DSA, medically called digital subtraction angiography, mainly injects contrast into the patient’s veins and arteries separately to visualize the vessels so that the doctor can determine the disease based on the changes in the distribution, morphology, and location of the vessels, and can perform interventional treatment via catheter. It can be used clinically for the examination and treatment of blood vessels in the heart, large blood vessels, head and neck, abdomen and limbs. In addition, DSA can also be used for interventional radiotherapy.1. Cardiac vessels: the morphology of each atrium of the heart and the thickness of the heart wall can be observed, and its motility, volume and blood displacement can be measured, which can detect some cardiac malformation diseases and determine the location and size of some tumors and thrombi.2. Thoracic vessels: the calcium spots of the arterial wall, the degree of expansion and elongation of the artery itself and the thickness of the lumen can be detected, and the site and size of aortic aneurysms can also be determined. The location, size and shape of the aortic aneurysm and the presence of thrombus within the aneurysm can be determined. In the case of pulmonary artery embolism, interruption of the vessel, intra-luminal clot, filling defect in the parenchymal phase of the lung and contrast reversal can be observed. 3. Head and neck vessels: The neck vessels can be seen in the site, degree and extent of carotid artery stenosis and the presence of thrombus, and the size and shape of the thyroid gland and the presence of tumors and nodules can also be observed. Intracranial vascular diseases such as aneurysms, arteriovenous malformations and arteriovenous fistulas can be diagnosed from the DSA images. Intracranial occupying lesions can be shown by DSA with displacement of blood vessels and tumor staining. 4. abdomen and limbs: renal artery stenosis and blood supply of intrarenal tumors can be observed, and the vascular conditions of liver, spleen, abdominal cavity and limbs can be well displayed. 5. interventional radiotherapy: DSA can also be used for interventional treatments such as angioplasty, embolization and drug perfusion.