Small nodular foci in the lower lobe of the right lung are found under chest CT examination. The high-density shadow located in the right lower lung is considered to be an old lesion, which may be left over from previous inflammation or tuberculosis that has been treated or cured by autoimmunity. At this time, it is necessary to observe the size of the diameter of the nodule, the smoothness of the margins, the presence of lobulation, burr-like, bronchial inflation signs, pleural traction signs, etc., which are all signs of malignant nodules. If the nodule is less than 5mm in diameter and has smooth edges, it is generally considered a benign nodule and can be reviewed by chest CT after one year. if the nodule is larger than 1cm, it is generally not called a small pulmonary nodule, and further surgical examination is needed to see if surgical extraction of pathological tissue is required for further examination.