Since the image is electronic it can easily be reversed so that blacks become white and whites become black. At times this makes some structures more easily appreciated. On a conventional mammogram the only way to see structures in the dark portions of the film is to use a bright light. A digital image, however, can be adjusted so that all areas of the image are visible by using such techniques as histogram equalization or unsharp masking in which the darker areas are lightened without altering the visibility of structures in the lighter portions of the image. With a digital image computers can be used to analyze the image, and the image can be securely stored.
Digital images offer enormous advantages over analog images.
It is the ability of x-ray imaging to demonstrate the internal structures of the breast at high resolution, and the concomitant detection of breast cancer at a smaller size and earlier stage than any other method, that has been shown to reduce the death rate from breast cancer. Subsequently, fluorescent screens were developed that converted the x-ray photons into light. The light from the screen was more efficient in exposing the film. The efficiency gained by coupling a screen with the film permitted a major reduction in the dose required to image the breast. Advantages of Film Film has significant advantages.