Various new specific therapies target tumour vasculature or tumour neoangiogenesis. It is not uncommon that these targeted therapies have pronounced cytostatic and not predominantly cytotoxic effects. This limits the usefulness of size-based morphological tumour response assessments. Of newer CT or magnetic resonance imaging (MRI) modalities, perfusion has emerged as valid marker of tumour-induced blood vessels and their function. Perfusion measures the vascularity within a tumour, as well as its component heterogeneous parts. Of parameters which can be measured to date, blood volume and permeability are commonly applied in patient studies. Blood volume measures the aggregate size of the vascular space, while the permeability function informs about the integrity of vessels and their ‚leakiness' to contrast agents. We will describe the use of MR perfusion to monitor new targeted therapies and discuss its advantages and disadvantages in comparison with CT perfusion protocols. Ultrasound as an alternate modality for perfusion assessment will be briefly presented. PET strategies for treatment-monitoring will be mentioned, with prospect on the role of combined vascular and metabolic imaging to further optimise non-invasive response assessment in specific anticancer therapies.