Diffused optical tomography using oxygen-sensitive luminescent contrast agent

We present results of diffused phosphorescence lifetime tomography performed on tissue-simulating phantoms for high contrast imaging of hypoxic breast tumors. Oxygen sensitive phosphor embedded in a versatile nanoparticle matrix was used as contrast agent to identify simulated hypoxic tumors in phantoms. The surface of these nanoparticles was decorated with F3 peptide that targets cell surface receptors that is often overexpressed in aggressive breast tumors. The surface functionalization did not interfere with the embedded phosphor´s characteristics. The phosphorescence intensity and lifetime was measured using single photon sensitive multi-pixel photon counting (MPPC) detectors in box-car geometry. The detection technique has a large dynamic range, high sensitivity and good resolution in oxygen concentration.