New contrast agent and molecular imaging method: Gold nanoroad detection using diffusion reflection measurements

Tissues are physically characterized by their optical parameters. The optical properties of a human tissue reflect the composition and the physiological state of the tissue. Most opticalphysiological diagnoses are based on the insertion of light, with known parameters, to a tested tissue, followed by the measurement of the reflected, transmitted or absorbed light. Changes in the optical properties of this light such as its spectrum, polarization and intensity, compared to the injected light, result from interactions of the irradiated light with the tissue's components. Gold nanoparticles (GNP) have long been used in the detection and imaging of biological processes and diseases as main contrast agents. In the talk I will present a new, simple and very sensitive method for cancer detection based on diffusion reflection (DR) measurements of gold nanorods (GNR). We specifically used GNR since GNR exhibit unique absorption properties in the near infrared (NIR) region, where light penetration through the tissues is relatively high (up to a few centimeters). The new method eliminates the noise of the regular molecular imaging method using GNP. Our intensity-based DR measurements have proven to be a successful tool for the detection of Head and Neck cancer (HNC), which is a subcutaneous tumor. Now we extend our method by the use of the frequency domain photon migration (FDPM) method for deep GNR imaging. By using this new method we create "standard operating procedures" (SOP) using DR technology and GNR, for medical non-invasive applications that can be used with monoclonal antibodies for specific targeting to the cancer cell receptors. By this method tumor margins can be detected. We actually developed a new method for real-time intraoperative tumor margin detection.