This study is being done to see how long [18F]-SKI-249380 stays in the blood, when it is given to people in tiny amounts by an injection into a vein in their arm, and to see where [18F]-SKI-249380 goes in the body. If the results of this trial are good, then the study doctors plan to use [18F]-SKI-249380 in another trial to see if scans with [18F]-SKI-249380 are better for finding tumors compared to the standard types of scans that doctors use.