The difference between Lurads 3 and Lurads 2 is that Lurads 3 is an uncharacterized nodule and Lurads 2 is a benign nodule. The acronym LU-RADS refers to a method of categorizing low-dose CT scans of the lungs that reveal lung nodules. They can be categorized into the following 6 categories. Category 1 nodules are those that are absent or are benign. category 2 nodules are benign; category 3 nodules are uncharacterized nodules but are considered more likely to be benign; category 4A nodules are considered malignant. category 5 nodules are those where CT suggests that a malignant nodule is a possibility; and category 6 nodules are those that are histologically confirmed to be malignant. The higher the classification, the more malignant the nodule. Lurads2 nodules can be screened with LDCT once a year, Lurads3 nodules, if <1cm nodule, need to do 3 months follow-up, if the condition is stable you can do 6 months as well as 1 year review, if >1cm nodule, the first follow-up needs to be 1-2 months review, if there is no change you can do another review after 6 months. In addition, the diagnosis of lung shadow needs comprehensive examination and judgment, and it cannot be clearly diagnosed by imaging alone. Therefore, it is recommended to go to the hospital and actively cooperate with the relevant examinations and treatments under the guidance of the physician, so as to avoid delaying the condition.