[Oncological imaging for therapy response assessment]

This review illustrates different radiological methods for therapy response assessment in the field of oncological imaging. Unidimensional measurement of tumor size according to the response evaluation criteria in solid tumors (RECIST) is of utmost importance. The established RECIST definitions of changes in size are decisive for subdivision into the categories complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD), which are generally accepted as the concise characterization for therapy response. Problems with size-dependent response assessment occur particularly in targeted therapy and by phenomena, such as pseudoprogression. Several variants of functional imaging and their role in cancer imaging regarding practical requests are introduced.