Improved compounds have been developed which are structured to be sequestered with very high specificity in acidic areas of tissues. When the compounds contain a radioisotope effective to report the presence of the compound the compounds are for detecting tumors containing hypoxic/acidic areas. When the compounds contain radioisotopes effective to kill cells the compounds are for treating tumors containing hypoxic/acidic areas. Methods for detecting and treating tumors with such compounds are also disclosed.
