Small nodule foci indicate the occurrence of nodules and masses in the body, but the nodules are relatively small, such as thyroid nodules, breast nodules, liver nodules, and lung nodules, etc. Small nodules do not indicate that the nodules are benign, but may also be malignant, and further clarification is needed with ultrasound or CT. If a thyroid nodule is found to be hypoechoic, with unclear borders, aspect ratio >1, internal pitting calcification, or even abnormal blood flow signal, it is suggested to be thyroid cancer. ＜A nodule of <1 cm suggests a microscopic cancer. For the treatment of thyroid cancer, if the nodule is suspected to be malignant by ultrasound, radical nail cancer surgery is required, and pathological examination is sent for further clarification during the surgery. If the pathology confirms that it is thyroid cancer, lymph node dissection in the central region is also required.