Inclusion Criteria:

- Patients must have histologic proof of a thoracic or abdominal malignancy, confirmed
at MSKCC and suitable for radiation therapy, in order to be eligible for this study.
Thoracic malignancies (study group 1) include those in lung and gastro-esophageal
junction. Abdominal malignancies (study group 2) include those in liver and pancreas.
Patients having both thoracic and abdominal malignancies will be placed in only one
of the study groups, because the limited field-of-view of the CBCT precludes imaging
of both malignancies in the same scan. Patients must be older than 18 years of age

- At least part of the tumor must be visible as observed in a diagnostic or planning
CT. The tumor must exhibit at least 5 mm motion from respiration as observed in the
respiration-correlated CT (RCCT) at simulation. The RCCT scan must be interpretable
and not exhibit excessive motion artifacts caused by irregular patient breathing.

- Patients must have Karnofsky Performance Status ≥ 70%

Exclusion Criteria:

- Mesothelioma and other tumors of the pleura

- Pregnant Women

- Allergic to iodine or intravenous contrast agent (applies only to patients with a
pancreas or liver malignancy)

- Renal impairment due to the use of a contrast agent

- Patients with pacemakers and defibrillators