Equilibration between breast surface and ambient temperature by liquid crystal thermography.

Controversy surrounds the need for a waiting period (equilibration, or cooling period) before obtaining a breast thermogram. Temperature differences between an intrinsic lesion (carcinoma) and the overlying skin are said to be amplified by cooling of the skin. Some investigators have found no qualitative difference between thermographic evaluations done 3-15 minutes after the patient disrobes; others assert that tests done within this period are invalid. We evaluated nine ovulatory women thermographically twice during a menstrual cycle (proliferative and secretory phases) to ascertain the significance of such a waiting period and to investigate when thermal equilibrium is achieved with the environment. Breast thermograms were obtained with a cholesteric liquid crystal contact plate at 1-minute intervals for a 20-minute period following exposure of the breast to a room temperature of 72 F (22 C). A significant drop in breast skin temperature was found to occur during the first 15 minutes before equilibrium takes place; this finding suggests that a waiting period is necessary for accurate evaluation.