Radiation Therapy and Cardiac Enzymes

1. A total of thirty patients will be prospectively enrolled in this study. Patients with tumors in the chest including histologically proven primary lung cancer, esophageal cancer, thymoma or mesothelioma to be treated with RT with or without concurrent chemotherapy to a final dose of \>/=45 Gy will be included in this study. 2. Patients with tumors in close proximity to the heart where the treating radiation oncologist anticipates the mean cardiac dose will exceed 20Gy. 3. All patients must sign a study-specific informed consent form. If the patient's mental status precludes his/her giving informed consent, written informed consent may be given by the patient's legal representative. 4. Age \>/= 18 5. Women of childbearing potential (A woman of child-bearing potential is a sexually mature woman who has not undergone a hysterectomy or who has not been naturally postmenopausal for at least 24 consecutive months \[i.e., who has had menses at any time in the preceding 24 consecutive months\]. For women of childbearing potential, a blood pregnancy test must be performed within 72 hours prior to the start of protocol treatment.

1. Patients who receive 5-fluorouracil or adriamycin as part of their chemotherapy regimen. 2. Patients with recent myocardial infarction in the past month, decompensated heart failure or myocarditis/pericarditis in the past month 3. Patients with renal failure indicated by a serum creatinine level of \>/= 2.0. 4. Patients in the intensive care unite (ICU). 5. Patients with systemic sepsis. 6. Patients with acute pulmonary embolism in the past month. 7. Women who are pregnant or nursing are not eligible as treatment involves unforeseeable risks to the fetus or child. 8. Inability to obtain histologic proof of malignancy.