Prospective Study on Radiation Induced Cardiotoxicity Assessed By PET-CT for Locally Advanced Non-Small Cell Lung Cancer (NSCLC)

1. Age ≥ 18 at time of consent 2. Ability to provide written informed consent and HIPAA authorization 3. Stage III NSCLC per AJCC 8th edition guideline, confirmed by pathological diagnosis and PET/CT. 4. To receive standard definitive concurrent chemoradiation therapy per NCCN guidelines. 5. Tumor estimated to be within 2cm of heart contour or anticipated MHD\>10Gy per treating physician.

1. Patients treated with stereotactic body radiotherapy (SBRT). 2. Prior thoracic radiotherapy. Exclusion for Coronary computed tomography angiography (CCTA) 1. History of a severe anaphylactic reaction to iodinated contrast. 2. Renal insufficiency (defined as estimated CrCl less than 30 mL/min). 3. Inability to hold breath for more than 5 seconds. 4. Patients on radioactive iodine therapy. Exclusion for 18F-Flurpiridaz PET/CT Test 1. Second-degree AV block, third-degree AV block, and sinus node disease (such as sick sinus syndrome or symptomatic bradycardia) without a functioning pacemaker. Note: Resting 12-lead EKG will be ordered at the time of enrollment to be performed prior to PET/CT stress test. 2. Patients with bronchospastic diseases including asthma and chronic obstructive pulmonary disease (COPD) who have an acute exacerbation or active wheezing (a high-pitched, musical, adventitious lung sound produced by airflow through the narrowed airways) on the day of PET CT exam. 3. Patients who are hypotensive (systolic blood pressure less than 90 mm Hg) on the day of the PET/CT scan.