AI-Assisted Management of Pulmonary Nodules Found on Low-Dose CT in Health Screening

Inclusion Criteria:

* Age 18 years or older.
* Undergoing chest low-dose computed tomography at a participating health examination branch during the study recruitment period.
* At least one pulmonary nodule is identified on the index LDCT and requires risk stratification and a management decision regarding follow-up, repeat imaging, or specialist evaluation.
* Thin-section reconstructed images are of sufficient quality for clinical interpretation and, where applicable, AI analysis.
* Required clinical risk information is available, including age, sex, smoking history, history of malignancy, family history of lung cancer, and available prior chest imaging.
* Included under the ethics committee-approved consent, simplified notification, waiver, and/or opt-out process, with no documented refusal of research data use.

Exclusion Criteria:

* Previously diagnosed lung cancer or currently receiving lung cancer-related treatment.
* Known pulmonary metastasis from another malignancy.
* Imaging findings that clearly require immediate entry into a lung cancer specialty diagnostic or treatment pathway and are not appropriate for routine pulmonary nodule risk-stratified management.
* An urgent thoracic condition requiring immediate management, such as pneumothorax, large pleural effusion, or acute pulmonary embolism.
* Severe imaging artifact, incompatible slice thickness or reconstruction, or a lesion type, imaging parameter, or disease extent outside the prespecified locked scope of the AI system.
* Previous enrollment in this study.
* Explicit refusal of research data use, or another reason judged by the investigator to make inclusion inappropriate.