This is a randomized controlled trial. 80 patients with thoracic radiotherapy will be included. Participants will be randomly divided into experimental group or control group. Before radiotherapy, echocardiography, 2D STE, CK, CK-MB, cTnT, NT-proBNP, electrocardiogram (ECG), and hs-CRP will be detected. During subsequent follow-up, echocardiography, 2D STE, CK, CK-MB, cTnT, NT-proBNP, ECG, and hs-CRP will be collected at every follow-up time.

This is a randomized controlled trial. 80 patients with thoracic radiotherapy will be included in Peking University Third Hospital from May 15, 2021 to August 31, 2022. Participants will be randomly divided into experimental group or control group. Before radiotherapy, echocardiography, 2D STE, CK, CK-MB, cTnT, NT-proBNP, electrocardiogram (ECG), and hs-CRP will be detected. All participants will be followed up after completion of RT, 3 months after RT, 6 months after RT, and 12 months after RT. During subsequent follow-up, echocardiography, 2D STE, CK, CK-MB, cTnT, NT-proBNP, ECG, and hs-CRP will be collected at every follow-up time.

Inclusion Criteria:

• lung tumor patients; 18-80 years old; will be treated by stereotactic body radiotherapy

Exclusion Criteria:

• Prior radiotherapy; ACS; heart failure (NYHA III-IV); arrhythmia requiring intervention; echocardiographic images that could not be satisfactorily obtained; significant valvular heart disease (defined as more than mild valvular regurgitation or stenosis).