation.