Image subtraction by solid state electroradiography

An analog radiographic image subtraction technique is presented. A selenium photoconductor is used as the radiation sensitive medium and image subtraction is achieved by electrostatically adding latent images of opposite polarities to get a latent image of the region of interest. In principle, the technique is simple and a comparison with commercial digital techniques shows a similar image quality, suggesting that the electrostatic subtraction technique could be developed into a clinical tool as an inexpensive alternative to digital radiography.