Adjustment of Gradation Characteristics in Chest Radiography Obtained by Two Computed Radiography Models Through Luminance Measurement

作者：Ogasawara Kazuhiro; Tsunemaru Taketoshi; Ogasawara Katsuhiko

来源：Journal of Medical Imaging and Health Informatics, 2014, 4(5): 733-736.

DOI：10.1166/jmihi.2014.1311

• Computed Radiography (CR)
• Luminance
• Gradation Characteristic
• Receiver Operating Characteristic (ROC) Analysis
• Digital Radiography (DR)

The gradation characteristics and imaging techniques of computed radiography (CR) systems vary with the manufacturer. Consequently, there are differences in the obtained images, especially follow-up chest X-ray images. The conventional gradation measurement method has some disadvantage when the diagnosis is done on a monitor, and the aim of this study was the achievement of unification by aajusting the gradation of the measured luminance of the images displayed on the monitor, and by analysis of the receiver operating characteristic (ROC). An aluminum step wedge was exposed and the images were processed using two CR devices, namely FCR5501 and Regius190. Regius190 used three types of look-up tables (LUTs), namely THX-01, -02, and -07. From the luminance measurements of the images displayed on the monitor, we selected the LUT image of Regiusl 90 that was closest to the FCR5501 image. A chest phantom was photographed and the densities of the lung and mediastinum were set. The two images processed by Regius190 and FCR 5501 exhibited similar luminance characteristics, and we used the determined parameters to conduct visual assessments by ROC analysis. We demonstrated that it was possible to combine the gradation characteristics of entirely different systems. Our proposed luminance method is simple and effective and solves the problems of the traditional method.

• 出版日期2014-10