Computer-assisted quantification and image processing of whole-body autoradiograms

A computerized image-processing system especially adapted for analysis of whole-body autoradiograms has been developed. It consists of commercially available standard components, including a black-and-white video camera, a microcomputer, and graphics equipment. The lower performance of the hardware has been compensated for by more flexible software. When the system was calibrated, special attention was paid to local variations in the measuring system in different parts of the picture. Utility programs for the manipulation of contrast, pseudocoloring, and image enhancement, etc., are available. Some programs have been especially designed to comply with specific problems and demands related to different autoradiographic applications. A program displaying the density histogram for an area of interest is particularly useful for the quantitation of whole-body autoradiograms. It allows the operator to select interactively a range of densities. Image elements (pixels) corresponding to the densities in this range are shown in red on the monitor, and their average true density is calculated. This procedure permits the marking and analysis of delicate structures on autoradiograms. Other programs allow a picture, stored in memory, to be rotated or translated, and two pictures to be superimposed for comparison. Various applications of using image analyses in whole-body autoradiography are presented and illustrated.