Sci‐PM Fri ‐ 03: Potential use of diffusion theory for quantitative in vivo fluorescence and bioluminescence imaging

In recent years, there has been increasing interest in the potential of optical methods to detect and monitor in vivo minimal residual disease and metastasis in animal cancer models. The overall objective of the present work is to develop analytical methods and instrumentation to construct quantitative bioluminescence and fluorescence images of bone metastases. The diffusion approximation was investigated as a mathematical model of light propagation in tissue. Testing of the model against Monte Carlo simulation data showed that the optical properties could be retrieved from a reflectance curve with an accuracy of better than 2%. The evaluation of the model was also performed on liquid tissue‐simulating phantoms by using the tip of an optical fiber to simulate a point source. A charge‐coupled device (CCD) camera was used to acquire images of the surface of the phantom with the point source inserted at different depths. In addition, a non‐invasive measurement of the optical properties of the phantom was performed. Results showed that, for the depth ranges where diffusion theory was expected to be valid, the depth could be reconstructed with 15% accuracy and the fitted relative intensities of the source were consistent to expected values within 30%.