Current methods in diagnostic medical ultrasound produce images based on the relative amplitude of sound reflected from any particular region. With recent increases in computational speed and memory, new methods of creating images based on the numerical value of physical properties of tissue are possible. These physical properties include speed of sound, tissue elasticity, absorption of sound, and backscatter coefficient. The values of these properties are indicators of disease, including cancer, inflammation, fibrous tissue, and fat content. This talk will describe the physics of some of these new methods of creating ultrasound images and efforts to determine the accuracy and variability of these measurements.