It is important to have a small nodule in the thyroid gland. When a nodule appears in the thyroid gland, regardless of the size or number of nodules, it is necessary to come to the hospital for examination because there is a possibility of thyroid cancer, also known as malignant nodules. Often, multiple nodules suggest a higher likelihood of benign, while single nodules may be malignant, but ultrasound or fine needle aspiration pathology examination prevails. If ultrasound reveals hypoechoic nodules, unclear borders, internal calcifications, aspect ratio greater than one, or even abnormal blood flow signals around the nodules, it is usually indicated as malignant nodules, that is, thyroid cancer. If the ultrasound cannot confirm the benignity or malignancy, a small amount of tissue can be taken by fine needle aspiration for pathological examination to further clarify.