Effect of refraction on dose reconstruction in optical-CT gel dosimetry

We address the problem of dose reconstruction based on limited experimentally accessible data due to the effect of refraction in optical-CT gel dosimetry. The refractive index mismatch between the components of the optical-CT scanner result in light scattering and ultimately in the inability to capture parts of the projection datasets. We determine the maximum loss of data and the corresponding refractive index mismatch for which accurate dose reconstruction in the central part of the phantom is still possible. Also, a mathematical formalism that indicates how exact reconstructions can be obtained using a priori knowledge of the optical attenuation coefficient of the gel is presented. This study establishes rigorous design principles for accurate 3D dose reconstruction.