A study of factors influencing detectability of breast tumour in microwave radiometry

Survival rate for breast cancer is directly related to the stage at diagnosis, therefore clinical emphasis is on early screening and detection. Microwave radiometry is a passive imaging modality proposed for breast cancer detection without the need for ionizing radiation. Detection of breast tumor using radiometry is challenging as the intensity of the thermal radiation received by the antenna is influenced by tumor stage, location, physiological conditions and the imaging setup. In this work we have identified tissue compression (c), ambient temperature (T_a), and convection cooling of tissue surface (h) as the controllable parameters and study their influence on tumour detectability in medical microwave radiometry. A 3D coupled multi-physics model of the breast with the chestwall is developed in this study. Simulations are carried out for a 1.5 cm diameter tumour centrally located in a 14 cm diameter breast for 0-20% tissue compression factor (c), 16-25°C ambient temperature (T_a) and 5-10 W/m2K convection cooling (h). Temperature distributions inside the breast and power received by a circular aperture antenna at 1.3 GHz are simulated for varying values of c, T_a and h to assess the influence of these external imaging parameters on the detectability of breast tumour. Simulation results indicate improved detectability for tissue under compression, higher convection cooling and lower ambient temperature.