There is a large body of evidence suggesting that blood ¡ and oxygenation of human tumors
ate important research topics which may explain, in particular, resistance to radiation and to many antineo-
plastic drugs, which can limit the curability of solid tumors by radiotherapy and chemotherapy. This manus-
cirpt reviews the clinical investigations which have been perforrned regarding blood flow and oxygenation
status of human tumors in radiation oncology