Phantom experimentation on infrared and optical tomography

Accurate reconstruction of abnormalities inside biological tissues based on the detected temperature distribution presents a major challenge in emission thermography. The present study focuses on the relationship between the physical characteristics, such as the location and the emission power, of an embedded heat source inside an absorbing medium and the measured temperature distribution on the surface by means of infrared imaging. A phantom capable of emitting thermal radiation was constructed with temperature controlled resistance heaters and projections were obtained with an infrared-thermal camera system. The phantom was immersed in different density agar-composed absorbing media and its selected temperature scale was mammal´s core temperatures (35⁰-40⁰C). The planar information was further analyzed to reconstruct the tomographic images and from them the final 3D image of the phantom. The reconstruction procedure was performed with iterative algorithms (MLEM and accelerated ART). In order to investigate scattering and absorption effects, the same reconstruction procedure has been applied to optical (fluorescence) tomography with appropriately constructed phantoms. Reconstructions results are presented in this study for different phantom depth locations and heat generation rates.