Breast cancer is one of the malignant tumors that can reduce the mortality rate through screening. The most effective screening method is to have regular mammograms, and both breasts should be examined at the same time. This is because the breast mainly consists of three parts: breast ducts, glands and interstitium (including fibrous tissue, fat, blood vessels and lymphatic vessels), and the ratio of these three components is affected by various factors such as age, breast development, nutritional status, menstrual cycle, pregnancy, breastfeeding and endocrine, and their imaging performance varies. The respective mammary glands should be compared bilaterally to detect small asymmetries and fine calcified foci to facilitate the diagnosis of early breast lesions. However, in practice, people often find such a misunderstanding: due to economic considerations or lack of awareness, many people, including some doctors in accordance with the “headache doctor, foot pain doctor ” misconceptions, only to the symptomatic side of the breast to do the examination, while completely ignoring the other side. The aforementioned Ms. Li, who was hospitalized for surgery for a left breast lump, would not have found a cluster of sediment-like calcifications in the right breast if her doctor had not insisted that she do a bilateral breast examination. Because the calcification in Ms. Li’s right breast was not palpable, preoperative guidewire localization was done under x-ray mammography guidance, which guided the surgeon to accurately remove the calcified foci. Fortunately, the lesion in her right breast was an intraductal carcinoma, which is an early stage breast cancer, and only a local excision was needed, and no radiation or chemotherapy was required. As a result, she was able to save her breast, reduce her pain, and ensure her future quality of life. If this patient stubbornly insisted on having a mammogram on only one side of the lump, the lesion in the right breast would have continued to grow, and when the lump was palpable or the calcification was more extensive, the best time for treatment would have been missed. Breast cancer is not scary, the key is early detection, early diagnosis and thus early treatment. Patients with early stage cancer and microscopic cancer can receive breast-conserving surgery, which can improve the quality of women’s survival. She recommends that symptomatic women should have regular bilateral mammograms every year to ensure that breast cancer can be detected at an early stage, so that early measures can be taken to eliminate future problems.