Advantages and disadvantages of breast ultrasound Advantages: 1. For areas where X-ray molybdenum and palladium irradiation techniques are difficult or impossible to illuminate. (e.g. breast margins, internal breast area, tumors located deep near the chest wall and small dysplastic mammary glands, etc.). 2.The identification of cystic or solid masses in the breast is better than any examination method. 3.High resolution of high frequency probe can find 0,3-0,5cm tiny masses and 0,1-1,0mm microcalcification foci. 4.While examining the breast, it can also observe whether there are metastatic lymph nodes in the axilla and supraclavicular fossa on the same side of the lesion. Diagnostic ability of ultrasound for breast diseases: it can detect 2-3mm cystic lesions; 3-4mm substantial lesions; it can show 1mm ductal structures and lesions in the milk ducts; it can show microcalcified foci within breast cancer; it can detect enlarged lymph nodes in the parasternal, axillary, supraclavicular and cervical areas. Disadvantages: 1.It is difficult to diagnose the tiny masses <0 or 5 cm, especially those in hyperplastic glands, which are easily misdiagnosed as hyperplastic nodules or missed. 2.It is still difficult to differentiate inflammatory masses in the breast from inflammatory breast cancer. 3.It is not clear for very tiny fine sandy or punctate calcification. Defects: 1.Low sensitivity in detecting tiny calcified foci in the breast, which makes some early breast cancers missed. 2. Poor diagnostic specificity for <1cm masses. Mammography - The commonly used method is mammography: 1. The radiation dose is <0.01gy, and the risk of cancer is close to the natural incidence. 2. The X-ray of breast cancer shows a swollen fast shadow of increased density with irregular border or burr sign. 3.X-ray of breast cancer sometimes shows calcified spots with fine and dense particles. 4.When there are more than 15 calcification points per square centimeter, the possibility of breast cancer is high.