Differences of Radiographic Quality and Exposure Index on Computed Radiography Using Imaging Plate with Different Reading Time Period

Abstract

ABSTRACT Introduction: Computed Radiography (CR) is the process of digitizing images using photostimulable plate to acquire image. The energy stored in the imaging plate disappears over the time, so imaging plate should be read as soon as possible to avoid the loss of image information. Objective: This study aimed at determining the profile of Exposure Index (EI), radiographic density and contrast on radiographs produced using CR with various reading time: 0 hours (without a break), 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22 and 24 hours after exposure. Methods: The type of research is observational study with cross-sectional design where data were collected by survey and analyzed using descriptive analysis. Result: The results showed that the profile of the exposure index (EI) value decreased irregularly. The average value of the highest and lowest EI on each object were 1394.33 and 1127.67 (cranium), 1871.33 and 1573.33 (elbow joint), while the largest percentage of degradation was at 22-hour reading time. Conclusion: The profile of radiographic density and contrast values varied at each lag time. The highest contrast were 1.24 (cranium) and 0.40 (elbow joint) that resulted at 0 hours lag time, whereas the lowest contrast value where 0.81 (cranium) and 0.34 (elbow joint) that resulted at 16 hours lag time. The image contrast was still editable till 10 hours lag time (cranium) and 12 hours lag time (elbow joint). Keywords: exposure index, computed radiography, radiographic quality.