Tumor angiogenesis targeting using imaging agents

The inhibition of tumor induced angiogenesis is an emerging therapeutic str ategy in clinical oncology aimed at halting cancer progression by suppressi ng tumor blood supply. As anti-angiogenic therapy is primarily cytostatic a nd not cytotoxic, the established criteria for assessing tumor response to chemo- and radiotherapy cannot be applied to anti-angiogenic therapy. There fore, functional and molecular parameters for imaging of tumor angiogenesis are being intensively studied. Computed tomography, magnetic resonance ima ging, ultrasound and scintigraphic techniques can assess changes in vascula r permeability and tumor blood now during anti-angiogenic therapy. Scintigr aphic techniques, especially positron emission tomography (PET), may be use d to monitor the consequences of anti-angiogenic therapy on tumor cell meta bolism, proliferation and apoptosis. The high sensitivity of PET which allo ws measurements of tracer concentrations in the picomolar range is promisin g for the visualization of specific molecular targets prior to therapy thus identifying patients most likely benefit from a particular form of anti-an giogenic therapy.