In fact, for the breast, both tests are necessary. Ultrasound, as a non-invasive test, is inexpensive and cost-effective, so we all use it as a medical checkup. The point of ultrasound is that it is very sensitive and effective in finding breast lumps; mammogram is the opposite, it has radiation, but its dose is very low, so it can be done once a year as a medical checkup. That is also understandable. The role of mammography is to detect calcified foci, because some tumors do not start with a mass, but with calcified foci, so we emphasize to do it together for women over 35 years old; for those under 35 years old, it usually depends on the situation, such as family history and the specific situation of the mass. In any case, the first choice is definitely ultrasound. There is no such thing as who is better than who between the two, because the focus of the two examinations is different!