A method for detecting abnormal tissue in a region of healthy tissue, comprising:a) making a first measurement of ultrasound backscattered from the regionb) heating the region, at least after the first measurementc) making one or more additional measurements of ultrasound backscattered from the region after some or all of the heating andd) analyzing the measurements to detect the abnormal tissue by finding one or both of differences in changes in temperature and differences in thermal expansion, caused by the heating, between the abnormal tissue and the healthy tissue.
