Effect of digital image processing on radiographic interpretation of pneumoconiosis

Fuji Computed Radiography (FCT) is a newly developed digital radiography which has a potential capability of replacing conventional radiography. In order to evaluate the applicability of the FCR system for radiographic diagnosis of pneumoconiosis, the present study has been undertaken. As the first step, an investigation has been made on the fact that the diagnostic accuracy of pneumoconiosis radiograph might be influenced by the reduction of film size and image processing methods. The ILO standard films and test films selected from training film of pneumoconiosis in U.S.A. were digitized by using a drum scanner. Digitized images were processed with the several contrast and spatial frequency characteristics which were similar to those employed in FCR system, and finally written optically onto X-ray film in reduced size using a drum scanner. Two steps of experiments on interpretation for the radiograph of pneumoconiosis were performed. In the first step, the ILO standard films were processed in various ways and four methods of image processing were chosen which were suitable for the diagnosis of pneumoconiosis. The second step was performed to read the radiographs which were processed with the methods determined in the first experiment. In this step, the test films of reduced size were processed with the four different methods and diagnosed by comparing with both the original and the processed (also reduced size) ILO standard films. From these experiments, it is concluded that diagnosis of pneumoconiosis can be made by the processed film of reduced size (1/2 in length) with the same accuracy as the original films. Thus, the FCR system may be utilized for the radiographic diagnosis of pneumoconiosis. (author)