Numerical analysis of the influence of thermophysical parameters on the surface temperature of breast substitute geometry obtained from infrared images

The need of research in new methods for screening, diagnosis, classification, and treatment of breast cancer arose from the high incidence and mortality rates of this kind of cancer. The investigation presented in this article is based on the knowledge that at the beginning of the formation of a breast abnormality, there is an increase in the blood perfusion rate around the abnormality due to the creation of new blood vessels, in a process that is called neoangiogenesis. Consequently, there is an increase in the temperature caused by the augmented blood perfusion in the referred region, Thus, this article is a part of a study aimed to understand the relationship between the thermophysical parameters of breast and tumor tissues and, combined with other techniques including artificial intelligence, to prove that using infrared images can be an important auxiliary tool for detecting breast abnormalities. The interest on the thermophysical parameters of the breast is due to the uncertainties of accurate values available in the literature. In general, those values are not directly measured, they vary from person to person. Many of them were measured in vitro or in animal living tissues. Therefore, experiments designed to validate the aforementioned parameters are essential, particularly when employing numerical simulations, in order to obtain the most accurate values possible. This study analyzes the influence of eight parameters on numerical simulations of the surface temperature of a breast substitute geometry obtained from infrared (IR) images, ultrasound (US), and clinical examinations of two patients from the Hospital das Clínicas at the Federal University of Pernambuco (HC-UFPE), Pernambuco - Brazil. One of the patients had a malignant tumor, and the other had a benign tumor. The Design of Experiments (DOE) technique was employed to conduct the analyses, which required 256 numerical simulations. The actual breast geometry of each patient was reconstructed from the dimensions obtained through infrared (IR) imaging, complemented by a metallic grid positioned in front of the patient to ensure spatial calibration. Two studies were conducted for each patient. In the first study, the breast tumor was modeled according to the tumor dimensions identified during the patient's US examination. In the second, the dimensions of the breast tumor were artificially increased to verify the influence of tumor size on the breast temperatures. Therefore, we concluded that the thermophysical parameters of the tumor have less influence than the thermophysical parameters of the breast when calculating the temperature profiles under study. The thermal conductivity and blood perfusion of the breast were the parameters with the most significant influence on the surface temperature of the breast over the tumor region, for all patients observed.