Medical Thermal Tomography—Different Approaches

Thermal tomography is a new tool in medical diagnosis. It is based on so-called cold provocation. It is practically realized be a weak cooling of an upper layer of the skin. As it is noninvasive and harmless it can be applied as a screening procedure and repeated frequently. Using thermographic camera, the temperature recovery of the skin in time is measured and analyzed. In this chapter, three new methods of thermal tomography are presented. First, one is based on the analysis in time domain. The temperature versus time is approximated by the function which is a combination of exponential and error functions. The chosen parameters of this approximation that can be interpreted as the time constants are used then to visualize the blood vessels. The second approach uses the thermal modeling of the multilayer skin structure. The inverse thermal problem in frequency domain is solved to estimate the thermal parameters of each layer of the skin, including perfusion. The last procedure uses the wavelet transform (WT) to convert the large sequence of thermal images and reduce it just one amplitude and one phase image for an appropriate scale. The new two-step algorithm of WT for the image sequence is presented. This approach speeds up the analysis significantly.