This study has two primary objectives. The first objective is to determine the maximal tolerated dose (MTD) that can be delivered with stereotactic radiosurgery in patients with inoperable malignant lung tumors. Once the MTD is established, the second objective is to determine the efficacy of radiosurgical ablation of lung tumors in terms of symptoms and radiographic responses.

Inclusion Criteria:1.Lung tumor >= 5.0 cm.

2.Age > 18 years,

3.Histologic confirmation of malignancy (primary lung or metastatic tumor)

4.Deemed unresectable either by radiographic criteria (such as direct invasion of the mediastinum, heart, great vessels, or trachea), by virtue of excessive risk to patient, patient refusal to undergo surgery, or prior operative findings.

5.Performance status of 0-2 by Eastern Clinical Oncology Group criteria Exclusion Criteria:1. No chemotherapy within 2 weeks of radiation treatment.

2. Refusal to sign informed consent.

3. Refusal to take a pregnancy test prior to treatment if the patient is a woman with child bearing potential.