 Following enrollment in the study, each subject will receive an initial placement of one or more geographically separate injections of India ink into the tissue of interest i.e., tumor andor tumor bed andor adjacent tissue using the established procedures for the injection of the ink. The subject is expected to agree to periodic measurements of all injection sites unless the ink injection has been surgically removed; the subject will be told to expect six or more visits for measurements during treatment, but must agree to have at least one measurement per injection site. Each measurement will typically consist of 3 ten minute consecutive periods during which the subject initially breathes room air, then 100 oxygen delivered through a non-rebreather face mask followed by a period breathing room air. 