The abnormal thermogram has been shown to be a reliable indicator of a high risk of breast cancer, but an open question
is how to quantify the complex relationships between the breast thermal behaviors and the underlying
physiological/pathological conditions. Previous thermal modeling techniques generally did not utilize the breast
geometry determined by the gravity-induced elastic deformations arising from various body postures. In this paper, a 3-D
finite-element method is developed for combined modeling of the thermal and elastic properties of the breast, including
the mechanical nonlinearity associated with large deformations. The effects of the thermal and elastic properties of the
breast tissues are investigated quantitatively. For the normal breast in a standing/sitting up posture, the gravity-induced
deformation alone is found to be able to cause an asymmetric temperature distribution even though all the thermal/elastic
properties are symmetrical, and this temperature asymmetry increases for softer and more compressible breast tissues.
For a tumorous breast, we found that the surface-temperature alterations generally can be recognizable for superficial
tumors at depths less than 20 mm. Tumor size plays a less important role than the tumor depth in determining the tumor-induced
temperature difference. This result may imply that a higher thermal sensitivity is critical for a breast thermogram
system when deeper tumors are present, even if the tumor is relatively large. We expect this new method to provide a
stronger foundation for, and greater specificity and precision in, thermographic diagnosis and treatment of breast tumors.