A small nodule of 4mm in the lung is not a problem. If it is an isolated nodule and there is only one nodule, regular chest CT examinations are sufficient. If there is no cough or sputum, no fever, etc., no treatment can be given, and if there is no change in the nodule, the CT chest can be reviewed after 6 months or even a year. If the nodules shrink significantly, inflammatory nodules will be considered. If the nodules increase in size and are larger than 8mm, lung nodule aspiration is recommended to rule out lung cancer or tumors from other organs metastasizing to the lungs.