Measuring changes in human tumour vasculature in response to therapy usingfunctional imaging techniques

Antiangiogenic and antivascular agents provide new approaches to treating t umours. These may avoid many of the problems experienced with current appro aches such as inherent and acquired resistance to treatment. Tumours do not grow beyond 1-2 mm(3) in size without the development of new vessels (Folk man, 1971). Such neo-vascularization (angiogenesis) allows tumour cells to increase their nutrient supply, survive and proliferate despite the new ves sels often having structural and functional differences compared to normal tissue vasculature. Treatments targeted at tumour vasculature have produced impressive results in animal models (Lindsay et al, 1996; Watson et al, 19 96; O'Reilly, 1997; Horsman et al, 1998). These therapies are now entering clinical trials, However, the successful introduction of these therapies in to clinical practice will require the development of reliable ways to asses s angiogenesis and its modification or inhibition in vivo. Here we discuss some of the emerging imaging techniques that may be useful. (C) 2001 Cancer Research Campaign.