Photoacoustic tomography assessment of vascular targeted therapy to determine vessel regrowth following treatment

Photoacoustic tomography (PAT) is ideally suited to image tissue vasculature and is therefore able to provide functional response data for the pharmacodynamic time course of vascular targeted therapies. We show in a preclinical model of colorectal carcinoma that 40mg/kg of the vascular disrupting agent OXi4503 causes central tumour blood vessel destruction that can be assessed by PAT at 48 hours. This is confirmed with histological haematoxylin and eosin staining. Outward growth of solid tumours is then static until 16 days post-dose whilst vessel regrowth occurs inwardly to repopulate the necrotic core.