|
Understanding the complex relationship between the thermal contrasts on the breast surface and the underlying
physiological and pathological factors is important for thermogram-based breast cancer detection. Our previous
work introduced a combined thermal-elastic modeling method with improved ability to simultaneously
characterize both elastic-deformation-induced and tumor-induced thermal contrasts on the breast. In this paper,
the technique is further extended to investigate the dynamic behaviors of the breast thermal contrasts during cold
stress and thermal recovery procedures in the practice of dynamic thermal imaging. A finite-element method
(FEM) has been developed for dynamic thermal and elastic modeling. It is combined with a technique to address
the nonlinear elasticity of breast tissues, as would arise in the large deformations caused by gravity. Our
simulation results indicate that different sources of the thermal contrasts, such as the presence of a tumor, and
elastic deformation, have different transient time courses in dynamic thermal imaging with cold-stress and
thermal-recovery. Using appropriate quantifications of the thermal contrasts, we find that the tumor- and
deformation-induced thermal contrasts show opposite changes in the initial period of the dynamic courses,
whereas the global maxima of the contrast curves are reached at different time points during a cold-stress or
thermal-recovery procedure. Moreover, deeper tumors generally lead to smaller peaks but have larger lags in the
thermal contrast time course. These findings suggest that dynamic thermal imaging could be useful to
differentiate the sources of the thermal contrast on breast surface and hence to enhance tumor detectability.
|
