Lung nodules are round or round-like, high-density lesions with a diameter of less than 3 cm on chest radiographs or chest CT. Inflammatory lung nodules are nodules in the lungs caused by inflammation, with a maximum diameter of no more than 3 cm. Bacteria, tuberculosis, fungi and other pathogens can lead to infectious diseases of the lungs, causing inflammatory nodules in the lungs, the size of the nodule diameter varies greatly from one individual to another, and the diameter of the lesion can be more than 3cm, but when it exceeds 3cm, it is a lung mass rather than a nodule, and if it is limited to a nodule, the maximum diameter is not more than 3cm. Non-infectious factors can also lead to lung nodules, such as nodular disease for granulomatous inflammation, the disease caused by lung nodules, although most of the small nodules, the diameter of not more than 1cm. but in a few cases the diameter of the lesion is larger, and even more than 3cm, as mentioned above, from the concept of the once more than 3cm that is characterized as a mass, so non-infectious factors lead to the inflammation of the nodule diameter of the maximum diameter does not exceed 3cm.