With the increase of people’s health awareness and the popularity of high-resolution CT, the detection rate of lung nodules is getting higher and higher, many people are confused when they see the chest CT report suggesting lung nodules, do I have lung cancer? What should I do? Which department should I consult? What is a lung nodule? Lung nodules are focal round dense shadows of various sizes with clear or blurred margins and a diameter of less than or equal to 3 cm on lung images. Causes of pulmonary nodules include: 1) Smoking. 2) Working in dusty jobs: Pulmonary nodules may form when the lungs inhale too much dust, which exceeds the lungs’ ability to clean themselves. 3) Infection of the lungs with germs: Tuberculosis, for example, can also manifest as pulmonary nodules. 4) Air pollution: Pulmonary nodules may form when you are in places with poor air quality for a long time. As observed by CT imaging, pulmonary nodules present in different states and are mainly classified according to density as: solid nodules, partially solid nodules (mixed nodules), and frosted glass nodules; frosted glass nodules are more typical and appear as cloudy pale shadows/round nodules with mildly increased density, looking like frosted glass. It can be a diffuse scattered growth or it can be clustered only locally and look like a small ground glass nodule. Are all lung nodules malignant? Most small pulmonary nodules are benign and may be the result of scarring after healing from a previous infection such as pneumonia, tuberculosis, or trauma. They may also be infected or non-infected granulomas, or benign tumors. However, some nodules are malignant, and some benign lung nodules may also become malignant. Early stage lung cancer is usually asymptomatic and tumor marker tests are not very helpful in detection. Low-dose CT can usually detect and show nodule features well, while ground glass density nodules can currently only be detected by low-dose CT. How are pulmonary nodules treated? Most of them can resolve on their own. Stable, asymptomatic small nodules may not require treatment for the time being, but regular imaging is necessary, and it is recommended to review chest CT at 6 months to 1 year. Note: ground glass nodules do not require an enhanced CT scan!!! Although many hospitals do routinely perform enhanced CT. Do I need PET/CT for lung nodules? PET-CT has its own indications. According to the guidelines, PET is not necessary for pure ground glass nodules or mixed ground glass nodules with a solid component of less than 6 mm. Solid nodules larger than 8 mm may be necessary. So if you have a ground glass nodule and your doctor suggests PET, you can say “no”! When a nodule is found in the lung, the treatment is determined mainly by the size and shape of the nodule. 1, nodules less than 5 mm is generally regarded as benign nodules, patients do not need to worry too much, benign nodules do not need special treatment, patients only need to regularly go to the hospital for lung CT examination can be. Benign nodules may disappear after a period of time. If the nodules are found to be larger with burrs on the edges after follow-up, malignancy is likely; 2. Nodules larger than 8mm may be malignant nodules, and patients should visit the oncology department or thoracic surgery department to further confirm the diagnosis through sputum cytology and fiberoptic bronchoscopy. If the test result is malignant nodules need to be treated by surgical resection or stereotactic radiation therapy to the chest (SBRT). More advanced malignant nodules need to be treated with a combination of oncologic treatments. There is no need to be overly anxious and fearful after finding nodules in the lungs, which are not necessarily lung cancer, but may also be other benign diseases, and it is recommended to follow medical advice for relevant treatment. It is recommended that patients should not be under too much pressure, wear a good mask in public places to avoid aggravation of the disease, and exercise more often to enhance immunity.